Yubi-Wakka Test for Sarcopenia Screening in the Community: Comparative Agreement, Diagnostic Performance and Validity with Calf Circumference Measurements.

BACKGROUND: Screening tools such as calf circumference (CC) and Yubi-wakka (finger-ring) test have been recognized as effective tools by Asian Working Group for Sarcopenia 2019 (AWGS'19) for sarcopenia screening but their comparative agreement, diagnostic performance and validity are unclear. OBJECTIVES: This study aims to determine: (i)agreement between calf and finger-ring circumference, (ii)diagnostic performance for low muscle mass and AWGS'19 sarcopenia diagnosis, (iii)correlation with muscle mass, strength, and physical performance, and (iv)association with frailty, life space mobility and physical activity. METHODS: We studied 187 healthy community-dwelling older adults (mean age=66.8+7.0years) from the GERILABS-2 study. CC was measured via (i) both calves in sitting and standing positions, and (ii) Yubi-wakka test by encircling the thickest part of the non-dominant calf with index fingers and thumbs of both hands. We performed Cohen's kappa to check for agreement, area under receiver operating characteristic curve (AUC) to compare diagnostic performance, partial correlations adjusted for age and gender to compare convergent validity, and logistic regression to determine predictive validity for outcome measures. RESULTS: Sarcopenia prevalence was 24.0% (AWGS'19). Yubi-wakka identified 16.6% of participants as screen-positive ("smaller"), showing moderate agreement only with non-dominant sitting CC measurements (k=0.421,p<0.001) and having lower diagnostic performance in determining low muscle mass (AUC=0.591 vs 0.855-0.870,p<0.001; sensitivity=57.1% vs 75.5-90.8%; specificity=58.4% vs 70.8-80.9%) and sarcopenia diagnosis (AUC=0.581 vs 0.788-0.818,p<0.001; sensitivity=55.6% vs 57.5-71.8%; specificity=74.4% vs 75.6-88.9%) compared to CC measurements. Yubi-wakka correlated significantly with muscle mass, grip strength and knee extension but not physical performance. When adjusted for age, gender and hypertension, Yubi-wakka was significantly associated with frailty (OR=3.96,95%CI:1.09-14.38), life space mobility (OR=2.38,95%CI:1.08-5.24) and physical activity (OR=2.50,95%CI:1.07-5.86). DISCUSSION AND CONCLUSIONS: Yubi-wakka provides a self-administered, low-cost and practicable community screening tool for sarcopenia. Our study affirmed the convergent and predictive validity of Yubi-wakka, albeit with lower sensitivity and specificity in diagnostic performance compared to CC measurements.

Stunting and food insecurity among children from low socioeconomic family during COVID-19 pandemic in urban area in Selangor.

INTRODUCTION: Food insecurity is often link with nutritional status. An increased rate of food insecurity can have a severe impact on children's growth. During the COVID-19 outbreak, little is known regarding its effect on food security and nutritional status, especially concerning vulnerable groups such as children. The purpose of this study was to assess household food security status, children's nutritional status along with their association, and the determinants of food insecurity during the COVID-19 pandemic. MATERIALS AND METHODS: This cross-sectional study was conducted from May to July 2022 in urban areas in Selangor among children aged less than two years old from B40 households using purposive sampling through both online surveys and face-to-face interviews. There were 112 children aged < 2 years old from B40 households participating in this study. The data obtained on maternal sociodemographic, Household Food Insecurity Scale (HFIAS), and children's anthropometric measurements were analysed by using the WHO Anthro Survey, descriptive analysis, Person's Chisquare test and Fischer's exact test. RESULTS: The prevalence of food insecurity was more significant than the prevalence of food secured, at 55.4% and 44.6% respectively. The stunting among the children rated at 34.8%, followed by 7.2% of the sample found underweight, 7.8% (BAZ) and 16.1% (BAZ) of them were wasted, and overweight & obese, proportionately. This study discovered that household size was the sole determinant of household food security status. This finding suggested that size of a household influenced the odds of a household being food insecure. CONCLUSION: The findings of this study provide insights into how the COVID-19 pandemic have an impact on children's nutritional status especially those from low-income and bigger size households. Therefore, more thorough and effective interventions should be designed particularly targeting this urban poor community to enhance their nutritional status and health.

A Multicenter Retrospective Cohort Study on Management Protocols and Clinical Outcomes After ABO-incompatible Kidney Transplantation in India.

BACKGROUND: There is no robust evidence-based data for ABO-incompatible kidney transplantation (ABOiKT) from emerging countries. METHODS: Data from 1759 living donor ABOiKT and 33 157 ABO-compatible kidney transplantations (ABOcKT) performed in India between March 5, 2011, and July 2, 2022, were included in this retrospective, multicenter (n = 25) study. The primary outcomes included management protocols, mortality, graft loss, and biopsy-proven acute rejection (BPAR). RESULTS: Protocol included rituximab 100 (232 [13.18%]), 200 (877 [49.85%]), and 500 mg (569 [32.34%]); immunoadsorption (IA) (145 [8.24%]), IVIG (663 [37.69%]), and no induction 200 (11.37%). Mortality, graft loss, and BPAR were reported in 167 (9.49%), 136 (7.73%), and 228 (12.96%) patients, respectively, over a median follow-up of 36.3 mo. In cox proportional hazard model, mortality was higher with IA (hazard ratio [HR]: 2.53 [1.62-3.97]; P < 0.001), BPAR (HR: 1.83 [1.25-2.69]; P = 0.0020), and graft loss (HR: 1.66 [1.05-2.64]; P = 0.0310); improved graft survival was associated with IVIG (HR: 0.44 [0.26-0.72]; P = 0.0010); higher BPAR was reported with conventional tube method (HR: 3.22 [1.9-5.46]; P < 0.0001) and IA use (HR: 2 [1.37-2.92]; P < 0.0001), whereas lower BPAR was reported in the prepandemic era (HR: 0.61 [0.43-0.88]; P = 0.008). Primary outcomes were not associated with rituximab dosing or high preconditioning/presurgery anti-A/anti-B titers. Incidence of overall infection 306 (17.39%), cytomegalovirus 66 (3.75%), and BK virus polyoma virus 20 (1.13%) was low. In unmatched univariate analysis, the outcomes between ABOiKT and ABOcKT were comparable. CONCLUSIONS: Our largest multicenter study on ABOiKT provides insights into various protocols and management strategies with results comparable to those of ABOcKT.

Emergence of Canonical and Noncanonical Genomic Variants following In Vitro Exposure of Clinical Mycobacterium tuberculosis Strains to Bedaquiline or Clofazimine.

In Mycobacterium tuberculosis, bedaquiline and clofazimine resistance occurs primarily through Rv0678 variants, a gene encoding a repressor protein that regulates mmpS5/mmpL5 efflux pump gene expression. Despite the shared effect of both drugs on efflux, little else is known about other pathways affected. We hypothesized that in vitro generation of bedaquiline- or clofazimine-resistant mutants could provide insight into additional mechanisms of action. We performed whole-genome sequencing and determined phenotypic MICs for both drugs on progenitor and mutant progenies. Mutants were induced through serial passage on increasing concentrations of bedaquiline or clofazimine. Rv0678 variants were identified in both clofazimine- and bedaquiline-resistant mutants, with concurrent atpE SNPs occurring in the latter. Of concern was the acquisition of variants in the F420 biosynthesis pathway in clofazimine-resistant mutants obtained from either a fully susceptible (fbiD: del555GCT) or rifampicin mono-resistant (fbiA: 283delTG and T862C) progenitor. The acquisition of these variants possibly implicates a shared pathway between clofazimine and nitroimidazoles. Pathways associated with drug tolerance and persistence, F420 biosynthesis, glycerol uptake and metabolism, efflux, and NADH homeostasis appear to be affected following exposure to these drugs. Shared genes affected by both drugs include Rv0678, glpK, nuoG, and uvrD1. Genes with variants in the bedaquiline resistant mutants included atpE, fadE28, truA, mmpL5, glnH, and pks8, while clofazimine-resistant mutants displayed ppsD, fbiA, fbiD, mutT3, fadE18, Rv0988, and Rv2082 variants. These results show the importance of epistatic mechanisms as a means of responding to drug pressure and highlight the complexity of resistance acquisition in M. tuberculosis.

Effects of Group-I Elements on Output Voltage Generation of ZnO Nanowires Based Nanogenerator; Degradation of Screening Effects by Oxidation of Nanowires.

Here, we report the successful incorporation of group I elements (K, Na, Li) to ZnO nanowires. Three distinct (2, 4, and 6 wt.%) doping concentrations of group I elements have been used to generate high piezoelectric voltage by employing a vertically integrated nanowire generator (VING) structure. X-ray photoelectron spectra (XPS) indicated the seepage of dopants in ZnO nanowires by substitution of Zn. Shallow acceptor levels (LiZn, NaZn, KZn) worked as electron trapping centers for intrinsically n-type ZnO nanowires. Free moving electrons caused a leakage current through the nanowires and depleted their piezoelectric potential. Reverse leakage current is a negative factor for piezoelectric nanogenerators. A reduction in reverse leakage current signifies the rise in output voltage. A gradual rise in output voltage has been witnessed which was in accordance with various doping concentrations. K-doped ZnO nanowires have generated voltages of 0.85 V, 1.48 V, and 1.95 V. For Na-doped ZnO nanowires, the voltages were 1.23 V, 1.73 V, and 2.34 V and the voltages yeilded for Li-doped ZnO nanowires were 1.87 V, 2.63 V, and 3.54 V, respectively. Maximum voltage range has been further enhanced by the surface enrichment (oxidized with O2 molecules) of ZnO nanowires. Technique has been opted to mitigate the screening effect during an external stress. After 5 h of oxidation in a sealed chamber at 100 ppm, maximum voltage peaks were pronounced to 2.48 V, 3.19 V, and 4.57 V for K, Na, and Li, respectively. A low-cost, high performance mechanical transducer is proposed for self-powered devices.

Evaluation of taste active peptides and amino acids from anchovy proteins in fish sauce by in silico approach.

Enzymatic activity and microbial fermentation play a prominent role in the bioconversion of complex muscle tissue into smaller units of peptides and amino acids, possibly contribute to sensory properties. Thus, this study screens and evaluate anchovy proteins with taste-active peptides and amino acids by the reaction of multiple enzymes using an in silico approach. Information about sensory components was provided based on an in silico analysis using tools available in the BIOPEP-UWM database. Proteins from anchovy, namely myosin heavy chain 6 alpha, myosin light chain 1, cytochrome B, and NADH ubiquinone oxidoreductase, were subjected to in silico digestion with the combination of 23 enzymes. This led to the release of taste-active peptides and amino acids, including umami, sweet, salty, sour, and bitter sensory properties. The combination of multiple enzymes released a more significant number of taste-active peptides and amino acids for both myosins compared to other proteins.

Post-cardiac surgery outcomes following COVID-19 infection in unvaccinated patients.

The provision of cardiac surgery services nationwide has been affected by the COVID-19 pandemic. We noticed a high COVID-19 mortality rate in unvaccinated patients who were diagnosed with COVID-19 after recent cardiac surgery. All the patients were tested negative for COVID-19 before surgery. We conducted a review of our hospital data and reported our findings. We identified 15 patients and reported 7 deaths (46.7%). All the patients died from COVID-19 or its complications. We recommend that cardiac centres actively promote vaccination before cardiac surgery and also enhance infection control measures to prevent nosocomial infections.

Clinical Profile and Outcome in Long-term Hemodialysis: A Comparative Study of Hospital-based Versus Standalone Units.

Introduction: Chronic hemodialysis (CHD) remains the most "resorted to" renal-replacement option in India. Pursuit for accessible and affordable dialysis has resulted in setting up standalone centers (SACs). We need more Indian data on the profile of CHD population and outcome of SAC compared to hospital-based units (HBUs). Material and Methods: We analyzed the clinical profile of patients on CHD for >5 years, compared the outcome between HBU and SAC, and analyzed the factors associated with mortality. Patients initiated between January 1, 2006 and December 31, 2012 and who have survived 5 years on CHD at HBU or SAC were enrolled and followed up prospectively for 2 years. Their clinical and biochemical profile, comorbidities, long-term complications, and mortality were analyzed. Results: The study included 137 patients, 41 (30%) from HBU and 96 (70%) from SACs. In both groups, the patients were predominantly male, aged 51-70 yrs, diabetic, unplanned initiation through catheters, and had average-dialysis vintage between 83 and 85 months. SAC had more patients with hemoglobin (> 11 gm/dL) and hyperparathyroidism with elevated SAP levels (P < 0.05). Both groups had comparable iron stores, serum calcium, and phosphorus. Comparable between groups, infections, coronary artery disease, and access complications accounted for most hospitalizations and sudden cardiac death and sepsis accounted for most mortality. A trend of better survival was seen in SAC. Multivariate analysis showed anemia, DM and hospitalizations were associated with mortality. Conclusion: We conclude that the outcomes of long-term CHD at SACs are not inferior to HBUs. Anemia, diabetes, and hospitalizations were associated with overall mortality. Benefits of SACs in cost, QOL, and employment opportunities need to be studied in the Indian context.

Hemodialysis-related Portal-systemic Encephalopathy: A Rare Cause of Recurrent Encephalopathy among Patients on Maintenance Hemodialysis.

Portal-systemic venous shunts can rarely develop without any intrinsic liver diseases. However, the cause of shunt formation in these cases are not very clear. Literature suggests that hemodialysis can precipitate symptoms in patients with asymptomatic portal-systemic venous shunts (PSVS). Rare presentations of recurrent encephalopathy due to PSVS in the absence of liver dysfunction has been described in patients undergoing hemodialysis. We report a rare case of recurrent Hemodialysis Related Porto-Systemic Encephalopathy (HRPSE) in a 50-year old male during maintenance hemodialysis secondary to a PSVS between the portal vein and left renal vein. Shunt embolism by an 18 mm Amplatzer vascular plug (AVR II) was done and follow up CT showed complete occlusion of collaterals. Post-procedure, he is undergoing thrice-weekly Hemodialysis of 4 hours duration till date with no further incidence of encephalopathy. Our report indicates that recurrent encephalopathy can occur in dialysis patients due to symptomatic PSVS and HRPSE should be considered even in non-cirrhotic cases for early detection and effective management.

Longitudinal Association between Sarcopenia and Cognitive Impairment among Older Adults in Rural Malaysia.

Sarcopenia is a condition that is highly prevalent among older adults. This condition is linked to numerous adverse health outcomes, including cognitive impairment that impairs healthy ageing. While sarcopenia and cognitive impairment may share a common pathway, limited longitudinal studies exist to show the relationship between these two conditions. Therefore, this study aimed to examine the longitudinal association between sarcopenia and cognitive impairment. This is a cohort study among older adults residing in Kuala Pilah District, Negeri Sembilan, Malaysia. There were 2404 respondents at the baseline and 1946 respondents at one-year follow-up. Cognitive impairment was determined using Mini-mental State Examination scores. Sarcopenia was identified using the Asian Working Group for Sarcopenia 2019 criteria, gait speed was measured using a 4-meter gait test, handgrip strength was assessed using Jamar handheld dynamometer, and appendicular skeletal muscle mass was measured using bioelectrical impedance analysis. Generalized estimating equation (GEE) was used to determine the longitudinal association between sarcopenia and cognitive impairment, presented as relative risk (RR) and its 95% confidence interval. The prevalence of sarcopenia was 5.0% (95% CI 4.00-5.90), and severe sarcopenia was 3.60% (95% CI 2.84-4.31). Upon adjusting for covariates, older adults with sarcopenia have an 80 per cent increased risk of cognitive impairment compared to those without (RR 1.80; 95% CI 1.18-2.75). Similarly, severe sarcopenia was found to significantly increase the risk of cognitive impairment by 101 per cent in the adjusted model (RR 2.01; 95% CI 1.24-3.27). Our study showed that sarcopenia, severe sarcopenia, low physical activity, depressive symptoms, hearing impairment and chronic pain were associated with a higher risk of cognitive impairment among community-dwelling older adults. Therefore, early intervention to prevent sarcopenia, depressive symptoms, hearing impairment, chronic pain, and higher physical activity among older adults is recommended.

A Pragmatic Approach to the Management of Severe Awake Bruxism in an Adolescent with Cerebral Palsy and Global Developmental Delay.

Cerebral palsy is a neurological and motor condition characterised by muscle balance and posture impairments. Bruxism and malocclusion were frequently observed in patients with cerebral palsy, in contrast to other oral anomalies. The report outlines how severe awake bruxism is managed in a 16-year-old Korean boy who has nonverbal spastic cerebral palsy and global developmental delay. The treatment protocol involved the fabrication of soft occlusal splints of three and four millimetres in thickness, followed by the placement of stainless-steel crowns on all first permanent molars whilst video recording and a bruxism diary was kept. Fixed restorations demonstrate increased endurance in withstanding bruxism force in persons who are dependent on their caretaker.

Validation of Cardiac Surgery-Associated Neutrophil Gelatinase-Associated Lipocalin Score for Prediction of Cardiac Surgery-Associated Acute Kidney Injury.

BACKGROUND: The Cardiac Surgery-Associated Neutrophil Gelatinase-Associated Lipocalin (CSA-NGAL) score has been developed to stratify patients with cardiac surgery-associated acute kidney injury (CSA-AKI). Its predictive power needs to be validated to guide clinical decision for such high-risk patients. METHODS: A prospective study was conducted on 637 consecutive adult patients who developed postoperative AKI after cardiac surgery with cardiopulmonary bypass. AKI was defined according to Kidney Disease: Improving Global Outcomes criteria (KDIGO). The CSA-NGAL score was calculated. Assessment of the diagnostic performance of the scoring model was performed by area under the receiver operating curve analysis. RESULTS: The area under the curve for the postoperative Urinary NGAL showed an area under the curve ([standard error (SE)] 0.80 (0.38); p<0.001; 95% CI 0.72-0.87). Its sensitivity for CSA-AKI in the first 24 hours was 66% and specificity was 80% (cut-off value 300.1 ng/mL). There was a positive correlation between NGAL score and KDIGO criteria, with a significant increase in postoperative mean Urinary NGAL values as the KDIGO stage increased. CONCLUSION: The CSA-NGAL score has a high sensitivity, specificity and positive predictive value that can translate into improved outcomes and resource allocation. It is believed that adding it to the existing clinical scoring systems for AKI prediction will be productive.

Epidemiology and clinical profiles of cutaneous graft versus host disease in allogeneic peripheral blood stem cell transplantation.

INTRODUCTION: The epidemiology of cutaneous graft versus host disease (GVHD) in allogeneic peripheral blood stem cell transplantation (PBSCT) in Malaysia has not been described. MATERIALS AND METHODS: We retrospectively analysed 691 allogeneic PBSCT patients between 2010-2017 in two centers. RESULTS: The prevalence of cutaneous GVHD was 31.4% (217/691). No associations were detected with race, age or gender of donor and recipients. Cutaneous GVHD was associated with host cytomegalovirus (CMV) seropositivity (p<0.01), conditioning (p<0.01), GVHD prophylaxis (p=0.046) and survival (p<0.01). Majority developed the acute form (58.1%;126/217). Biopsies in 20.7% (45/217) showed 55.6% positivity for GVHD. Overall, involvement was non-severe. A majority demonstrated complete response (CR) to first-line corticosteroids (70.0%;152/217). Secondline therapies (extracorporeal phototherapy (ECP), psolaren ultraviolet A (PUVA), mycophenolate, tumour necrosis factor (TNF) inhibitors, interleukins inhibitors, or CD20 monoclonal antibodies) were required in 65/217, with 38.5% CR. Second-line therapy was associated with gender (p=0.042), extra-cutaneous GVHD (p=0.021), treatment outcomes (p=0.026) and survival (p=0.048). Mortality in cutaneous GVHD was 24.0% with severe sepsis being the leading cause at Day 100 (7.8%) and 5-years (7.8%), and relapsed disease at 2-years (32.7%). In steroid refractoriness, severe GVHD caused 30.8% mortality. In cutaneous GVHD, survival at Day 100 was 95.4%; 80.2% at 2-years and 73.1% at 5-years. The median survival in cutaneous GVHD was significantly shorter at 55 months, compared to those without GVHD at 69 months (p=0.001). CONCLUSION: Cutaneous involvement is the commonest clinical manifestation of GVHD. A larger national study is warranted to further analyse severity and outcome of multiorgan GVHD, and factors associated with steroid refractoriness.

Disentangling the Relationship between Frailty and Intrinsic Capacity in Healthy Community-Dwelling Older Adults: A Cluster Analysis.

BACKGROUND: Frailty and intrinsic capacity (IC) are distinct but interrelated constructs. Uncertainty remains regarding how they are related and interact to influence health outcomes. We aim to understand the relationship between frailty and IC by identifying subgroups based on frailty criteria and IC domains and studying one-year outcomes. METHODS: We studied 200 independent community-dwelling older adults (mean age 67.9±7.9 years, Modified Barthel Index (MBI) score 99±2.6). Frailty was defined by modified Fried criteria. Scores (range: 0-2) were assigned to individual IC domains (cognition, psychological, locomotion, and vitality) to yield a total IC score of 8. To identify subgroups, two-step cluster analysis was performed with age, frailty and IC domains. Cluster associations with one-year outcomes (frailty, muscle strength (grip strength, repeated chair stand test), physical performance (gait speed, Short Physical Performance Battery), function (MBI) and quality-of-life (EuroQol (EQ)-5D)) were examined using multiple linear regression adjusted for age, gender and education. RESULTS: Three distinct clusters were identified - Cluster 1: High IC/Robust (N=74, 37%); Cluster 2: Intermediate IC/Prefrail (N=73, 36.5%); and Cluster 3: Low IC/Prefrail-Frail (53, 26.5%). Comparing between clusters, IC domains, cognition, depressive symptoms, nutrition, strength and physical performance were least impaired in Cluster 1, intermediate in Cluster 2 and most impaired in Cluster 3. At one year, the proportion transitioning to frailty or remaining frail was highest in Cluster 3 compared to Cluster 2 and Cluster 1 (39% vs 6.9% vs 2.8%, P<0.001). Compared to Cluster 1, Cluster 3 experienced greatest declines in grip strength (ß=-4.1, P<.001), MBI (ß=-1.24, P=0.045) and EQ-5D utility scores (ß=-0.053, P=0.005), with Cluster 2 intermediate between Cluster 1 and Cluster 3. CONCLUSIONS: Amongst independent community-dwelling older adults, IC is complementary to frailty measures through better risk-profiling of one-year outcomes amongst prefrail individuals into intermediate and high-risk groups. The intermediate group merits follow-up to ascertain longer-term prognosis.

Antibacterial and Antifouling Properties of the Horseshoe Crab Carcinoscorpius rotundicauda.

<b>Background and Objective:</b> Horseshoe crabs are widely used in both traditional and modern pharmaceutical applications. Most of the previous studies on horseshoe crabs focused on their blood which contains hemolymph and amoebocyte lysate. This study aimed to determine the potential antibacterial and antifouling properties of different extracts from the carapace and the book gills of <i>Carcinoscorpius rotundicauda</i>. <b>Materials and Methods:</b> The crude extracts were subjected to the bioactivity tests using the disc-diffusion and the inhibition of biofilm-formation measurement assays, for both the antibacterial and antifouling activities respectively. <b>Results:</b> The results obtained indicated that the carapace extracts had stronger antibacterial and antifouling effects compared to the book gills extracts. Extracts obtained from the male displayed more activity compared to the extracts from the female with a few exceptions. Methanol and acetone carapace crude extracts showed the best overall performance. A sterol compound was isolated from the carapace acetone extracts of the male of <i>C. rotundicauda</i>. However, the compound did not display strong activity compared to the crude extract. The compound might be contributing to the observed activity with other components through a synergistic effect. <b>Conclusion:</b> The presence of antibacterial and antifouling activities in the carapace and book gills extracts could be added to the complexity of the defence mechanisms of horseshoe crabs. The results of this study, therefore, may contribute to the knowledge of the defence mechanisms of <i>C. rotundicauda</i>. Further research is needed to determine the bioactivities of other parts of the animal and to explore their potential applications.

Passively mode locked thulium and thulium/holmium doped fiber lasers using MXene Nb2C coated microfiber.

As a result of the emergence of two-dimensional (2D) materials for various opto-electronics applications, a new class of materials named MXenes have been attracting interests due to their outstanding nonlinear properties. In this work, an MXene niobium carbide (Nb2C) was proposed and demonstrated as a saturable absorber to induce mode-locking in thulium- and thulium/holmium-doped fiber lasers. The Nb2C solution was first prepared using the liquid exfoliation technique, and then deposited onto a microfiber for integration into the laser cavity. Stable mode-locking operation was observed in both laser cavities, where the center wavelengths of the laser were recorded at 1944 nm for the TDFL and 1950 nm for the THDFL. The generated pulses in the TDFL and THDFL had repetition rates of 9.35 and 11.76 MHz respectively, while their corresponding pulse widths were 1.67 and 1.34 ps. Both of the lasers were highly stable, having SNR values of more than 52 dB and showed no major fluctuations when tested for their long-term stabilities. The results demonstrate an excellent performance of the Nb2C as a saturable absorber, offering opportunities to further explore MXenes for future photonics devices.

Entropy Generation and Exergy Analysis of Premixed Fuel-Air Combustion in Micro Porous Media Burner.

The performance of porous media micro-burners plays an important role in determining thermal efficiency and improving our daily life. Nowadays, a lot of scholars are actively involved in this research area and ongoing studies are still being carried out due to the burners' excellent performance. The exergy efficiency and entropy generation of a porous media burner are strongly dependent on the characteristics of the flame and its thermal behavior. In this study, a single-layer and double-layer porous media form were constructed to investigate the effects of various types of porous foam arrangement in a cylindrical burner. The burner was operated using premixed butane-air combustion with an inner diameter of 23 mm and a length of 100 mm. The experiments were carried out in rich fuel conditions with an equivalence ratio, φ ranging from 1.3 to 2.0. The results showed significant improvement in the thermal and exergy efficiency with an increase in the equivalence ratio in a double-layer compared with a single-layer. The peak temperature recorded was 945.21 °C at φ = 1.3 for a porcelain single-layer, and the highest exergy efficiency was 83.47% at φ = 2.0 for an alumina-porcelain double-layer burner. It was also found that the average temperature of the burner wall decreased with an increase in the equivalence ratios for PMB2 and PMB4, whereas the average wall temperature for PMB3 was largely unaffected by the equivalence ratios. The total entropy generation rate reached the highest value at φ = 2.0 for all PMB configurations, and the highest percentage increase for total entropy generation rate was 46.09% for PMB1. The exergy efficiency for all burners was approximately similar with the highest exergy efficiency achieved by PMB4 (17.65%). In addition, the length and location of the flame with thermal distribution was significantly affected by the equivalence ratio between the single-layer and double-layer porous material. Overall, a double-layer porous media burner showed the best performance calculated based on the second law of thermodynamics when compared with other configurations, and it is ideal for domestic application.