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131 result(s) for "Hasan, Jafar"
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Nanoscale Topography on Black Titanium Imparts Multi-biofunctional Properties for Orthopedic Applications
We have developed a chlorine based reactive ion etching process to yield randomly oriented anisotropic nanostructures that render the titanium metal surface ‘black’ similar to that of black silicon. The surface appears black due to the nanostructures in contrast to the conventional shiny surface of titanium. The nanostructures were found to kill bacteria on contact by mechanically rupturing the cells as has been observed previously on wings of certain insects. The etching was optimized to yield nanostructures of ≈1 μm height for maximal bactericidal efficiency without compromising cytocompatibility. Within 4 hours of contact with the black titanium surface, 95% ± 5% of E. coli, 98% ± 2% of P. aeruginosa , 92% ± 5% of M. smegmatis and 22% ± 8% of S. aureus cells that had attached were killed. The killing efficiency for the S. aureus increased to 76% ± 4% when the cells were allowed to adhere up to 24 hours. The black titanium supported the attachment and proliferation of human mesenchymal stem cells and augmented osteogenic lineage commitment in vitro . Thus, the bioinspired nanostructures on black titanium impart multi-biofunctional properties toward engineering the next-generation biomaterials for orthopedic implants.
Antibacterial surfaces: the quest for a new generation of biomaterials
In this review we attempt to clarify the notion of what is meant by the term antibacterial surfaces and categorise the approaches that are commonly used in the design of antibacterial surfaces. Application of surface coatings and the modification of the surface chemistry of substrata are generally considered to be a chemical approach to surface modification (as are surface polymerisation, functionalisation, and derivatisation), whereas, modification of the surface architecture of a substrate can be considered a physical approach. Here, the antifouling and bactericidal effects of antibacterial surfaces are briefly discussed. Finally, several recent efforts to design a new generation of antibacterial surfaces, which are based on mimicking the surface nanotopography of natural surfaces, are considered.
Selective bactericidal activity of nanopatterned superhydrophobic cicada Psaltoda claripennis wing surfaces
The nanopattern on the surface of Clanger cicada ( Psaltoda claripennis ) wings represents the first example of a new class of biomaterials that can kill bacteria on contact based solely on its physical surface structure. As such, they provide a model for the development of novel functional surfaces that possess an increased resistance to bacterial contamination and infection. Their effectiveness against a wide spectrum of bacteria, however, is yet to be established. Here, the bactericidal properties of the wings were tested against several bacterial species, possessing a range of combinations of morphology and cell wall type. The tested species were primarily pathogens, and included Bacillus subtilis , Branhamella catarrhalis , Escherichia coli , Planococcus maritimus , Pseudomonas aeruginosa , Pseudomonas fluorescens , and Staphylococcus aureus . The wings were found to consistently kill Gram-negative cells (i.e., B . catarrhalis , E . coli , P . aeruginosa , and P . fluorescens ), while Gram-positive cells ( B . subtilis , P . maritimus , and S . aureus ) remained resistant. The morphology of the cells did not appear to play any role in determining cell susceptibility. The bactericidal activity of the wing was also found to be quite efficient; 6.1 ± 1.5 × 10 6 P . aeruginosa cells in suspension were inactivated per square centimeter of wing surface after 30-min incubation. These findings demonstrate the potential for the development of selective bactericidal surfaces incorporating cicada wing nanopatterns into the design.
Chronic kidney disease biomarkers and mortality among older adults: A comparison study of survey samples in China and the United States
Among older adults in China and the US, we aimed to compare the biomarkers of chronic-kidney-diseases (CKD), factors associated with CKD, and the correlation between CKD and mortality. China and the US. Cross-sectional and prospective cohorts. We included 2019 participants aged 65 and above from the Chinese Longitudinal Healthy Longevity Study (CLHLS) in 2012, and 2177 from US National Health and Nutrition Examination Survey (NHANES) in 2011-2014. Urinary albumin, urinary creatinine, albumin creatinine ratio (ACR), serum creatinine, blood urea nitrogen, plasma albumin, uric acid, and estimated glomerular filtration rate (eGFR). CKD (ACR ≥ 30 mg/g or eGFR< 60 ml/min/1.73m2) and mortality. Logistic regression and Cox proportional hazard models. Covariates included age, sex, race, education, income, marital status, health condition, smoking and drinking status, physical activity and body mass index. Chinese participants had lower levels of urinary albumin, ACR, and uric acid than the US (mean: 25.0 vs 76.4 mg/L, 41.7 vs 85.0 mg/g, 292.9 vs 341.3 μmol/L). In the fully-adjusted model, CKD was associated with the risk of mortality only in the US group (hazard ratio [HR], 95% CI: 2.179, 1.561-3.041 in NHANES, 1.091, 0.940-1.266 in CLHLS). Compared to eGFR≥90, eGFR ranged 30-44 ml/min/1.73m2 was only associated with mortality in the US population (HR, 95% CI: 2.249, 1.141-4.430), but not in the Chinese population (HR, 95% CI: 1.408, 0.884-2.241). The elderly participants in the US sample had worse CKD-related biomarker levels than in China sample, and the association between CKD and mortality was also stronger among the US older adults. This may be due to the biological differences, or co-morbid conditions.
Molecular Organization of the Nanoscale Surface Structures of the Dragonfly Hemianax papuensis Wing Epicuticle
The molecular organization of the epicuticle (the outermost layer) of insect wings is vital in the formation of the nanoscale surface patterns that are responsible for bestowing remarkable functional properties. Using a combination of spectroscopic and chromatographic techniques, including Synchrotron-sourced Fourier-transform infrared microspectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS) depth profiling and gas chromatography-mass spectrometry (GCMS), we have identified the chemical components that constitute the nanoscale structures on the surface of the wings of the dragonfly, Hemianax papuensis. The major components were identified to be fatty acids, predominantly hexadecanoic acid and octadecanoic acid, and n-alkanes with even numbered carbon chains ranging from C14 to C30. The data obtained from XPS depth profiling, in conjunction with that obtained from GCMS analyses, enabled the location of particular classes of compounds to different regions within the epicuticle. Hexadecanoic acid was found to be a major component of the outer region of the epicuticle, which forms the surface nanostructures, and was also detected in deeper layers along with octadecanoic acid. Aliphatic compounds were detected throughout the epicuticle, and these appeared to form a third discrete layer that was separate from both the inner and outer epicuticles, which has never previously been reported.
Integration of a multicomponent intervention for hypertension into primary healthcare services in Singapore—A cluster randomized controlled trial
Despite availability of clinical practice guidelines for hypertension management, blood pressure (BP) control remains sub-optimal (<30%) even in high-income countries. This study aims to assess the effectiveness of a potentially scalable multicomponent intervention integrated into primary care system compared to usual care on BP control. A cluster-randomized controlled trial was conducted in 8 government clinics in Singapore. The trial enrolled 916 patients aged ≥40 years with uncontrolled hypertension (systolic BP (SBP) ≥140 mmHg or diastolic BP (DBP) ≥90 mmHg). Multicomponent intervention consisted of physician training in risk-based treatment of hypertension, subsidized losartan-HCTZ single-pill combination (SPC) medications, nurse training in motivational conversations (MCs), and telephone follow-ups. Usual care (controls) comprised of routine care in the clinics, no MC or telephone follow-ups, and no subsidy on SPCs. The primary outcome was mean SBP at 24 months' post-baseline. Four clinics (447 patients) were randomized to intervention and 4 (469) to usual care. Patient enrolment commenced in January 2017, and follow-up was during December 2018 to September 2020. Analysis used intention-to-treat principles. The primary outcome was SBP at 24 months. BP at baseline, 12 and 24 months was modeled at the patient level in a likelihood-based, linear mixed model repeated measures analysis with treatment group, follow-up, treatment group × follow-up interaction as fixed effects, and random cluster (clinic) effects. A total of 766 (83.6%) patients completed 2-year follow-up. A total of 63 (14.1%) and 87 (18.6%) patients in intervention and in usual care, respectively, were lost to follow-up. At 24 months, the adjusted mean SBP was significantly lower in the intervention group compared to usual care (-3.3 mmHg; 95% CI: -6.34, -0.32; p = 0.03). The intervention led to higher BP control (odds ratio 1.51; 95% CI: 1.10, 2.09; p = 0.01), lower odds of high (>20%) 10-year cardiovascular risk score (OR 0.67; 95% CI: 0.47, 0.97; p = 0.03), and lower mean log albuminuria (-0.22; 95% CI: -0.41, -0.02; p = 0.03). Mean DBP, mortality rates, and serious adverse events including hospitalizations were not different between groups. The main limitation was no masking in the trial. A multicomponent intervention consisting of physicians trained in risk-based treatment, subsidized SPC medications, nurse-delivered motivational conversation, and telephone follow-ups improved BP control and lowered cardiovascular risk. Wide-scale implementation of a multicomponent intervention such as the one in our trial is likely to reduce hypertension-related morbidity and mortality globally. Trial Registration: Clinicaltrials.gov NCT02972619.
Biopsychosocial experiences and coping strategies of elderly ESRD patients: a qualitative study to inform the development of more holistic and person-centred health services in Singapore
Background As the incidence and prevalence rates of end stage renal disease (ESRD) rise globally, a disproportionate increase has been observed in the elderly population. Singapore has the fifth highest incidence of treated ESRD worldwide, with the upward trend of ESRD being most apparent among those aged 70 years and older. Although it is well-documented that ESRD patients suffer an impaired quality of life compared to the general population, there is limited research focusing on the unique experiences and needs of elderly ESRD patients in Asian populations. To address the knowledge gap, this study seeks to explore the impact of ESRD and dialysis on the quality of life of elderly (≥70 years old) ESRD patients in Singapore and examine the coping strategies utilised by these patients. Methods This qualitative study involved semi-structured, in-depth interviews with 7 peritoneal dialysis patients, 5 haemodialysis patients, 4 patients on non-dialysis supportive care and 7 caregivers in Singapore. Interviews were conducted in English, Chinese, and Malay and fully transcribed. QSR NVivo 11 software was used for analysis. Results Participants reported that ESRD and dialysis had an impact on three highly interconnected areas of their quality of life: (a) biological/physical (general symptoms, neuromuscular problems, skin problems and poor sleep quality); (b) psychological (depressive symptoms, anxiety and fears, stress and negative self-perceptions); and (c) social (increased dependence on family and loss of social life). There were four key strategies that participants used to cope with these biopsychosocial challenges: (a) family support (financial, practical and emotional support); (b) religious/spiritual support (experiencing gratitude/contentment, the power of prayer and belonging to a faith community); (c) avoidance (cognitive avoidance and distraction techniques); and (d) acceptance (positive thinking and problem solving). Conclusions This study has provided insights into the biopsychosocial impact of ESRD and dialysis, as well as cultural and religious factors that shape the experiences and coping mechanisms of elderly ESRD patients and caregivers in Singapore, which can be used to further the development and implementation of more holistic and person-centred services to help each patient achieve a better quality of life.
Solitary Osteochondroma at Unusual Sites: A Case Report and Literature Review
Osteochondromas (OCs) are bone lesions composed of cartilaginous and medullary bone capped with hyaline cartilage. OCs result from the separation of epiphyseal growth plate cartilage, pushing through the periosteal bone cuff. They commonly appear as pedunculated or sessile masses in the metaphysis of long bones and are the most common benign bone tumors. While rare in the scapula, OCs can occur there. Symptoms may arise from fractures, osseous abnormalities, or potential malignant transformation, especially in the presence of hereditary multiple exostoses (HME). The estimated rate of malignant transformation in solitary lesions is 1%, whereas in hereditary multiple OCs, it can reach up to 3-5%. We report a case of a 10-year-old female who presented with a gradually progressive swelling on the back of her right scapula. This progressive growth has been observed over the course of the past two years accompanied by mild pain. The pain was intermittent and did not affect her daily activities. On examination, a hard, tender, non-mobile swelling of approximately 2 × 2 cm was found over the right scapula. The patient had a normal range of motion in the shoulder and scapulothoracic regions. In conclusion, since solitary scapular OCs are extremely rare, they are quite common when associated with HME. This study aimed to increase awareness of the unusual site of OCs. Furthermore, we have included a full account of the surgical therapy we administered to this patient in order to assist future surgeons who may come across similar conditions.
Balancing the books and values: the interplay of ethics in tertiary accounting education
The study explored students' perception regarding how ethical considerations are integrated into accounting curricula at the tertiary level in Ghana, guided by both the International Education Standards (IES) and the CIPP model. It questions the effectiveness of accounting education in adequately preparing students to face ethical challenges, with a specific focus on tertiary institutions in Ghana. Using a positivist paradigm and a cross-sectional survey methodology, the study targeted final-year undergraduate accounting students in public tertiary institutions. Multiple sampling techniques, including proportionate, stratified, and simple sampling, were utilized to select 307 students for the study. The collected data underwent analysis using descriptive statistics (frequency, percentage, mean and standard deviation) and inferential statistics (multiple linear regression). The study found a significant 70% alignment between the curricula of the sampled universities and the requirements of IES 4. Moreover, it revealed a limited use of participative teaching approaches in ethics within accounting lessons. Additionally, the findings revealed that students have a low perception of the effectiveness of accounting curricula in addressing their professional ethical needs. This perception was influenced by factors such as age, religiosity and, to a lesser extent, gender.
Chronic kidney disease biomarkers and mortality among older adults: A comparison study of survey samples in China and the United States
ObjectivesAmong older adults in China and the US, we aimed to compare the biomarkers of chronic-kidney-diseases (CKD), factors associated with CKD, and the correlation between CKD and mortality.SettingChina and the US.Study designCross-sectional and prospective cohorts.ParticipantsWe included 2019 participants aged 65 and above from the Chinese Longitudinal Healthy Longevity Study (CLHLS) in 2012, and 2177 from US National Health and Nutrition Examination Survey (NHANES) in 2011-2014.OutcomesUrinary albumin, urinary creatinine, albumin creatinine ratio (ACR), serum creatinine, blood urea nitrogen, plasma albumin, uric acid, and estimated glomerular filtration rate (eGFR). CKD (ACR ≥ 30 mg/g or eGFR< 60 ml/min/1.73m2) and mortality.Analytical approachLogistic regression and Cox proportional hazard models. Covariates included age, sex, race, education, income, marital status, health condition, smoking and drinking status, physical activity and body mass index.ResultsChinese participants had lower levels of urinary albumin, ACR, and uric acid than the US (mean: 25.0 vs 76.4 mg/L, 41.7 vs 85.0 mg/g, 292.9 vs 341.3 μmol/L). In the fully-adjusted model, CKD was associated with the risk of mortality only in the US group (hazard ratio [HR], 95% CI: 2.179, 1.561-3.041 in NHANES, 1.091, 0.940-1.266 in CLHLS). Compared to eGFR≥90, eGFR ranged 30-44 ml/min/1.73m2 was only associated with mortality in the US population (HR, 95% CI: 2.249, 1.141-4.430), but not in the Chinese population (HR, 95% CI: 1.408, 0.884-2.241).ConclusionsThe elderly participants in the US sample had worse CKD-related biomarker levels than in China sample, and the association between CKD and mortality was also stronger among the US older adults. This may be due to the biological differences, or co-morbid conditions.