Hydroxyapatite Mineralization on the Calcium Chloride Blended Polyurethane Nanofiber via Biomimetic Method

Polyurethane nanofibers containing calcium chloride (CaCl2) were prepared via an electrospinning technique for the biomedical applications. Polyurethane nanofibers with different concentration of CaCl2 were electrospun, and their bioactivity evaluation was conducted by incubating in biomimetic simulated body fluid (SBF) solution. The morphology, structure and thermal properties of the polyurethane/CaCl2 composite nanofibers were characterized by means of scanning electron microscopy (SEM), field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetry. SEM images revealed that the CaCl2 salt incorporated homogeneously to form well-oriented nanofibers with smooth surface and uniform diameters along their lengths. The SBF incubation test confirmed the formation of apatite-like materials, exhibiting enhanced bioactive behavior of the polyurethane/CaCl2 composite nanofibers. This study demonstrated that the electrospun polyurethane containing CaCl2 composite nanofibers enhanced the in vitro bioactivity and supports the growth of apatite-like materials

Very Light Magnetized Jets on Large Scales - I. Evolution and Magnetic Fields

Magnetic fields, which are undoubtedly present in extragalactic jets and responsible for the observed synchrotron radiation, can affect the morphology and dynamics of the jets and their interaction with the ambient cluster medium. We examine the jet propagation, morphology and magnetic field structure for a wide range of density contrasts, using a globally consistent setup for both the jet interaction and the magnetic field. The MHD code NIRVANA is used to evolve the simulation, using the constrained-transport method. The density contrasts are varied between \eta = 10^{-1} and 10^{-4} with constant sonic Mach number 6. The jets are supermagnetosonic and simulated bipolarly due to the low jet densities and their strong backflows. The helical magnetic field is largely confined to the jet, leaving the ambient medium nonmagnetic. We find magnetic fields with plasma \beta \sim 10 already stabilize and widen the jet head. Furthermore they are efficiently amplified by a shearing mechanism in the jet head and are strong enough to damp Kelvin-Helmholtz instabilities of the contact discontinuity. The cocoon magnetic fields are found to be stronger than expected from simple flux conservation and capable to produce smoother lobes, as found observationally. The bow shocks and jet lengths evolve self-similarly. The radio cocoon aspect ratios are generally higher for heavier jets and grow only slowly (roughly self-similar) while overpressured, but much faster when they approach pressure balance with the ambient medium. In this regime, self-similar models can no longer be applied. Bow shocks are found to be of low excentricity for very light jets and have low Mach numbers. Cocoon turbulence and a dissolving bow shock create and excite waves and ripples in the ambient gas. Thermalization is found to be very efficient for low jet densities.Comment: 20 pages, 29 figures. Accepted for publication in MNRA

Epidemiology of Acute Myocarditis/Pericarditis in Hong Kong Adolescents Following Comirnaty Vaccination

BACKGROUND: Age-specific incidence of acute myocarditis/pericarditis in adolescents following Comirnaty vaccination in Asia is lacking. This study aimed to study the clinical characteristics and incidence of acute myocarditis/pericarditis among Hong Kong adolescents following Comirnaty vaccination. METHODS: This is a population cohort study in Hong Kong that monitored adverse events following immunization through a pharmacovigilance system for COVID-19 vaccines. All adolescents aged between 12 and 17 years following Comirnaty vaccination were monitored under the COVID-19 vaccine Adverse Event Response and Evaluation Programme. The clinical characteristics and overall incidence of acute myocarditis/pericarditis in adolescents following Comirnaty vaccination were analysed. RESULTS: Between 14 June 2021 and 4 September 2021, 33 Chinese adolescents who developed acute myocarditis/pericarditis following Comirnaty vaccination were identified. 29 (87.88%) were males and 4 (12.12%) were females, with a median age of 15.25 years. 27 (81.82%) and 6 (18.18%) cases developed acute myocarditis/pericarditis after receiving the second and first dose, respectively. All cases are mild and required only conservative management.The overall incidence of acute myocarditis/pericarditis was 18.52 (95% Confidence Interval [CI], 11.67-29.01) per 100,000 persons vaccinated. The incidence after the first and second doses were 3.37 (95%CI 1.12-9.51) and 21.22 (95%CI 13.78-32.28 per 100,000 persons vaccinated, respectively. Among male adolescents, the incidence after the first and second doses were 5.57 (95% CI 2.38-12.53) and 37.32 (95% CI 26.98-51.25) per 100,000 persons vaccinated. CONCLUSIONS: There is a significant increase in the risk of acute myocarditis/pericarditis following Comirnaty vaccination among Chinese male adolescents, especially after the second dose

Nurses' perceived barriers to the implementation of a Fall Prevention Clinical Practice Guideline in Singapore hospitals

BackgroundTheories of behavior change indicate that an analysis of barriers to change is helpful when trying to influence professional practice. The aim of this study was to assess the perceived barriers to practice change by eliciting nurses\u27 opinions with regard to barriers to, and facilitators of, implementation of a Fall Prevention clinical practice guideline in five acute care hospitals in Singapore.MethodsNurses were surveyed to identify their perceptions regarding barriers to implementation of clinical practice guidelines in their practice setting. The validated questionnaire, \u27Barriers and facilitators assessment instrument\u27, was administered to nurses (n = 1830) working in the medical, surgical, geriatric units, at five acute care hospitals in Singapore.ResultsAn 80.2% response rate was achieved. The greatest barriers to implementation of clinical practice guidelines reported included: knowledge and motivation, availability of support staff, access to facilities, health status of patients, and, education of staff and patients.ConclusionNumerous barriers to the use of the Fall Prevention Clinical Practice Guideline have been identified. This study has laid the foundation for further research into implementation of clinical practice guidelines in Singapore by identifying barriers to change in acute care settings.<br /

Exploration of Shared Genetic Architecture Between Subcortical Brain Volumes and Anorexia Nervosa

In MRI scans of patients with anorexia nervosa (AN), reductions in brain volume are often apparent. However, it is unknown whether such brain abnormalities are influenced by genetic determinants that partially overlap with those underlying AN. Here, we used a battery of methods (LD score regression, genetic risk scores, sign test, SNP effect concordance analysis, and Mendelian randomization) to investigate the genetic covariation between subcortical brain volumes and risk for AN based on summary measures retrieved from genome-wide association studies of regional brain volumes (ENIGMA consortium, n = 13,170) and genetic risk for AN (PGC-ED consortium, n = 14,477). Genetic correlations ranged from − 0.10 to 0.23 (all p > 0.05). There were some signs of an inverse concordance between greater thalamus volume and risk for AN (permuted p = 0.009, 95% CI: [0.005, 0.017]). A genetic variant in the vicinity of ZW10, a gene involved in cell division, and neurotransmitter and immune system relevant genes, in particular DRD2, was significantly associated with AN only after conditioning on its association with caudate volume (pFDR = 0.025). Another genetic variant linked to LRRC4C, important in axonal and synaptic development, reached significance after conditioning on hippocampal volume (pFDR = 0.021). In this comprehensive set of analyses and based on the largest available sample sizes to date, there was weak evidence for associations between risk for AN and risk for abnormal subcortical brain volumes at a global level (that is, common variant genetic architecture), but suggestive evidence for effects of single genetic markers. Highly powered multimodal brain- and disorder-related genome-wide studies are needed to further dissect the shared genetic influences on brain structure and risk for AN

A new, improved sensor for ascorbate determination at copper hexacyanoferrate modified carbon film electrodes

A new, improved sensor for the electrocatalytic determination of ascorbate has been developed that has both a low applied operating potential and a low detection limit. The sensor was constructed by depositing copper hexacyanoferrate film either electrochemically or chemically onto carbon film electrode, and it was then characterised by cyclic voltammetry and electrochemical impedance spectroscopy. Chemically deposited films were shown to be the best for ascorbate determination and were used as an amperometric sensor at +0.05 V versus SCE to determine ascorbate in wines and juice. The linear range extended to 5 mM with a limit of detection of 2.1 µM, the sensor was stable for more than four months, and it could be used continuously for at least 20 days

Plasmid profile and construction of a small shuttle vector in Laribacter hongkongensis

Among 21 human strains of Laribacter hongkongensis, small plasmids were observed in four strains, and large ones in six strains. The smallest, 3264-bp plasmid, pHLHK19, has only one ORF that encodes a putative replication initiator protein and a predicted origin of replication (ori) with a DnaA box, three 18-bp direct repeats and five pairs of inverted repeats. An Escherichia coli-L. hongkongensis shuttle vector was constructed by ligating the HindIII-digested pHLHK19, containing the replication initiator protein and ori of pHLHK19, to HindIII-digested pBK-CMV. This shuttle vector can propagate in E. coli and L. hongkongensis with good transformation efficiencies. © 2007 Springer Science+Business Media B.V.link_to_subscribed_fulltex

Malnutrition in hospitalized geriatric patients

The incidence of hospital malnutrition has not been systematically studied in Hong Kong hospitals. This study was initiated to determine if malnutrition in geriatric patients is being under reported and to evaluate the efficacy of a modified monitoring and reporting procedure. Subjects (>65 yr) on congee or enteral diet were medically stable. In the control phase (3 months), newly admitted patients received standard hospital care and 9 out of 67 (13%) were identified as malnourished (CM). The study phase started one month after the last control subject was recruited. Plasma albumin (ALB) <28 g/l and the presence of diarrhea were used as criteria in identifying the malnourished (SM). 16 out of 51 (31%) newly admitted patients were SM. At identification, ALB levels were low (19.5 g/l) but similar between CM & SM. Prealbumin (PA) levels of the SM, however, were higher than that of the CM (0.117 vs 0.087 g/l, p<0.05). A similar trend was observed for plasma transferrin (TRF) (1.34 vs 1.03 g/l, p=0.07). Upon three weeks of nutritional intervention, PA levels were increased by 56% and 66% in the CM and SM, respectively. TRF levels were also increased significantly by 32% and 19%. These data suggest that malnutrition in geriatric patients is a serious problem. A routine but effective procedure should be enforced for early detection and intervention.link_to_subscribed_fulltex

Construction of an inducible expression shuttle vector for Laribacter hongkongensis, a novel bacterium associated with gastroenteritis

An Escherichia coli-Laribacter hongkongensis shuttle vector (pPW380) was constructed by ligating the 4701-bp EcoRI digested fragment of pHLHK8 to EcoRI digested pBK-CMV. An E. coli-L. hongkongensis inducible expression shuttle vector was further constructed by ligating a 2105-bp fragment that contains the tetracycline repressor and tetracycline-inducible promoter region of pALC2084 to the 8897-bp fragment of pPW380, deletion of the green fluorescent protein gene, and insertion of a multiple cloning site. This inducible expression system was able to express two commonly used reporter genes, the green fluorescent protein gene and the glutathione S-transferase gene, efficiently in E. coli and L. hongkongensis. © 2005 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.link_to_subscribed_fulltex