Exogenous Melatonin Use in University Students: A Cross-Sectional Survey.

To assess the prevalence of melatonin use and its perceived benefits among university students in different specialties in Saudi Arabia, a cross-sectional survey was conducted between March and June 2023. Data about demographics, time of melatonin use, perceived reasons for exogenous melatonin use, melatonin use in relation to exam periods, perceived safety, and adverse effects was gathered. Of 380 students, ~52% reported using exogenous melatonin for sleep disorders. Most participants reported using melatonin during and after exam periods. Additionally, several (n = 157; 75.4%) believed that its use was safe. The predominant use patterns were daily and as needed, and this study observed a higher rate of use compared with previous studies in Saudi Arabia. The most frequently reported adverse effect was headache (n = 36; 37.5%). A significant number of undergraduate male students in health specialties used melatonin. A high rate of melatonin use was noted during exam periods, which was attributed to sleep deprivation. Additionally, a significant number of students from private universities reported using exogenous melatonin. Melatonin use is common among university students. Future research should use a reliable psychometric measure to test its effect on university students' sleep quality and quantity.

Community Pharmacists' Knowledge, Attitudes and the Perceived Safety and Effectiveness of Melatonin Supplements: A Cross-Sectional Survey.

Melatonin, which is classified as a dietary supplement by the Saudi Food and Drug Authority, is used to manage sleep disorders. In this study, community pharmacists' knowledge and attitudes about dispensing melatonin supplements and the perceived safety and effectiveness of melatonin were assessed. A cross-sectional survey of community pharmacists in Jeddah, Saudi Arabia was conducted from March-June 2023. Community pharmacists' knowledge and attitudes towards prescribing and dispensing melatonin supplements, the methods of dispensing melatonin supplements (prescription, over the counter, self-administered), indications, ages of users, dosage forms, and adverse drug reactions related to melatonin use among consumers were surveyed using a questionnaire. Potential participants were approached face to face, a questionnaire was administered to those agreeing to participate in the study, and responses were recorded electronically. The response rate of the 300 community pharmacists who participated in this study was 83.5%. The mean age of participants was 33.6 years, and 89.3% (n = 268) of community pharmacists reported dispensing melatonin supplements. Self-medication and over the counter (n = 213; 71.2%) were the most common dispensing and prescribing patterns (p = 0.001). Awareness rates about melatonin supplement pharmacokinetics and pharmacodynamics among community pharmacists were 38% and 37%, respectively. Despite its popularity, community pharmacists reported relatively low rates of awareness of melatonin supplement pharmacokinetics and pharmacodynamics. Further attention to this issue is needed.

The multifactorial role of vanillin in amelioration of aluminium chloride and D-galactose induced Alzheimer's disease in mice.

The onset and progression of Alzheimer's disease (AD) are influenced by a variety of factors. These include oxidative stress, overexpression of acetylcholinesterase (AChE), depletion of acetylcholine levels, increased beta-secretase mediated conversion of Amyloid Precursor Protein (APP) to Amyloid Beta (Abeta), accumulation of Abeta oligomers, decrease in Brain Derived Neurotrophic factor (BDNF) and accelerated neuronal apoptosis due to elevated levels of caspase-3. The currently available therapeutic approaches are inadequate in affecting these pathological processes except maybe the overexpression of AChE (AChE inhibitors like donepezil, rivastigmine). There is an urgent need to develop disease modifying pharmacotherapeutic interventions which have appreciable safety and cost effectiveness. From previously reported in vitro studies and a preliminary assessment of neuroprotective effect in scopolamine induced dementia-like cognitive impairment in mice, vanillin has been used as the compound of interest in the present study. Vanillin, a phytoconstituent, has been used in humans, safely, in the form of a flavouring agent for various foods, beverages, and cosmetics. Owing to its chemical nature i.e. being a phenolic aldehyde, it has an additional antioxidant property that is congruent to the desirable characteristics that are sought in a suitable novel anti-AD agent. In our study, vanillin proved to have a nootropic effect in healthy Swiss albino mice as well as an ameliorative effect in aluminium chloride and D-galactose induced AD model in mice. Apart from tackling oxidative stress, vanillin was found to reduce the levels of AChE, beta secretase, caspase-3, enhance degradation of Abeta plaques and elevate the levels of BDNF, in cortical and hippocampal regions. Vanillin is a promising candidate for being incorporated into the search for safe and effective anti-AD molecules. However, further research might be needed to warrant its application clinically.

Entropy optimization and response surface methodology of blood hybrid nanofluid flow through composite stenosis artery with magnetized nanoparticles (Au-Ta) for drug delivery application.

Entropy creation by a blood-hybrid nanofluid flow with gold-tantalum nanoparticles in a tilted cylindrical artery with composite stenosis under the influence of Joule heating, body acceleration, and thermal radiation is the focus of this research. Using the Sisko fluid model, the non-Newtonian behaviour of blood is investigated. The finite difference (FD) approach is used to solve the equations of motion and entropy for a system subject to certain constraints. The optimal heat transfer rate with respect to radiation, Hartmann number, and nanoparticle volume fraction is calculated using a response surface technique and sensitivity analysis. The impacts of significant parameters such as Hartmann number, angle parameter, nanoparticle volume fraction, body acceleration amplitude, radiation, and Reynolds number on the velocity, temperature, entropy generation, flow rate, shear stress of wall, and heat transfer rate are exhibited via the graphs and tables. Present results disclose that the flow rate profile increase by improving the Womersley number and the opposite nature is noticed in nanoparticle volume fraction. The total entropy generation reduces by improving radiation. The Hartmann number expose a positive sensitivity for all level of nanoparticle volume fraction. The sensitivity analysis revealed that the radiation and nanoparticle volume fraction showed a negative sensitivity for all magnetic field levels. It is seen that the presence of hybrid nanoparticles in the bloodstream leads to a more substantial reduction in the axial velocity of blood compared to Sisko blood. An increase in the volume fraction results in a noticeable decrease in the volumetric flow rate in the axial direction, while higher values of infinite shear rate viscosity lead to a significant reduction in the magnitude of the blood flow pattern. The blood temperature exhibits a linear increase with respect to the volume fraction of hybrid nanoparticles. Specifically, utilizing a hybrid nanofluid with a volume fraction of 3% leads to a 2.01316% higher temperature compared to the base fluid (blood). Similarly, a 5% volume fraction corresponds to a temperature increase of 3.45093%.

Knowledge and Attitude of Saudi Physicians Toward Cannabidiol for Pediatric Epilepsy: A Cross-Sectional Study.

Background Epilepsy is one of the most common neurological diseases. Various institutions have shown an interest to investigate the role of cannabidiol (CBD) in treating pediatric epilepsy. CBD is a chemical extracted from the cannabis plant and lacks the euphoria-inducing characteristic. Despite the FDA approval, the physicians' attitude toward CBD is controversial. Therefore, we aim to measure physicians' knowledge and acceptance of the use of CBD in managing epilepsy patients in Saudi Arabia. Objectives The aim of this study is to measure the knowledge and attitude of physicians regarding CBD use in pediatric epilepsy. Methods In this cross-sectional study, a validated electronic survey was distributed in the period between September 2021 and October 2021 among pediatricians and neurologists at King Abdulaziz Medical City. The survey consisted of four sections: demographics, the perceived knowledge regarding CBD, the knowledge test, and the attitudes toward CBD. Three-scoring systems were established to assess these sections. Results A total of 94 participants were included in this study; 50% of them were males, 81.9% of the participants were in the pediatric field, 13.8% were in the field of neurology, and 4.3% were pediatric neurologists. As for the professional tenure, approximately half of the participants were residents/trainees. Overall, respondents tend to have low perceived knowledge (94.7%) and attitude (93.6%) regarding CBD use. The perceived knowledge and attitude levels were found to be significantly associated with specialty (p < 0.001 and p = 0.001, respectively). Pediatric neurologists had a significantly higher self-assessment score, while pediatricians had the lowest attitude level (p < 0.05). For the knowledge test, surprisingly only one respondent answered all questions correctly, and age was found to be significantly associated with knowledge score (p = 0.001). Conclusion This study demonstrates that physicians have poor knowledge and attitude levels regarding the usage of CBD in pediatric epilepsy. Therefore, more education is highly suggested before the introduction of this medication to Saudi patients.

Acute Disseminated Encephalomyelitis Post COVID-19 Pneumonia.

Acute disseminated encephalomyelitis (ADEM) is a monophasic condition characterized by inflammation of the central nervous system. Besides multiple sclerosis, optic neuropathy, acute transverse myelitis, and neuromyelitis optica spectrum disorder, ADEM is a primary inflammatory demyelinating disorder of the central nervous system. It is estimated that approximately three-quarters of cases of encephalomyelitis occur after an infection or immunization, where the onset of neurological disease is coincident with a febrile event. Here, we report an 80-year-old woman with coronavirus disease pneumonia who developed sudden onset of decreased level of consciousness, focal seizure, and right-side weakness. Magnetic resonance imaging (MRI) of the brain showed a multifocal hemorrhagic lesion with surrounding edema, suggesting ADEM. An electroencephalogram (EEG) revealed moderate generalized encephalopathy. The patient received alternating pulse steroids with plasma exchange for five days. Subsequently, her Glasgow coma scale score continued to decrease, and thus, she required inotropic support until she expired.

Treatment Beliefs and Practices towards Low Back Pain among Teachers in Asir Region, Saudi Arabia-A Cross-Sectional Study.

The prevalence of low back pain (LBP) is increasing exponentially, with this public health issue affecting over 70% of the population. However, sedentary careers exacerbate the problem further, with professions such as teaching disproportionately affected. In addition, the general population does not seek interventions from medical professionals for LBP; instead, they opt to manage their pain with over-the-counter medications, such as sedatives. The purpose of this study was to explore practices and beliefs related to back pain treatment among schoolteachers in the Asir region. This cross-sectional study included a sample of 312 teachers from the Asir region, with data collected regarding the prevalence of back pain, management approaches, and beliefs surrounding medical interventions. Chi-square or exact tests defined the association between variables, with significance determined at p < 0.05. Our results revealed that 67.3% of Saudi Arabian teachers experienced LBP within the last two months, with a continuous condition representing 36.7% of cases. This study identified several different treatment modalities the participants use to manage their pain, including sedatives, best rest, kaiy (traditional cautery), and local adhesives, with sedatives being the most employed method. It also highlighted that increased daily working hours and total days worked significantly increased the prevalence of LBP (p < 0.05). Although a considerable number of the included teachers were highly educated, with some teaching experience, they had a poor level of awareness and an incorrect attitude towards pain management. Enhanced efforts should be made to improve teachers' awareness regarding back pain causes and management methods.

Comparing Surgical Techniques for Meniscal Tears: A Systematic Review of Radiographic and Functional Outcomes.

Meniscal tears are a common orthopedic injury. The management approaches for meniscal tears include both surgical and non-surgical procedures; however, the majority of the surgeons opt for various surgical interventions. This systematic review aimed to compare the outcomes of different surgical techniques for meniscal tears. The systemic search was carried out in various databases including PubMed, Web of Science, CINAHL, and Scopus. Studies that investigated surgical techniques for meniscal repair and published between 2010 to 2023 were included. Out of the 7,421 potential studies identified from databases and Google Scholar search, only 17 studies were included in our systemic review. The follow-up periods ranged from 6 weeks to 123 months. Adverse effects were reported in some studies, including joint line tenderness, swelling, and loss of flexion, while others reported no significant adverse events. Pull-out repair and refixation techniques demonstrated better clinical outcomes and slower arthritic progression than partial meniscectomy. Mason-Allen stitches and simple stitches yielded comparable results, and both inside-out and all-inside techniques had similar clinical and functional outcomes. This systematic review provides valuable insights into the outcomes of different surgical techniques for meniscal tears. Further studies with longer follow-up periods may help assess the long-term effectiveness of these surgical techniques.

Knowledge and Attitude Regarding Monkeypox Virus among Physicians in Saudi Arabia: A Cross-Sectional Study.

The growing incidence of human monkeypox cases emphasizes the significance of prevention, early detection, and prompt responses for healthcare providers. The aim of this study was to assess the knowledge and attitudes toward monkeypox infection among physicians, a frontline healthcare worker group, in Saudi Arabia. A cross-sectional survey assessing knowledge and attitudes towards monkeypox infection on multiple-item scales was sent to physicians in Saudi Arabia. The associations between independent factors and either knowledge or attitude were assessed. The final analysis included 398 participants. Approximately 55% of the surveyed participants had a "good knowledge" score about human monkeypox. The adjusted logistic regression analysis showed that being a female physician, working in the private sector, and having information on human monkeypox during medical school or residency years were the only factors associated with a good level of knowledge about human monkeypox. However, physicians' knowledge and attitudes regarding monkeypox infection are inadequate and influenced by various factors. There is a significant knowledge gap between the therapeutic management of monkeypox and its vaccination. Training and knowledge assessments are important, especially when studies show significant improvement in related and specific knowledge.

Metabolic and hormonal changes after laparoscopic sleeve gastrectomy in pediatric population: An observational study.

Introduction: Despite the growing popularity of laparoscopic sleeve gastrectomy (SG) for managing severe obesity in children, adolescents, and adults, there is a paucity of studies reporting the effects of SG on metabolic and hormonal outcomes in pediatric populations. Methodology: In this single-centre, retrospective study, we assessed nutritional biomarkers (hemoglobin, ferritin, iron profile, Vitamin B12, Vitamin D, and calcium), glucose homeostasis indicators (C-peptide, HbA1C, and random blood glucose), blood lipids (triglycerides and cholesterol components), hormones involved in the hypothalamic-pituitary-adrenal axis (cortisol and adrenocorticotropic hormone), and thyroid hormones (T3, T4, thyroid-stimulating hormone, and parathyroid hormone) preoperatively and 12-month after SG in children aged 5-15 years. Results: This study included 64 adolescents (mean age = 11.2 ± 2.3 years) who underwent laparoscopic SG. Significant reduction in circulatory C-peptide (-62.1%; p = 0.005), HbA1C (-10.9%; p = 0.001), random blood glucose (-15.4%; p = 0.036), and triglycerides (-39.4%; p = 0.003) were observed postoperatively at 12 months compared to baseline. Although we did not observe any changes in cortisol levels, adrenocorticotropic hormone levels declined significantly by -40.9% postoperatively (p = 0.033). However, cholesterol components, thyroid hormones, and nutritional biomarkers remained unchanged from baseline. Conclusions: Consistent with prior literature, our study demonstrates improvement or resolution of diabetes and hypertriglyceridemia in the year following SG. However, given that blood cholesterol components, nutritional biomarkers, and thyroid profiles remained unchanged warrants long-term monitoring of nutritional, metabolic, and endocrine factors in adolescents undergoing laparoscopic SG. To the best of our knowledge, this is the first study reporting the effects of SG on thyroid and hypothalamic-pituitary-adrenal axis hormones in pediatric populations.

Assessment of Knowledge of Monkeypox Viral Infection among the General Population in Saudi Arabia.

Monkeypox is re-emerging and spreading over the world, posing a serious threat to human life, especially in non-endemic countries, including Saudi Arabia. Due to the paucity of research on knowledge about monkeypox in Saudi Arabia, this study aimed to evaluate the general population's knowledge of monkeypox in a sample of the country. A web-based cross-sectional survey was conducted from 25 May 2022 to 15 July 2022. Participants' knowledge about monkeypox on a 23-item scale and socio-demographic characteristics were gathered in the survey. Pearson's Chi-square test was used to compare knowledge level (categorized into high and low) and explanatory variables. Out of 480, only 48% of the respondents had high knowledge (mean score > 14). Participants' age, marital status, residential region, living in the urban area, education level, employment status, being a healthcare worker, income, and smoking status were significantly associated with the level of knowledge about monkeypox (p < 0.01). Overall, social media (75.0%) was the most frequently reported source from where participants obtained monkeypox-related information followed by TV and radio (45.6%), family or friend (15.6%), and healthcare provider (13.8%). We found that overall knowledge of monkeypox infection was slightly poor among the Saudi population. These findings highlight the urgent need for public education on monkeypox to promote awareness and engage the public ahead of the outbreak.

Effect of Laparoscopic Sleeve Gastrectomy on HbA1C Level in Children with Type 2 Diabetes Mellitus.

Background and Objectives: A third of the American adult population is currently pre-diabetic/morbidly obese and is, therefore, at an elevated risk for developing type 2 diabetes. Unfortunately, such a condition does not spare children from also developing morbid obesity, where incidence rates of childhood obesity-coupled with type 2 diabetes-are markedly elevated. Laparoscopic sleeve gastrectomy (LSG) is gradually becoming the novel benchmark in bariatric surgery for the treatment of morbid obesity and associated co-morbidities, also within pediatric cases. However, no comprehensive study has been conducted in children that emphasizes the effect of LSG on HbA1C levels within such a patient population suffering from type 2 diabetes. Aim: Since HbA1C is a major biomarker for type 2 diabetes progression, this study aimed to identify any dysregulated serum levels for this key molecular player (together with other parameters), for post-surgical monitoring of the beneficial metabolic effects of LSG surgery on type 2 diabetes amelioration/remission within pediatric patients. Materials and Methods: A total of 64 pediatric patients, ranging in age from 5 to 14 years old, were enrolled in this retrospective study. Multiple laboratory-based analyses datasets were also collected from individual study participants, including HbA1C and random blood sugar (RBS). All participating patients were designated for undergoing laparoscopic sleeve gastrectomy, as per standardized surgical protocols and each participant was followed-up for two years post-surgery. Laboratory investigations were re-performed in order to identify any major variations in clinical parameters. Results: HbA1c was significantly reduced among children, from 6.0 ± 0.8 (pre-LSG) to 5.4 ± 0.4 post-surgery, with a reduction rate of 10.9% (p = 0.001). Furthermore, RBS significantly decreased from 102.9 ± 34.0 (pre-LSG) to 87.1 ± 17.3 post- surgery, with a reduction rate of 15.4% (p = 0.036). Conclusions: This study provides further concrete evidence for the beneficial metabolic influence provided by LSG surgery on morbidly obese, childhood-aged patient populations, with effectiveness in reducing co-morbidity progress, in the form of type 2 diabetes, through the reduction in HbA1c levels within such patients post-surgery.

Uptake of COVID-19 Booster Dose among Saudi Arabian Population.

Backgroundand objectives: Although several vaccines have been produced and administered around the world, new SARS-CoV-2 worsened the COVID-19 infection risk and impacted the initial vaccine dosage effectiveness. Based on studies indicating that the third and fourth COVID-19 vaccine doses significantly reduced COVID-19 transmission, Saudi Arabia has been administering COVID-19 booster vaccine doses to its citizens. The purpose of this study was to evaluate the uptake of the COVID-19 vaccine booster in relation to the socio-demographic characteristics and other associated factors among the Saudi population. Materials and Methods: This study was an online analytical cross-sectional study using a self-administered questionnaire. Pearson Chi-square test and multiple logistic regression analyses were used to determine factors associated with the uptake of COVID-19 booster dose vaccines. Results: A total of 2332 responded to our study. Overall, 527 (22.6%) participants had received a booster dose. An age of 55 and above (aOR: 5.415; 95% CI: 2.719-10.783), Eastern region (aOR: 2.513; 95% CI: 1.566-4.033), history of influenza vaccination at annual intervals (aOR: 2.387; 95% CI: 1.730-3.293), the first dose of Moderna vaccine (aOR: 1.324; 95% CI: 1.160-1.510), and cancer (aOR: 2.161; 95% CI: 1.218-3.879) were independent factors most associated with a higher uptake of the COVID-19 vaccine booster dose. In contrast, the second dose of Moderna vaccine (aOR: 0.794; 95% CI: 0.683-0.922), AstraZeneca vaccine (aOR: 0.691; 95% CI: 0.509-0.939), strong symptoms from side effects after the second dose of the COVID-19 vaccine (aOR: 0.615; 95% CI: 0.404-0.935) were independent factors most associated with a lower uptake of the COVID-19 vaccine booster dose. Conclusions: Our findings indicate low COVID-19 vaccine booster uptake. This necessitates the need for strategies to address discouraging factors of the COVID-19 vaccine booster dose uptake and engage the Saudi population to raise awareness about the importance of the booster dose.

New-Onset Henoch-Schonlein Purpura after COVID-19 Infection: A Case Report and Review of the Literature.

Extrapulmonary manifestations of COVID-19 infection include a wide spectrum of cutaneous, endocrine, and cardiovascular complications. We report three cases of new-onset Henoch-Schonlein purpura (HSP) in COVID-19 infected children that were diagnosed and treated in Abha Maternity and Children Hospital, Saudi Arabia, between 28th July 2020 and 10th August 2020. All three cases were males younger than 5 years of age that presented with Henoch-Schonlein purpura characteristic rash and arthralgia without a recent history of any infection, especially respiratory infections. They all tested positive for COVID-19. At the time of the admission, pediatric COVID-19 cases were managed conservatively and we ruled out any other diagnosis before establishing the diagnosis of Henoch-Schonlein purpura according to the clinical picture. The three boys responded significantly to prednisolone and achieved a rapid recovery. We present the clinical scenario and laboratory tests of these children along with pictures of the lesions detected in each case.

Prevalence and factors associated with mental health problems in Saudi general population during the coronavirus disease 2019 pandemic: A systematic review and meta-analysis.

This systematic review and meta-analysis generates evidence of the prevalence and associated factors of common mental disorders (i.e., depression, anxiety, and stress) related to the pandemic among the Saudi general population. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a comprehensive literature search was performed in the respective databases (e.g., PubMed, Scopus, Web of Science), from 22 July to 17 August 2021, and identified a total of 220 articles. Adhering to the inclusion criteria (i.e., original research concerning the prevalence and/or associated factors of depression and/or anxiety and/or stress disorders among the general Saudi population, published in English peer-reviewed journals), 15 studies were included in this review which consisted of a total of 262,656 participants. The overall prevalence of depression, anxiety, and stress was 30% (95% confidence interval [CI]: 22% to 38%, I2  = 99.58%), 20% (95% CI: 16% to 24%, I2  = 99.32%), and 29% (95% CI: 11% to 47%, I2  = 99.76%), respectively. Risk factors of mental health problems were found to be female sex, younger age group, single/divorced marital status, lower education, lower income, non-Saudis, unemployment status, students, being in a small family and living with elderly of the sociodemographic factors. Smokers, less physical activities, lower resilience, reduced immune status, chronic health problems, and psychiatric illness history were associated with a higher degree of mental health problems. In addition, coronavirus disease 2019 (COVID-19)-related risk factors of mental illness included lack of knowledge, fear, worry and concern, family member or friends' infection or death, lockdown restrictions, quarantine, confirmed or suspected of COVID-19 infection, and even pandemic effects. In conclusion, appropriate mental health preventive approaches for the Saudi general people are highly needed, where this review can be worthy of help by providing in detailed information to the respective authorities.

Electroosmosis-modulated bio-flow of nanofluid through a rectangular peristaltic pump induced by complex traveling wave with zeta potential and heat source.

Electrokineticmicroperistaltic pumps are important biomechanical devices that help in targeted drugging of sick body parts. This article is focused on mathematical modeling and analysis of some important aspect of such flows in a rectangular duct with wall properties. Effects of zeta potential, heat source, and deby length are also studied. Carbon nanotubes (CNTs) in the Newtonian base fluid are assumed as drugging material. A comparison of single-walled CNTs and multiwalled CNTs is also presented. It is considered that the walls are flexible and encapsulating the region with limited permeability. The defined flow problem is modeled and analyzed analytically for the transport of CNT-water nanofluid. It is accepted that the flow is steady, nonturbulent, and propagating waves do have a considerably longer wavelength when compared to amplitude. The conditions and assumptions lead to a model of coupled partial differential equations of order two. The exact results using the eigenfunction expansion method are procured and shown accordingly. The predictions about the behavior of important parameters are displayed for single-walled CNT and multiwalled CNT-water nanofluidic behavior-using figures. The impact of sundry parametersis are analyzed. The application of the current study involved a transporting/targeted drug delivery system using peristaltic micropumps and magnetic fields in pharmacological engineering.

Stability theory of nano-fluid over an exponentially stretching cylindrical surface containing microorganisms.

This research is emphasized to describe the stability analysis in the form of dual solution of the flow and heat analysis on nanofluid over an exponential stretching cylindrical surface containing microorganisms. The research is also implemented to manifest the dual profiles of velocity, temperature and nanoparticle concentration in the effect of velocity ratio parameter ([Formula: see text]). Living microorganisms' cell are mixed into the nanofluid to neglect the unstable condition of nano type particles. The governing equations are transformed to non-linear ordinary differential equations with respect to pertinent boundary conditions by using similarity transformation. The significant differential equations are solved using build in function bvp4c in MATLAB. It is seen that the solution is not unique for vertical stretching sheet. This research is reached to excellent argument when found results are compared with available result. It is noticed that dual results are obtained demanding on critical value ([Formula: see text]), the meanings are indicated at these critical values both solutions are connected and behind these critical value boundary layer separates thus the solution are not stable.

Room-Temperature Quantum Emitter in Aluminum Nitride.

A device that is able to produce single photons is a fundamental building block for a number of quantum technologies. Significant progress has been made in engineering quantum emission in the solid state, for instance, using semiconductor quantum dots as well as defect sites in bulk and two-dimensional materials. Here we report the discovery of a room-temperature quantum emitter embedded deep within the band gap of aluminum nitride. Using spectral, polarization, and photon-counting time-resolved measurements we demonstrate bright (>105 counts s-1), pure (g (2)(0) < 0.2), and polarized room-temperature quantum light emission from color centers in this commercially important semiconductor.

Analytical estimations of temperature in a living tissue generated by laser irradiation using experimental data.

This paper presents an analytical approach associated with Laplace transformation, experimental temperature data, and a sequential concept over time to obtain the thermal damage and the temperature in a living tissue due to laser irradiation. The analytical solutions in the Laplace domain are appreciably obtainable. The thermal damage to the tissue is completely assessed by the denatured protein range using the formulation of Arrhenius. Numerical outcomes for temperatures and the thermal damages are graphically introduced. Besides, the comparison between the numerical computations and the existing experimental study shows that a current mathematical model is an effective tool for evaluating the biological heat transfer in biological tissues.

On mechanically driven biological stimulus for bone remodeling as a diffusive phenomenon.

In the past years, many attempts have been made in order to model the process of bone remodeling. This process is complex, as it is governed by not yet completely understood biomechanical coupled phenomena. It is well known that bone tissue is able to self-adapt to different environmental demands of both mechanical and biological origin. The mechanical aspects are related to the functional purpose of the bone tissue, i.e., to provide support to the body and protection for the vitally important organs in response to the external loads. The many biological aspects include the process of oxygen and nutrients supply. To describe the biomechanical process of functional adaptation of bone tissue, the approach commonly adopted is to consider it as a 'feedback' control regulated by the bone cells, namely osteoblasts and osteoclasts. They are responsible for bone synthesis and resorption, respectively, while osteocytes are in charge of 'sensing' the mechanical status of the tissue. Within this framework, in  Lekszycki and dell'Isola (ZAMM - Zeitschrift für Angewandte Mathematik und Mechanik 92(6):426-444, 2012), a model based on a system of integro-differential equations was introduced aiming to predict the evolution of the process of remodeling in surgically reconstructed bones. The main idea in the aforementioned model was to introduce a scalar field, describing the biological stimulus regulating the interaction among all kinds of bone cells at a macroscale. This biological field was assumed to depend locally on certain deformation measures of the (reconstructed) bone tissue. However, biological knowledge suggests that this stimulus, after having been produced, 'diffuses' in bone tissue, so controlling in a complex way its remodeling. This means that the cells which are target of the stimulus may not be located in the same place occupied by the cells producing it. In this paper, we propose a model which intends to explain the diffusive nature of the biological stimulus to encompass the time-dependent and space-time displaced effects involved in bone reconstruction process. Preliminary numerical simulations performed in typical cases are presented. These numerical case studies suggest that the 'diffusive' model of stimulus is promising: we plan to continue these kinds of studies in further investigations.