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1.
Mar Drugs ; 22(3)2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38535454

RESUMO

Muscle atrophy is a detrimental and injurious condition that leads to reduced skeletal muscle mass and disruption of protein metabolism. Oyster (Crassostrea nippona) is a famous and commonly consumed shellfish in East Asia and has become a popular dietary choice worldwide. The current investigation evaluated the efficacy of C. nippona against muscle atrophy, which has become a severe health issue. Mammalian skeletal muscles are primarily responsible for efficient metabolism, energy consumption, and body movements. The proteins that regulate muscle hypertrophy and atrophy are involved in muscle growth. C. nippona extracts were enzymatically hydrolyzed using alcalase (AOH), flavourzyme (FOH), and protamex (POH) to evaluate their efficacy in mitigating dexamethasone-induced muscle damage in C2C12 cells in vitro. AOH exhibited notable cell proliferative abilities, promoting dose-dependent myotube formation. These results were further solidified by protein expression analysis. Western blot and gene expression analysis via RT-qPCR demonstrated that AOH downregulated MuRF-1, Atrogin, Smad 2/3, and Foxo-3a, while upregulating myogenin, MyoD, myosin heavy chain expression, and mTOR, key components of the ubiquitin-proteasome and mTOR signaling pathways. Finally, this study suggests that AOH holds promise for alleviating dexamethasone-induced muscle atrophy in C2C12 cells in vitro, offering insights for developing functional foods targeting conditions akin to sarcopenia.


Assuntos
Crassostrea , Animais , Atrofia Muscular , Suplementos Nutricionais , Serina-Treonina Quinases TOR , Dexametasona , Mamíferos
2.
Chem Soc Rev ; 50(11): 6423-6482, 2021 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-34100047

RESUMO

Periodic nanostructures, a group of nanomaterials consisting of single or multiple nano units/components periodically arranged into ordered patterns (e.g., vertical and lateral superlattices), have attracted tremendous attention in recent years due to their extraordinary physical and chemical properties that offer a huge potential for a multitude of applications in energy conversion, electronic and optoelectronic applications. Recent advances in the preparation strategies of periodic nanostructures, including self-assembly, epitaxy, and exfoliation, have paved the way to rationally modulate their ferroelectricity, superconductivity, band gap and many other physical and chemical properties. For example, the recent discovery of superconductivity observed in "magic-angle" graphene superlattices has sparked intensive studies in new ways, creating superlattices in twisted 2D materials. Recent development in the various state-of-the-art preparations of periodic nanostructures has created many new ideas and findings, warranting a timely review. In this review, we discuss the current advances of periodic nanostructures, including their preparation strategies, property modulations and various applications.

3.
BMC Infect Dis ; 21(1): 978, 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34544380

RESUMO

BACKGROUND: Dengue fever is a common mosquito borne viral infection. Severe dengue fever associated severe hepatitis carries high mortality. Based on the beneficial effect of N-acetylcysteine (NAC) in paracetamol poisoning and non-acetaminophen induced liver failure, it is used in dengue fever associated hepatitis in clinical practice. We aim to study the reversal of liver enzymes with NAC in the setting of severe hepatitis due to severe dengue infection. METHODS: A retrospective analysis was conducted on hospitalized 30 adults with severe dengue fever with severe hepatitis. These 30 patients had aspartate transaminase (AST) and alanine transaminases (ALT) more than 500 U/L and/or PT INR (prothrombin time and international normalized ratio) more than 1.5. They were treated with NAC infusion of 100 mg/h for 3 to 5 days. RESULTS: The mean age of the group was 49.9 ± 11.46 years and 18 (60%) patients were males. Nineteen patients (63%) developed dengue shock. Of them 12 patients (40%) developed hepatic encephalopathy. Median AST on the day of administration of NAC was 1125 U/L interquartile range (IQR) 1653.25 while median ALT was 752 (IQR 459.25). There was a statistically significant reduction of both ALT (p = 0.034) and AST (p = 0.049) from day 1 to 4 after NAC infusion. Rise of platelet count between day 1 and day 4 also showed statistically significant difference (p = 0.011) but the reduction of prothrombin time and international normalized ratio (PT/INR) from 1 to day 4 did not show statistical significance difference. Mean duration of treatment with NAC was 3.61 ± 0.75 days while mean length of hospital stay was 6.2 ± 1.27 days. Only one patient died (3.3%). None of the patients reported adverse drug reaction due to NAC. CONCLUSION: Majority of patients demonstrated marked clinical and biochemical improvements and they recovered fully. We observed faster and significant recovery of liver enzymes following administration of NAC. Based on the above findings, this study provides preliminary evidence for the beneficial effect of NAC in severe hepatitis in dengue infection with greater survival benefits.


Assuntos
Hepatite , Dengue Grave , Acetaminofen , Acetilcisteína/uso terapêutico , Adulto , Animais , Humanos , Recém-Nascido , Masculino , Estudos Retrospectivos , Dengue Grave/tratamento farmacológico
4.
J Obstet Gynaecol ; 41(1): 1-6, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32172646

RESUMO

The proportion of Group B Streptococcus (GBS) colonisation in pregnant women >35 weeks of gestation was 18% and 49% by culture and real-time PCR respectively in selected hospitals from the Western Province of Sri Lanka. A Descriptive cross-sectional study was conducted from January to April 2019. Two low vaginal and rectal swabs were collected from 100 pregnant women. Identification of GBS was done by culture and real-time PCR. GBS isolates were found to be sensitive to penicillin, ampicillin, cefotaxime, vancomycin, while 5 and 4 isolates out of 18 were resistant to erythromycin and clindamycin, respectively. Further, there was a significant association between GBS colonisation and a history of vaginal discharge and unemployment.IMPACT STATEMENTWhat is already known on this subject? Prevalence of GBS colonisation in the vagina and rectum of pregnant women in developing countries ranges from 8.5% to 22%. The Conventional method of culture has been considered the gold standard for diagnosis, however, the culture method does not give positive results for all cases of GBS. Polymerase chain reaction (PCR) has been found to be more sensitive for the detection of GBS than culture. In Sri Lanka, ante-natal screening for GBS is not practiced as the prevalence of GBS is still unlcear due to non-availably of data. Only a few scattered studies have been conducted using culture in Sri Lanka. Thus there is an urgent need to determine the magnitude of the GBS colonisers of ante-natal women in order to set up guidelines for screening and management of GBS.What do the results of this study add? In this study, the overall GBS colonisation rate which was detected using both culture and PCR was 50% in Western Province of Sri Lanka. That was a high figure when compared to the figures which were detected previously in Sri Lanka using only conventional culture methods. The risk factors for GBS colonisation were found to have a significant relationship with the history of abnormal vaginal discharge. Further, it was found that when Candida species coexisted with GBS, the existence of GBS was enhanced. Penicillin remains the antibiotic of choice for GBS.What are the implications of these findings for clinical practice and/or further research? This study emphasises the importance of establishing national policies for screening of pregnant women of >35 weeks of gestation to reduce the risk of neonatal infection. Further, it gives an insight into the options of antibiotics that can be used for treatment of these GBS colonisers from Sri Lanka.


Assuntos
Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana/efeitos dos fármacos , Complicações Infecciosas na Gravidez/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus agalactiae/efeitos dos fármacos , Adulto , Estudos Transversais , Feminino , Humanos , Testes de Sensibilidade Microbiana , Gravidez , Complicações Infecciosas na Gravidez/diagnóstico , Complicações Infecciosas na Gravidez/epidemiologia , Cuidado Pré-Natal , Prevalência , Reto/microbiologia , Sri Lanka/epidemiologia , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/epidemiologia , Streptococcus agalactiae/isolamento & purificação , Centros de Atenção Terciária , Vagina/microbiologia
5.
J Food Sci Technol ; 58(6): 2078-2088, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33967306

RESUMO

Sea cucumbers are considered healthy and high in nutritive value. Conversely however, limited consumption of sea cucumbers has been reported in many parts of the world. This study was done to produce a ready-to-prepare soup mix incorporating the sea cucumber aiming to popularize the sea cucumber consumption. The highly abundant low-value Bohadschia vitiensis in the coastal waters of Sri Lanka was selected to prepare this soup mix. Fresh B. vitiensis samples (n = 250) were collected from major sea cucumber landing sites of the northwest coast. Out of the seven compositions prepared initially, three compositions; 20%, 40% and 60% were selected. The best composition among these was selected through a sensory test performed using a semi-trained panel (n = 30) at the University of Sri Jayewardenepura, Sri Lanka. The initial chemical and microbial qualities of the selected soup mix were analyzed and the best packaging material was selected. Results showed that the soup mix with 40% sea cucumber flour was the best composition as it reported significantly higher sensory scores than the other two mixes (p ≤ 0.05, Friedman). This soup mix exhibited high protein (21.43 ± 1.21%), low fat (4.98 ± 0.23%) and its oxygen radical absorbance capacity was 1.04 ± 0.13 mg Trolox equivalents/g. Coliforms and Staphylococcus aureus colonies were absent in the soup mix. The total plate count (1.9 × 102 CFU/g), yeast and mold count (0.7 × 102 CFU/g) and the heavy metal contents were within the safe limit for human consumption. The Polyester-Aluminum-PE was selected as the best packaging material which ensured 6 weeks storage time at room temperature.

6.
J Am Chem Soc ; 142(2): 1083-1089, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31846313

RESUMO

Cations are crucial components in emerging functional polyelectrolytes for a myriad of applications. Rapid development in this area necessitates the exploration of new cations with advanced properties. Herein we describe a combination of computational and experimental design of cobaltocene metallo-cations that have distinct electronic and redox properties. One of the direct outcomes on the first synthesis of a complete set of cation derivatives is to discover highly stable cations, which are further integrated to construct metallo-polyelectrolytes as anion-exchange membranes in solid-state alkaline fuel cells. The device performance of these polyelectrolytes under highly basic and oxidative environments is competitive with many organo-polyelectrolytes.

7.
BMC Neurol ; 20(1): 320, 2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32859166

RESUMO

BACKGROUND: Thalamic blood supply consists of four major vascular territories. Out of them paramedian arteries supply ipsilateral paramedian thalami and occasionally rostral mid brain. Rarely both paramedian arteries arise from a common trunk that arise from P1 segment of one sided posterior cerebral artery (PCA). This is usually due to hypoplastic or absent other P1 and this common trunk is termed Artery of Percheron (AOP). Its prevalence is in the range of 7-11% among the general population and AOP infarcts account in an average of 0.4-0.5% of ischemic strokes. Clinical presentation of AOP infarction is characterized by impaired arousal and memory, language impairment and vertical gaze palsy. It also can present with cerebellar signs, hemi paresis and hemi sensory loss. We herein present a case of AOP infarction presenting as transient loss of consciousness and nuclear third nerve palsy. CASE PRESENTATION: A 51 year old previously healthy male, was brought to us, with a Glasgow coma scale (GCS) of 7/15. GCS improved to 11/15 by the next day, however he had a persisting expressive aphasia. Right sided nuclear third nerve palsy was apparent with the improvement of GCS. He did not have pyramidal or cerebellar signs. Thrombolysis was not offered as the therapeutic window was exceeded by the time of diagnosis. Diagnosis was made using magnetic resonance imaging (MRI) that was done after the initial normal non-contrast computer tomography (NCCT) brain. He was enrolled in stroke rehabilitation. Aspirin and atorvastatin was started for the secondary prevention of stroke. He achieved independency of advanced daily living by 1 month, however could not achieve full recovery to be employed as a taxi driver. CONCLUSIONS: Because of the rarity and varied clinical presentation with altered levels of consciousness, AOP infarcts are easily overlooked as a stroke leading to delayed diagnosis. Timely diagnosis can prevent unnecessary investigations and the patient will be benefitted by early revascularization. As it is seldom reported, case reports remain a valuable source of improving awareness among physicians about this clinical entity.


Assuntos
Infarto Cerebral/diagnóstico , Doenças do Nervo Oculomotor/diagnóstico , Inconsciência/etiologia , Artérias/patologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , Acidente Vascular Cerebral/prevenção & controle , Tálamo/irrigação sanguínea
8.
J Food Sci Technol ; 55(5): 1933-1941, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29666546

RESUMO

Processing and its impacts on proximate composition and fatty acid profile of six sea cucumber species; Bohadschia marmorata, Stichopus chloronotus, Holothuria spinifera, Thelenota anax, Holothuria scabra and Bohadschia sp. 1 collected from the northwest coast of Sri Lanka were analyzed. Sea cucumbers are processed into bêche-de-mer by both domestic and industrial level processors following the similar steps of cleaning, evisceration, first boiling, salting, second boiling and drying. However, domestically processed bêche-de-mer always reported a higher percentage of moisture, crude ash, crude fat and lower percentage of crude protein than industrially processed products. Although processing resulted in a significant reduction of total SFA and MUFA in fresh individuals of most of these species, total PUFA increased significantly in processed individuals excluding Bohadschia species. Palmitic acid was found to be the most dominant fatty acid in all these species followed by eicosapentaenoic acid, which showed a significant increase in processed products, except Bohadschia sp. 1. Total MUFA were higher than total SFA in all sea cucumber species having exceptions in Bohadchia sp.1 and fresh S. chloronotus. These findings will make a significant contribution to fill the gaps in existing information as no any previous information is available for species like H. spinifera and S. chloronotus.

9.
Phys Chem Chem Phys ; 17(36): 23326-31, 2015 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-26156795

RESUMO

We investigate the effect of confinement on the crystalline microstructure of the polymer component of polymer : fullerene bulk heterojunction thin films using grazing incidence wide angle X-ray scattering. We find that the polymer crystallite size decreases and the alignment of the molecules along the surface normal increases, as the thin-film thickness is reduced from 920 nm to <20 nm and approaches the thin-film confinement regime. Furthermore, we find that the polymer crystallite size near the surface (air interface) is lower than the crystallite size in the bulk or the bottom (substrate interface) of bulk heterojunction films thicker than the confinement regime. Variation in polymer crystallite size can cause changes in charge carrier mobility and recombination rates, which in turn affect the performance of bulk heterojunction thin film devices such as photovoltaics and photodetectors.

10.
J Wound Care ; 24(1): 5-10, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25543818

RESUMO

OBJECTIVE: Antiseptics are widely used in wound management to prevent or treat wound infections due to their proven wound healing properties regardless of their cytotoxicity. The objective of this study was to determine the bactericidal effects of three antiseptics on pathogens known to cause wound infections. METHOD: The study was carried out at a tertiary care hospital and a university microbiology laboratory in Sri Lanka in 2013. The three acids (acetic acid, ascorbic acid and boric acid) in increasing concentration (0.5%, 0.75% and 1%) were tested against bacterial suspensions equivalent to 0.5 McFarland standard. The Bacteria isolates used were isolated from wound and standard strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. RESULTS: There were 33 (68.8%) Coliforms, 10 (20.8%) Pseudomonas species, and 5 (10.4%) strains of Staphylococcus aureus. Acetic acid at concentration of 0.5% inhibited growth of 37 (77%) and 42 (87.5%) of tested isolates when exposed for 30 and 60 minutes, respectively. However 100% inhibition was achieved at four hours. At a concentration of 0.75%, 40 (83.3%) and 44 (91.7%) were inhibited when exposed for 30 and 60 minutes, respectively, with 100% inhibition at 4 hours. At concentration of 1%, 46 (95.8%) inhibition was seen at 30 minutes and 100% inhibition at 60 minutes. Ascorbic acid, at 0.5% and 0.75 % concentrations, inhibited growth of 45(93.7%) and 47(97.9%) of isolates respectively when exposed for 30 minutes. At these two concentrations, 100% inhibition was achieved when exposed for one hour. At 1% concentration, 100% inhibition was achieved at 30 minutes. Boric acid did not show bactericidal effect at concentrations of 0.5%, 0.75 % and 1%. Pseudomonas species were inhibited at 30 minutes by 0.5% acetic acid. Bactericidal effect against all the standard strains was seen with three acids at each concentration tested from 30 minutes onwards CONCLUSION: Ascorbic acid was bactericidal for all organisms tested within the shortest exposure time at the lowest concentration compared to other two acids. Despite promising bactericidal effects, further studies warrant, as ongoing debates on toxicity of acids on tissue epithelialisation. Application of antiseptics for a shorter duration could overcome this problem without losing bactericidal activity. DECLARATION OF INTEREST: The authors have no conflict of interest and no funding was received for this study.


Assuntos
Antibacterianos/farmacologia , Anti-Infecciosos Locais/farmacologia , Bactérias/efeitos dos fármacos , Ferimentos e Lesões/microbiologia , Ácido Acético/farmacologia , Ácido Ascórbico/farmacologia , Técnicas Bacteriológicas/métodos , Ácidos Bóricos/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Humanos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Ferimentos e Lesões/tratamento farmacológico
11.
Ceylon Med J ; 60(1): 10-2, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25804911

RESUMO

INTRODUCTION: Although dengue management guidelines do not advice on use of antibiotics in dengue shock syndrome, unrecognised bactraemia is likely to contribute to morbidity and mortality. OBJECTIVES: To assess the occurance of secondary bacteraemia in adult patients with prolonged dengue fever. METHODS: A prospective study was conducted recruiting patients with confirmed acute dengue infection who had prolonged fever (>5 days). Two sets of blood cultures were taken in such patients prior to institution of antibiotic therapy. Demographic, clinical, haematological and biochemical parameters were recorded. Development of ascites and pleural effusions were detected using ultrasonography. RESULTS: Fourty patients (52.5% males) with a mean age of 29.8 years (SD 13.6) were studied. The average duration of fever was 7.9 days (SD 1.8). Ten patients (25%) had bacterial isolates in their blood cultures; Staphylococcus aureus (n=2), coliforms (n=3), pseudomonas (n=1) and 4 had mixed growths. The culture positive group had severe body aches at admission and higher fever, third space fluid accumulation, a significant drop in platelets and a higher CRP. CONCLUSIONS: A quarter of dengue patients with prolonged fever had a bacterial isolate. Culture positive patients appeared more ill with body aches and had higher degrees of fever during the latter part of the illness. Increased vascular permeability may predispose to bacterial seepage into blood. Although white cell count is not helpful in detecting bacteraemia, low platelet count and elevation of CRP seem to be helpful.


Assuntos
Bacteriemia/epidemiologia , Coinfecção/epidemiologia , Dengue/epidemiologia , Infecções por Enterobacteriaceae/epidemiologia , Infecções por Pseudomonas/epidemiologia , Infecções Estafilocócicas/epidemiologia , Adolescente , Adulto , Distribuição por Idade , Bacteriemia/sangue , Proteína C-Reativa/metabolismo , Coinfecção/sangue , Dengue/sangue , Progressão da Doença , Infecções por Enterobacteriaceae/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Estudos Prospectivos , Infecções por Pseudomonas/sangue , Distribuição por Sexo , Sri Lanka/epidemiologia , Infecções Estafilocócicas/sangue , Adulto Jovem
12.
J Nanosci Nanotechnol ; 14(2): 1033-50, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24749411

RESUMO

Semiconducting polymers have been developed during the last few decades and are currently used in various organic electronics applications. Regioregular poly(3-hexylthiophene) (P3HT) is the most employed semiconducting polymer for organic electronics applications. The development of living Grignard metathesis polymerization (GRIM) allowed the synthesis of P3HT with well-defined molecular weights and functional end groups. A large number of block copolymers containing P3HT have been reported, and their opto-electronic properties have been investigated. The performance of P3HT homopolymer and block copolymers in field-effect transistors and bulk heterojunction solar cells are discussed in this review. The morphology of the P3HT materials is also discussed.


Assuntos
Cristalização/métodos , Fontes de Energia Elétrica , Eletrodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Compostos Organosselênicos/química , Transistores Eletrônicos , Condutividade Elétrica , Desenho de Equipamento , Análise de Falha de Equipamento , Nanotecnologia/instrumentação , Tamanho da Partícula
13.
Ceylon Med J ; 59(1): 21-3, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24682194

RESUMO

Tendency to falling in older people, with and without cognitive impairment, living in an elderly home was assessed. A descriptive analytical study was carried out with 50 elderly people (25 males) aged between 60 - 85 years. Timed Up and Go (TUG) test and, Five Times Sit to Stand Test (FTSST) were used to determine risk of falling and functional lower extremity strength of each participant. The Folstein Mini Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were used to assess cognition.The cognitive scores were significantly lower in fallers compared to non-fallers (p=0.0001). Fallers demonstrated significantly poor lower extremity strength (p=0.0001). Older people with cognitive impairment demonstrated poor functional lower extremity strength than those without cognitive impairement (p=0.002). The difference in falling tendency between males and females was not statistically significant.


Assuntos
Acidentes por Quedas/estatística & dados numéricos , Transtornos Cognitivos/epidemiologia , Instituição de Longa Permanência para Idosos , Extremidade Inferior/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiopatologia , Medição de Risco , Idoso , Idoso de 80 Anos ou mais , Transtornos Cognitivos/psicologia , Feminino , Humanos , Masculino , Entrevista Psiquiátrica Padronizada , Pessoa de Meia-Idade , Sri Lanka
14.
Comp Immunol Microbiol Infect Dis ; 105: 102123, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38217950

RESUMO

Escherichia coli (E. coli) causes various infections in humans and animals. The biofilm-forming ability of E. coli has increased antimicrobial resistance and capacity to cause recurrent and chronic infections. This study determined the biofilm-forming ability of E. coli isolated from extraintestinal infections of humans, chickens, and dogs in relation to the phylogroup, type of infection, and antibiotic resistance. Isolates from chickens showed significantly higher biofilm-forming ability compared to those causing urinary tract infections in humans (p = 0.0001). Further, isolates belonging to phylogroup B1 displayed a higher likelihood to form biofilms. Resistance to ciprofloxacin and trimethoprim-sulfamethoxazole was positively correlated with biofilm-forming ability. Harbouring plasmid-mediated quinolone resistance gene, qnrS was also positively correlated with biofilm formation. This study provides insight into factors such as phylogroup and the type of infections that could enhance biofilm formation, as well as genotypic and phenotypic antibiotic resistance that could correlate with the ability to form biofilms.


Assuntos
Infecções por Escherichia coli , Infecções Urinárias , Humanos , Animais , Cães , Escherichia coli , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Galinhas , Infecções por Escherichia coli/veterinária , Infecções por Escherichia coli/tratamento farmacológico , Filogenia , Biofilmes , Infecções Urinárias/veterinária , Resistência Microbiana a Medicamentos
15.
Phys Chem Chem Phys ; 15(38): 16294-302, 2013 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-23999829

RESUMO

The electronic structure and magnetism of nanocrystalline graphite prepared by ball milling of graphite in an inert atmosphere have been investigated using valence band spectroscopy (VB), core level near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and magnetic measurements as a function of the milling time. The NEXAFS spectroscopy of graphite milled for 30 hours shows simultaneous evolution of new states at ~284.0 eV and at ~290.5 eV superimposed upon the characteristic transitions at 285.4 eV and 291.6 eV, respectively. The modulation of the density of states is explained by evolution of discontinuities within the sheets and along the fracture lines in the milled graphite. The magnetic measurements in the temperature interval 2-300-2 K at constant magnetic field strength show a correlation between magnetic properties and evolution of the new electronic states. With the reduction of the crystallite sizes of the graphite fragments, the milled material progressively changes its magnetic properties from diamagnetic to paramagnetic with contributions from both Pauli and Curie paramagnetism due to the evolution of new states at ~284 and ~290.5 eV, respectively. These results indicate that the magnetic behaviour of ball-milled graphite can be manipulated by changing the milling conditions.


Assuntos
Grafite/química , Magnetismo , Elétrons , Teoria Quântica , Temperatura , Espectroscopia por Absorção de Raios X
16.
Ceylon Med J ; 58(1): 6-10, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23549716

RESUMO

OBJECTIVES: In early nineties investigators noticed an alarmingly high incidence of an apparently new form of chronic kidney disease of unknown aetiology (CKD-U) in some parts of Sri Lanka. The aim of the study was to investigate the geographical distribution of CKD-U using GIS and GPS mapping. METHODS: Community based information was collected from 11,630 patients for GIS mapping using ARC 9.2 software. Based on GIS mapping, two locations were selected for GPS mapping to locate the households of 863 CKD-U patients with reference to reservoirs, irrigation canals and the topography of the areas. RESULTS: GIS mapping indicated five high prevalence areas of CKD-U. Communities who consumed water from natural springs showed a low prevalence of the disease. GPS mapping showed that most of the affected villages were located below the reservoirs and canals with stagnant irrigated water. CONCLUSION: Epidemiological data on geographical distribution infers that while older foci of CKD-U are persisting, there is an emergence of new foci with time. The location of the affected villages below the level of the reservoirs/canals may indicate the possibility of draining of irrigated water to the shallow wells of the households, which is the source of drinking water.


Assuntos
Mapeamento Geográfico , Insuficiência Renal Crônica/epidemiologia , Adolescente , Adulto , Distribuição por Idade , Idoso , Criança , Pré-Escolar , Água Potável , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Prevalência , Insuficiência Renal Crônica/etiologia , Distribuição por Sexo , Sri Lanka/epidemiologia , Abastecimento de Água/estatística & dados numéricos , Adulto Jovem
17.
FEMS Microbiol Lett ; 3702023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-37708035

RESUMO

A heavy metal-resistant bacterial strain, TWSL_22 was isolated from an industrial effluent sample and tested for heavy metal tolerance and resistance. The strain was molecularly characterized as Staphylococcus epidermidis based on 16S rDNA gene analysis and the sequence was deposited in the NCBI repository (accession number KT184893.1). Metal removal activity (P < .001) of TWSL_22 was 99.99 ± 0.001%, 74.43 ± 2.51%, and 51.16 ± 4.17% for Cd, Pb, and Cu, respectively. Highest MIC was observed for Cd. Antibiotic susceptibility assays revealed the strain TWSL_22 to be resistant to several antibiotics. The strain was screened for possible heavy metal-resistant genes and presence of cadA, copA, and cadD was confirmed by PCR. A DNA fragment containing complete sequence of cadD (618 bp) was isolated and cloned into pET 21a(+), transformed into E. coli BL21 and designated as E. coli/cadDET. E. coli/cadDET showed high metal tolerance capacity and could remove over 82% of heavy metals (Zn2+, Cd2+, Cu2+, and Cr3+) in the industrial effluent.


Assuntos
Metais Pesados , Staphylococcus aureus Resistente à Meticilina , Escherichia coli/genética , Staphylococcus epidermidis/genética , Cádmio , Biodegradação Ambiental , Metais Pesados/farmacologia
18.
RSC Adv ; 13(27): 18605-18613, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-37346959

RESUMO

A new approach was used to produce electrically conductive polyamide yarns, employing an electroless plating technique, which involved stabilizing silver nanoparticles on the surface of the yarn using Sn2+. First, the [Ag(NH3)2]+ complex was reduced using Sn2+ to produce silver nanoparticle seed layers on the fiber surface, followed by a formaldehyde reduction. The nucleation and growth of silver nanoparticles on the fiber surface were observed through SEM images, demonstrating varying degrees of silver deposition depending on the silver concentration. This deposition variation was confirmed through XRD patterns, TGA data and UV-vis spectra. Additionally, XPS characterization showed the evolution of the chemical state of silver and tin during the silver reduction process. Electrical resistance revealed that the resistance per unit length of the yarn ranged from 3 ± 0.3 Ω cm-1 to 70 ± 6 Ω cm-1, depending on the silver concentration. The resulting silver-plated yarn was incorporated into a stretchable device, demonstrating stable resistance over multiple cycles. This method of fabricating conductive yarn has the potential to open up new possibilities in the design and manufacture of stretchable conductive devices for flexible electronics.

19.
Radiography (Lond) ; 29(2): 319-326, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36689834

RESUMO

INTRODUCTION: This study was carried out to evaluate the awareness of radiation protection, radiation types, medical imaging equipment and radiation effects among nurses for the first time in Sri Lanka. Since nurses are involved as direct caregivers in diagnostic and therapeutic radiography and radiation treatment procedures, they need to have a good understanding of the areas mentioned above. METHODS: A self-administered questionnaire was used to collect data from 391 nurses working in hospitals, clinics, and other healthcare settings. Forwarded questions gathered the participants' demographic details and assessed their awareness of radiation protection, medical imaging equipment, radiation type and radiation effects. The average score per awareness area for each demographic characteristic was calculated based on the responses. Additionally, the percentage of participants who scored above 50 and 75 was calculated for each awareness area. RESULTS: The majority were female participants (81.1%) and possessed a diploma in nursing (66.0%) with 10.8 years of average work experience. 92.3%, 74.7%, 69.8% and 22.3% of the participants scored more than 50 marks for the questions related to radiation protection, medical imaging equipment, radiation type and radiation effects, respectively. The level of nursing education and prior training in radiation protection significantly influenced all awareness areas, whereas participants with a graduate qualification in nursing and with prior radiation protection training scored the highest average marks. CONCLUSION: Based on the scores obtained, the Sri Lankan nurses have satisfactory awareness of the essential concepts related to radiation types, medical imaging equipment and radiation protection. However, there is a significant lacking of awareness of radiation effects. This can be attributed to the fact that most participants did not have any formal training in radiation protection. The results implicate that proper training in radiation protection can significantly influence awareness of radiation protection and related concepts. Therefore, it is a timely requirement to initiate short awareness programs and continuing education programs on radiation protection for nurses working in specialised radiation units. IMPLICATIONS FOR PRACTICE: The study suggests the necessity of initiating continuous education programs for nursing staff radiation protection to overcome the awareness gaps.


Assuntos
Recursos Humanos de Enfermagem , Proteção Radiológica , Humanos , Masculino , Feminino , Sri Lanka , Diagnóstico por Imagem , Inquéritos e Questionários
20.
R Soc Open Sci ; 10(3): 221514, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36908995

RESUMO

Nano-zirconia (ZO) was synthesized using a microwave-assisted one-pot precipitation route. Two biopolymers, chitosan (CTS) and carboxymethyl cellulose were blended with ZO at different w/w ratios. The formulation with 30% w/w chitosan (ZO-CTS) was found to give enhanced uptake of F- and As(V). ZO and the most effective ZO-CTS system were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. These confirmed the formation of a composite system containing nanoparticles of 50 nm in size, in which ZO was present in the amorphous form. It was observed that the combination of ZO with CTS improved the F- and As(V) adsorption capacity most notably at pH 5.5. Fluoride adsorption by ZO-CTS followed the Freundlich isotherm model, with an adsorption capacity of 120 mg g-1. Adsorption of As(V) by ZO-CTS could be fitted with both the Langmuir and Freundlich isotherm models and was found to have a capacity of 14.8 mg g-1. Gravity filtration studies conducted for groundwater levels indicated the effectiveness of ZO-CTS in adsorbing As(V) and F- at a pH of 5.5. The ability of the ZO-CTS in removing Cd(II) and Pb(II) was also investigated, and no such enhancement was observed, and found the neat ZO was the most potent sorbent here.

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