Poly(lactic acid) (PLA) synthesized from renewable resources has drawn a great deal of interest in packaging, electronics and automotive applications. However, poor flame retardancy of PLA, ...especially its ease of ignitability and heavily flaming drips, represents a major obstacle for its potential application. The article outlines the recent advances in the field of flame-retarded PLA. Current development trends based on the direct incorporation of flame retardant additives, chemical modification, hybridization and synthesis of flame retardants were reported. Results obtained from UL 94 vertical burning, limiting oxygen index (LOI) and cone calorimetry (CCM) tests for each type of flame retardants were discussed and analyzed. Test results summarized in a UL 94-LOI matrix found to be a useful tool to determine the effectiveness of flame retardants in PLA. The UL 94-LOI comparison matrix and CCM test results revealed that the combined use of flame retardants (containing intumescent formulation) is one of the promising strategies to reach the flame retardancy of PLA needed by practical applications. This review ends with a brief summary of and outlook on future developments of flameretarded PLA systems.
Carbapenem-resistant Enterobacteriaceae represents a major public health issue. This study investigated the clonality and resistance mechanisms of 92 carbapenem-resistant
E. coli
(
n =
21) and
K. ...pneumoniae
(
n =
71) isolates collected consecutively from clinical specimens and patients at high risk of carriage between 2010 and 2012 in a healthcare region in Hong Kong. Combined disk tests (CDTs) and the Carba NP test were used for phenotypic detection of carbapenemases. PCR assays were used to detect carbapenemase genes. All isolates were intermediate or resistant to at least one carbapenem. Nine (9.8 %) isolates were genotypic carbapenemase producers and included six
K. pneumoniae
(one ST1306/
bla
IMP-4
, one ST889/
bla
IMP-4
, two ST11/
bla
KPC-2
, one ST258/
bla
KPC-2
, one ST483/
bla
NDM-1
) and three
E. coli
(one ST131/
bla
IMP-4
, two ST744/
bla
NDM-1
) isolates. All nine isolates carrying carbapenemase genes could be detected by the CDTs and the Carba NP test. PCR identified
bla
CTX-M
and
bla
AmpC
alone or in combination in 77.8 % (7/9) and 96.4 % (80/83) of the carbapenemase-producers and non-producers, respectively. Porin loss was detected in 22.2 % (2/9) and 59.0 % (49/83) of the carbapenemase-producers and non-producers, respectively. Overall, the
E. coli
clones were diverse (14 different STs), but 36.6 % (26/71) of the
K. pneumoniae
isolates belonged to ST11. In conclusion, the prevalence of carbapenemases among carbapenem-nonsusceptible
E. coli
and
K. pneumoniae
remained low in Hong Kong. Porin loss combined with AmpC and/or CTX-M type ESBL was the major mechanism of carbapenem resistance in the study population.
Aims
To investigate plasmid‐mediated fosfomycin resistance related to fosA3 in Escherichia coli isolates collected from different animals in Hong Kong, China, 2008–2010.
Methods and Results
In total, ...2106 faecal specimens from 210 cattle, 214 pigs, 460 chickens, 398 stray cats, 368 stray dogs and 456 wild rodents were cultured. The faecal colonization rates of fosfomycin‐resistant E. coli were as follows: 11·2% in pigs, 8·6% in cattle, 7·3% in chickens, 2·4% in dogs, 0·8% in cats and 1·5% in rodents. The cultures yielded 1693 isolates of which 831 were extended‐spectrum β‐lactamases (ESBL) producers. Fosfomycin‐resistant isolates were more likely than fosfomycin‐susceptible isolates to be producers of ESBL and to have resistance to chloramphenicol, ciprofloxacin, cotrimoxazole, gentamicin and tetracycline. Of the 101 fosfomycin‐resistant isolates, 97 (96·0%) isolates were fosA3 positive and 94 (93·1%) were blaCTX‐M positive. PCR mapping showed that the fosA3‐containing regions were flanked by IS26, both upstream and downstream in 81 (83·5%) isolates, and by an upstream blaCTX‐M‐14‐containing transposon‐like structure (ΔISEcp1‐blaCTX‐M‐14‐ΔIS903 or ISEcp1‐IS10 ‐blaCTX‐M‐14‐ΔIS903) and a downstream IS26 in 14 (14·4%) isolates. For the remaining two isolates, fosA3 was flanked by a downstream IS26 but the upstream part cannot be defined. In a random subset of 18 isolates, fosA3 was carried on transferable plasmids with sizes of 50–200 kb and the following replicons: F2:A‐B‐ (n = 3), F16:A1:B‐ (n = 2), F24:A‐B‐ (n = 1), N (n = 1), B/O (n = 1) and untypeable (n = 3).
Significance and Impact of the Study
This study demonstrates the emergence of fosA3‐mediated fosfomycin resistance among multidrug‐resistant E. coli isolates from various animals. IS26 transposon‐like structures might be the main vehicles for dissemination of fosA3.
Helicobacter pylori infection is associated with a variety of clinical
outcomes including gastric cancer and duodenal ulcer disease.
The reasons for this variation are not clear, but the gastric ...physiological
response is influenced by the severity and anatomical distribution of gastritis
induced by H. pylori. Thus, individuals with gastritis predominantly
localized to the antrum retain normal (or even high) acid secretion,
whereas individuals with extensive corpus gastritis develop hypochlorhydria
and gastric atrophy, which are presumptive precursors of gastric
cancer. Here we report that interleukin-1 gene cluster polymorphisms
suspected of enhancing production of interleukin-1-beta are associated with
an increased risk of both hypochlorhydria induced by H. pylori and
gastric cancer. Two of these polymorphism are in near-complete linkage disequilibrium
and one is a TATA-box polymorphism that markedly affects DNA-protein
interactions in vitro. The association with disease may be explained
by the biological properties of interleukin-1-beta, which is an important
pro-inflammatory cytokine and a powerful inhibitor of gastric
acid secretion. Host genetic factors that affect interleukin-1-beta
may determine why some individuals infected with H. pylori develop
gastric cancer while others do not.
Abstract Background During 2008, Singapore experienced its largest ever outbreak of hand, foot and mouth disease (HFMD), resulting in 29 686 cases, including four cases of encephalitis and one ...fatality. Methods A total of 51 clinical specimens from 43 patients with suspected HFMD at the National University Hospital, Singapore were collected for virus isolation and identification by reverse transcription polymerase chain reaction (RT-PCR) and sequencing. Results Enteroviruses were identified in 34 samples (66.7%), with 11 samples (21.6%) being positive for enterovirus 71 (EV71). Other non-EV71 enteroviruses (including coxsackievirus A4, A6, A10, and A16) were identified in 23 samples (45.1%). The most prevalent virus serotypes were CA6, CA10, and EV71. CA6 and CA10 accounted for 35.3% of all HFMD cases, which may explain the high transmissibility and low fatality that characterized this unprecedented epidemic associated with relatively mild disease. Phylogenetic analyses of 10 circulating EV71 strains indicated that they belonged to two subgenogroups, i.e., B5 (80%) and C2 (20%). The VP1 sequences of the 2008 EV71 strains also exhibited continuous mutations during the outbreak, reflecting the relatively high mutation rate of the EV71 capsid protein, which may have implications for future vaccine development. Conclusions A safe and effective vaccine against EV71 is certainly warranted in view of its potential neurovirulence and its role in HFMD epidemics of recurring frequency with resultant fatalities in Asia, as well as other parts of the world.
Three-dimensionally printed nasopharyngeal swabs (3DP swabs) have been used to mitigate swab shortages during the coronavirus disease 2019 (COVID-19) pandemic. Clinical validation for diagnostic ...accuracy and consistency, as well as patient acceptability, is crucial to evaluate the swab's performance.
To determine the accuracy and acceptability of the 3DP swab for identifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
A diagnostic study was conducted from May to July 2020 at 2 tertiary care centers in Singapore with different reference swabs (FLOQSwab COPAN Diagnostics or Dacron swab Deltalab) and swab processing techniques (wet or dry) to evaluate the performance of the 3DP swab compared with traditional, standard-of-care nasopharyngeal swabs used in health care institutions. The participants were patients with COVID-19 in the first 2 weeks of illness and controls with acute respiratory illness with negative test results for SARS-CoV-2. Paired nasopharyngeal swabs were obtained from the same nostril and tested for SARS-CoV-2 by reverse-transcriptase polymerase chain reaction. The sequence of swabs was randomized based on odd and even participant numbers.
Primary outcome measures were overall agreement (OA), positive percentage agreement (PPA), and negative percentage agreement of the 3DP swab compared with reference swabs. Secondary outcome measures were the correlation of cycle threshold (Ct) values of both swabs.
The mean (SD) age of participants was 45.4 (13.1) years, and most participants were men (87 of 89 97.8%), in keeping with the epidemiology of the COVID-19 pandemic in Singapore. A total of 79 patients with COVID-19 and 10 controls were recruited. Among the patients with COVID-19, the overall agreement and PPA of the 3DP swab was 91.1% and 93.5%, respectively, compared with reference swabs. The PPA was 100% for patients with COVID-19 who were tested within the first week of illness. All controls tested negative. The reverse-transcriptase polymerase chain reaction Ct values for the ORF1ab and E-gene targets showed a strong correlation (intraclass correlations coefficient, 0.869-0.920) between the 3DP and reference swab on independent testing at each institution despite differences in sample processing. Discordant results for both gene targets were observed only at high Ct values.
In this diagnostic study of 79 patients with COVID-19 and 10 controls, the 3DP swab performed accurately and consistently across health care institutions and could help mitigate strained resources in the escalating COVID-19 pandemic.
Abstract
Nickel-based complex oxides have served as a playground for decades in the quest for a copper-oxide analog of the high-temperature superconductivity. They may provide clues towards ...understanding the mechanism and an alternative route for high-temperature superconductors. The recent discovery of superconductivity in the infinite-layer nickelate thin films has fulfilled this pursuit. However, material synthesis remains challenging, direct demonstration of perfect diamagnetism is still missing, and understanding of the role of the interface and bulk to the superconducting properties is still lacking. Here, we show high-quality Nd
0.8
Sr
0.2
NiO
2
thin films with different thicknesses and demonstrate the interface and strain effects on the electrical, magnetic and optical properties. Perfect diamagnetism is achieved, confirming the occurrence of superconductivity in the films. Unlike the thick films in which the normal-state Hall-coefficient changes signs as the temperature decreases, the Hall-coefficient of films thinner than 5.5 nm remains negative, suggesting a thickness-driven band structure modification. Moreover, X-ray absorption spectroscopy reveals the Ni-O hybridization nature in doped infinite-layer nickelates, and the hybridization is enhanced as the thickness decreases. Consistent with band structure calculations on the nickelate/SrTiO
3
heterostructure, the interface and strain effect induce a dominating electron-like band in the ultrathin film, thus causing the sign-change of the Hall-coefficient.
Objective
Determine the associations between factors and sexual practices and the composition of the vaginal microbiome (VM) of women treated for bacterial vaginosis (BV).
Design
Prospective cohort ...study.
Setting
The Melbourne Sexual Health Centre, Melbourne, Australia.
Population
Seventy‐five reproductive‐age women diagnosed with clinical BV, treated with first‐line antibiotics and followed for up to 6 months.
Methods
Women self‐collected vaginal swabs and completed questionnaires at enrolment, the day following antibiotics and monthly for up to 6months until BV recurrence or no BV recurrence (n = 430 specimens). Bacterial composition was determined using 16S rRNA gene amplicon sequencing. The effects of ongoing factors on VM composition (utilising 291 monthly specimens) were assessed using generalised estimating equations population‐averaged models, which accounted for repeated measures within individuals.
Main outcome measures
The relative abundance of vaginal bacterial taxa.
Results
Women who reported ongoing sex with a regular sexual partner (RSP) had a VM comprised of increased relative abundance of non‐optimal BV‐associated bacteria (Adjusted co‐efficient Adjusted co‐eff = 11.91, 95% CI 3.39to20.43, P = 0.006) and a decreased relative abundance of optimal, Lactobacillus species (Adjusted co‐eff = −12.76, 95% CI −23.03 to −2.49, P = 0.015). A history of BV was also associated with a decreased relative abundance of Lactobacillus spp. (Adjusted co‐eff = −12.35, 95% CI −22.68, P = 0.019). The relative abundance of Gardnerella, Atopobium and Sneathia spp. increased following sex with an RSP.
Conclusions
Sex with an untreated RSP after BV treatment was associated with a VM comprised of non‐optimal BV‐associated bacteria. BV treatment approaches may need to include partner treatment if they are to achieve a sustained optimal VM associated with improved health outcomes.
Tweetable
Sex drives a return to a ‘non‐optimal’ vaginal microbiota after antibiotics for bacterial vaginosis.
Tweetable
Sex drives a return to a ‘non‐optimal’ vaginal microbiota after antibiotics for bacterial vaginosis.
Accumulating evidence suggests that the protective pathways of the renin-angiotensin system are enhanced in women, including the angiotensin type 2 receptor (AT2R), which mediates vasodilatory and ...natriuretic effects. To provide insight into the sex-specific ability of pharmacological AT2R stimulation to modulate renal function in hypertension, we examined the influence of the AT2R agonist, compound 21 (100-300 ng/kg per minute), on renal function in 18- to 19-week-old anesthetized male and female spontaneously hypertensive rats. AT2R stimulation significantly increased renal blood flow in female hypertensive rats (PTreatment<0.001), without influencing arterial pressure. For example, at 300 ng/kg per minute of compound 21, renal blood flow increased by 14.3±1.8% from baseline. Furthermore, at 300 ng/kg per minute of compound 21, a significant increase in urinary sodium excretion was observed in female hypertensive rats (+180±59% from baseline; P<0.05 versus vehicle-treated rats). This was seen in the absence of any major change in glomerular filtration rate, indicating that the natriuretic effects of AT2R stimulation were likely the result of altered renal tubular function. Conversely, we did not observe any significant effect of AT2R stimulation on renal hemodynamic or excretory function in male hypertensive rats. Finally, gene expression studies confirmed greater renal AT2R expression in female than in male hypertensive rats. Taken together, acute AT2R stimulation enhanced renal vasodilatation and sodium excretion without concomitant alterations in glomerular filtration rate in female hypertensive rats. Chronic studies of AT2R agonist therapy on renal function and arterial pressure in hypertensive states are now required to establish the suitability of AT2R as a therapeutic target for cardiovascular disease, particularly in women.
Background:
Elevated fibroblast growth factor 21 (FGF21) levels have been suggested, from cross-sectional studies, as an indicator of subclinical diabetic nephropathy. We investigated whether serum ...FGF21 was predictive of the development of diabetic nephropathy.
Method:
Baseline serum FGF21 levels were measured in 1136 Chinese type 2 diabetic subjects recruited from the Hong Kong West Diabetes Registry. The role of serum FGF21 in predicting decline in estimated glomerular filtration rate (eGFR) over a median follow-up of 4 years was analyzed using Cox regression analysis.
Results:
At baseline, serum FGF21 levels increased progressively with eGFR category (P for trend <.001). Among 1071 subjects with baseline eGFR ≥ 30 mL/min/1.73 m2, serum FGF21 levels were significantly higher in those with eGFR decline during follow-up (n = 171) than those without decline (n = 900) (P < .001). In multivariable Cox regression analysis, baseline serum FGF21 was independently associated with eGFR decline (hazard ratio, 1.21; 95% confidence interval CI, 1.01–1.43; P = .036), even after adjustment for baseline eGFR. In a subgroup of 559 subjects with baseline eGFR ≥60 mL/min/1.73 m2 and normoalbuminuria, serum FGF21 level remained an independent predictor of eGFR decline (hazard ratio, 1.36; 95% CI, 1.06–1.76; P = .016). Integrated discrimination improvement (IDI) suggested that the inclusion of baseline serum FGF21 significantly improved the prediction of eGFR decline (IDI, 1%; 95% CI, 0.1–3.0; P = .013) in this subgroup, but not in the initial cohort involving all subjects.
Conclusions:
Elevated serum FGF21 levels may be a useful biomarker for predicting kidney disease progression, especially in the early stages of diabetic nephropathy.
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