Tetraalkylammonium salts (TAS) in solar energy applications - A review on in vitro and in vivo toxicity.

Tetraalkylammonium salt (TAS) is an organic salt widely employed as a precursor, additive or electrolyte in solar cell applications, such as perovskite or dye-sensitized solar cells. Notably, Perovskite solar cells (PSCs) have garnered acclaim for their exceptional efficiency. However, PSCs have been associated with environmental and health concerns due to the presence of lead (Pb) content, the use of hazardous solvents, and the incorporation of TAS in their fabrication processes, which significantly contributes to environmental and human health toxicity. As a response, there is a growing trend towards transitioning to safer and biobased materials in PSC fabrication to address these concerns. However, the potential health hazards associated with TAS necessitate a thorough evaluation, considering the widespread use of this substance. Nevertheless, the overexploitation of TAS could potentially increase the disposal of TAS in the ecosystem, thus, posing a major health risk and severe pollution. Therefore, this review article presents a comprehensive discussion on the in vitro and in vivo toxicity assays of TAS as a potential material in solar energy applications, including cytotoxicity, genotoxicity, in vivo dermal, and systemic toxicity. In addition, this review emphasizes the toxicity of TAS compounds, particularly the linear tetraalkyl chain structures, and summarizes essential findings from past studies as a point of reference for the development of non-toxic and environmentally friendly TAS derivatives in future studies. The effects of the TAS alkyl chain length, polar head and hydrophobicity, cation and anion, and other properties are also included in this review.

Separable mixing: The general formulation and a particular example focusing on mask efficiency.

The aim of this short note is twofold. First, we formulate the general Kermack-McKendrick epidemic model incorporating static heterogeneity and show how it simplifies to a scalar Renewal Equation (RE) when separable mixing is assumed. A key general feature is that all information about the heterogeneity is encoded in one nonlinear real valued function of a real variable. Next, we specialize the model ingredients so that we can study the efficiency of mask wearing as a non-pharmaceutical intervention to reduce the spread of an infectious disease. Our main result affirms that the best way to protect the population as a whole is to protect yourself. This qualitative insight was recently derived in the context of an SIR network model. Here, we extend the conclusion to proportionate mixing models incorporating a general function describing expected infectiousness as a function of time since infection.

Ten-year territory-wide trends in the utilisation and clinical outcomes of extracorporeal membrane oxygenation in Hong Kong.

INTRODUCTION: The utilisation of extracorporeal membrane oxygenation (ECMO) has been rapidly increasing in Hong Kong. This study examined 10-year trends in the utilisation and clinical outcomes of ECMO in Hong Kong. METHODS: We retrospectively reviewed the records of all adult patients receiving ECMO who were admitted to the intensive care units (ICUs) of public hospitals in Hong Kong between 2010 and 2019. Temporal trends across years were assessed using the Mann-Kendall test. Observed hospital mortality was compared with the Acute Physiology and Chronic Health Evaluation (APACHE) IV-predicted mortality. RESULTS: The annual number of patients receiving ECMO increased from 18 to 171 over 10 years. In total, 911 patients received ECMO during the study period: 297 (32.6%) received veno-arterial ECMO, 450 (49.4%) received veno-venous ECMO, and 164 (18.0%) received extracorporeal cardiopulmonary resuscitation. The annual number of patients aged ≥65 years increased from 0 to 47 (27.5%) [P for trend=0.001]. The median (interquartile range) Charlson Comorbidity Index increased from 1 (0-1) to 2 (1-3) [P for trend<0.001] while the median (interquartile range) APACHE IV score increased from 90 (57-112) to 105 (77-137) [P for trend=0.003]. The overall standardised mortality ratio comparing hospital mortality with APACHE IV-predicted mortality was 1.11 (95% confidence interval=1.01-1.22). Hospital and ICU length of stay both significantly decreased (P for trend=0.011 and <0.001, respectively). CONCLUSION: As ECMO utilisation increased in Hong Kong, patients put on ECMO were older, more critically ill, and had more co-morbidities. It is important to combine service expansion with adequate resource allocation and training to maintain quality of care.

Exploring multiple stressor effects with Ecopath, Ecosim, and Ecospace: Research designs, modeling techniques, and future directions.

Understanding the cumulative effects of multiple stressors is a research priority in environmental science. Ecological models are a key component of tackling this challenge because they can simulate interactions between the components of an ecosystem. Here, we ask, how has the popular modeling platform Ecopath with Ecosim (EwE) been used to model human impacts related to climate change, land and sea use, pollution, and invasive species? We conducted a literature review encompassing 166 studies covering stressors other than fishing mostly in aquatic ecosystems. The most modeled stressors were physical climate change (60 studies), species introductions (22), habitat loss (21), and eutrophication (20), using a range of modeling techniques. Despite this comprehensive coverage, we identified four gaps that must be filled to harness the potential of EwE for studying multiple stressor effects. First, only 12% of studies investigated three or more stressors, with most studies focusing on single stressors. Furthermore, many studies modeled only one of many pathways through which each stressor is known to affect ecosystems. Second, various methods have been applied to define environmental response functions representing the effects of single stressors on species groups. These functions can have a large effect on the simulated ecological changes, but best practices for deriving them are yet to emerge. Third, human dimensions of environmental change - except for fisheries - were rarely considered. Fourth, only 3% of studies used statistical research designs that allow attribution of simulated ecosystem changes to stressors' direct effects and interactions, such as factorial (computational) experiments. None made full use of the statistical possibilities that arise when simulations can be repeated many times with controlled changes to the inputs. We argue that all four gaps are feasibly filled by integrating ecological modeling with advances in other subfields of environmental science and in computational statistics.

A review of heart valve disease research in Malaysia.

INTRODUCTION: Heart valve disease comprises a cluster of conditions affecting the aortic, mitral, pulmonary and tricuspid valves. This paper reviews all the research on heart valve disease in Malaysia published between the years 2000- 2016. METHODS: The methodology was based on the search process described in the paper, "Bibliography of clinical research in Malaysia: methods and brief results". The search databases included PubMed, Scopus and several Malaysian journals such as MyJurnal and UKM Journal Repository, by using the following keywords: (heart valve disease OR infective endocarditis OR rheumatic heart disease) and (Malaysia). RESULTS: In all 94 papers were identified of which 39 papers were selected and reviewed on the basis of their relevance. The local studies contributed to the knowledge and understanding of the epidemiology, aetiology, pathophysiology, clinical presentations, investigations, treatment, and outcomes of heart valve disease in the country. DISCUSSION: The clinical relevance of the studies performed in the country is discussed along with recommendations for future research.

Spatial and temporal variations of coastal microplastic pollution in Hong Kong.

Further to our 2015-16 investigation, this study revealed the repeated presence of microplastics (MPs) in the coastal environment (Deep Bay, Tolo Harbour, Tsing Yi and Victoria Harbour) of Hong Kong from July 2016 to March 2017. The highest level of MPs in coastal surface water (17,182 particles/100 m3) was detected in Tsing Yi. Microplastic abundance in sediments of different sites (59 to 225 plastic particles/kg), however, did not vary significantly. MPs in the size of ≤1 mm were predominated in surface waters (53.3% to 98.6%) and sediments (79.1% to 96.8%). MPs in the shape of pellets and fragments were prevalent in surface waters and sediments respectively. Seasonal pattern of microplastic pollution was consistently observed in Victoria Harbour and Tsing Yi, where the number of MPs was always higher in dry season than in wet season for two consecutive years.

Anomalous aortic origin of a coronary artery (AAOCA): A case report.

Anomalous Aortic Origin of a Coronary Artery (AAOCA) is a rare anomaly of the coronary artery with a considerable risk of sudden cardiac death due to ischaemia of the heart. Symptoms may include chest pain on exertion, breathlessness or dizziness. We encountered a case of a 46- year-old female who complained of exertional chest pain with a positive-stress test and subsequently diagnosed with AAOCA through CT angiography (CTA). She successfully underwent a coronary artery bypass graft (CABG) surgery using a saphenous vein graft with uneventful recovery. Right internal mammary artery (RIMA) was not used as it was flimsy and the flow was very poor.

A review of aortic disease research in Malaysia.

INTRODUCTION: Aortic disease includes conditions such as chronic aortic aneurysms, acute aortic syndromes and congenital aortic abnormalities, amongst others. This paper reviews all research on aortic disease performed in Malaysia and published between 2000-2016. METHODS: A literature search was conducted in PubMed, Scopus, MyJurnal and the UKM Journal Repository. The search process was based on a previously published methodology. The medical subject headings (MeSH) search terms used were "aortic", "aorta" and "Malaysia". RESULTS: Two-hundred-thirteen papers were identified, of which 60 papers were selected and reviewed on the basis of their relevance. The epidemiology, pathophysiology, clinical presentations, case reports, investigations, treatment and outcomes of aortic disease in Malaysia were reviewed and summarised. The clinical relevance of the studies performed are discussed. CONCLUSION: The review provided an insight into the pathophysiology, prevalence and epidemiology of aortic diseases in Malaysia, how the condition is managed, and the outcomes of treatment. Limitations of the research performed in Malaysia to date were identified and recommendations for further research and improvement in clinical practice were recommended.

Viral activity and outcome of hepatitis B surface antigen-positive grafts in deceased liver transplantation.

Indications of liver transplantation are extensive, but deceased donation does not meet the demand. Hepatitis B surface antigen (HBsAg)-positive grafts used to be discarded in the past. The aim of this study was to examine viral activity and outcome of HBsAg-positive deceased grafts transplanted to HBsAg-positive recipients. Eleven HBsAg-positive deceased grafts were transplanted to HBsAg-positive patients with acute liver failure (3 patients), hepatocellular carcinoma (6 patients) and repeatedly bleeding varices (2 patients). Postoperatively, hepatitis B virus (HBV) infection was treated by a combination of antiviral nucleoside and nucleotide analogues. HBV DNA and HBsAg were measured periodically. The median (interquartile) model of end-stage liver disease score for the recipients was 19 (16-32) with a range from 11 to 40. HBV DNA was detected in 6 patients with a range from 61 to 1083 IU/mL before transplantation. After transplantation, HBV DNA was detected in 4 patients in the first month and 2 patients in the 6th month and became undetectable for all patients at end of the first year. The quantitative HBsAg ranged from 0.86 to 241.1 IU/mL at 6 months and 0.34 to 238.5 IU/mL at 24 months (P = .135). Three of the patients died in the early phase, and the other patients were followed up for 40.0 ± 19.2 months with normal liver function. In conclusion, HBsAg-positive deceased liver grafts function well with minimal viral activity under treatment of combined antiviral nucleoside and nucleotide analogues. Use of HBsAg-positive deceased grafts is feasible and increases the donor pool to rescue dying patients.

Electrical stimulation as a conditioning strategy for promoting and accelerating peripheral nerve regeneration.

The delivery of a nerve insult (a "conditioning lesion") prior to a subsequent test lesion increases the number of regenerating axons and accelerates the speed of regeneration from the test site. A major barrier to clinical translation is the lack of an ethically acceptable and clinically feasible method of conditioning that does not further damage the nerve. Conditioning electrical stimulation (CES), a non-injurious intervention, has previously been shown to improve neurite outgrowth in vitro. In this study, we examined whether CES upregulates regeneration-associated gene (RAG) expression and promotes nerve regeneration in vivo, similar to a traditional nerve crush conditioning lesion (CCL). Adult rats were divided into four cohorts based on conditioning treatment to the common peroneal (fibular) nerve: i) CES (1h, 20Hz); ii) CCL (10s crush); iii) sham CES (1h, 0Hz); or iv) naïve (unconditioned). Immunofluorescence and qRT-PCR revealed significant RAG upregulation in the dorsal root ganglia of both CES and CCL animals, evident at 3-14days post-conditioning. To mimic a clinical microsurgical nerve repair, all cohorts underwent a common peroneal nerve cut and coaptation one week following conditioning. Both CES and CCL animals increased the length of nerve regeneration (3.8-fold) as well as the total number of regenerating axons (2.2-fold), compared to the sham and naïve-conditioned animals (p<0.001). These data support CES as a non-injurious conditioning paradigm that is comparable to a traditional CCL and is therefore a novel means to potentially enhance peripheral nerve repair in the clinical setting.

Difficult Situation of Pancreas Transplantation in the Setting of Scarce Organ Donation.

BACKGROUND: Currently, pancreas transplantation has been a promising strategy to restore long-term normoglycemia as well as to improve life quality for patients with insulin-dependent diabetes mellitus (DM). However, the discrepancy between the number of organs needed and the number donated for transplantation is always enormous. Under a setting of scarce organ donations, we examined our limited experience of pancreas transplantation. METHODS: A retrospective review of pancreas transplantations was performed with the use of data from the Taiwan Organ Registry and Sharing Center and the Ministry of Health and Welfare. Pancreas transplantations in the Organ Transplantation Institute of Chang Gung Memorial Hospital also were reviewed. RESULTS: At present, there are 5 medical centers approved for pancreas transplantation in Taiwan. Overall, a total of 156 pancreas transplantations were performed from 2005 to the end of 2016; only 9 of them were performed in the Organ Transplantation Institute of Chang Gung Memorial Hospital. Although the number of organ donations is rising, pancreas transplantation numbers remain low. More than 20 pancreas transplantations were performed in 2016, yet there remained a total of 111 patients registered on the wait list for pancreas transplantation at the end of this study. Thus the gap between organ donation and transplantation is still vast. CONCLUSIONS: With continuing improvements in Taiwanese health policies and public education regarding organ transplantation, organ donation rates have risen steadily in recent years. Moreover, quality control and continuing evolution in organ transplantation is crucial to ameliorate the difficult situation of pancreas transplantation and other solid organ transplantation in the context of low levels of donation.

Pre-Transplantation Immune Cell Distribution and Early Post-Transplant Fungal Infection Are the Main Risk Factors of Liver Transplantation Recipients in Lower Model of End-Stage Liver Disease.

BACKGROUND: The prognosis of patients after liver transplantation (LTx) with high Model of End-Stage Liver Disease (MELD) score (>30) is predicted, but patients with lower MELD scores (<30) have no conclusive studies of pre- and post-transplant risk factors that influence the long-term outcome. METHODS: This retrospective study reviewed 268 recipients with MELD score <30, from 2008 to 2013 in our institution, for evaluation of pre-transplant risk factors including patients' clinical background data, pre-transplant lymphocyte subpopulation, and early post-transplant infection complication as predictors for long-term survival after LTx. RESULTS: The post-transplant patients' survival estimates were 90.7%, 85.1%, and 83.6% at 1, 3, and 5 years, respectively. In multivariate analysis, age >55years, presence of ascites, cluster of differentiation (CD)3 < 93.2 (count/µL), CD4/CD8 <2.4, fungal infection, and more than one site of fungal colonization significantly influenced survival (P = .0003, P = .002, P = .04, P = .004, P < .0001, and P > .0001, respectively). We also noticed that these five factors accumulatively influence the long-term survival rate; this means that in the presence of any two risk factors, the 5-year survival can still be 88.4%, whereas in the presence of any three risk factors, the survival rate dropped to only 57.1%. CONCLUSIONS: Older patients in the presence of pre-transplant low immune cell number and ascites in association with post-transplant fungal infection are the independent risk factors in MELD scores <30 LTx groups for long-term survival. Patients in these groups with any of the three factors had inferior long-term survival results.

Microplastic pollution in the marine waters and sediments of Hong Kong.

The presence of plastic waste with a diameter of less than 5mm ("microplastics") in marine environments has prompted increasing concern in recent years, both locally and globally. We conducted seasonal surveys of microplastic pollution in the surface waters and sediments from Deep Bay, Tolo Harbor, Tsing Yi, and Victoria Harbor in Hong Kong between June 2015 and March 2016. The average concentrations of microplastics in local coastal waters and sediments respectively ranged from 51 to 27,909particles per 100m3 and 49 to 279particles per kilogram. Microplastics of different shapes (mainly fragments, lines, fibers, and pellets) were identified as polypropylene, low-density polyethylene, high-density polyethylene, a blend of polypropylene and ethylene propylene, and styrene acrylonitrile by means of Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy. This is the first comprehensive study to assess the spatial and temporal variations of microplastic pollution in Hong Kong coastal regions.

Application of CD8+ Cells Count as a Guide of Immunosuppressive Regimen Introduction for Very Sick Patients Undergoing Liver Transplantation.

BACKGROUND: Immunosuppression (IS) protocols should be individualized according to the individual recipient's immunity to minimize adverse effects. The aim of this study was to determine whether preoperative levels of CD8+ T lymphocytes could be used as a guide for the introduction of IS. METHODS: Sixteen adult liver transplantations in our institute were retrospectively analyzed. The immunosuppressive agents were temporarily withheld for 8 patients with a lower (<10%) preoperative percentage of CD8+ cells after transplant (classified as group A). In this group, postoperative immunosuppressive agents had never been used until acute rejection was suspected. Another 8 patients receiving classic IS were classified as group B. We collected their demographic features and analyzed the clinical courses. RESULTS: The postoperative IS-free period of group A was 5 to 120 days (median, 31 days). Our data showed an inverse correlation between CD8+ levels and the severity of liver disease. Although the IS-free protocol did not present a lower incidence of infection-related events, most of them were effectively treated with antibiotics. The 1-, 3-, and 5-year overall patient survival rates were not different between those with a short-term IS-free period and those with regular IS (87.5% vs 100%, 75% vs 100%, and 62.5% vs 87.5%; P = .468). No patient died of graft failure due to acute rejection. CONCLUSIONS: Postoperative immunosuppressive agents can be safely withheld for a period of time to preserve proper immune responses against infections in very sick recipients guided by using the CD8+ levels.

A Review of Coronary Artery Disease Research in Malaysia.

Coronary artery disease is the major cause of mortality and morbidity in Malaysia and worldwide. This paper reviews all research and publications on coronary artery disease in Malaysia published between 2000-2015. 508 papers were identified of which 146 papers were selected and reviewed on the basis of their relevance. The epidemiology, etiology, risk factors, prevention, assessment, treatment, and outcomes of coronary artery disease in the country are reviewed and summarized. The clinical relevance of the studies done in the country are discussed along with recommendations for future research.

A Review of Lung Cancer Research in Malaysia.

Lung cancer is a major cause of mortality and morbidity in Malaysia and worldwide. This paper reviews all research and publications on lung cancer in Malaysia published between 2000-2015. 89 papers were identified, of which 64 papers were selected and reviewed on the basis of their relevance to the review. The epidemiology, risk factors, cell types, clinical presentation, diagnosis, treatment, outcomes, prevention, and the social impact of lung cancer in the country are reviewed and summarized. The clinical relevance of the studies done in the country are discussed along with recommendations for future research.

The use of brief post-surgical low frequency electrical stimulation to enhance nerve regeneration in clinical practice.

Despite efforts to enhance peripheral nerve regeneration, there has been little progress in improving clinical outcomes. Recently, a method of brief post-surgical low frequency electrical stimulation of surgically repaired nerves has been developed. It was shown to accelerate axon outgrowth across the repair site and it hastened target reinnervation. In this brief review, we describe the mechanistic insights and functional impacts of the post-surgical electrical stimulation that have been gained through animal studies. Brain-derived neurotrophic factor, cyclic AMP and regeneration-associated genes play a vital role in expediting the outgrowth of axons across the injury site. The method of stimulation has also been shown to be effective in patients with severe compressive neuropathy as well as those with digital nerve laceration. Its clinical feasibility and positive impact open the door of further clinical translation in other peripheral nerve injuries.

Hypertrophic obstructive cardiomyopathy: the mitral valve could be the key.

OBJECTIVES: As we strongly believe that treating the mitral valve abnormalities is a key feature of hypertrophic obstructive cardiomyopathy (HOCM), we have systematically corrected both the anterior and posterior leaflet (PL) size and geometry. We have analysed our immediate results and at mid-term follow-up. METHODS: From March 2010 until June 2015, 16 patients with HOCM underwent surgical correction of obstruction. The mean age was 51 years old (range, 32-72 years). All were symptomatic being New York Heart Association (NYHA) class 3 (n = 4) or 4 (n = 12). All had systolic anterior motion at echocardiogram with severe mitral regurgitation (MR). Intraventricular gradient preoperatively was 73.5 mmHg (range, 50-120 mmHg). All patients underwent a double-stage procedure: first septal resection through (i) the aortic valve and (ii) the detached anterior leaflet (AL) of the mitral valve and at second, mitral valve repair by (i) reducing PL height (leaflet resection or artificial neochordae) (ii) increasing AL height with pericardial patch. RESULTS: There was no in-hospital or late death. All patients were Class 1 NYHA at latest follow-up. Control echocardiography showed no MR, mean rest intraventricular gradient was 15 mmHg (range, 9-18 mmHg). CONCLUSIONS: Our good mid-term results support the concept that HOCM is not only a septal disease and that the mitral valve pathology is a key component that should be addressed. For most patients, the ideal surgical treatment should consist in a two-step procedure. It is even necessary to be studied whether treating the mitral valve alone could not suffice.

Broader Geographic Sharing of Pediatric Donor Lungs Improves Pediatric Access to Transplant.

US pediatric transplant candidates have limited access to lung transplant due to the small number of donors within current geographic boundaries, leading to assertions that the current lung allocation system does not adequately serve pediatric patients. We hypothesized that broader geographic sharing of pediatric (adolescent, 12-17 years; child, <12 years) donor lungs would increase pediatric candidate access to transplant. We used the thoracic simulated allocation model to simulate broader geographic sharing. Simulation 1 used current allocation rules. Simulation 2 offered adolescent donor lungs across a wider geographic area to adolescents. Simulation 3 offered child donor lungs across a wider geographic area to adolescents. Simulation 4 combined simulations 2 and 3. Simulation 5 prioritized adolescent donor lungs to children across a wider geographic area. Simulation 4 resulted in 461 adolescent transplants per 100 patient-years on the waiting list (range 417-542), compared with 206 (range 180-228) under current rules. Simulation 5 resulted in 388 adolescent transplants per 100 patient-years on the waiting list (range 348-418) and likely increased transplant rates for children. Adult transplant rates, waitlist mortality, and 1-year posttransplant mortality were not adversely affected. Broader geographic sharing of pediatric donor lungs may increase pediatric candidate access to lung transplant.