bluuebunny/crossref_metadata_2025 huggingface dataset:
Pars Plana Capsulovitrectomy for Posterior Capsular Opacification in Children
Authors: Mitra Sandip , Ganesh Anuradha
Published: August 2021

Posterior capsular opacification (PCO) is a common complication following cataract surgery in the pediatric age group. Despite various techniques to prevent its occurrence, cases often require postoperative Nd:YAG laser capsulotomy. Cases with PCO are described in which the Nd:YAG laser was ineffective in clearing the visual axis and pars plana capsulovitrectomy was performed to penetrate the thick pupillary membranes.
[Ophthalmic Surg Lasers Imaging 2003; 34:327–331.]
Combined effects of singular and exponential nonlinearities in fractional Kirchhoff problems
Authors: Mukherjee Tuhina , Pucci Patrizia , Xiang Mingqi
Published: August 2021

In this paper we establish the existence of at least two (weak) solutions for the following fractional Kirchhoff problem involving singular and exponential nonlinearities

   \begin{document}$ \begin{cases} M\left(\|u\|^{{n}/{s}}\right)(-\Delta)^s_{n/s}u = \mu u^{-q}+ u^{r-1}\exp( u^{\beta})\quad\text{in } \Omega,\\ u>0\qquad\text{in } \Omega,\\ u = 0\qquad\text{in } \mathbb R^n \setminus{ \Omega}, \end{cases} $\end{document}

where \begin{document}$ \Omega $\end{document} is a smooth bounded domain of \begin{document}$ \mathbb R^n $\end{document}, \begin{document}$ n\geq 1 $\end{document}, \begin{document}$ s\in (0,1) $\end{document}, \begin{document}$ \mu>0 $\end{document} is a real parameter, \begin{document}$ \beta <{n/(n-s)} $\end{document} and \begin{document}$ q\in (0,1) $\end{document}.The paper covers the so called degenerate Kirchhoff case andthe existence proofs rely on the Nehari manifold techniques.
Study on improving interface bonding performance of magnesium potassium phosphate cement mortar
Authors: Zhang J. , Ji Y. ,  Xu Z. , Xue Q. , Zhou Y. , Jin C.
Published: August 2021

To enhance the interfacial bonding performance between magnesium potassium phosphate cement (MKPC) repair mortar and matrix concrete, in this study, MKPC modified mortar was used as the repair material to splice long prismatic test pieces. The four-point bending test was used to determine the flexural bearing capacity of the long prism, and the influence of changing the interface conditions and the modifying the MKPC repair mortar on the improvement of the basic performance of the splicing component is investigated.The research results show that, when the matrix concrete section is in a natural state, applying silica-fume modified MKPC interface agents on the interface with a repair thickness of 3 cm can improve the interface bonding performance. Furthermore, the working performance and mechanical properties of the MKPC repair mortar modified using nickel-iron slag and steel fibers have been significantly improved.
New methods for assessing brick resistance to freeze-thaw cycles
Authors: Netinger-Grubeša I. , Benšić M. , Vračević M.
Published: August 2021

The aim of this research is to analyse the reliability of the existing methods, and find new ones, for assessing brick resistance to freeze-thaw cycles. A series of bricks were tested against a range of properties; compressive strength ratios pre- to post-freezing and Maage’s factor, were calculated. Using a database created in this way, an analysis of existing classifiers was carried out and new ones were established based on which bricks could be classified into resistant and non-resistant to freeze-thaw cycles. The median pore radius, the ratio of compressive strengths pre- to post-freezing and the water desorption coefficient at 180-360 minutes proved to be good classifiers with a clearly specified cut-off for the distinction between resistant and non-resistant bricks with an acceptable risk of a wrong decision. The ratio of compressive strengths pre to post freezing and the water desorption coefficient at 180-360 minutes were described using the pore system in the brick.
Os primeiros professores de língua inglesa do século XIX
Authors: Santos Elaine Maria
Published: August 2021

O presente artigo tem como objetivo principal relacionar a trajetória de três professores de língua inglesa do século XIX com o processo de institucionalização do ensino da língua inglesa, frente à hegemonia francesa. Para tanto, os pressupostos da Nova História Cultural foram utilizados, privilegiando-se de fontes diversas, como documentos oficiais, jornais oitocentistas e prefácios de compêndios publicados pelos professores selecionados. Os achados da pesquisa nos mostram que as lutas enfrentadas pelos docentes tiveram grande importância para a consolidação de um campo de trabalho em momentos diferentes do século XIX, levando-se em consideração que o francês ocupava um papel hegemônico no que se refere ao ensino de línguas vivas
Relationship between Kinematic Viscosity and Cluster Size in Multicomponent Metal Melts
Authors: Tsepelev Vladimir S. , Starodubtsev Yuri N. , Kochetkova Yekaterina A.
Published: August 2021

We analyzed the temperature dependences of the kinematic viscosity and density of Fe73.5Cu1M3Si13.5B9 melts, where M = Nb, Mo, V, and Cr, in the temperature range from 1450 to 1950 K using the transition state theory. It is shown that the activation energy of viscous flow is proportional to the particle size on a natural logarithmic scale. The lowest viscosity and the highest free volume has the Nb melt. In melts with Mo, V, and Cr, the structural units of viscous flow upon heating and cooling are clusters about 0.6 nm in size. In a melt with Nb, at the initial stage of heating, the vibrations of individual atoms prevail, the movement of which creates viscosity. After heating the Nb melt above the critical temperature of 1770 K, the viscous flow is associated with clusters about 1 nm in size. At the cooling stage, the cluster structure of the Nb melt is retained up to a temperature of 1450 K.
Development of Hardening Technology for Oil and Gas Pumping and Compressor Equipment Using Laser Hardening
Authors: Kurnoskin Ivan A. , Krylova Svetlana E. , Plesovskikh Alexey Yu.
Published: August 2021

This paper considers the results of modes testing for surface laser hardening. It also includes the development of compositions for light-absorbing coating for industrial application of laser hardening. The paper presents the influence of the light-absorbing coating on the structuring of the surface layer under laser hardening of medium-carbon alloy steel.
Contact Surfaces Preparation in Manufacturing of Bimetallic Strips CuZn10 Brass - C22E Steel - CuZn10 Brass
Authors: Shaparev Alexander V.
Published: August 2021

Contact surfaces preparation before cold cladding is one of the most important technological operations. A joint plastic components deformation of the of bimetal 1 according to OST 3-6648-91 and bimetal 3 according to OST 3-6649-91 CuZn10 brass - C22E steel - CuZn10 brass (according to EN standard) should be performed with the strongest possible compression to obtain the required layers connection strength, ensuring strip winding into a roll without delamination. We investigated influence of some factors on the bond strength of bimetal layers: surface hardening of contact surfaces, presence of an underlayer on a steel base, contact surfaces micro geometry, components heating temperature in the deformation zone, diffusion annealing after cladding and a bimetal layers thicknesses ratio effect. Cold cladding technological recommendations have been developed for manufacturing of bimetal 1 according to OST 3-6648-91 and bimetal 3 according to OST 3-6649-91 (CuZn10 brass - C22E steel - CuZn10 brass).
Effect of Phosphorus on Crystallization of Alkaline Molybdenum-Containing Borosilicate Glasses
Authors: Eremyashev Viacheslav E. , Korinevskaya Galina G. , Zherebtsov Dmitry A.
Published: August 2021

The effect of additives of P2O5 on the solubility of molybdenum in the amorphous part of glass and on the phase composition of the crystallized part of the highly alkaline glasses of the Li2O–(Na2O–K2O)–B2O3-SiO2 system was studied. The comparison of the phase composition of samples with or without phosphorus prior and after annealing allowed to determine the change of solubility of molybdenum in the amorphous part of the samples and to evaluate the thermal stability of the synthesized glass-ceramic materials. It was found, that for the compositions without phosphorus and the samples without lithium, when molybdenum is added at the synthesis stage, almost all of the molybdenum is included only in the crystalline molybdates. The study has shown an increase in the solubility of molybdenum only in the structure of lithium-containing glasses with phosphorus.
A Life Cycle Assessment Study on a New Countertop Material
Authors: Silva Luiza , Silva Elisabete , Brás Isabel , Domingos Idalina , Wessel Dulcineia , Ferreira José
Published: August 2021

The Life Cycle Assessment (LCA) is one of the most important analytical tools available to provide the scientific basis of engineering solutions for sustainability. The focus of this study was a LCA (cradle to gate) of a product intended to be used in countertops. The functional unit chosen was 1 m2 of finished panel (countertop) and the boundary system involved the study of raw materials and product packaging and the panel’s production process. The chosen method for impact assessment was EPD (2018) available in SimaPro PhD software and Acidification, Eutrophication, Global Warming, Photochemical Oxidation, Abiotic Depletion (elements), Abiotic Depletion (fossil fuels), Water Scarcity and Ozone Layer Depletion were the impact categories considered. Results showed that the panel’s manufacturing is the process that presented the highest influence in all categories analyzed ranging from 88% on Abiotic Depletion to approximately 101% on Water Scarcity. Polyvinylchloride (PVC) is the greatest contributors to all impact categories except to Photochemical Oxidation that is the Polyester.
Study of Micro-Upsetting by Finite Element Simulation Based on Crystal Plasticity and Grain Boundary Strengthening Theories
Authors: Zheng Jun Yuan , Fu M.W.
Published: August 2021

The properties of individual grains affect the mechanical behaviors and response of materials in micro-scaled deformation, viz., microforming, and there are unknown phenomena and deformation behaviors existing and limiting the wide application of microforming due to size effect. In this paper, a composite model combining crystal plasticity and grain boundary strengthening theories was developed for numerical investigation into the effect of grain boundaries on the plastic deformation of copper micro-upsetting. By comparing the results with and without grain-boundary structure, it is revealed that grain boundaries, which act as the barriers of crystal slip, result in the enhanced flow stress and the discontinuous distribution of stress and strain. The grain size effect is also considered in this research, and the results show the coarse-grained material reduces the flow stress and enhances the inhomogeneous deformation.
Prediction of Mechanical Properties of Iron and Steel Based on the Quantile Model of Generalized Radial Basis Neural Network
Authors: Tian Tong , Huang Si Yu
Published: August 2021

Hot rolled steel is a material made by heating at high temperature. It has strong plasticity and is used in shipping industry, automobile industry, manufacturing industry, etc. Tensile strength refers to the maximum resistance to uniform plastic deformation of the material. It is an index of the mechanical properties of steel and determines the quality of steel to a certain extent. The influencing factors of tensile strength include steel processing parameters and chemical composition. As an improved model of RBF neural network, the generalized RBF neural network reduces the complexity of the model, improves the generalization ability of the model, and makes its application more extensive. In this paper, a generalized RBF neural network quantile regression model (QR-GRBFNN) is established to predict the mechanical properties of hot rolled strip, the mean percentage error (MAPE) and root mean square error (RMSE) are used as evaluation indexes. Experiments show that the model has better predictive performance.
Aqueous Stability of Cross-Linked Thermal Responsive Tissue Engineering Scaffold Produced by Electrospinning Technique
Authors: Yong Hsin Nam Ernest , Tshai Kim Yeow , Lim Siew Shee
Published: August 2021

Poly (N-isopropylacrylamide) (PNIPAm) has been one of the most widely studied thermal responsive polymer in tissue engineering owing to its reversible hydrophilic-hydrophobic phase transition across its lower critical solution temperature (~32°C) that is close to human physiological temperatures. Among tissue engineering constructs, nanofibrous scaffolds offer an added advantage in mimicking the morphology of the native extracellular matrix (ECM). Electrospinning has been reported as one of the most facile method to produce PNIPAm nanofibres and neat electrospun nanofibres scaffold is known to possess poor aqueous stability, limiting its use in tissue engineering applications. In contrast, numerous studies on PNIPAm hydrogels have shown relatively good aqueous stability owing to the hydrophilic 3D crosslinked structure of the hydrogel which resist instant dissolution but rather swell to a greater or lesser extent. However, the presence of crosslinkages in PNIPAm hydrogels causes it to be hardly electrospinnable into nanofibres. In the present work, crosslinker free PNIPAm was radical polymerized to a high molecular weight of 385 kDa. To produce nanofibers, electrospinning was carried out on a dedicated %wt of PNIPAm solution containing octaglycidyl polyhedral oligomeric silsesquioxane (OpePOSS) and 2-ethyl-4-methylimidazole (EMI). Resulting PNIPAm nanofibrous network was found to strongly resemble the ECM morphology with fiber diameter of 436.35 ± 187.04 nm, pore size 1.24 ± 1.27 μm and 63.6% total porosity. Aqueous stability was studied in cell culture media over the course of 28 days. The current result shows significant improvement with a gradual mass loss up to a maximum of 35% instead of the near immediate dissolution observed in the case of electrospun neat PNIPAm scaffold without crosslinks.
Degradation of Virgin and Recycled Polylactic Acid/Eggshell Composites Buried in Soil
Authors: Budin Salina
Published: August 2021

Development of polylactic acid (PLA) composites using various filler have extensively being been in focus. One of the possible natural filler is eggshell (ES) which are abundantly available derived from food industry waste. This work attempted to investigate the effect of eggshell (ES) filler on the degradation of virgin-PLA and recycled-PLA. The virgin-PLA/ES composites and recycled-PLA/ES composites were prepared using solvent casting method. The content of eggshell filler varied in the range of 0 – 20 wt%. Degradation of virgin-PLA/ES composites and recycled-PLA/ES composites were evaluated by soil buried test. After soil buried for 10 weeks, the maximum weight loss for virgin-PLA/ES composites was 14 wt% which noted at the composition of 95 wt% virgin-PLA/5 wt% ES. Nevertheless, for recycled-PLA/ES composites, the maximum weight loss observed at the composition of 90 wt% recycled-PLA/ 10 wt% ES at the value of 21 wt%. However, further addition of eggshell filler content in PLA/ES composites led to lower weight loss. Hence, the degradation of recycled-PLA/ES composites were more accelerated as compared to virgin-PLA/ES composites. The results revealed the potential of eggshell waste as a bio-filler in PLA matrix.
A Study of the Effect of Reaction Time on the Preparation of Zirconium Based UiO-66 MOF
Authors: Koriem Omneya A. , El-Shazly Ahmed H. , El-Kady Marwa F.
Published: August 2021

UiO-66 is a zirconium-based metal organic framework (MOF). It was synthesized and used by researchers due to its high water, chemical and thermal stability. The mentioned reasons in addition to other excellent properties made them a highly competitive materials for a variety of industrial problems. This study investigates the effect of the reaction time on the characteristics of the prepared UiO-66 nanoparticles. UiO-66 was synthesized by the solvothermal method and the reaction was left to take place for 18, 21 and 24 hours. UiO-66 was characterized using X-ray Diffraction (XRD) and Fourier-Transform Infrared (FTIR), the results showed that it has the same patterns and functional groups of the previously reported UiO-66. In addition, Scanning Electron Microscopy (SEM) was used to confirm the morphology of UiO-66. The smallest particle size around 200 nm was obtained at 18 hours. To investigate the thermal stability of the prepared UiO-66, Thermogravimetry analysis (TGA) was conducted. The results matched well with the literature and confirm that UiO-66 is thermally stable up to 500°C.
Piezoelectric PVDF Nanofibrous Membrane Electrospinning Optimization Parameters
Authors: Essam Aliaa , El-Shazly Ahmed H. , Shokry Hassan
Published: August 2021

The application of piezoelectric polyvinylidene fluoride (PVDF) has become of a great interest. Due to its piezoelectric properties, PVDF is used in various applications, namely, microdevices and sensors. Electrospinning was found to be the most suitable and efficient method to synthesis PVDF nanofibers. It is used to obtain PVDF nanofibers without additional mechanical stretching and with high β phase content. For these reasons, it is considered to be an economic technique. In the present paper, the parameters affecting the synthesis of PVDF nanofibers such as solution concentration, flow rate, voltage and Tip to Collector Distance (TCD), have been investigated. The optimum conditions were found to be 18% concentration, 15 cm TCD, 1 mL/h flowrate and 19 kV voltages. The fabricated nanofiber has been characterized using SEM, FTIR, XRD and a conductivity test.
A Comparative Study of the Manufacturing of BPSCCO Superconducting Wire with TiO2 Dopants
Authors: Herbirowo Satrio , Pratama Hedy Putra , Yuwono Akhmad Herman , Sofyan Nofrijon , Imaduddin Agung
Published: August 2021

Bi-Pb-Sr-Ca-Cu-O (BPSCCO) superconductors are recognized as a projectable high-temperature superconductor for high-efficiency electrical applications. The addition of Ti enhances the formation of the Bi-2223 phase from the BPSCCO superconductor. The process of producing BPSCCO superconducting materials with TiO2 dopants is performed by the solid-state process and the production of wire rolling, consisting of bismuth (III) oxide powder (Bi2O3 = 99%), Strontium Carbonate powder (SrCO3 = 99%), Calcium Carbonate powder (CaCO3 = 99%), Copper Oxide powder (CuO2 = 99%), Lead Oxide powder (PbO2 = 98%) Bi: Pb: Sr: Ca: Cu ratio: 1.6: 0.4:2:2:3 doped by 1 %wt Titanium Oxide powder (TiO2 = 98.5%). The variables used in this study were the comparison of the sintering method at 860°C for 24 hours and 820 °C calcination for 20 hours, and 850°C sintering for 20 hours. The superconductor characterization was tested through the X-Ray Diffraction (XRD) test, Scanning Electron Microscopy (SEM), and Resistivity test. XRD test results showed the formation of Bi2Sr2CuO6 and Bi2Sr5Cu3O16 phase. SEM results showed an increase in grain size. The resistivity test results showed that all samples formed critical temperatures, 9.6 and 9.5K respectively.
Racket or Bat Sports: No Association With Thumb-Base Osteoarthritis
Authors: Driban Jeffrey B. , Lo Grace H. , Roberts Mary B. , Harkey Matthew S. , Schaefer Lena F. , Haugen Ida K. , Smith Stacy E. , Duryea Jeffrey , Lu Bing , Eaton Charles B. , Hochberg Marc C. , Jackson Rebecca D. , Kwoh C. Kent , Nevitt Michael C. , McAlindon Timothy E.
Published: August 2021

Context

Repetitive joint use is a risk factor for osteoarthritis, which is a leading cause of disability. Sports requiring a racket or bat to perform repetitive high-velocity impacts may increase the risk of thumb-base osteoarthritis. However, this hypothesis remains untested.

Objective

To determine if a history of participation in racket or bat sports was associated with the prevalence of thumb-base osteoarthritis.

Design

Descriptive epidemiologic study.

Setting

Four US clinical sites associated with the Osteoarthritis Initiative.

Patients or Other Participants

We recruited 2309 men and women from the community. Eligible participants had dominant-hand radiographic readings, hand symptom assessments, and historical physical activity survey data.

Main Outcome Measure(s)

A history of exposure to racket or bat sports (badminton, baseball or softball, racketball or squash, table tennis [or ping pong], tennis [doubles], or tennis [singles]) was based on self-reported recall data covering 3 age ranges (12–18, 19–34, and 35–49 years). Prevalent radiographic thumb-base osteoarthritis was defined as Kellgren-Lawrence grade >2 in the first carpometacarpal joint or scaphotrapezoidal joint at the Osteoarthritis Initiative baseline visit. Symptomatic thumb-base osteoarthritis was defined as radiographic osteoarthritis and hand or finger symptoms.

Results

Radiographic or symptomatic thumb-base osteoarthritis was present in 355 (34%) and 56 (5%), respectively, of men (total = 1049) and 535 (42%) and 170 (13%), respectively, of women (total = 1260). After adjusting for age, race, and education level, we found no significant associations between a history of any racket or bat sport participation and thumb-base osteoarthritis (radiographic or symptomatic; odds ratios ranged from 0.82 to 1.34).

Conclusions

In a community-based cohort, a self-reported history of participation in racket or bat sports was not associated with increased odds of having radiographic or symptomatic thumb-base osteoarthritis in the dominant hand.
Automated Landing Error Scoring System Performance and the Risk of Bone Stress Injury in Military Trainees
Authors: Eckard Timothy G. , Miraldi Story F.P. , Peck Karen Y. , Posner Matthew A. , Svoboda Steven J. , DiStefano Lindsay J. , Padua Darin A. , Marshall Stephen W. , Cameron Kenneth L.
Published: August 2021

Context

Lower extremity bone stress injuries (BSIs) place a significant burden on the health and readiness of the US Armed Forces.

Objective

To determine if preinjury baseline performance on an expanded and automated 22-item version of the Landing Error Scoring System (LESS-22) was associated with the incidence of BSIs in a military training population.

Design

Prospective cohort study.

Setting

US Military Academy at West Point, NY.

Patients or Other Participants

A total of 2235 incoming cadets (510 females [22.8%]).

Main Outcome Measure(s)

Multivariable Poisson regression models were used to produce adjusted incidence rate ratios (IRRs) to quantify the association between preinjury LESS scores and BSI incidence rate during follow-up and were adjusted for pertinent risk factors. Risk factors were included as covariates in the final model if the 95% CI for the crude IRR did not contain 1.00.

Results

A total of 54 BSIs occurred during the study period, resulting in an overall incidence rate of 0.07 BSI per 1000 person-days (95% CI = 0.05, 0.09). The mean number of exposure days was 345.4 ± 61.12 (range = 3–368 days). The final model was adjusted for sex and body mass index and yielded an adjusted IRR for a LESS-22 score of 1.06 (95% CI = 1.002, 1.13; P = .04), indicating that each additional LESS error documented at baseline was associated with a 6.0% increase in the incidence rate of BSI during the follow-up period. In addition, 6 individual LESS-22 items, including 2 newly added items, were significantly associated with the BSI incidence.

Conclusions

We provided evidence that performance on the expanded and automated version of the LESS was associated with the BSI incidence in a military training population. The automated LESS-22 may be a scalable solution for screening military training populations for BSI risk.
Effects of at-home and in-office bleaching and three composite types (hybrid, microhybrid, and nanofilled) on repair shear bond strength of aged composites
Authors: Zakavi Faramarz , Johar Najmeh , Moalemnia Mina , Rakhshan Vahid
Published: August 2021

Background:

Only a few controversial studies have assessed the repair bond strength of a fresh composite to aged composite. Moreover, no studies exist on repair bond strength of fresh composites to bleached composites. Therefore, this preliminary study was conducted to assess repair shear bond strength (SBS) of three composites bonded to nonbleached and at-home and in-office bleached composites.

Materials and Methods:

In this experimental in vitro study, 108 disks (36 specimens per composite) of hybrid, microhybrid, and nanofilled composites were divided into three subgroups of three bleaching treatments: no bleaching (control), at-home bleaching, and in-office bleaching. Composite disks were incubated for 4 weeks in artificial saliva (also dipped in tea and coffee for 3 h a day). They were then thermocycled (5000 cycles). Afterward, the control group remained unbleached, while the other groups were bleached according to office and home bleaching methods. They were repaired with the same composite type. Their repair SBS and mode of failure were measured and analyzed using two-way ANOVA, Tukey, one-sample t-test, and Chi-square tests (α = 0.05, β = 0.2).

Results:

The mean (standard deviation) SBS values of hybrid, microhybrid, and nanofilled composites were 20.71 ± 5.99, 21.06 ± 6.68, and 9.46 ± 4.32 MPa, respectively. The mean SBS values of the bleaching techniques “home bleaching, office bleaching, and no bleaching (control)” were, respectively, 16.35 ± 7.13, 16.39 ± 8.07, and 18.49 ± 8.35 MPa. There was a significant difference among composites (two-way ANOVA P = 0.000) but not among nonbleaching/bleaching methods (P = 0.176). Their interaction was significant (P = 0.017). The difference between hybrid and microhybrid was not significant. Nevertheless, nanofilled had significantly poorer results compared to both hybrid and microhybrid composites (Tukey P = 0.000). Both hybrid and microhybrid were capable of producing satisfactory clinical repair bond strengths (above 20 MPa) regardless of bleaching or lack of it. Nanofilled composite failed to provide proper repair SBS values, even in the control (no-bleaching) group. By moving from Z100 or from Z250 to Z350, modes of failure shifted from mostly cohesive to mostly adhesive (P < 0.05).

Conclusion:

Bleaching of an aged composite might not affect the repair bond strength. Hybrid and microhybrid composites can provide clinically acceptable repair bond strengths, regardless of bleaching. Nonetheless, nanofilled composite is inferior to them and cannot provide appropriate repair bond strengths (regardless of bleaching).
Histological assessment of the local effect of different concentrations of aminoguanidine hydrochloride on bone healing in rats
Authors: Farhad Ali Reza , Razavi Fahimeh , Razavi Sayed Mohammad , Saatchi Masoud , Manshaei Maziar
Published: August 2021

Background:

Nitric oxide (NO) has several functions in bone healing and affects bone metabolism. Selective inducible NO synthase (iNOS) inhibitors can be used to assess the efficacy of NO for healing of bone defects. This study sought to assess the local effect of different concentrations of aminoguanidine hydrochloride (AG), a selective iNOS inhibitor, on bone healing in rats.

Materials and Methods:

In this animal experimental study, 72 rats were divided into six groups of control, placebo, 5% AG, 10% AG, 15% AG, and 20% AG. A bone defect measuring 5 mm × 5 mm was created in the femur. The defect remained empty in the control group. In the placebo group, neutral gel was placed in the bone defect, and in the remaining four AG groups, different concentrations of AG were applied to the defects. Bone healing was assessed histologically. The healing score in the six groups was analyzed by the Kruskal–Wallis test. A P < 0.05 was considered statistically significant.

Results:

The healing score in 20%, 15%, 10%, and 5% AG groups was significantly higher than that in the neutral gel and control groups (P < 0.01). Among the four groups of AG, 20% concentration showed better results, but the difference was not significant.

Conclusion:

Four concentrations of AG caused greater bone healing compared to the other two groups. Selective iNOS inhibitors such as AG can be used to promote local bone healing.
The effect of complete dentures on edentulous patients’ oral health-related quality of life in long-term
Authors: Martins Angela M. C. , Guimarães Ludmila S. , Campos Camila H. , Küchler Erika C. , Pereira Daniele M. S. , Maia Lucianne C. , Antunes Leonardo S. , Antunes Lívia A. A.
Published: August 2021

Background:

To evaluate whether the long-term use of complete dentures (CD) into promotes significant changes in the oral health-related quality of life (OHRQoL) in edentulous patients.

Methods:

A systematic review and meta-analysis was conducted. A broad search in Pubmed, Web of Science, Scopus, Cochrane Library, Grey Literature, clinical trials registers and manual search was done. The eligibility criteria were based on population, intervention, comparisons and outcome: (P) edentulous patients, (I) CDs rehabilitation, (C) OHRQoL after CD, (O) change in scores of OHRQoL. Two independent reviewers applied the eligibility criteria, collected qualitative data, performed methodological quality and evaluated the certainty of the evidence (grading of recommendations assessment, development and evaluation). The meta-analysis was analyzed in RevMan 5.4 with 95% confidence intervals (CIs) and P < 0.05.

Results:

A total of 2452 records were identified. Twenty-four articles were included in qualitative synthesis. Nineteen studies were qualified as good, 3 as fair and 2 as poor quality. Twelve studies were included in quantitative analysis (meta-analysis). The use of CD did not improved OHRQoL in a period of 3 months through the assessment of the Geriatric Oral Health Assessment Index (GOHAI) instrument (P = 0.55; CI; 6.86 [−15.60, 29.31]), and Oral Health Impact Profile-14 (OHIP-14) (P = 0.05; CI; −14.91 [−29.87, 0.04]), with very low certainty of evidence. In a long term, 6 months, GOHAI instrument (P < 0.00001; CI; 16.22 [10.70, 21.74]), OHIP 20 (P = 0.02; CI; −11.09 [−20.54, −1.64]) and OHIP-EDENT (P = 0.0004; CI; −8.59 [−13.32, −3.86]) showed improvement on OHRQoL, with very low and low evidence of certainty, respectively.

Conclusion:

CD has the strong potential to contribute to oral health-related quality of life in long-term.
IL29 expression in gingival tissues of chronic periodontitis and aggressive periodontitis patients
Authors: Tabari Zahra Alizadeh , Hematzadeh Somayeh , Keshani Forooz
Published: August 2021

Background:

Interleukin-29 (IL-29) is one of the cytokines which has immunomodulatory properties and might play a role in the pathogenesis of periodontal diseases. The aim of this study was an immunohistochemical analysis of IL-29 in gingival tissues of chronic and aggressive periodontitis.

Materials and Methods:

In this cross-sectional study based on clinical evaluation and inclusion and exclusion criteria, 20 patients with generalized chronic periodontitis, 13 patients with generalized aggressive periodontitis, and 20 periodontally healthy individuals were enrolled. Gingival tissue samples were obtained during periodontal flap and crown lengthening surgery in periodontal patients and healthy individuals, respectively. Tissue samples were examined to determine the level of IL-29 expression by immunohistochemistry. The data were analyzed using SPSS and paired t-test, ANOVA test, and Tukey’s test (P < 0.05).

Results:

A total of 53 participants (34 females and 19 males) were enrolled in this study. IL-29 expression in the connective tissue of the patient groups was more than the healthy one (P < 0.001). In the aggressive periodontitis group, there was a significant increase of IL-29 expression compared to the other two groups, but there was no significant difference between the chronic periodontitis and healthy groups.

Conclusion:

According to the results of this study, IL-29 expression was increased in the gingival tissue of aggressive and chronic periodontitis. IL-29 local expression in aggressive periodontitis is higher than the chronic periodontitis and healthy groups, which could suggest the role of IL-29 in the etiopathogenesis of aggressive periodontitis.
Oral manifestations among COVID-19
Authors: Subramaniam Tulsi , Nikalje Monali R. , Jadhav Sameer
Published: August 2021

Background:

COVID-19 outbreak in 2019 took the entire world by a storm with the medical fraternity struggling to understand and comprehend its complex nature. A number of patients who are COVID positive have reported oral lesions. However, there is still a lingering question, whether these lesions are because of coronavirus infection or they are secondary to the patient’s systemic condition. This article aims to report the oral findings of an observational study of 713 patients diagnosed with COVID-19.

Materials and Methods:

A singlssswe-institution, short-term observational study was conducted on patients admitted to Symbiosis University Hospital and Research Centre, Lavale, Pune who were positive to coronavirus, who presented varied oral findings such as herpes simplex, candidiasis, geographic tongue, and aphthous ulcer.

Results:

A total of 713 patients, 416 males and 297 females, who were positive to coronavirus, were screened from April 2020 to June 30, 2020, for oral ulcers. In this group, nine patients reported oral discomfort due to varied forms of oral lesions ranging from herpes simplex ulcers to angular cheilitis (1.26%).

Conclusion:

This study supports the hypothesis that oral manifestations in patients diagnosed with COVID-19 could be secondary lesions resulting from local irritants or from the deterioration of systemic health or could be just coexisting conditions. No specific pattern or characteristic oral lesions were noted in a study of 713 COVID-positive patients in our study to qualify these lesions as oral manifestations of SARS-CoV-2 infection.
Comparative clinical evaluation of modified and conventional Grayson’s presurgical nasoalveolar molding technique in infants with complete unilateral cleft lip and palate
Authors: Thakur Seema , Jishad C. , Singhal Parul , Chauhan Deepak
Published: August 2021

Background:

Presurgical nasoalveolar molding (PNAM) was introduced by Grayson et al., in 1993 to presurgically mold the alveolus, lip, and nose in infants with cleft lip and palate (CLP). The aim of this comparative clinical trial was to evaluate the efficacy and efficiency of Modified and Conventional Grayson’s PNAM in patients concerning morphological and anatomical changes in maxillary alveolus, nasal symmetry, number of visits, and duration of treatment.

Materials and Methods:

In this comparative clinical trial study, 16 infants with unilateral complete CLP were equally divided into two groups: Group I (modified PNAM technique using titanium molybdenum alloy [TMA] wire nasal stent) and Group II (conventional PNAM technique using stainless steel wire nasal stent). Patient photographic evaluation of nasal symmetry and maxillary study model CAD-CAM analysis, pre- and post-operatively in both groups, were compared using a paired t-test between the groups using the Chi-square test with P < 0.05 as statistically significant.

Results:

In both groups, on evaluating nasal measurements, statistically significant (P < 0.05) decrease in nasal width and increase in columella deviation angle, a decrease of nostril length, and an increase of columella length in Group I were observed. On maxillary study model evaluation, a statistically significant (P < 0.05) decrease in width of the alveolar cleft was noticed in both groups and lateral deviation of the incisal point in Group I and width of the palatal cleft in Group II was noticed.

Conclusion:

This study showed a morphological improvement in nasal symmetry and maxillary alveolar morphology in complete unilateral CLP patients, treated with both Modified and Conventional PNAM techniques, with the Modified PNAM technique being more efficient for treatment duration and the number of adjustments as there are less number of visits.
Adropin and Spexin Hormones Regulate the Systemic Inflammation in Adenine-Induced Chronic Kidney Failure in Rat
Authors: Memi Gulsun , Yazgan Burak
Published: August 2021

Chronic kidney disease is one of the major global health problems. Chronic renal failure is stimulated by many cytokines and chemokines. Adropin and spexin (SPX) are peptides hormones. These peptides could affect inflammatory conditions, but this is unclear. Due to the limited information, we planned to investigate the impact of adropin and SPX hormones on systemic inflammation in adenine induced chronic kidney failure rat model. Chronic kidney failure was induced by administering adenine hemisulfate. Renal functions were measured by an autoanalyzer. Granulocyte colony-stimulating factor (G-CSF), interferon-gamma (IFN-γ), interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, IL-17A, tumor necrosis factor-alpha, Eotaxin, growth-regulated oncogene-alpha, IP-10, monocyte chemoattractant protein (MCP)-1, MCP-3, macrophage inflammatory protein (MIP)-1α, MIP-2, and RANTES levels were determined by Luminex. We observed an increase in 24-h urine volume and serum creatinine. Blood urea nitrogen (BUN) and urine protein levels were also significantly higher in the chronic kidney failure (CKF) group. Urine protein and 24-h urine volume were reduced with adropin and SPX treatments. Furthermore, G-CSF, IFN-γ, IL-4, IL-5, IL-10, IL-12, IL-17A, and GRO-α significantly increased by CKF induction; however, these cytokines and chemokines significantly decreased by adropin treatment in the CKF group. Furthermore, adropin increased IP-10, MCP-1, MIP-1α, and MIP-2 levels. In addition, SPX treatment had a more limited effect, decreasing only G-CSF, IFN-γ, and IL-5 levels. The combined adropin + SPX treatment significantly reduced G-CSF, IFN-γ, IL-4, IL-5, IL-12, and IL-17A. Furthermore, IP-10, MCP-1, MCP-3, and MIP-2 were significantly increased by these combined treatments. Our findings indicate that renal functions and inflammatory response were modulated by adropin and SPX peptides. These peptides may have protective effects on systemic inflammation and renal failure progression.
Live Birth after Treatment of a Ruptured Ectopic in a Spontaneous Heterotopic Pregnancy
Authors: Ubom Akaninyene Eseme , Owolabi Alexander Tuesday , Fadare Oluwatoyin Oyenike , Akindojutimi Jerrie Akinyemi , Adekunle Isiaka Ayofe
Published: August 2021

Heterotopic pregnancy, though more common in pregnancies achieved by assisted reproduction, is extremely rare following natural conception. Owing to this rarity, the diagnosis is oftentimes missed or made late, usually following rupture of the extrauterine gestation. Heterotopic pregnancy, therefore, expectedly carries significant maternal mortality and morbidity. With the advancement in assisted reproductive techniques, and improvement in the diagnosis of ectopics using transvaginal ultrasound and beta-human chorionic gonadotropin assay, the frequency of heterotopic pregnancy is likely to increase, especially so in a country like Nigeria, with high twinning and ectopic pregnancy rates. To promptly diagnose heterotopic pregnancy and timely intervene, a high level of clinical suspicion is required. This would mitigate maternal morbidity and mortality, as well as preserve and continue the intrauterine pregnancy. With early diagnosis and prompt intervention, intrauterine pregnancy has a favourable outcome in the majority of cases. We present a 37-year-old multigravida with naturally conceived heterotopic pregnancy, in which the ectopic pregnancy ruptured. She subsequently had spontaneous vaginal delivery following surgical management (laparotomy) of the ruptured ectopic pregnancy.
Mothers' Perception of COVID-19 Infection in Their Under-Five Children Presenting in a Tertiary Health Institution in South-East Nigeria and Associated Factors
Authors: Chinawa Awoere Tamunosiki , Chinawa Josephat Maduabuchi , Ossai Edmund Ndudi , Igwe Wilson Chukwuneke , Nduaguba Obinna Chukwuebuka , Aronu Ann Ebele
Published: August 2021

Background:

Maternal attitude to health-seeking behavior of their under-five children in the COVID-19 pandemic is not well-known.

Objectives:

This study is aimed at determining mothers' perception of COVID-19 pandemic among their under-five children and associated factors.

Methodology:

This is a prospective and observational study carried out in two health institutions in South-East Nigeria.

Results:

Most subjects, 243 (65.3%) noted that someone without showing symptoms of COVID-19 could transmit the virus. Of the mothers of children under-five, 271 (72.8%) highlighted the possibility of COVID-19 infection in the under-five. A small number of participants 53 (14.2%) showed awareness that people should cough into their elbows as a way of preventing the transmission of COVID-19. A small number of participants, 160 (43.0%) had a good perception of COVID-19. Majority of mothers who were married, 148 (44.7%) showed a good perception of COVID-19 when compared with those who were single, 12 (29.3%); however, this is not significant, (χ2 = 3.550, P = 0.060). A large number of participants who have attained tertiary education, 92 (48.9%) had a good perception of COVID-19 which is higher than that seen in mothers with secondary education 68 (37.0%) (χ2
= 5.444, P = 0.020). Participants who were 30–34 years had 1.8 times higher odds of good perception of COVID 19 compared with mothers who were more than 35 years (adjusted odds ratio = 1.803, 95% confidence interval = 1.026–3.170).

Conclusion:

Although most mothers affirm that a child could be infected by COVID-19, a small number of them actually had a good perception of COVID-19 infection. Good perception of COVID-19 among the under-five is enhanced by the high level of education and age of 32–34 years.
Review of COVID-19 Vaccine
Authors: Efuntoye Oluwafemi , Obafemi Olufemi , Folayan Olumuyiwa , Amoo Abimbola , Ogundipe Habeeb D. , Enebeli Ugo , Ogbonna Vivian Ifeoma , Kanmodi Kehinde , Olalere Toluwani , Obazenu Lawson , Adebayo Oladimeji
Published: August 2021

Coronavirus disease 2019 (COVID-19) accounts for over 92 million confirmed cases worldwide, with over 2.06 million deaths. In the past year, more than 290 candidate vaccines have been tested; COVID-19 vaccine development was sped up, with shortened timeline, due to the urgent global need in the face of the pandemic. In addition, people with the highest risk of contracting the disease, such as health workers with a high risk of exposure, elderlies, and people with underlying comorbidities, were prioritized with vaccination rollout. The article narratively reviewed original and review articles available on PubMed and Google Scholar related to the theme to provide up-to-date information. The different templates developed and studied for COVID-19 vaccines include the whole-virus vaccine, viral vector vaccine, nucleic acid (deoxyribonucleic acid and ribonucleic acid), and protein subunit vaccine. Myths impede vaccine uptake in this part of the globe. Adopting these myths leads to sharing and spreading, which negatively impacts the prevention of COVID-19 and vaccine uptake. Adverse event following immunizations (AEFIs) is classified based on severity, from minor to severe. The minor ones are common events that pose no potential health risks to the receiver of the vaccine. The type determines the safety profile, severity, and frequency of AEFIs observed with the vaccine administration. Overall, this pandemic has heightened the global level of threat awareness; it has also provided motivation to prepare for future pandemics by developing new vaccines.
Knowledge, Attitude, Practice and Predictors of Preventive Practices Toward COVID-19 among Healthcare Workers in Ogbomoso, Nigeria
Authors: Adeoye Philip Adewale , Oke Gabriel Ilerioluwa , Fadele Kehinde Precious , Awotunde Titilope Abisola
Published: August 2021

Background:

COVID-19 quickly assumed a global epidemic with its attendant health, socio-political and economic impacts. Healthcare workers are particularly at increasing risk of being infected and transmitting the virus. This study assessed knowledge, attitude, practice and predictors of preventive practices toward COVD-19 among healthcare workers in Ogbomoso, Nigeria.

Study Design:

Cross-sectional study. Data were collected online among health workers across health facilities in Ogbomoso. Factors associated with good practices were analyzed using Chi-square. Predictors of good preventive practices were determined by multivariate binary logistic regression. The level of statistical significance was determined to be at P < 0.05.

Results:

There were 132 study participants; with an average age of 31 years. Fifty-eight percent were medical laboratory scientists. Levels of good knowledge, attitude, and practices were 59.1%, 58.3%, and 38.6%, respectively. Eight-seven percent of respondents sourced COVID-19 related information via the mass media. Ninety-four percent of respondents will not stay at home if sick because of work. Age, profession, and knowledge are significantly associated with COVID-19 preventive practices. The predictors (Model II) of good COVID-19 preventive practices include being a laboratory scientist (odds ratio [OR]: 2.44 [95% confidence interval (CI): 1.05, 6.71]; P = 0.039), working in primary health facility (OR: 4.72 [95%CI: 1.08, 20.67]; P = 0.039) and having good COVID-19 knowledge (OR: 3.71 [95%CI: 1.49–9.925]; P = 0.005).

Conclusion:

Our study has shown the predictors of good COVID-19 preventive practices among healthcare workers and the need for policy and practice change as it relates to COVID-19 infection prevention and mitigation among healthcare workers.
Awareness and Acceptance of Harm Reduction Services in a Nigerian Psychiatric Hospital
Authors: Onu Justus Uchenna , Chinawa Francis C. , Nduanya Ujunwa C. , Maduka Nonso B. C. , Iyidobi Theclar Ogochukwu , Igwe Monday N.
Published: August 2021

Introduction:

There are burgeoning data on harm reduction services (HRSs) as a viable alternative to the traditional means of dealing with substance abuse in the developed countries. Despite the numerous benefits, its awareness and acceptability in developing economies such as Nigeria have been constrained by sociocultural and political factors. However, the specific patients' and caregivers' barriers to its uptake have not been evaluated in Nigeria.

Aim:

This study aimed to examine the awareness and acceptability of HRS among patients and caregivers in Enugu, South-Eastern Nigeria.

Materials and Methods:

This study was a descriptive survey of patients with substance use disorders and their family caregivers at Enugu. Awareness and acceptance of HRS were assessed using questions adapted from the harm reduction survey.

Results:

The majority of patients and caregivers (76.5% and 88.2%, respectively) were not aware of HRS. Compared to family caregivers, the patients were more likely to rate themselves more favourably disposed to accepting HRS (U = 2750.00, p < 0.001). The common reasons given for accepting HRS among the patients were centered on autonomy and the unrealistic nature of abstinence. The reasons for rejection by family caregivers were hinged on encouraging use, community resistance, and scandals to the family.

Conclusion:

This study highlighted the low awareness of both patients and their caregivers to the availability of HRS as a treatment option in Nigeria. It is hoped that these findings will provide some invaluable data to policy makers and clinicians in designing policies and in public education to improve service utilization by the public.