Background: Singapore General Hospital (SGH) is the largest acute tertiary-care hospital in Singapore. Healthcare workers (HCWs) are at risk of acquiring COVID-19 in both the community and workplaces. SGH has a robust exposure management process including prompt contact tracing, immediate ring fencing, lock down of affected cubicles or single room isolation for patient contacts, and home isolation orders for staff contacts of COVID-19 cases during the containment phase of the pandemic. Contacts were also placed on enhanced surveillance with PCR testing on days 1 and 4 as well as daily antigen rapid tests (ARTs) for 10 days after exposure. Here, we describe the characteristic of HCWs with COVID-19 during the third wave of the COVID-19 pandemic. Methods: This retrospective observational study included all SGH HCWs who acquired COVID-19 during the third wave (ie, the 18-week period from September 1 to December 31, 2021) of the COVID-19 pandemic. Univariate analysis was used to compare characteristics of work-associated infection (WAI) and community-acquired infection (CAI) among HCWs. Results: Among a workforce of >10,000 at SGH, 335 HCWs acquired COVID-19 during study period. CAI (exposure to known clusters or household contact) accounted for 111 HCW infections (33.1%). Also, 48 HCWs (14.3%) had a WAI (ie, acquired at their work places where there was no patient contact). Among WAsI, only 5 HCWs had hospital-acquired infection (confirmed by phylogenetic analysis). The sources of exposure for the remaining 176 HCWs were unknown. Weekly incidence of COVID-19 among HCWs was comparable to the epidemiology curve of all cases in Singapore (Fig. 1 and 2). The mean age of HCWs with COVID-19 was 39.6 years, and most were women. At the time of positive SARS-CoV-2 PCR test, 223 HCWs were symptomatic, and 67 (20.0%) of them had comorbidities. Only 16 HCWs (4.8%) required hospitalization, and all recovered fully with no mortality (Table 1). Being female was associated with community COVID-19 acquisition (OR, 4.6, P Conclusions: During the thrid wave of the COVID-19 pandemic, a higher percentage of HCWs at SGH acquired the infection from the community than from the workplace. Safe management measures, such as universal masking, social distancing, and robust exposure management processes including prompt contact tracing and environmental disinfection, can reduce the risk of COVID-19 in the hospital work environment.

Funding: None

Disclosures: None

Saetaspongia so far cannot be confidently assigned to any class-level crown group. Clarifying its phylogenetic position requires new information provided by more detailed studies of previously described and/or new material. Some sponge fossils with the typical skeletal architecture of Saetaspongia have recently been recognized in the Cambrian (Stage 4) Balang Biota of Guizhou, China, including S. jianhensis new species and S. cf. S. densa. The new taxon is characterized by the following features: spicules are fine monaxons and are inclined to be loosely to densely arranged into plumose arrays; skeleton is composed primarily of one major plumose bundle, with an uncertain number (perhaps two) of small plumose arrays; and primary skeleton is occasionally interspersed with some irregularly oriented individual spicules. An additional specimen consisting of large monaxons, with plumose structures and overlying irregular coarse monaxons, closely fits the description and illustrations of previously described S. cf. S. densa. By combining information from previous studies and the present research, fossil evidence indicates that the plumose architecture is a critical feature diagnostic of Saetaspongia and that there are no hexactine-based spicules in this genus. The new material from the Balang Biota further supports the notion that Saetaspongia has a protomonaxonid rather than a hexactinellid affinity. Fossil evidence suggests that Saetaspongia had a wide biogeographic distribution during the early Cambrian and the stratigraphic distribution of this genus extends up to Stage 4.

UUID: http://zoobank.org/e9ca5e4a-134c-4daa-9266-19085e32614f.

Background: The optimal prevention of healthcare onset Clostridium difficile infection (CDI) has been a challenging one in an acute tertiary-care hospital with limited number of single rooms. Asymptomatic patients with CDI are nursed in open wards but tagged with a green sticker to alert staff of their status. This signal prompts cleaning staff to use 5,000 ppm sodium hypochlorite to clean environmental surfaces in the multibed room and to continue with modified contact precautions. Methods: We conducted a survey on infection prevention measures used in the management of CDI patients over 2 weeks among senior nurse managers, clinicians, and registered nurses in 38 inpatient wards. We categorized the survey results into 4 types of practices: established practices, nonestablished practices (easy implementation), nonestablished practices (lack of resources), and nonestablished practices (staff resistance). We then identified barriers to determine reasons for resistance to nonestablished practices before the implementation of the CDI bundle in May 2019. The bundle comprised the following components: contact precautions, antimicrobial stewardship, isolation of CDI patient with diarrhea in single room, environment, and equipment hygiene. Following the survey, we enhanced the signage for CDI patients to be more obvious. Monthly, we monitored the incidence of HO-Clostridium difficile to assess effectiveness of implementation measures. Results: Nonestablished practices (easy implementation) included uncertainty of diarrhea definition and the recommended environmental hygiene disinfectant, lack of understanding of the importance of complying to personal protective equipment (PPE), and inconsistency in conveying CDI status. Among nonestablished practices (lack of resources), shortage of isolation beds for CDI patients with diarrhea and unavailability of electronic alert system for CDI patients within the institution are the major issues faced by clinical staff. Unavailability of CDI indicator stickers, contact precaution posters, and sporicidal wipes were noted in 6 medical and surgical wards. Nonestablished practices (staff resistance) were related to the time taken to don full PPE and reluctance to arrange for an isolation bed due to increased workload and unavailability of isolation beds. A shift was noted in the control chart for HO-Clostridium difficile after the implementation of the CDI bundle in May 2019. Conclusions: The categorization of practices into established and nonestablished practices can help to identify barriers that may interfere with successful implementation of an infection prevention bundle.

Funding: None

Disclosures: None

Background and Objective. A growing body of literature indicates a significant contribution and role of positive and negative emotions (specifically expressivity) in post-traumatic stress disorder's (PTSD) symptomatology. The current study examined the facet-level relationships between emotional expressivity and PTSD. Specifically, we investigated which emotional expressivity dimension (impulse strength, negative emotional expressivity, and positive emotional expressivity) most strongly related to DSM-5 PTSD symptom clusters severity (intrusions, avoidance, negative alterations in cognition and mood, and alterations in arousal and reactivity). Methods. The sample of 123 trauma-exposed participants seeking mental health treatment completed the PTSD Checklist for DSM-5 (PCL-5) and the Berkeley Expressivity Questionnaire (BEQ). Results. Results of multivariate multiple regression analysis indicated that only intensity of emotion and difficulty in controlling such emotions (i.e., impulse strength) was strongly related to all four PTSD symptom clusters. The valence of emotional expressivity (positive or negative) was not related to any of the PTSD symptom clusters. Conclusions. Study findings highlight the role of emotional expressivity, specifically impulse strength, in PTSD's symptomatology and may inform guidelines for emotion-focused clinical work for trauma-exposed individuals with PTSD symptoms.

Both short- and long-term effects of fertilizers on crops and soils are often studied only in arid or paddy soils, whereas less is known about the long-term effects in paddy-upland rotations, particularly with multiple crops and frequent tillage in subtropical areas. Therefore, an 18-year field experiment was initialized to assess the effects of different types of fertilization (no fertilizer; chemical fertilizer (CF); and manure in combination with CF (MCF)) on yield and soil chemical and microbial properties in a crop rotation involving rice (Oryza sativa L., summer), rapeseed (Brassica campestris L., winter), tobacco (Nicotiana tabacum L., the following summer), and hairy vetch (Vicia villosa Roth, the following winter). MCF caused higher yields of rapeseed grains and tobacco leaves than CF after 3 or 4 years of implementing the experiment, while rice yields varied little between MCF and CF, with one exception in 2011. Compared with the initial soil properties, providing soil with MCF increased organic matter (OM), while the opposite trend was found with CF. Higher microbial biomasses, enzyme activities, bacterial operational taxonomic units, and richness and diversity indexes of bacterial communities were found in soils receiving MCF, implying the improvement of soil microbial properties in the paddy-upland rotation system with multiple crops and frequent tillage. The experimental soils under varying fertilization were dominated by four bacterial phyla (Proteobacteria, Acidobacteria, Actinobacteria, and unclassified groups), which accounted for approximately 70% of the 16S rDNA sequences. Among the top 20 predominant bacteria, 14 were commonly found in all soil samples irrespective of which fertilizer treatment was implemented. Thus, the presence of those bacteria was stable in the soil and to some extent was influenced by fertilization. Most of them were facultative anaerobic bacteria, which can adapt to both anaerobic paddy soil and aerobic drylands. The dominant bacteria at various taxonomic levels found in soils might reflect multiple soil processes such as OM turnover, nutrient cycling, physical structure formation, and xenobiotic detoxification.

The present study investigated the effects of glutamine (GLN) pretreatment on CD4+ T cell polarisation and remote kidney injury in mice with gut-derived polymicrobial sepsis. Mice were randomly assigned to three groups: normal control fed with American Institute of Nutrition (AIN)-93G diet and two sepsis groups provided with either AIN-93G-based diet or identical components, except part of casein was replaced by GLN. Mice were given their respective diets for 2 weeks. Then, mice in the sepsis groups were performed with caecal ligation and puncture and were killed 72 h after the surgery. Blood, spleens and kidneys were collected for further examination. The results showed that sepsis resulted in decreased circulating and splenic total T lymphocyte and CD4+ T cell percentages, whereas IL-4-, and forkhead box p3 (Foxp3)-expressing CD4+ T cells percentages were up-regulated. Compared with the sepsis control group, pretreatment with GLN maintained blood T and CD4+ T cells and reduced percentages of IL-4- and Foxp3-expressing CD4+ T cells. Also, a more pronounced activation and increased anti-apoptotic Bcl-2 gene expression of splenic CD4+ T cells were observed. Concomitant with the decreased plasma IL-6, keratinocyte-derived chemokine (KC) levels, the gene expression of KC, macrophage inflammatory protein-2 and renal injury biomarker kidney injury molecule-1 (Kim-1) were down-regulated when GLN was administered. These findings suggest that antecedent of GLN administration elicit a more balanced blood T helper cell polarisation, sustained T cell populations, prevented splenic CD4+ T cell apoptosis and attenuated kidney injury at late phase of polymicrobial sepsis. GLN may have benefits in subjects at risk of abdominal infection.

The associations between Chinese adolescents’ family (maternal, paternal, and sibling) relationship qualities and their adjustment were examined among 540 Chinese families over a one-year period. Path analysis revealed that father-offspring positivity was associated with lower levels of internalising problems, whereas mother-offspring conflict predicted youths’ depressive symptoms and loneliness. Controlling for parent-offspring relationships, sibling intimacy inversely predicted youths’ internalising and externalising problems, whereas sibling conflict predicted youths’ loneliness. Multigroup comparisons revealed that youth gender moderated the associations between maternal conflict and youths’ depressive symptoms, as well as sibling intimacy and youths’ loneliness. Overall, results highlight the importance of family systems for Chinese youths’ mental health and the need to study sibling relationships in future studies of Chinese families.

The effects of the thermal cyclic aging treatment on the microstructure and mechanical properties of 2060 Al–Li alloy laser beam welded joints were investigated. Aging treatments were conducted at different temperatures and for different cycles. Test results showed that the tensile strength of the weld joints increased and the elongation slightly decreased after the thermal cycling treatment. It was also found that the heat affected zone (HAZ) of the welds exhibited a significant increase in microhardness, whilst the microhardness variation of the nondendrite equiaxed zone (EQZ) can be neglected. The strengthening effect of the thermal cycling became more obvious as the temperature and cycles increased. The highest strength of around 513 MPa (96% of the base metal) was obtained at the temperature of 180 °C. Reprecipitation of strengthening phases such as T1 in the HAZ at 180 °C was observed by TEM, which can be considered as the main reason for the strengthening effect of the aging treatment.

In this paper, numerical simulations of solid particle erosion phenomena on H-type finned circular/elliptic tube surface, which is of great significance to the antiwear design of heat exchanger, are presented. The Eulerian-Lagrangian approach is applied to simulate the dilute gas-solid flow through H-type finned circular/elliptic tubes. A semi-empirical model is adopted to predict the erosion rate. The dynamics behavior of the entrained solid particles in the flow is presented. The geometry of eroded tube surface is changed with the predicted erosion which is taken into account by a UDF and the flow field is re-solved for the eroded tube surface at every time step. The influences of ten parameters (the tube bundle arrangement, particle size, particle concentration, fluid Reynolds number, fin thickness, fin pitch, fin length, fin width, slit width and the transverse tube pitch) on the maximum erosion depth of the H-type circular/elliptic finned tube surface are investigated. Using H-type finned elliptic tube surface can effectively reduce the erosion rate of tube surface comparedwith that using H-type finned circular tube surface. The erosion in in-line arrangement is less severe than that in staggered arrangement. With the increase of particle size, particle concentration and the fluid Reynolds number, the erosion rate of the tube surface rises. The numerically predicted effect of Reynolds number is in good agreement with previous test data. Among the six geometry parameters, the most influential parameter is the transverse tube pitch.

Interleukin (IL)-13-associated signal pathway plays an important role in schistosomiasis hepatic fibrosis. In this study we tried to investigate the effects of corilagin to ameliorate schistosomiasis hepatic fibrosis through regulating IL-13-associated signal pathway in vitro and in vivo. Cellular model was set up with hepatic stellate cells-T6 cells stimulated by rIL-13 and male Balb/c mice were infected with Schistosoma japonicum cercariaeas as animal model. Liver histological changes were observed with haematoxylin and eosin staining. Masson staining was employed to observe the change of egg granulomas. Expression of Col (collagen) and Col III were examined with Immunohistochemistry. Western bolt was employed to detect the JAK-1 and IL13Rα1 proteins. The mRNA expression of Col I, Col III, IL-13, JAK-1 and IL13Rα1 were tested by quantitative polymerase chain reaction. As a result, less inflammatory changes were found in all corilagin groups compared with model group and praziquantel group. The mRNA levels of Col I, Col III, IL-13, JAK-1 and IL13Rα1 were significantly decreased after corilagin intervention (P < 0·01). JAK-1 and IL-13Rα1 protein levels were also greatly decreased in the corilagin groups (P < 0·01). In conclusion, corilagin could ameliorate schistosomiasis hepatic fibrosis by down-regulating the expression of IL-13 and signal molecules in IL-13 pathway.

The information on the Closest Point of Approach (CPA) of another vessel to own ship is required in a potential collision situation as it helps determines the risk to each vessel. CPA is usually calculated based on the speed and direction of the approaching ship neglecting the Change Of Speed (COS) and the Rate Of Turn (ROT). This will make the CPA less useful. To improve the CPA calculation, Automatic Identification System (AIS) information containing the Speed Over Ground (SOG), Course Over Ground (COG), COS and ROT is used. Firstly, a model using these four factors is built to predict ship positions better. Secondly, a three-step CPA searching method is developed. The developed CPA calculation method can assist in informing the navigation decisions and reducing unnecessary manoeuvres. Through the analysis of a real collision scenario, this paper shows that the proposed method can help identify and warn of anomalous ship behaviours in a realistic time frame.

Crack propagation behaviors in a precracked single crystal Ag under mode I loading at different temperatures are studied by molecular dynamics simulation. The simulation results show that the crack propagation behaviors are sensitive to external temperature. At 0 K, the crack propagates in a brittle manner. Crack tip blunting and void generation are first observed followed by void growth and linkage with the main crack, which lead to the propagation of the main crack and brittle failure immediately without any microstructure evolution. As the temperature gets higher, more void nucleations and dislocation emissions occur in the crack propagation process. The deformation of the single crystal Ag can be considered as plastic deformation due to dislocation emissions. The crack propagation dynamics characterizing the microstructure evolution of atoms around the crack tip is also shown. Finally, it is shown that the stress of the single crystal Ag changes with the crack length synchronously.

This study investigated the effects of glycinin on the growth, intestinal oxidative status, tight junction components, cytokines and apoptosis signalling factors of fish. The results showed that an 80 g/kg diet of glycinin exposure for 42 d caused poor growth performance and depressed intestinal growth and function of juvenile Jian carp (Cyprinus carpio var. Jian). Meanwhile, dietary glycinin exposure induced increases in lipid peroxidation and protein oxidation; it caused reductions in superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities; and it increased MnSOD, CuZnSOD, GPx1b and GPx4a mRNA levels, suggesting an adaptive mechanism against stress in the intestines of fish. However, dietary glycinin exposure decreased both the activity and mRNA levels of nine isoforms of glutathione-S-transferase (GST) (α, μ, π, ρ, θ, κ, mGST1, mGST2 and mGST3), indicating toxicity to this enzyme activity and corresponding isoform gene expressions. In addition, glycinin exposure caused partial disruption of intestinal cell–cell tight junction components, disturbances of cytokines and induced apoptosis signalling in the distal intestines>mid intestines>proximal intestines of fish. Glycinin exposure also disturbed the mRNA levels of intestinal-related signalling factors Nrf2, Keap1a, Keap1b, eleven isoforms of protein kinase C and target of rapamycin/4E-BP. Interestingly, glutamine was observed to partially block those negative influences. In conclusion, this study indicates that dietary glycinin exposure causes intestinal oxidative damage and disruption of intestinal physical barriers and functions and reduces fish growth, but glutamine can reverse those negative effects in fish. This study provides some information on the mechanism of glycinin-induced negative effects.

Epidemiological studies have demonstrated inconsistent associations between tea consumption and mortality of all cancers, CVD and all causes. To obtain quantitative overall estimates, we conducted a dose–response meta-analysis of prospective cohort studies. A literature search in PubMed and Embase up to April 2015 was conducted for all relevant papers published. Random-effects models were used to calculate pooled relative risks (RR) with 95 % CI. In eighteen prospective studies, there were 12 221, 11 306 and 55 528 deaths from all cancers, CVD and all causes, respectively. For all cancer mortality, the summary RR for the highest v. lowest category of green tea and black tea consumption were 1·06 (95 % CI 0·98, 1·15) and 0·79 (95 % CI 0·65, 0·97), respectively. For CVD mortality, the summary RR for the highest v. lowest category of green tea and black tea consumption were 0·67 (95 % CI 0·46, 0·96) and 0·88 (95 % CI 0·77, 1·01), respectively. For all-cause mortality, the summary RR for the highest v. lowest category of green tea and black tea consumption were 0·80 (95 % CI 0·68, 0·93) and 0·90 (95 % CI 0·83, 0·98), respectively. The dose–response analysis indicated that one cup per d increment of green tea consumption was associated with 5 % lower risk of CVD mortality and with 4 % lower risk of all-cause mortality. Green tea consumption was significantly inversely associated with CVD and all-cause mortality, whereas black tea consumption was significantly inversely associated with all cancer and all-cause mortality.

Predator–prey interactions play major and direct roles in the structuring of zooplankton communities. Asplanchna usually predates ciliates, rotifers, cladocerans and sometimes even copepods, its predation may drive not only the ecological, but also the evolutionary dynamics of prey populations. In the present study, the life-table demography and the population growth of Asplanchna brightwelli were investigated at four temperatures (16, 20, 24 and 28°C) using Brachionus angularis as prey at four densities (10, 20, 30 and 40 ind.mL−1). The results showed that temperature affected significantly all the life-table demographic parameters (age-specific survivorship and fecundity, average lifespan, life expectancy at hatching, generation time, net reproductive rate and intrinsic rate of population increase) and the population growth rate obtained from the population growth studies, prey density affected the generation time, the net reproductive rate, the intrinsic rate of population increase and the population growth rate, and the interaction between temperature and prey density affected the generation time and the population growth rate. Both the average lifespan and the life expectancy at hatching were the longest at 16°C, the generation times were longer at lower temperatures (16 and 20°C) and higher prey densities (30 and 40 ind.mL−1), the net reproductive rates were higher at lower temperatures (16 and 20°C) and 20–40 ind.mL−1 of B. angularis, and the population growth rates were higher at 20°C under 20–40 ind.mL−1 of B. angularis.