bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of environmental agents on non-woven polylactide/natural rubber agrofiber
Authors: Tertyshnaya Yulia , Zakharov Maksim , Ivanitskikh Alina , Popov Anatoliy
Published: July 2021

In the work an eco-friendly non-woven fiber made of polylactide and natural rubber with a rubber content from 0 to 15 wt.% was obtained by electrospinning. The influence of distilled water and UV irradiation on the agrofibers has been investigated. The water sorption test showed that the addition of natural rubber into the polylactide matrix does not significantly affect the degree of water absorption of the fibrous materials, which is in the range of 49-50.6%. Thermal characteristics after 180 days of degradation in distilled water at 22±2 oC and UV irradiation at a wavelength of 365 nm during 100 hours were determined using the differential scanning calorimetry. Changes in the values for glass transition and melting temperatures, and the degree of crystallinity were determined.
Modeling and Simulation of Non-Contact Base Excited AFM
Authors: Bahrami Mohammad Reza
Published: July 2021

AFM has some unique properties such as higher spatial resolution, mapping even a single molecule, simple sample preparation, scanning in different types of medium, and can obtain a 3D scan of the sample surface. Therefore, with the help of AFM, one can obtain a unique understanding of the structure and functional behavior of materials. In this article, to construct the mathematical model of the base excited AFM cantilever mass spring system (lumped parameter model) is used and the solution obtained by the method of Multiple scales. Here, in this work, we consider the AFM operates in the non-contact mode. To study the effect of the non linearity, amplitude of excitation, and damping coefficient, frequency response equation obtained.
Algorithm of Strength Calculation of Drive Elements of a Roller Conveyor
Authors: Androsenko Mariya , Tyuteryakov Nail , Kulikova Ekaterina , Deryabina Lyubov , Krayniy Ivan
Published: July 2021

The paper shows an algorithm for determining the load on the electric motor of run-out conveyor starting from determination of the first moment of no load operation during slab conveying, slipping torque of the rollers along the surface of the conveyed billet and ending with the choice of the electric motor. It also covers an algorithm for strength calculations of the run-out conveyor roller, which includes the calculation of the moments and forces acting on the conveyor roller and its supports, the calculation of static strength and torsion strength, calculation of roller deflection of the conveyor rollers as well as the selection and verification calculation of conveyor roller bearings.
HIC and SSC of Carbon Steel in High Partial Pressure CO2 Environments with Elevated H2S
Authors: Abas Ahmad Zaki , Nor Azmi Mohammed , Suhor Muhammad Firdaus , Rusli Ahmad Mustaza Ahmad , Ismail Mokhtar Che
Published: July 2021

The Hydrogen Induced Cracking (HIC) and Sulfide Stress Cracking (SSC) behaviours of sour service and non-sour service carbon steel API 5L X65 were investigated under high pressure carbon dioxide environments, containing elevated amount of hydrogen sulphide (H2S); the test environments simulated offshore pipelines transporting full-well streams in high carbon dioxide (CO2) environments with elevated H2S concentrations. It was systematically studied under standard NACE condition and high pressure carbon dioxide field condition with variation in other key parameters (temperature, pressure and hydrogen sulfide concentration). The HIC and SSC were tested using a High Pressure and High Temperature (HPHT) Autoclave. The surface cracking morphology was analysed using Scanning Electron Microscopy (SEM), Ultrasonic Technique (UT) and Magnetic Particle (MP). The results showed that no cracks were detected in NACE standard and field-condition SSC tests for both sour service and non-sour services carbon steel. In HIC test, crack was detected on non-sour service carbon steel in NACE standard test while no crack was detected on field condition-based tests for both types of carbon steel.
Effect of Carbon Dioxide (CO2) concentration in the gas feed on Carbon Dioxide Absorption Performance using Aqueous Potassium Carbonate promoted with Glycine
Authors: Mustafa Nur Farhana Ajua , Shariff Azmi Mohd , Tay WeeHorng , Yusof Siti Munirah Mhd
Published: July 2021

This paper presented the effect of CO2concentration in the gas feed to the CO2absorption performance using a green solvent, potassium carbonate promoted with glycine (PCGLY). Recently, the performance of this solvent (with precipitates) was hindered by its poor mass transfer performance due to the blockage in packings and piping. Therefore, this study focused to study the CO2 absorption performance of non-precipitating potassium carbonate promoted with glycine. This green solvent contains aqueous blend of 15wt% potassium carbonate and 3 wt% glycine. The absorption performance of the solvent was obtained by demonstrated a few experimental works using a bench scale packed absorption column. The packing type was Sulzer metal gauze and the column consisted of six sampling point which located equidistance along the packing.The effect of CO2 concentration at the gas feed was assessed in term of its CO2 removal efficiency and concentration profile along the packing. The study shows the decreasing trend of CO2 removal as CO2 inlet concentration in the gas feed increases. The reason of this behavior is due to the limited reactant of liquid phase to absorb high CO2concentration in gas phase. The main outcome of this study demonstrated the efficient absorption which can absorb up to 79.24 % of CO2from natural gas using non-precipitated PCGLY.
Development of αFe2O3-TiO2/PPOdm Mixed Matrix Membrane for CO2/CH4 Separation
Authors: Yap Yun Kee , Oh Pei Ching , Chin Evan Yew Jin
Published: July 2021

Magnetophoretic dispersion of magnetic fillers has been proven to improve gas separation performances of mixed matrix membrane (MMM). However, the magnetic field induced is usually in a horizontal or vertical direction during membrane casting. Limited study has been conducted on the effects of rotational magnetic field direction towards dispersion of particles. Thus, this work focuses on the rearrangement of paramagnetic iron oxide-titanium dioxide (αFe2O3-TiO2) nanocomposite in poly (2,6-dimethyl-1,4-phenylene oxide) (PPOdm) membrane via rotational magnetic field to investigate the dispersion of filler and effects towards its overall gas separation performance. The paramagnetic fillers were incorporated into polymer via dry phase inversion method at different weight loading. MMM with 3 wt% loading shows the best performance in terms of particle dispersion and gas separation performance. It shows the greatest relative particles count and least agglomerates via OLYMPUS™ Stream software with image taken by optical microscope. Relative to pristine membrane, it displays a permeability and selectivity increment of 312% and 71%. MMM with 3 wt% loading was refabricated in the presence of rotational magnetic field to enhance the dispersion of paramagnetic fillers. Results display an increment of selectivity by 8% and CO2 permeability by 46% relative to unmagnetised MMM of 3 wt% loading.
Conversion of palm oil to new sulfur-based polymer by inverse vulcanization
Authors: Abbasi Amin , Nasef Mohamed Mahmoud , Yahya Wan Zaireen Nisa , Moniruzzaman Muhammad
Published: July 2021

The conversion of palm oil into a sulfur-based polymer by copolymerization with sulfur powder at its molten state is herein reported. The obtained sulfur-containing polymer was characterized using Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to demonstrate the successful conversion. The disappearance of the peaks related to vinylic groups of oil together with the appearance of a peak representing C-H rocking vibrations in the vicinity of C-S bonds confirmed the copolymerization of sulfur with oil. TGA revealed that the polymers have thermal stability up to 230°C under nitrogen and the polymers leave 10% sulfur-rich ash. DSC proved that a small amount of elemental sulfur remained unreacted in the polymer, which showed amorphous and heavily crosslinked structure resembling thermosets. These copolymers are an environmental-friendly polymeric material promoting the utilization of the abundant sulfur while also adding value to palm oil.
Heat Transfer Performance of Different Fluids During Natural Convection in Enclosures with Varying Aspect Ratios
Authors: Pendyala Rajashekhar , Umer Ilyas Suhaib , Sang Wong Yean
Published: July 2021

The heat transfer process takes place in numerous applications through the natural convection of fluids. Investigations of the natural convection heat transfer in enclosures have gained vital importance in the last decade for the improvement in thermal performance and design of the heating/cooling systems. Aspect ratios (AR=height/length) of the enclosures are one of the crucial factors during the natural convection heat transfer process. The investigated fluids consisting of air, water, engine oil, mercury, and glycerine have numerous engineering applications. Heat transfer and fluid flow characteristics are studied in 3-dimensional rectangular enclosures with varying aspect ratios (0.125 to 150) using computational fluid dynamics (CFD) simulations. Studies are carried out using the five different fluids having Prandtl number range 0.01 to 4500 in rectangular enclosures with the hot and cold surface with varying temperature difference 20K to 100K. The Nusselt number and heat transfer coefficients are estimated at all conditions to understand the dependency of ARs on the heat transfer performance of selected fluids. Temperature and velocity profiles are compared to study the flow pattern of different fluids during natural convection. The Nusselt number correlations are developed in terms of aspect ratio and Rayleigh number to signify the natural convection heat transfer performance.
Multiscale fault classification framework using kernel principal component analysis and k-nearest neighbors for chemical process system
Authors: Nawaz Muhammad , Shah Maulud Abdulhalim , Zabiri Haslinda
Published: July 2021

Process monitoring techniques in chemical process systems help to improve product quality and plant safety. Multiscale classification plays a crucial role in the monitoring of chemical processes. However, there is a problem in coping with high-dimensional correlated data produced by complex, nonlinear processes. Therefore, an improved multiscale fault classification framework has been proposed to enhance the fault classification ability in nonlinear chemical process systems. This framework combines wavelet transform (WT), kernel principal component analysis (KPCA), and K nearest neighbors (KNN) classifier. Initially, a moving window-based WT is used to extract multiscale information from process data in time and frequency simultaneously at different scales. The resulting wavelet coefficients are reconstructed and fed into the KPCA to produce feature vectors. In the final step, these vectors have been used as inputs for the KNN classifier. The performance of the proposed multi-scale KPCA-KNN framework is analyzed and compared using a continuous stirred tank reactor (CSTR) system as a case study. The results show that the proposed multiscale KPCA-KNN framework has a high success rate over PCA-KNN and KPCA-KNN methods.
Behaviour of Ionic Liquid-Derived Naphthenate Salts Under Desalting Conditions
Authors: Hussain Azlan Shah , Law Poh Gaik , Basar Jamali
Published: July 2021

Pyrenees crude oil containing high napthenic acids (NAs) content of more than 1.6 mg KOH/g oil was treated with methyltrimethylammonium methylcarbonate [N4441][MeCO3] as to reduce its acidity to the refinery permissible limit of 0.3 mg KOH/g oil. The treated crude oils are subjected to Emulsion Stability Test (EST) as to mimic the operating conditions of a desalter. The results indicate the electrostatic conditions can facilitate the recovery of the napthenate salts post neutralization with high recovery rate of more than 79.6% with basic sediments & water (BSW) to be 1.96%. The conductivity of the treated crude oil also was found to increase as a function of temperature. The ionic liquid mediated-deacidification of crude oil can be performed under existing desalting conditions should the recovery of the naphthenate salts is acceptable at 70%.
Bioinformatics exploration of olive oil: molecular targets and properties of major bioactive constituents
Authors: Fatoki Toluwase Hezekiah , Akintayo Cecilia O. , Ibraheem Omodele
Published: July 2021

Olive oil possesses medicinal properties which include antimicrobial, antioxidant and anti-inflammatory, anti-diabetes, and anti-cardiovascular diseases. Oleic acid is the most abundant (95%) constituent of olive oil and others include linoleic acid, oleuropein, oleanolic acid, maslinic acid, melatonin, and others. The objective of this study is to predict the molecular targets and properties of key bioactive components of olive oil in human. Bioinformatics methods, which involved pharmacokinetics prediction, target prediction and gene network analyses, were used. The results showed that oleic acid has similar targets with linoleic acid, and showed significant probability of binding to several targets such as fatty acid-binding proteins in the adipose, epidermal, liver and muscle as well as alpha, delta and gamma peroxisome proliferator-activated receptors (PPARs). Carbonic anhydrase showed to be the only significant target of tyrosol, while protein-tyrosine phosphatase 1B, and CD81 antigen were targeted by maslinic acid and oleanolic acid. This study has applauded oleic acid, linoleic acid and tyrosol as olive oil bioactive constituents that have several potential pharmacological effects in humans that modulate several enzymes, receptors and transcription factors. The future work will be to investigate the effects of oleic acid on fatty acid-binding proteins and telomerase reverse transcriptase; melatonin on quinone reductase 2; tyrosol on carbonic anhydrase II; maslinic acid and oleanolic acid on protein-tyrosine phosphatase 1B.
Möglichkeiten und Grenzen eines dosierten Krafttrainings bei
Patienten nach kardiochirurgischen Eingriffen
Authors: Schwan Uwe , Scherer Lena , Zoller Nadine , Nechwatal Robert , Woll Alexander
Published: July 2021

In Deutschland werden jährlich ca. 95 000 Operationen mittels
Sternotomie und minimalinvasiv durchgeführt. Dennoch gibt es für
Inhalte, Trainingsplanung und Durchführung der Bewegungstherapie keine
einheitlichen Empfehlungen. Die vorliegende Studie soll eine Möglichkeit
aufzeigen, das sporttherapeutische Spektrum von herzoperierten Patienten zu
erweitern und die Machbarkeit eines gerätegestützten
Krafttrainings bereits ab der 3. Woche postoperativ aufzeigen.

Dafür wurden 42 Patienten nach kardiochirurgischen Eingriffen einem
dosierten, schmerzadaptierten Krafttraining an Sequenztrainingsgeräten
während einer Anschlussheilbehandlung unterzogen. Die Effekte wurden
mittels eines Maximalkrafttests und subjektivem Belastungsempfinden (BORG-Skala)
überprüft.

Die Patienten trainierten bei 65% der Maximalkraft nach dem Modus
2–3 Serien à 10 Wiederholungen. Bei allen Patienten kam es zu
einer signifikanten Steigerung der Maximalkraft, ohne dass
Wundheilungsstörungen oder Sternuminstabilitäten auftraten. Kein
Patient musste das Training schmerzbedingt abbrechen. Die Gewichtsbelastung lag
über den allgemeinen Empfehlungen aus den chirurgischen Zentren. Somit
wäre eine Überarbeitung der Empfehlungen
wünschenswert.
Peroral cholecystoscopy using a multibending ultraslim endoscope through a lumen-apposing metal stent for endoscopic ultrasound-guided gallbladder drainage: a feasibility study
Authors: Yoo Hae Won , Moon Jong Ho , Lee Yun Nah , Song Yeon Han , Yang Jae Kook , Lee Tae Hoon , Cha Sang-Woo , Cho Young Deok , Park Sang-Heum
Published: July 2021

Background Endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) using a lumen-apposing metal stent (LAMS) has rendered endoscopic gallbladder assessment through a stent possible, but an appropriate endoscope is required. We assessed the feasibility of peroral cholecystoscopy (POCC) using a multibending ultraslim endoscope passed through a LAMS after EUS-GBD.

Methods 14 patients with a LAMS for EUS-GBD who consecutively underwent POCC were included. POCC was performed using a multibending endoscope inserted through the LAMS. The primary outcome was the technical success rate, defined as complete endoscopic examination of the gallbladder from the orifice of the cystic duct to the fundus. The types of intervention and adverse events were recorded.

Results 17 POCCs were performed in 14 patients. Of the 17 POCCs, 15 (88.2 %) were technically successful. Narrow-band imaging endoscopy was performed in 12 procedures (70.6 %), and cholecystoscopy-guided target biopsies were obtained in six. Gallstone extraction was performed in two patients. After POCC, all LAMSs remained stable and no adverse events were observed.

Conclusions POCC using a multibending ultraslim endoscope can be effectively and safely performed through a LAMS after EUS-GBD.
The Reassessed Impact of Nicotine against Neurotoxicity in Mesencephalic Dopaminergic Cell Cultures and Neuroblastoma N18TG2 Cells
Authors: Delijewski Marcin , Radad Khaled , Krewenka Christopher , Kranner Barbara , Moldzio Rudolf
Published: July 2021

Neuroprotective effects of nicotine are still under debate, so further studies on its effectiveness against Parkinsonʼs disease are required. In our present study, we used primary dopaminergic cell cultures and N18TG2 neuroblastoma cells to investigate the effect of nicotine and its neuroprotective potential against rotenone toxicity. Nicotine protected dopaminergic (tyrosine hydroxylase immunoreactive) neurons against rotenone. This effect was not nAChR receptor-dependent. Moreover, the alkaloid at a concentration of 5 µM caused an increase in neurite length, and at a concentration of 500 µM, it caused an increase in neurite count in dopaminergic cells exposed to rotenone. Nicotine alone was not toxic in either cell culture model, while the highest tested concentration of nicotine (500 µM) caused growth inhibition of N18TG2 neuroblastoma cells. Nicotine alone increased the level of glutathione in both cell cultures and also in rotenone-treated neuroblastoma cells. The obtained results may be helpful to explain the potential neuroprotective action of nicotine on neural cell cultures.
Role of Interim PET Scan after 2 Cycles of ABVD in Pediatric Hodgkin Lymphoma: Retrospective Multicenter Study from South India
Authors: Karpurmath Shashidhar V. , Rathnam Krishnakumar , Seshachalam Arun , Srinivasan Arathi , Scott Julius , G. Raman S. , Janarthinakani M. , Prasad Krishna , Patil Channappa , Anoop Parameswaran , Reddy Neelesh , Anumula Satish Kumar , Roopa Sirigeri Prabhakar , Golamari Krishna Reddy , Danthala Madhav , Malipatil Basawantrao , Rangarajan Bharath , Udupa Karthik S. , Nandennavar Manjunath , Niraimathi Kesavan
Published: July 2021

Introduction Most Indian centers use Adriamycin/Bleomycin/Vinblastine/Dacarba-zine (ABVD) chemotherapy for pediatric Hodgkin lymphoma (pHL). To reduce the late toxicity, robust predictive markers are needed to risk stratify pHL patients, thereby limiting the number of chemotherapy cycles and omitting radiation for low-risk and intensifying treatment for high-risk children.

Objective This study was conducted to analyze the outcome of pHL patients treated with ABVD and various factors predicting the outcome.

Materials and Methods This retrospective study analyzed the outcome of 113 consecutive pHL children treated with ABVD chemotherapy from 11 tertiary care centers in South India from 2009 to 2019.

Results The median duration of follow-up was 2.73 years. The median age was 13 years. B symptoms are seen in 50.5% patients, bulky disease in 23%, and stage IV in 28.3%. Of 113 pHL, 69% had a positron emission tomography (PET) and 31% had computed tomography (CT)-based staging. Stage IV (37.1%) and extranodal involvement (31.2%) were seen more often with PET than with CT staging (8.5 and 2.8%, respectively). Among 64 patients with interim PET scan after two cycles (iPET2), 20.3% did not achieve complete remission (CR) and no factors were significantly associated. The 4-year event-free survival (EFS) rate of the entire cohort was 86%. The 4-year EFS rate was 93% for patients with CR in iPET2 and 52% for patients not achieving CR. The only independent predictor of low EFS was iPET2 response (p < 0.05).

Conclusion Our study confirms the prognostic role of PET scan staging and response assessment. Not achieving CR on the iPET2 scan indicates poor prognosis and warrants clinical trial enrollment for a better outcome.
Review of Applied Anatomy, Hemodynamics, and Endovascular Management of Ectopic Varices
Authors: Barath Sitaram , Kheradia Dharav , Gopalkrishnan Shakti Parvathy , R. Rahul K. , K. Mohammed Rafeeque P.
Published: July 2021

Portal hypertension leads to the opening up of collateral pathways to bypass the occlusion or resistance in the portal system. Ectopic varices are formed by such collaterals at many various sites along the gastrointestinal tract other than the usual location, that is, gastroesophageal region. Early diagnosis of ectopic varices needs strong clinical suspicion and contrast-enhanced computed tomography scan as endoscopy may often fail to pinpoint a source. In contrast to gastric varices where the understanding of the disease, as well as endovascular management, is widely studied and documented, the same is not true for ectopic varices due to low incidence. Understanding the applied anatomy and hemodynamic classification is important to decide the most suitable therapy. Interventional radiological procedures are aimed at either decompressing the varices or obliterating them and depend on the patency of the portal system, underlying etiology, and local expertise.
Dupuytren's Disease: An Outcomes-Focused Update
Authors: Almadani Yasser H. , Vorstenbosch Joshua , Efanov Johnny Ionut , Xu Liqin
Published: July 2021

Dupuytren's disease (DD) remains a common fibroproliferative condition with significant sequelae and impact on patient's lives. The etiology of DD is poorly understood, and genetic predisposition is thought to be a strongly associated factor. Despite remarkable strides in improving our molecular understanding of DD, clinical treatment options have not yet overcome the frequently encountered challenge of recurrence. Recurrence rates continue to shape the prognosis of this fibrotic condition. In this outcomes-focused article, the various treatment modalities are reviewed. This further emphasizes the importance of patient education and providing them with the information to make informed decisions about their treatment.
Can We Predict Unplanned Intensive Care Unit Admission in Hip and Knee Arthroplasty?
Authors: Sinclair SaTia T. , Emara Ahmed K. , Briskin Isaac N. , Klika Alison K. , Piuzzi Nicolas S. , Kamath Atul F.
Published: July 2021

Preoperative risk stratification remains important for both patient safety and cost-effective allocation of resources in total joint arthroplasty. Limited literature exists investigating risk factors for unplanned intensive care unit (ICU) admission following arthroplasty. Therefore, the purpose of this study was to assess a broader spectrum of factors that may increase the risk of ICU admission across multiple surgical settings. We retrospectively reviewed 18,169 patients who underwent a hip (40.7%) or knee (59.3%) arthroplasty procedure (primary: n = 13,384, 90%; revision: n = 1,485, 10%) between August 1, 2015, and January 31, 2019, across nine sites at a single institution. Patient demographics, laboratory data, surgical parameters, and preoperative scores on the Hip Disability and Osteoarthritis Outcome Score (HOOS) or Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Veterans RAND 12-Item Health Survey (VR-12) were recorded. A univariate analysis was conducted to identify differences between patients who required an ICU admission and those with no ICU involvement. Logistic regression was then used to generate predicted risk of ICU Involvement. A total of 147 patients (0.99%) required an ICU admission. Increasing age, higher Charlson's comorbidity index, American Society of Anesthesiologists (ASA) class 3 or greater, elevated blood urea nitrogen (BUN), elevated creatinine, decreased preoperative hemoglobin level, general anesthesia, surgical setting, revision procedure, and lower baseline scores on the KOOS Quality of Life (QOL) subscale (17 vs. 22.5, p = 0.032), VR-12 physical component score (PCS; 24.4 vs 27.1, p = 0.001), and VR-12 mental component score (MCS; 45.9 vs. 49.6, p = 0.003) were associated with a statistically significant increase in the risk of ICU admission. As performance of arthroplasty shifts in both the setting of care and the complexity of patients, identifying patients most at risk of requiring higher acuity of care is important. Preoperative assessment of comorbidities, kidney function, surgical setting, KOOS QOL subscale score, and VR-12 scores may provide guidance for the improvement of value-based care pathways.
Bioengineering platforms for cell therapeutics derived from pluripotent and direct reprogramming
Authors: Jin Yoonhee , Cho Seung-Woo
Published: July 2021

Pluripotent and direct reprogramming technologies hold great potential for tissue repair and restoration of tissue and organ function. The implementation of induced pluripotent stem cells and directly reprogrammed cells in biomedical research has resulted in a significant leap forward in the highly promising area of regenerative medicine. While these therapeutic strategies are promising, there are several obstacles to overcome prior to the introduction of these therapies into clinical settings. Bioengineering technologies, such as biomaterials, bioprinting, microfluidic devices, and biostimulatory systems, can enhance cell viability, differentiation, and function, in turn the efficacy of cell therapeutics generated via pluripotent and direct reprogramming. Therefore, cellular reprogramming technologies, in combination with tissue-engineering platforms, are poised to overcome current bottlenecks associated with cell-based therapies and create new ways of producing engineered tissue substitutes.
Energization of cold ions by electromagnetic ion cyclotron waves: Magnetospheric multiscale (MMS) observations
Authors: Abid A. A. , Lu Quanming , Gao X. L. , Alotaibi B. M. , Ali S. , Qureshi M. N. S. , Al-Hadeethi Y. , Wang Shui
Published: July 2021

Electromagnetic ion cyclotron (EMIC) waves have been studied in this manuscript which are triggered by hot proton thermal anisotropy having energy ranging from 7  to 26 keV with a minimum resonant energy of 6.9 keV. However, an opposite effect can be observed for the hot protons for energy less than the minimum resonant energy. When the intensity of EMIC waves is large, the cold protons (ions) having low-energies can be energized by the EMIC waves. The possible reasons for this energization are the phase bunching of low energy ions with EMIC waves and the generation of electric fields at the relaxation time of substorm. As a consequence, these undetectable protons now become detectable, and the number density and temperature anisotropy of the protons also increase within the energy range from 1 to 100 eV. Accordingly, the helium ions are also energized by the EMIC waves.
Reduced thermal conductivity of epitaxial GaAsSb on InP due to lattice mismatch induced biaxial strain
Authors: Chu Yuanyuan , Sang Yuxiang , Liu Yizhe , Liu Yingmei , Xu Zhicheng , Chen Jianxin , Liu Fang , Li Shengjuan , Sun Bo , Wang Xingjun
Published: July 2021

High-quality lattice-matched and mismatched strained GaAs1−xSbx (0.37 < x < 0.57) sub-micrometer epilayers are grown on InP by molecular beam epitaxy. Based on a heat conduction model regarding the heat transfer process between the thin GaAsSb films and thick InP substrates, the corresponding thermal conductivity of GaAsSb epilayers was accurately extracted from the power and temperature micro-Raman measurement. Combined with time-domain thermoreflectance measurements, we found that in comparison to the lattice-matched sample with Sb = 47.7%, a significant reduction in thermal conductivity of the lattice-mismatched sample with Sb = 37.9% and Sb = 56.2% is observed. With the help of diffraction reciprocal space maps and temperature-dependent photoluminescence results, the reduction in thermal conductivity is attributed to lattice-mismatch-induced biaxial tensile and compressive strain that can cause the breakage of the cubic crystal symmetry and provoke more defects.
Microscopic phenomena inferred from the rheological analysis of an emulsion
Authors: Marín Castaño E. P. , Leite R. H. T. , de Souza Mendes P. R.
Published: July 2021

The rheological behavior of an emulsion is determined by microstructural changes caused by external loads. Some of these changes are irreversible due to the occurrence of the destabilization processes. Therefore, a deeper understanding of the system may be acquired by linking rheological characterization results with microscopic events. It is important to understand the rheological consequences of the occurrence of destabilization phenomena such as coalescence and flocculation. An experimental study was performed to verify the destabilization of samples during shear in a rheometer. Coalescence was assessed by measuring changes in the droplet size distribution functions, while the degree of flocculation was determined with the use of consecutive flow curves. Additionally, the occurrence of the non-equilibrium condition was studied. As a case study, the method developed in this paper was applied to a water-in-oil crude emulsion.
Optimisation of Iron Oxide Nanoparticles for Agglomeration and Blockage in Aqueous Flow Systems
Authors: Landowski Lila M. , Livesey Karen L. , Bibari Olivier , Russell Allanna M. , Taylor Madeleine R. , Ho Curtis C. , Howells David W. , Fuller Rebecca O.
Published: July 2021

The translation of nanoparticles to useful applications is often hindered by the reliability of synthetic methodologies to reproducibly generate larger particles of uniform size (diameter > 20 nm). The inability to precisely control nanoparticle crystallinity, size, and shape has significant implications on observed properties and therefore applications. A series of iron oxide particles have been synthesised and the impact of size as they agglomerate in aqueous media undergoing flow through a capillary tube has been studied. Reaction conditions for the production of large (side length > 40 nm) cubic magnetite (Fe3O4) have been optimised to produce particles with different diameters up to 150 nm. We have focussed on reproducibility in synthesis rather than dispersity of the size distribution. A simple oxidative cleavage of the as-synthesised particles surfactant coating transforms the hydrophobic oleic acid coated Fe3O4 to a hydrophilic system based on azelaic acid. The hydrophilic coating can be further functionalised, in this case we have used a simple biocompatible polyethylene glycol (PEG) coating. The ability of particles to either chain, flow, and fully/or partially aggregate in aqueous media has been tested in a simple in-house system made from commercial components. Fe3O4 nanoparticles (60–85 nm) with a simple PEG coating were found to freely flow at a 2 mm distance from a magnet over 3 min at a rate of 1 mL min−1. Larger particles with side lengths of ~150 nm, or those without a PEG coating were not able to fully block the tube. Simple calculations have been performed to support these observations of magnetic agglomeration.
Effect of vented helmets on heat stress during wildland firefighter simulation
Authors: Christison Katherine , Gurney Shae , Dumke Charles L.
Published: July 2021

Uncompensable heat from wildland firefighter personal protective equipment decreases the physiological tolerance while exercising in the heat. Our previous work demonstrated that the standard wildland firefighter helmet significantly increases both perceived and actual head heat. This study compared heat accumulation under simulated working conditions while wearing a standard non-vented helmet versus a vented helmet. Ten male subjects randomly completed two trials separated by a 2-week washout. Subjects walked 180 min (5.6 km h−1, 5% grade) in a heat chamber (35°C, 30% relative humidity) broken into three segments of 50 min of exercise and 10 min rest, followed by a work capacity test to exhaustion. Each trial measured the physiological strain index, perceived head heat, helmet temperature and relative humidity, rating of perceived exertion and heart rate. At the end of the 3-h trial heart rate, physiological strain, perceived exertion, helmet temperature and humidity showed the main effects of time (P < 0.05) but were not different between trials. Work capacity was significantly greater in the vented trial (P = 0.001). End-trial strain and heart rate were significantly related to work performed (r = –0.8, P < 0.001). Elevated work, trends for changes in perceived exertion, helmet microenvironment and perceived head heat suggest greater heat dissipation and comfort with the vented helmet.
Fossil dermal denticles reveal the preexploitation baseline of a Caribbean coral reef shark community
Authors: Dillon Erin M. , McCauley Douglas J. , Morales-Saldaña Jorge Manuel , Leonard Nicole D. , Zhao Jian-xin , O’Dea Aaron
Published: July 2021

Significance

How abundant were sharks on Caribbean coral reefs before human impact? To explore this question, we recovered fossilized shark dermal denticles (scales) from a ∼7,000-y-old reef in western Caribbean Panama and compared them with denticles found on modern reefs in the same area. Our data suggest that sharks were over three times more numerous before humans began using marine resources in the area and that shark communities were compositionally different in the past, containing a higher proportion of fast-swimming, pelagic sharks. This reconstruction of preexploitation shark communities using fossil denticle assemblages demonstrates their potential to help contextualize recent declines in shark abundance, examine the ecological consequences of those declines, and guide shark management.
Factors Associated with Repeat Sexual Offending among U.S. Military Veterans Compared to Civilians
Authors: Brooks Holliday Stephanie , Sreenivasan Shoba , Elbogen Eric , Thornton David , McGuire Jim
Published: July 2021

Veterans have higher rates of incarceration for sexual offenses than non-veterans, but little is known about the factors associated with repeat sexual offending among veterans. This study used the Survey of Inmates in State and Federal Correctional Facilities to examine whether the factors associated with repeat sexual offending differ between veterans and non-veterans. In a multivariate logistic regression, there were significant interactions between veteran status and both age and race. Diagnosis of personality disorder and history of violation of conditional release were also associated with repeat offense status. Findings can help inform intervention and risk management with veterans.
The effect of spacetime curvature on statistical distributions
Authors: Sato Naoki
Published: July 2021

The Boltzmann distribution of an ideal gas is determined by the Hamiltonian function generating single particle dynamics. Systems with higher complexity often exhibit topological constraints, which are independent of the Hamiltonian and may affect the shape of the distribution function as well. Here, we study a further source of heterogeneity, the curvature of spacetime arising from the general theory of relativity. The present construction relies on three assumptions: first, the statistical ensemble is made of particles obeying geodesic equations, which define the phase space of the system. Next, the metric coefficients are time-symmetric, implying that, if thermodynamic equilibrium is achieved, all physical observables are independent of coordinate time. Finally, ergodicity is enforced with respect to proper time, so that ambiguity in the choice of a time variable for the statistical ensemble is removed. Under these hypothesis, we derive the distribution function of thermodynamic equilibrium, and verify that it reduces to the Boltzmann distribution in the non-relativistic limit. We further show that spacetime curvature affects physical observables, even far from the source of the metric. Two examples are analyzed: an ideal gas in Schwarzschild spacetime and a charged gas in Kerr–Newman spacetime. In the Schwarzschild case, conservation of macroscopic constraints, such as angular momentum, combined with relativistic distortion of the distribution function can produce configurations with decreasing density and growing azimuthal rotation velocity far from the event horizon of the central mass. In the Kerr–Newman case, it is found that kinetic energy associated with azimuthal rotations is an increasing function of the radial coordinate, and it eventually approaches a constant value corresponding to non-relativistic equipartition, even though spatial particle density decreases.
A Morse theoretic approach to the geometrical feature terms specified in ISO 25178-2 and ISO 16610-85
Authors: Wolf Gert W
Published: July 2021

Morse theoretic concepts are today widely employed for the formal characterisation of surfaces and surface features. Although nowhere explicitly mentioned, several core concepts of surface metrology, such as the geometrical feature terms being specified in ISO 25178-2 and ISO 16610-85, are also closely related to Morse theory. The current lack of adequate formal definitions, however, implies that several inconsistencies and ambiguities can actually be found within the two standards. As a consequence, in the present paper the focus is laid on (a) the investigation of the interrelationships between Morse theory and the geometrical feature terms and (b) the presentation of some modifications of the existing definitions in order to eliminate the addressed ambiguities. Apart from the benefit of a consistent topological framework with respect to the definitions of the geometrical feature terms, the application of Morse theory would have the additional advantage that a powerful mathematical tool could be exploited in order to gain new insights into surface structures.
Green synthesis of cobalt oxide nanoparticles and the effect of annealing temperature on their physiochemical and biological properties
Authors: Haq Sirajul , Abbasi Farwah , Ben Ali Manel , Hedfi Amor , Mezni Amine , Rehman Wajid , Waseem Muhammad , Khan Abdul Rehman , Shaheen Hamayun
Published: July 2021

The cobalt oxide nanoparticles (Co3O4 NPs) were synthesized via the green method using Piper nigrum (P. nigrum) leaves extract and were calcined at different temperatures. The crystalline nature was studied through x-ray diffractometer (XRD). With increasing calcination, the amorphous phase transitioned to the crystalline phase. Diffuse reflectance spectroscopy (DRS) was used to observe UV-Visible light absorbance phenomenon, and Tauc’s plot was used to calculate the band gap energy, which was found to decrease with calcination. Scanning electron microscopy (SEM) was used to analyze the surface morphology, and Fourier transform infrared (FTIR) spectroscopy was used to classify the surface functional groups. The antibacterial efficacy of the Co3O4 NPs was examined against Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB), whereas its antioxidant potential was explored against ABTS free radicals. Antibacterial and antioxidant potentials of Co3O4 NPs were found to decrease with increasing calcination.
Novel polymeric hydrogel composites: Synthesis, physicochemical, mechanical and biocompatible properties
Authors: Nasalapure Anand V. , Chalannavar Raju K. , Kasai Deepak R. , Reddy Kakarla Raghava , Raghu Anjanapura V.
Published: July 2021

In this research study, novel hydrogel composite films were constructed using different ratios of poly (vinyl alcohol) (PVA)/kappa-carrageenan (KC) (PVA90/KC10%, PVA80/KC20%, PVA70/KC30%, PVA60/KC40%) crosslinked with glutaraldehyde (0.025%) and investigated their physicochemical characteristics such as mechanical, thermal, morphological, swelling behaviour, and cell viability. SEM and FTIR revealed that surface morphology changed to heterogeneous and the presence of molecular interaction among the polymers. PVA90KC10 and PVA60KC40 exhibited smaller and larger pores on surface respectively. The change in the proportion of PVA and KC also triggered the tensile strength (Ts) of the film and the highest Ts observed were 21.60 MPa for PVA60KC40. Moreover, the thermal analysis showed three-phase degradation, and an increase in KC40 concentration results inversely proportional to a decrease in the rate of thermal degradation. Further, swelling and in-vitro biodegradation study confirmed the enhanced perseverance of water uptake for PVA60KC40 (286%) due to pores structure of the hydrogel film and PVA and KC alone degraded faster as compare to other films results suggested higher concentration of PVA90KC10 showed lower degradation rate and highest for PVA60KC40 about 6% and 22% respectively. Further, the cell viability was studied with MTT assay method by using NIH3T3 and HEK-293 cells for biocompatibility study revealed NIH3T3 cells were more biocompatible than HEK-293 and cell viability percent for PVA60KC40 showed the highest cell attachment about 99%. Overall corroborating data obtained from the study attested to the average swelling, appreciable mechanical characters, good interaction between molecules, and cell viability of the constructed PVA/KC hydrogel film, these all characters pave to be used as a potential template for biomedical applications such as tissue engineering and drug delivery.
Assessing Energy Expenditure in Female Healthcare Workers in a University Hospital
Authors: Brückner Ulrike , Laux Sandra , Schneider-Lauteren Stephanie , Schneider Joachim
Published: July 2021

Introduction

The assessment of energy expenditure (EE) at workplaces maintains a central topic in occupational health due to increasing work-related issues. Today 80% of employees in the healthcare system are women. Limited research concerning their physical activity at work is available. The purpose of the study was the investigation of body composition, maximum physical capacity and quantification of physical work activity for female healthcare workers under real-time conditions.

Methods

Occupational physical activity (PA) of 33 female healthcare workers in a university hospital was quantified. Health associate professionals (HAP), health professionals (HP), and females working from cleaners and helpers (CH) department participated. All underwent cardio pulmonary exercise test. For every working task VO2, VCO2 and RER were measured and EE was calculated individually for each task.

Results

Forty-two different working tasks were identified and grouped in seven categories to compare physical activity (PA): ‘office and laboratory work’, ‘bedside patient care’, ‘instrument reprocessing, packing boxes’, ‘walking with patient, or alone’, ‘pushing carts or wheelchairs’, ‘strenuous cleaning in bent posture’ and ‘lifting heavy boxes, weights or items’. By comparing groups of healthcare workers, CH and HAP spent significant (p < 0.01) more EE (in kcal/min) 3.9 resp. 3.2 than HP 2.5. Light PA e.g. office and laboratory work (2.7 ± 0.6) and bedside patient care (2.9 ± 0.7) were accomplished by HP and HAP while HAP and CH performed moderate PA such as ‘packing boxes’ (3.6 ± 0.8), ‘pushing carts’ and ‘strenuous cleaning’ (4.7 ± 0.9). Work performed by CH and HAP, i.e. ‘strenuous cleaning’ and ‘lifting heavy items’ showed highest kcal per kg Fat Free Mass (FFM) per hour with 5.80 [4.05–7.81] and 6.94 [5.18–9.03] kcal/kgFFM/h.

Conclusion

Our findings lend preliminary support to the hypothesis that the majority of activities in female healthcare workers were of low and moderate PA and can be accomplished by middle aged and even older female workers. CH performed tasks with heavy physical activities (PA) like cleaning and lifting heavy weights. HAP performed light/moderate PA below their maximum physical capacity.
Automatic extraction and measurement of individual trees from mobile laser scanning point clouds of forests
Authors: Bienert Anne , Georgi Louis , Kunz Matthias , von Oheimb Goddert , Maas Hans-Gerd
Published: July 2021

Background and Aims

In addition to terrestrial laser scanning (TLS), mobile laser scanning (MLS) is increasingly arousing interest as a technique which provides valuable 3-D data for various applications in forest research. Using mobile platforms, the 3-D recording of large forest areas is carried out within a short space of time. Vegetation structure is described by millions of 3-D points which show an accuracy in the millimetre range and offer a powerful basis for automated vegetation modelling. The successful extraction of single trees from the point cloud is essential for further evaluations and modelling at the individual-tree level, such as volume determination, quantitative structure modelling or local neighbourhood analyses. However, high-precision automated tree segmentation is challenging, and has so far mostly been performed using elaborate interactive segmentation methods.

Methods

Here, we present a novel segmentation algorithm to automatically segment trees in MLS point clouds, applying distance adaptivity as a function of trajectory. In addition, tree parameters are determined simultaneously. In our validation study, we used a total of 825 trees from ten sample plots to compare the data of trees segmented from MLS data with manual inventory parameters and parameters derived from semi-automatic TLS segmentation.

Key Results

The tree detection rate reached 96 % on average for trees with distances up to 45 m from the trajectory. Trees were almost completely segmented up to a distance of about 30 m from the MLS trajectory. The accuracy of tree parameters was similar for MLS-segmented and TLS-segmented trees.

Conclusions

Besides plot characteristics, the detection rate of trees in MLS data strongly depends on the distance to the travelled track. The algorithm presented here facilitates the acquisition of important tree parameters from MLS data, as an area-wide automated derivation can be accomplished in a very short time.