bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional Gradient Heat-Resistant Materials Manufactured by Spark Plasma Sintering
Authors: Oglezneva Svetlana A. , Kachenyuk Maxim N. , Smetkin Andrey A. , Savich Vadim V.
Published: July 2021

The objects of the study were powder samples PV-NiCr16Al6Y and PV-Ni75Al23W, intended for the formation of a sublayer in heat-shielding coatings. The aim of this work is to develop and study a sublayer with a complexly organized structure of a functionally graded material of the superalloy-sublayer-ceramic system for operation under thermal cyclic loads and high-temperature gas corrosion. Experimental samples of binding materials for heat-protective coatings (HPC) were obtained by the method of spark plasma sintering (SPS) at T = 1050 °C / 15-30 MPa / 5 min. Methods of laser diffraction, X-ray structural analysis, optical and scanning electron microscopy, X-ray fluorescence spectroscopy, microdurometry were used to study powders and consolidated materials. It is shown that irregular powders contain individual particles of some components - in PV-NiCr16Al6Y powder these are particles of chromium and yttrium, in PV-Ni75Al23W - tungsten and chromium. Consolidated sublayers of such powders exhibit inhomogeneity and irregular porosity. To solve the problem of forming a homogeneous binder sublayer, mechanical alloying of the powders before sintering is proposed. It was found that MA increases the homogeneity of the structure, excludes local inclusions of unreacted particles, and increases the activation of consolidation. MA and subsequent sintering opens up wide possibilities for controlling the structure, including the porosity of the sublayers, and specifying various options for the HPC architecture. Experimental samples of HPC on an Inconel 625 substrate with a mechanically activated PV-Ni75Al23W sublayer and dioxides Zr/Y (YSZ) outer ceramics were obtained by the SPS method. A model of the architecture of a HPC made of a layered binder with different porosities is proposed.
Obtaining of Coatings from Ni-Al by Electro Spark Deposition and Surface Smoothing by Ultrasonic Plastic Deformation
Authors: Khimukhin Sergey N. , Eremina Kseniia P. , Nikolenko Sergey V.
Published: July 2021

The article presents the research results on obtaining coatings on steels 1030 and AISI 420 by the method of electrospark deposition and subsequent smoothing by means of ultrasonic surface plastic deformation (USPD). Intermetallic alloys consisting mainly of NiAl and Ni3Al phases were used as materials for obtaining coatings. It was found that the coatings consist of columnar crystallites of complex composition and have high plastic properties. To ensure the minimum parameters of the surface roughness of the obtained coatings, it is necessary to carry out 3-6 times of ultrasonic surface treatment.
Changing the Sizes of Details Made of Aluminum Alloys during Microarc Oxidation Process
Authors: Tchufistov Oleg , Tchufistov Evgeniy A. , Zolkin Alexey N.
Published: July 2021

It is shown that microarc oxidation (MAO) makes it possible to increase the size of aluminum alloy details by forming dense ceramic coatings (MAO-coatings) on them. Found that MAO-process a duration of 50...80 minutes in a liquid solution according to conventional technology allows you to increase the size of the details made of deformable alloy AMg3 and D16 by 78...80 % of the thickness formed on them MAO-coating and MAO-process in solution of corundum particles opens the possibility of increasing the same details by 98...100 % of the thickness formed on them more thick MAO coating. Revealed that increasing solution temperature from 15 to 45 оС leads to a reduction in the thickness of MAO coating and an even more significant reduction in growth dimensions, as well as to reduce the quality of their surfaces. It is shown that the removal of the outer layers of MAO coatings to a thickness of 20 ... 25 μm by grinding contributes to a significant reduction in the roughness of the surfaces of details. It is confirmed that MAO coatings obtained in liquid solution and in solution with corundum particles have a similar mainly polycrystalline structure, but MAO coatings obtained in solution with corundum particles differ in greater thickness and higher corundum content (α-Al2O3). It is established that the outer layers of MAO coatings are characterized by a relatively low content of modifications of crystalline aluminum oxide, so after their removal, the strength properties of the surfaces of details also improve. The principal possibility of increasing the size of details made of deformable aluminum alloys by 150 μm with ensuring high quality of their surfaces is proved.
Wear Resistance of Experimental Hard Alloys Grades with Co-Mo-Ti Binders upon Conditions of Friction without Lubricant on Stainless Steel
Authors: Fominov Evgeny V. , Egorov Maxim S. , Moiseev Denis V. , Dieudonne E. , Shuchev Constantine G.
Published: July 2021

The results of studies of wear resistance and tribological properties of experimental single carbide hard alloys grades with modified Co-Mo-Ti binders upon conditions of friction without lubricant on stainless steel are presented. All the data obtained were compared with similar parameters for the basic alloy VK8 (Co-Mo), on the basis of which the experimental grades were developed. Tribological tests were performed on tribometer which implemented a scheme of friction "pin on disk" at constant sliding speed and normal load values with artificially heated tribo contact zone. Studies have found that partial substitution of cobalt in a binder by Mo and Ti has led to a decrease in average friction rates. It was established that the greatest wear resistance and the best tribological characteristics were obtained for specimens of experimental grade 2.22 (5,65%Co+1,8%Mo+0,6%Ti). The process of friction for this pin material was characterized by the formation of secondary structures with high shielding properties, reducing of the adhesive interaction of materials, low volume wear intensity, minimal friction coefficient, as well as the least roughness of friction tracks on the counter body (disk). An increase in the proportion of molybdenum in the binder of more than 5% reduced the wear resistance of the experimental grades in comparison with the basic alloy VK8.
Dependence of Surface Profile on Diamond Impregnation Characteristics
Authors: Khripunov Nikolai V.
Published: July 2021

The paper presents the results of studies of the profile of the impregnated diamond surface depending on the grain size and initial roughness of the matrix. The experiments were carried out by impregnating powders of different grit size into a matrix made of low-carbon low-alloy steel with HB180 hardness using a ball indenter. The roughness parameters were measured using a contact profilometer. The height and step parameters of roughness and the curve of the profile bearing length were evaluated. In studying the effect of grain size on the surface profile, it was found that the optimal grain size should be 0.5...0.8 of the initial surface mean spacing profile irregularities. The shape of the Abbott-Firestone curve in this case corresponds to a flat profile. Experiments carried out with varying the initial roughness of the samples confirmed the dependence of the optimum grain size on the mean spacing of the profile irregularities. The developed research procedure can be used to design technological processes of hardening parts, tools and accessories by diamond impregnation.
Experimental Investigation of Nozzle Clogging Using Vibration Signal-Based Condition Monitoring for Fused Deposition Modeling
Authors: Jhodkar Durwesh , Nayak Ankit , Gupta Kapil
Published: July 2021

Fused deposition modeling (FDM) or 3D printing is one of the promising techniques widely preferred to fabricate complex and customized 3D objects or prototypes for various engineering and non-engineering applications. With the growing demands of customized prototypes, researchers are facing a major challenge for maintaining effective part quality with adequate surface finish and strength; and minimizing the cost, defects, and waste in 3D printing. Condition monitoring is one of the strategies to achieve the aforementioned. It has a huge potential to minimize defects and print failures in 3D printing. The main objective of this research work is to perform online condition monitoring of the nozzle status with the help of vibration signals in fused deposition modelling process. The effect of nozzle clogging on the consistency of material deposition and its effect on surface finish has experimentally investigated in this work. The set of experiments were performed by artificially creating the condition of nozzle clogging to investigate the effect of nozzle clogging on print quality (surface finish). Nozzle clogging condition was created by increasing the feed rate of polylactic acid (PLA) filament at a low heat supply rate to the nozzle by modifying the commands of 3D printer. The layer thickness was varied throughout the experiments to observe the nozzle clogging. The vibrations signals were acquired by using an accelerometer that was mounted near the nozzle. The data acquisition frequency of the accelerometer was 12500Hz. Further, the acquired vibration signals were analyzed using the Fast Fourier transformation (FFT) signal processing technique. Results revealed that nozzle clogging severely affects surface quality and geometrical accuracy of the fabricated 3D part due to nozzle vibration and non-uniform material deposition. Moreover, nozzle clogging and its relevant consequences like non uniform material deposition can be monitored using vibration signal-based condition monitoring during part fabrication and based upon that appropriate measures can be taken for defects and waste elimination.
Properties of Vibro-Abrasive Treatment by Combination the Kinds and Granulometric Characteristics of the Medium
Authors: Kolganova Yelena , Azarova Anna , Soldatov Boris , Koval Nikolai , Sanamyan Georgiy
Published: July 2021

The article presents the features of vibration processing of parts of electronic equipment in granular media. The method of combined processing by mixing granules with cutting and activating properties is considered as one of the ways to increase the intensity of vibration treatment. The increase in intensity is experimentally confirmed on the basis of a multivariate experiment with the construction of a regression model of the process.
Study of the Silicon Carbide Wear Area after Micro-Scratching of Titanium, Zirconium, Niobium and Molybdenum at a Speed of 35 m/s
Authors: Nosenko Vladimir A. , Fetisov Aleksandr V. , Nosenko Sergey V. , Karpov Viktor G. , Puzyrkova Valeria E.
Published: July 2021

The authors conducted the study at micro-scratching of titanium, zirconium, niobium and molybdenum alloys. The content of the main element in alloys was from 99.5 to 99.7 %. Micro-cutting was carried out by specially prepared indenters with silicon carbide mono-crystals of a given shape. The state of the relief and the chemical composition of the wear area were studied using a scanning two-beam electron microscope. The micro-scratching speed was 35 m/s without cooling. The condition of the contact surfaces of silicon carbide and metals was studied at a magnification up to 100,000 times with the rotation and tilt of the microscope slide. The content of chemical elements was determined at individual spots of an object by scanning along the line and area. The authors also studied the condition of the wear area after micro-scratching of metals and after removal of metal adhesions by chemical etching. The intensity of metal transfer was determined by the average concentration of metal atoms at the wear area. The article also gives a classification of metals according to the intensity of transfer immediately after grinding and removal of metal adhesions. The influence of metal and the depth of micro-scratching on the morphology of the wear site is shown. It was found that molybdenum, having a low adhesive activity to silicon carbide, is able to penetrate microcracks and other surface defects during micro-scratching. The width of microcracks and the depth of metal penetration were determined
Influence of the Form Factor on the Results of the Fracture Process Modeling under Uniaxial Tension
Authors: Taube Aleksandr O. , Novikov Roman E. , Storozheva Ekaterina I.
Published: July 2021

This paper provides a comparative assessment of the results of modeling the processes of deformation and destruction of objects under uniaxial tension in the MSC.Marc and DEFORM software packages and in a full-scale experiment, as well as a study of the influence of the form factor of these objects and the form of unit cells on the fracture parameters in modeling and experiment.
Experimental and Analytical Determination of the Coefficient of Dynamic Loading in the Contact Interaction of Bodies
Authors: Borodin Dmitry N. , Misirov Dinamutdin N. , Semergey Sergey V. , Borzilov Yuri P. , Yerovenko Victor N.
Published: July 2021

The calculation of the coefficient of dynamism of the contact interaction of bodies (lead balls and wheat grains with a moisture content of 11.5%) was carried out based on the hypothesis of equality of the work consumed during static and dynamic deformation of bodies, according to the formula:Θ=(So+Su)/(Sod+Su),where So – residual deformation of the body under static loading;Sod – residual deformation of the body under dynamic loading;Su – elastic deformation under static and dynamic loading.The components of the formula were determined on specially designed devices:– on an electromechanical press with static interaction of bodies, at a deformation rate of 0,055 m/s, the following values were determined from the load – discharge diagrams: the value of elastic deformation Su and the maximum residual deformation of bodies So.– on a vertical copra (at a contact interaction speed of 1-2 m/s) and a shock stand (at an impact speed of 11-15 m/s), the residual Sod deformation was determined by the size of the contact spot on the bodies after the impact.The calculated values of the dynamism coefficient were:for lead balls – 1,4-2,1;for wheat grains – 1,3-1,45.The results obtained indicate that the value of the dynamism coefficient increases with increasing impact velocity, with the same work spent on deformation, since the proportion of residual deformation in the total deformation of bodies decreases (bodies are strengthened).It is advisable to continue experiments to determine the coefficient of dynamism of bodies depending on the impact velocity, the configuration of the impact surface and the physical properties of the contacting bodies.
Neural Network Modeling of the Fatigue Strength of Metal Materials at Low Temperatures
Authors: Kabaldin Yury G. , Khlybov Alexander A. , Anosov Maksim S. , Ryabov Dmitry A. , Kiselev Andrey V.
Published: July 2021

An intelligent system has been developed to predict the fatigue strength of metallic materials over a wide temperature range. A neural network, properly trained, is a model of a dynamic system of fatigue failure of a part and is able to predict the values of the number of loading cycles to failure, as well as the onset of formation and growth rate of fatigue cracks for various test conditions, including at low temperatures.
Structural Changes in Concrete under the Influence of Reactor Spectrum Neutrons
Authors: Frolova Maria A. , Strekalov Sergey D. , Bezotosny Sergey S. , Ponomarenko Pavel A.
Published: July 2021

The paper considers structural changes in the concrete composition that occur under the influence of neutrons of the reactor spectrum, using the example of the IR-100 research nuclear reactor, taking into account its real time and operating conditions. Thus, taking into account the energy output, power operation modes, and neutron flux density in the core, over time, nuclides that are not characteristic of the original composition of the concrete component are formed in the nodes of the crystal lattice. However, these changes do not lead to significant structural changes.
Estimation of the Probability of Cracking of Facade Coatings
Authors: Loganina Valentina , Fediuk Roman , Taranov Daniil , Amran Y.H. Mugahed
Published: July 2021

Information on the stress state of protective and decorative coatings during the curing process, in particular on the cohesive state of destruction, is given. The influence of the type of substrate on the change in internal stresses in the coating is considered. It was revealed that the greatest value of shear stresses is observed in coatings on a heavyweight concrete substrate. The subsequent increase in temperature after curing to 50°C leads to an increase in the value of the normal stresses. The probability of cracking of coatings during thermal aging is estimated. It was revealed that during aging there is an exponential decrease in the cohesive strength of coatings and an increase in internal stresses. Aging tends to increase the likelihood of cracking of coatings. The change in stresses in coatings as a result of seasonal fluctuations in air temperature is considered.
Novel Materials for Myco-Decontamination of Cyanide-Containing Wastewaters through Microbial Biotechnology
Authors: Pavlov Igor N. , Litovka Yulia A.
Published: July 2021

This study examined the effectiveness of decontamination of industrial cyanide-containing water using mycelium-based lignocellulosic materials. These results suggest that fungi biomass and plant substrates can be used successfully in the treatment of wastewater contaminated by cyanide. Fungi were isolated from old wood samples taken from a tailing dam with high cyanide content (more than 20 years in semi-submerged condition). All isolated fungi belonged to the genus Fusarium. Fusarium oxysporum Schltdl. is most effective for biodegradation of cyanide-containing wastewaters (even at low temperatures). The most optimal lignocellulosic composition for production of mycelium-based biomaterial for biodegradation of cyanide wastewater consists of a uniform ratio of Siberian pine sawdust and wheat straw. The high efficiency of mycelium-based materials has been experimentally proven in vitro at 15-25 ° C. New fungal biomaterials are provide decrease in the concentration of cyanide ions to 79% (P <0.001). Large-scale cultivation of fungi biomass was carried out by the periodic liquid-phase cultivation. The submerged biomass from bioreactor was used as an inoculum for the production of mycelium-based materials for bioremediation of cyanide wastewater in situ (gold mine tailing).
Improving the Efficiency of Metal Production Waste Processing in Electromagnetic Field
Authors: Lebedev Valery A. , Vernigorov Yury M. , Shirin Andrey A. , Chunakhova Lidianna V. , Melnikova Elena P.
Published: July 2021

A set of theoretical and experimental studies showing the promising application of devices with the rotating electromagnetic field in the technology of processing sludge wastes of metal production is presented in the paper. Regularities of magneto-vibrational layer formation in those devices and parameters of its energy state control are disclosed. There has also a model of agglomerate destruction in the magneto-vibrational layer been proposed, which establishes a connection of agglomerate particle sizes with the strength of magnetic field induction required for its destruction. The results of studies of the process of ferromagnetic particle grinding are presented, factors affecting the degree of grinding are determined. The possibility of forming an ultradisperse fraction during grinding in the rotating electromagnetic field has been experimentally proved. The effect of porousness on the degree of ferromagnetic particle grinding is shown.
Implementing the IMU professionalism education framework in the MBBS programme
Authors: Thuraisingham C. , Krishnappa P. , Sui C. Y. , Ismail N. B. H. M.
Published: July 2021

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Does virtual simulation improve confidence levels in final year medical students?
Authors: Nichols C. , Scully A. , Trendall L. , Ong G. S. , Goodson M.
Published: July 2021

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Simulated vs video-assisted learning on clinical competency and retentivity; a preliminary study
Authors: Azizan A. B. B. , Subramaniam T. , Yan L. S. , Wen T. Y. , Sivanendran D. A. P. S. , Kirihettige D. R. G.
Published: July 2021

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Contextualised reflective competence: a new learning model promoting reflective practice for clinical
Authors: Lane S. , Roberts C.
Published: July 2021

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The design and development of a module applied to lesson plan in a blended approach
Authors: Hassan S.
Published: July 2021

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Challenges in making educational videos during the COVID-19 pandemic
Authors: Amirthalingam S. D. , Malanashita G. , Kwa S. K. , Zainab A. M. , Yu W. H. , Faiqah D. , Ismail A. B. , Ling Y. Y. , Jie E. K. Y.
Published: July 2021

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Usefulness of AMBOSS enhanced e-learning in COVID situation: feedback from medical students
Authors: Mitra N. K. , Kumar A. , Baloch H. Z. , Nadarajah V. D. , Höller-Fam M. , Schmok E.
Published: July 2021

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How equitable and diverse is health professional education scholarship?
Authors: Eva K.
Published: July 2021

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The anatomy of mentoring relationships: it takes two to tango
Authors: Ramani S.
Published: July 2021

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Re-thinking health professional education: ‘think global, act local’-ensuring inclusivity and diversity of medical education in the new norm
Authors: Roberts C. , Samarasekera D.
Published: July 2021

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Re-thinking health professional education: ‘think global, act local’-ensuring inclusivity and diversity of medical education in the new norm
Authors: Joynes V.
Published: July 2021

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How did the COVID-19 pandemic affect clinical training of Malaysian dental students: final year students' perspectives
Authors: Yew H. Z. , Dom T. N. M. , Rani H. , Chanthirasekar N. A. L. , Yin L. L. , Bukhari M. , Xin L. K. , Sabri B. A. M. , Rosdy N. M. M. N. M. , Esa R. , Kacharaju K. R. , Andiesta N. S. , Parolia A.
Published: July 2021

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A view of students learning experience & technical challenges in biology online practical sessions
Authors: Jayaseelan S. E.
Published: July 2021

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Evaluating student teaching style preferences in preparation for end of year exams: an analysis from Imperial College London
Authors: Chawla J. , Asumang J.
Published: July 2021

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What are the considerations for applying “World Café” in medical education?
Authors: Cheng Y. C. , Chen C. H. , Chang L. C. , Hsu C. Y. , Chao W. C. , Lee M. T.
Published: July 2021

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Paediatric palliative care: needs assessment for undergraduate medical and nursing education
Authors: Wong K. Y. , Victor Li W. T. V. , Yiu P. Y.
Published: July 2021

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Type of e-resources for asynchronous online learning in pre-clinical year 2 during the COVID-19 pandemic
Authors: Alwani S. F. , Shukri A. M.
Published: July 2021

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Pharmacology made easy workshops: a new approach to facilitating pharmacology learning in small group
Authors: Htet H.
Published: July 2021

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Virtual reality CSI – examining crime scenes in cyberspace
Authors: Lim C. L. , Raman V. K. , Gunasekaram J. , Bagali P. G.
Published: July 2021

NA
Is Yoga possible for elderly care?
Authors: Law Siukan , Leung Albert Wingnang , Xu Chuanshan
Published: July 2021

Yoga is possible for elderly care as it promotes and balance among mind–brainbody functions through mental, physical, and emotional practices. Growing evidence has shown that yoga practices strengthen muscle, body flexibility, and boost the immune system as well as improve the physical and psychological conditions.
Temporal Variations in Air Pollution at Two Roundabouts in the City of Cotonou (Benin)
Authors: Codjo-Seignon L.M. Karine , Houssou Vincentia M.C. , Kossolou Philippe , Sopoh Ghislain E. , Aina Martin P.
Published: July 2021

Background

Air pollution has caused health and environmental problems around the world. In this study we analysed the temporal evolution of air pollution in Cotonou regarding the standards of Benin and of World Health Organization (WHO).

Design and methods

Solar-powered electrochemical sensors (CO: carbon monoxide, SO2: sulphur dioxide, and O3/NO2: ozone/nitrogen dioxide) and photoionization detectors (for NMVOC: nonmethane volatile organic compounds) were permanently installed and monitored from June 2019 to March 2020 at Akpakpa PK3 (A) and Vèdokô Cica-Toyota (B) roundabouts.

Results

CO and SO2 concentrations at both roundabouts were significantly higher on weekends than on weekdays. The concentrations of NMVOC and O3 / NO2 on Sunday differed considerably from the other days of the week at A and B, respectively. There was a positive linear correlation between the concentrations of CO and SO2, O3 / NO2 and SO2, and CO O3 / NO2 to B, and only between CO and O3 / NO2, in A. At the two sites, the average of SO2 concentrations (in μg/m3) were higher than the WHO standard (500) for an exposure of 10 minutes (2258 A and 2143 B) and the Benin standard (1300) for 1 hour exposure (2181 in A and 2092 in B).

Conclusion

Air pollution varies in hours and days in Cotonou. Standards are respected, except for SO2. Particular attention should be paid to the concentrations and the possible sources of gas. More sophisticated monitoring system should be put in place.
Ambient measurement of diesel particulate matter and respirable combustible dust in Canadian Mines
Authors: Gangal M K , Dainty E D
Published: July 2021

CANMET/MRL has been contributing to an industry/government program to assess the quality of air in mines, and improve the working environment for Canadian miners. The ultimate aim of this program is to recommend a sampling methodology and appropriate
concentration limits for both the soot (diesel particulate matter - DPM) generated by diesel equipment, and respirable combustible dust (RCD) as measured underground.
The program was conceived by the Canadian Adhoc Diesel Committee, which consists of representatives from seven major Canadian mining companies, three provincial inspectorates, one union representative, two manufacturers of diesel equipment, and CANMET, a Federal Canadian research agency.
This paper describes the modification and laboratory confirmation of an existing methodology for the sampling and analysis of DPM/RCD, including sampling problems, filter selection, filter efficiency, DPM size distribution, the approximate performance of fractionating devices, and it reports the
results of current ambient measurements of exposure levels in Canadian underground mines.
Because of the concern about the health impact of DPM/RCD on mine workers, North American agencies are in the process of establishing limits for these aerosols. So far, the Province of British Columbia is tile only jurisdiction in North America to legislate the maximum exposure level of RCD in its
underground mines, i.e. 1.5 mg/m3 interim level recommended by the Adhoc Diesel Committee. It has also recommended the use of the CANMET/ADHOC RCD sampling protocol.
Siltuximab - A monoclonal antibody against the interleukin-6 receptor is not an ideal option for management of COVID-19
Authors: Michelle I Jerlin , Shevaani S. A. , Rathinam Kiran Kumar , Abraham Justin Jacob , Rajanandh Muhasaparur Ganesan , Vijayakumar Thangavel Mahalingam
Published: July 2021

The sudden outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which emerged in Wuhan city, China, has resulted in a global pandemic, posing a major health concern worldwide. Despite multiple therapeutic interventions, no treatment has yet proven effective in treating COVID-19. Furthermore, the complicated virology of SARS-CoV-2 makes the process of identifying effective treatments, an arduous task. COVID-19, being affecting the upper and lower respiratory tract, is associated with consequent release of pro-inflammatory cytokines in which interleukin (IL)-6 receptor plays a key role. The elevated inflammatory cytokines resulting in a cytokine storm play a major role in the pathology of COVID-19. Siltuximab has become a keen interest for researchers because it is a chimeric, human-murine, immunoglobulin G monoclonal antibody that binds and neutralises human IL-6 with high affinity and specificity. In this article, we tried to evaluate why siltuximab is not a suitable option for treating novel coronavirus from the clinical study evidence.
Asafoetida application causing ulceration of umbilical hernia with resultant rupture and bowel evisceration
Authors: Garg Vaibhav , Sengar Mamta , Viswanathan Vivek
Published: July 2021

Umbilical hernia is a very commonly encountered condition. Conservative management suffices in most of the cases. However, the complications such as incarceration, rupture with evisceration are extremely rare and warrants emergency surgery. We present the rare case of a 40-day-old female infant with ruptured umbilical hernia following ulceration due to the local application of Asafoetida paste. While many medicinal uses of Asafoetida have been reported in the past literature, there has been no mention of any complication due to its local application. Our patient was successfully managed with emergency mini-laparotomy and resection of approximately 40 cm of gangrenous small bowel with primary anastomosis. The patient has been attaining normal growth patterns on follow-up.
First Global Use of a Covera Plus Covered Stent Graft for Successful Endovascular Repair of a Ruptured Popliteal Artery Aneurysm
Authors: Bedi Harinder Singh , Singh Jiten , Arora Vikram
Published: July 2021

Popliteal artery aneurysms (PAAs) are the most common of all peripheral aneurysms. However, a ruptured PAA (rPAA) is rare, accounting for approximately 2% of all PAAs. We report a large rPAA successfully treated with endovascular repair using the Covera Plus covered stent graft. The patient did well. This is the first reported use in the world of a Covera stent for a rPAA.
The Persistent Sciatic Artery Aneurysm a Cause of Recurrent Limb Ischemia – A Rare Case Report
Authors: Kamerkar Dhanesh R , Pathak Nitin , Purandare Nachiket , Sarkar Nupur , Shinde Bhushan , Jaiswal Shishir
Published: July 2021

A persistent sciatic artery (PSA) is a rare vascular anomaly. It can cause complications, including acute and chronic limb ischemia, aneurysm formation, and compression of adjacent tissues during early embryonic development, the sciatic artery usually disappears when the superficial femoral artery has developed properly. PSA is usually an incidental finding and is exceedingly rare to find bilaterally. We are presenting a rare case of unilateral PSA aneurysm presented as an episode of recurrent acutely ischemic limb.
Management of Thigh Hemangioma by Laser Ablation
Authors: Bhalla Rusy S , Kapadia R Ashish
Published: July 2021

Intramuscular hemangiomas are 0.8% of soft-tissue swellings. They can be present in adipose tissue or intramuscular compartment. Conventional management includes Compression, sclerotherapy, embolization, corticosteroids, and surgical excision. The laser is now advocated for hemangiomas due to no cosmetic deformity and high effectiveness. Presenting a case of Thigh hemangioma involving Vastus lateralis muscle.
Graft Patency and Determinants of Outcome in Infrainguinal Bypasses - A Retrospective Study
Authors: Rajendran Sunil , Ramachandran Sreekumar , Sarma P S , Unnikrishnan Madathipat
Published: July 2021

Context:

Chronic lower limb ischemia, an important marker of atherosclerosis, is a common clinical problem prevalent in all socioeconomic groups in our country and across the globe. Infrainguinal bypass is mandated in a subset of patients with critical limb ischemia to provide immediate limb salvage as well as excellent long-term results.

Aim:

The purpose of our retrospective study is to elucidate the effect of various known factors on the long term patency of infrainguinal bypass grafts performed in our patient population at a tertiary referral hospital.

Methods:

We retrospectively reviewed follow up data of 110 patients who had undergone infrainguinal bypass grafting over a period of ten years in our Institutional vascular registry. Graft patency rates and factors affecting thereof over this period were studied and the data statistically analysed. Overall cumulative patency rates were calculated by the life table survival method and compared with that of the patency rates of above-knee bypass procedures in the world literature. Patency rates in a different subset of patients were calculated and compared using the Wilcoxon (Gehan) test and Fisher's exact test to assess the influence of various factors in the long term outcome of the procedure.

Results:

Cumulative patency in terms of graft survival probabilities based on the life table analysis was 0.84, 0.80, and 0.64 at 30, 60, and 90 months respectively. Grafts in patients who had continued to smoke post-operatively had failed when compared with those who did not smoke (P = 0.01). Cumulative patency rates of non- diabetics were higher as compared to non-diabetics (0.70 vs 0.44; P = 0.04).

Conclusion:

Our study shows that continued smoking and diabetes are the determinant factors associated with graft occlusion. Strict avoidance of smoking and optimal control of diabetes is likely to improve graft function and long-term patency in patients undergoing infra-inguinal bypass grafting.
Iatrogenic Ulnar Artery Pseudoaneurysm
Authors: Periyanarkunan Murugesan Ramaiya , Chinnasamy Ganesan , Murugan Murugan Sukumar , Elavarasan Soundarya
Published: July 2021

We present a patient with a rare vascular emergency of iatrogenic right ulnar artery pseudoaneurysm presented as an expanding hematoma with right forearm compartment syndrome following a percutaneous coronary intervention done to place stent in the left anterior descending artery through right transulnar approach (radial nondominant). A 71-year-old female was referred with a mass on the flexor aspect of the right forearm associated with severe localized pain, tenderness, and weakness of distal forearm and hand. Investigations had revealed a right ulnar artery pseudoaneurysm. Ultrasonography of the right forearm demonstrated a pseudoaneurysm with thrombus formation arising from the right ulnar artery and using a hand Doppler, no blood flow detected distal to the swelling. Surgical repair by an open approach was done to remove the hematoma and the ulnar artery puncture site was repaired. The postoperative period was uneventful.
Popliteal Artery Entrapment Syndrome
Authors: Kamerkar Dhanesh R , Purandare Nachiket , Sarkar Nupur , Shinde Bhushan , Jaiswal Shishir
Published: July 2021

The true incidence of popliteal entrapment cannot be estimated due to a lack of awareness, misdiagnosis, and the relative rarity of presentation. Likely, only the most severe cases present for evaluation and workup and obtain a true diagnosis. We are presenting four legs of popliteal entrapment in two patients at different times.
Sympathectomy in Postvascular Surgical Patients with Severe Pain in Distal Limb and/or Small Ulcers
Authors: Naithani Vinay , Bhatia Budhi Prakash , Chanda Dinesh Kumar , Sharma Ashok
Published: July 2021

Introduction:

Sympathectomy is used principally in patients of inoperable peripheral vascular disease, small vessel disease, and vasospastic disease. It is useful to alleviate symptoms of rest pain and as an adjunct to heal ischemic ulcers.

Aim and Objective:

This is a clinical study to evaluate the role of sympathectomy in postvascular surgical patients with persistent pain in distal limb (causalgia) with or without ischemic ulcers on the foot or hand.

Materials and Methods:

This study was performed between February 2015 and February 2020. We did 823 arterial surgical interventions including embolectomies, endarterectomy with patch arterioplasty, and interposition grafting in upper or lower limb vessels. These patients were diagnosed on clinical bases and with investigational modalities such as arterial Doppler study and computed tomography angiography. All these patients had chronic vascular obstruction. Out of them, we selected 54 patients having persistent pain distal limb (causalgia) not relieved by medications. Besides causalgia, 24 patients had ischemic ulcers either on foot or hand. Postoperative arterial Doppler study was satisfactory in these patients. Their complaint persisted for 3–4 months in spite of all medications. Chemical sympathectomy was tried in 21 patients but was ineffective. We did thoracic sympathectomy in 28 patients and lumbar sympathectomy in 26 patients on side affected. Observation and Results: There were 46 males and 8 females. Majority of these patients were in active phase of life with a mean age of 35 (±2). Pain was relieved in all patients. Ischemic ulcers present in 24 patients also healed within 3–6 weeks. Conclusion: Although no clear guidance exists for the role of sympathectomy in postsurgical patients, we observe it is a boon for postvascular surgical patients with persistent pain and small ischemic ulcers.
Influence of Concurrent and Adjuvant Temozolomide on Health-Related Quality of Life of Patients with Grade III Gliomas: A Secondary Analysis of a Randomized Clinical Trial (KNOG-1101 Study)
Authors: Ahn Grace S. , Hwang Kihwan , Kim Tae Min , Park Chul Kee , Chang Jong Hee , Jung Tae-Young , Kim Jin Hee , Nam Do-Hyun , Kim Se-Hyuk , Yoo Heon , Hong Yong-Kil , Kim Eun-Young , Lee Dong-Eun , Joo Jungnam , Kim Yu Jung , Choe Gheeyoung , Choi Byung Se , Kang Seok-Gu , Kim Jeong Hoon , Kim Chae-Yong
Published: July 2021

PurposeThe KNOG-1101 study showed improved 2-year PFS with temozolomide during and after radiotherapy compared to radiotherapy alone for patients with anaplastic gliomas. This trial investigates the effect of concurrent and adjuvant temozolomide on health-related quality of life (HRQoL).Materials and MethodsIn this randomized, open-label, phase II trial, 90 patients with World Health Organization grade III glioma were enrolled across multiple centers in South Korea between March 2012 to February 2015 and followed up through 2017. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire 30 (EORTC QLQ-C30) and 20-item EORTC QLQ-Brain Neoplasm (QLQ-BN20) were used to compare HRQoL between patients assigned to concurrent chemoradiotherapy with temozolomide followed by 6 cycles of adjuvant temozolomide (arm A) and radiotherapy (RT) alone (arm B).ResultsOf the 90 patients in the study, 84 patients (93.3%) completed the baseline HRQoL questionnaire. Emotional functioning, fatigue, nausea and vomiting, dyspnea, constipation, appetite loss, diarrhea, seizures, itchy skin, drowsiness, hair loss, and bladder control were not affected by the addition of temozolomide. All other items did not differ significantly between arm A and arm B throughout treatment. Global health status particularly stayed consistent at the end of adjuvant temozolomide (p=0.47) and at the end of RT (p=0.33).ConclusionThe addition of concurrent and adjuvant temozolomide did not show negative influence on HRQoL with improvement of progression-free survival for patients with anaplastic gliomas. The absence of systematic and clinically relevant changes in HRQoL suggests that an overall long-term net clinical benefit exists for concurrent and adjuvant temozolomide.
Nontame Morse–Smale flows and odd Chern–Weil theory
Authors: Cibotaru Daniel , Pereira Wanderley
Published: July 2021

Using a certain well-posed ODE problem introduced by Shilnikov in the sixties, Minervini proved the currential “fundamental Morse equation” of Harvey–Lawson but without the restrictive tameness condition for Morse gradient flows. Here, we construct local resolutions for the flow of a section of a fiber bundle endowed with a vertical vector field which is of Morse gradient type in every fiber in order to remove the tameness hypothesis from the currential homotopy formula proved by the first author. We apply this to produce currential deformations ofodd degree closed formsnaturally associated to any hermitian vector bundle endowed with a unitary endomorphism and metric compatible connection. A transgression formula involving smooth forms on a classifying space for oddK-theory is also given.
The in vitro effect of xylitol on chronic rhinosinusitis biofilms
Authors: Jain R. , Lee T. , Hardcastle T. , Biswas K. , Radcliff F. , Douglas R.
Published: July 2021

Introduction: Biofilms have been implicated in chronic rhinosinusitis (CRS) and may explain the limited efficacy of antibiotics. There is a need to find more effective, non-antibiotic based therapies for CRS. This study examines the effects of xylitol on CRS biofilms and planktonic bacteria. Methods: Crystal violet assay and spectrophotometry were used to quantify the effects of xylitol (5% and 10% solutions) against Staphylococcus epidermidis, Pseudomonas aeruginosa, and Staphylococcus aureus. The disruption of established biofilms, inhibition of biofilm formation and effects on planktonic bacteria growth were investigated and compared to saline and no treatment. Results: Xylitol 5% and 10% significantly reduced biofilm biomass (S. epidermidis), inhibited biofilm formation (S. aureus and P. aeruginosa) and reduced growth of planktonic bacteria (S. epidermidis, S. aureus, and P. aeruginosa). Xylitol 5% inhibited formation of S. epidermidis biofilms more effectively than xylitol 10%. Xylitol 10% reduced S. epidermidis planktonic bacteria more effectively than xylitol 5%. Saline, xylitol 5% and 10% disrupted established biofilms of S. aureus when compared with no treatment. No solution was effective against established P. aeruginosa biofilm. Conclusions: Xylitol has variable activity against biofilms and planktonic bacteria in vitro and may have therapeutic efficacy in the management of CRS.
Olfactory function in patients with hyposmia compared to healthy subjects - An fMRI study
Authors: Pellegrino R. , Hahner A. , Bojanowski V. , Hummel C. , Gerber J. , Hummel T.
Published: July 2021

Background: Individuals with hyposmia, or the partial loss of smell, represent a large sector (15 %) of the population that is likely to grow with the current aging population; however, our understanding to how hyposmics centrally process odors is still not clear. One popular non-invasive tool for in vivo imaging of biological activity among human brains has been function magnetic resonance imaging (fMRI) which uses blood-oxygenation level dependent (BOLD) signal as an indirect measurement. Therefore, the aim of this study was to understand differences in olfaction processing between patients with hyposmia and healthy controls using functional magnetic resonance imaging (fMRI). Methodology: Eleven hyposmic and 12 healthy, normosmic subjects were exposed to two different food-related odors (coffee and peach) during a block-designed fMRI session. Additionally, odor perception qualities were rated for each odor throughout the scanning session. Results: The activations of the normosmic group were localized in typical olfactory areas (insula, orbitofrontal cortex [OFC], limbic system and amygdala). The hyposmic group showed similar regions of activation (insula, OFC, limbic system), however, less activation was found in the amygdala, left anterior cingulate and right OFC, but higher activation was shown in the right parahippocampal and both the left and right posterior cingulate gyrus which are assumed to play an important role in the processing and remembrance of memories. Conclusions: These results indicate similar central olfactory processing among groups, yet subjects with partial loss may attempt to compensate smell impairment with odor memory or higher motivation to smell.
Assessment of the Prevalence of Soil-Transmitted Helminth Infections and Associated Risk Factors among School-Aged Children in a Flood-Affected Area of Northeast India
Authors: Deka Sangeeta , Barua Dipankar , Bahurupi Yogesh , Kalita Deepjyoti
Published: July 2021

Soil-transmitted helminthiasis is a major disease burden in developing countries, with a considerable share borne by India. Currently, the principal strategy of the World Health Organization for the control of soil-transmitted helminths (STHs) is mass deworming in the high-risk population based on the prevalence and intensity of infection in a region. However, the disease load of STH remains unknown in many regions. A cross-sectional study was conducted in 2017 among children in the age group of 5–13 years in Barpeta, Assam, to ascertain the prevalence of STH infection in school-aged children and its probable risk factors. Socio-demographic and epidemiologic data were gathered using a piloted questionnaire. Geohelminths were identified by the Kato–Katz method. Association with probable risk-factors was analyzed by binomial logistic regression. Overall, 16.3% [95% confidence interval (CI) = 12.9–19.8] of children were found to be infected with one or more of the three STHs. Ascaris, hookworm, and Trichuris infections were observed in 9.4%, 7.4%, and 5.3%, respectively. The strongest predictors for the presence of any STH with multivariable analysis were open defecation (habitual or occasional), lack of proper handwashing, living in homes affected by flood, and age group of 8–10 years. The availability of proper handwashing stations in schools was found to be protective against Trichuris. Awareness among the people regarding sanitation and personal hygiene, particularly in the post-flood scenario, is imperative for sustainable control of STH infections. Preventive deworming should be continued; however, the time and frequency must be adjusted according to the prevailing climatic conditions in the region under study.
Incidence of Laboratory-Confirmed Influenza among HIV-Infected versus HIV-Uninfected Individuals in Two Districts of Ghana, 2014 to 2016
Authors: Balachandran Neha , Ntiri Michael , Duque Jazmin , Addo Christabel , Edu-Quansah Elijah , Badji Edem , Brightson Kennedy , Houphouet Ekua Essumanma , Ndahwouh Talla Nzussouo , Koram Kwadwo , McMorrow Meredith , Ampofo William
Published: July 2021

Influenza is known to cause severe respiratory illness in HIV-infected adults, but there are few data describing the relationship between HIV infection and influenza in West African countries such as Ghana. We conducted a prospective cohort study in the Shai-Osudoku and Ningo Prampram districts of Ghana from 2014 to 2016. Beginning May 2014, 266 HIV-infected and 510 HIV-uninfected participants age 18 to 73 years were enrolled and monitored for 12 months. We observed 4 and 11 laboratory-confirmed influenza cases among HIV-infected and HIV-uninfected persons, respectively. The overall rate of laboratory-confirmed influenza among HIV-infected participants was 15.0 per 1,000 person years (PY) (95% CI, 0.3–29.80 per 1,000 PY), whereas that among HIV-uninfected participants was 21.6 per 1,000 PY (95% CI, 8.8–34.3 per 1,000 PY) (incidence density ratio, 0.70; P = 0.56). Our study found no significant difference in the incidence of laboratory-confirmed influenza-associated illness among HIV-infected and HIV-uninfected individuals in Ghana.
Acute Appendicitis Associated with Hantaan Virus Infection
Authors: Lim Sung-Chul , Lee Young Min , Kim Choon-Mee , Yun Na Ra , Kim Dong-Min
Published: July 2021

Hantaviruses are Bunyaviridae viruses that cause hemorrhagic fever with renal syndrome. Appendicitis caused by Hantaan virus has not been reported previously. An 81-year-old man who underwent laparoscopic appendectomy for suspected appendicitis based on abdominal pain, fever, hypotension, and computed tomography findings. Based on a suspicion of hemorrhagic fever with renal syndrome, the patient’s plasma was simultaneously analyzed using an indirect immunofluorescent antibody assay and nested reverse transcription–polymerase chain reaction (RT-PCR). The appendix tissue was also analyzed using nested RT-PCR and immunohistochemical (IHC) staining to identify the presence of Hantaan virus. Nested RT-PCR detected the presence of Hantaan virus, and indirect immunofluorescent antibody assay results revealed the presence of elevated antibody levels. Furthermore, IHC staining of the appendix tissue confirmed Hantaan virus antigens in the peripheral nerve bundle. Based on these findings, we confirmed the nerve tropism of the Hantaan virus. Hantaan virus in plasma and appendix tissue samples was confirmed using PCR and phylogenetic tree analysis. Moreover, we detected hypertrophy of the submucosa and periappendiceal adipose tissue nerve bundle along with Hantaan virus antigens in peripheral nerve bundles using IHC staining. Hence, we report that Hantaan virus infection may be accompanied by appendicitis.