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Poroelastic effects have been of great interest in the seismic literature as they have been identified as a major cause of wave attenuation in heterogeneous porous media. The observed attenuation in the seismic wave can be explained in part by energy loss to fluid motion in the pores. On the other hand, it is known that the attenuation is particularly pronounced in stratified structures where the scale of spatial heterogeneity is much smaller than the seismic wavelength. Understanding of poroelastic effects on seismic wave attenuation in heterogeneous porous media has largely relied on numerical experiments. In this work, we present a homogenisation technique to obtain an upscaled viscoelastic model that captures seismic wave attenuation when the sub-seismic scale heterogeneity is periodic. The upscaled viscoelastic model directly relates seismic wave attenuation to the material properties of the heterogeneous structure. We verify our upscaled viscoelastic model against a full poroelastic model in numerical experiments. Our homogenisation technique suggests a new approach for solving coupled equations of motion.
The compressibility effects on energy exchange mechanisms in a three-dimensional, spatially developing plane free shear layer are investigated via data produced by direct numerical simulation. The compressible shear layer is simulated using a high-order discontinuous spectral element method for convective Mach numbers $M_c = 0.3$, 0.5 and 0.7. The energy exchange mechanisms in the flow are examined by analysing the budget terms of mean kinetic, internal and turbulent kinetic energy transport equations, in both transition and turbulent regions. The results show that turbulent production, turbulent viscous dissipation, mean viscous dissipation, pressure dilatation and enthalpic production are the main mechanisms responsible for energy exchange among different forms of energy. The effects of compressibility on energy transfer mechanisms are studied based on the analyses of those five budget terms. The primary budget terms evolve differently in the transition and turbulent regions and change significantly for varying compressibility. In the transition region, a double-peak variation becomes a single peak in the streamwise profile of the turbulent production as $M_c$ increases from 0.3 to 0.7, due to significant changes in the vortex pairing structures. The shear layer centre slightly shifts to the high-speed side due to the appearance of the velocity deficit. The velocity deficit presence distance (VDPD) becomes longer as compressibility increases. However, in the turbulent region, the cross-stream profiles of the main budget terms significantly shift to the low-speed side because of the asymmetric mass entrainment and shift even further as $M_c$ increases.
It is important to understand the temporal trend of the paediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load to estimate the transmission potential of children in schools and communities. We determined the differences in SARS-CoV-2 viral load dynamics between nasopharyngeal samples of infected asymptomatic and symptomatic children. Serial cycle threshold values of SARS-CoV-2 from the nasopharynx of a cohort of infected children were collected for analysis. Among 17 infected children, 10 (58.8%) were symptomatic. Symptomatic children, when compared to asymptomatic children, had higher viral loads (mean cycle threshold on day 7 of illness 28.6 vs. 36.7, P = 0.02). Peak SARS-CoV-2 viral loads occurred around day 2 of illness in infected children. Although we were unable to directly demonstrate infectivity, the detection of significant amount of virus in the upper airway of asymptomatic children suggest that they have the potential to shed and transmit SARS-CoV-2. Our study highlights the importance of contact tracing and screening for SARS-CoV-2 in children with epidemiological risk factors regardless of their symptom status, in order to improve containment of the virus in the community, including educational settings.
Precise instrumental calibration is of crucial importance to 21-cm cosmology experiments. The Murchison Widefield Array’s (MWA) Phase II compact configuration offers us opportunities for both redundant calibration and sky-based calibration algorithms; using the two in tandem is a potential approach to mitigate calibration errors caused by inaccurate sky models. The MWA Epoch of Reionization (EoR) experiment targets three patches of the sky (dubbed EoR0, EoR1, and EoR2) with deep observations. Previous work in Li et al. (2018) and (2019) studied the effect of tandem calibration on the EoR0 field and found that it yielded no significant improvement in the power spectrum (PS) over sky-based calibration alone. In this work, we apply similar techniques to the EoR1 field and find a distinct result: the improvements in the PS from tandem calibration are significant. To understand this result, we analyse both the calibration solutions themselves and the effects on the PS over three nights of EoR1 observations. We conclude that the presence of the bright radio galaxy Fornax A in EoR1 degrades the performance of sky-based calibration, which in turn enables redundant calibration to have a larger impact. These results suggest that redundant calibration can indeed mitigate some level of model incompleteness error.
Determination of antibodies against ToRCH antigens at the beginning of pregnancy allows assessment of both the maternal immune status and the risks to an adverse pregnancy outcome. Age-standardised seroprevalences were determined in sera from 1009 women of childbearing age residing in Mexico, Brazil, Germany, Poland, Turkey or China using a multiparametric immunoblot containing antigen substrates for antibodies against Toxoplasma gondii, rubella virus, cytomegalovirus (CMV), herpes simplex viruses (HSV-1, HSV-2), Bordetella pertussis, Chlamydia trachomatis, parvovirus B19, Treponema pallidum and varicella zoster virus (VZV). Seroprevalences for antibodies against HSV-1 were >90% in samples from Brazil and Turkey, whereas the other four countries showed lower mean age-adjusted seroprevalences (range: 62.5–87.9%). Samples from Brazilian women showed elevated seroprevalences of antibodies against HSV-2 (40.1%), C. trachomatis (46.8%) and B. pertussis (56.6%) compared to the other five countries. Seroprevalences of anti-T. gondii antibodies (0.5%) and anti-parvovirus B19 antibodies (7.5%) were low in samples from Chinese women, compared to the other five countries. Samples from German women revealed a low age-standardised seroprevalence of anti-CMV antibodies (28.8%) compared to the other five countries. These global differences in immune status of women in childbearing age advocate country-specific prophylaxis strategies to avoid infection with ToRCH pathogens.
There is controversy regarding whether the addition of cover gowns offers a substantial benefit over gloves alone in reducing personnel contamination and preventing pathogen transmission.
Simulated patient care interactions.
To evaluate the efficacy of different types of barrier precautions and to identify routes of transmission.
In randomly ordered sequence, 30 personnel each performed 3 standardized examinations of mannequins contaminated with pathogen surrogate markers (cauliflower mosaic virus DNA, bacteriophage MS2, nontoxigenic Clostridioides difficile spores, and fluorescent tracer) while wearing no barriers, gloves, or gloves plus gowns followed by examination of a noncontaminated mannequin. We compared the frequency and routes of transfer of the surrogate markers to the second mannequin or the environment.
For a composite of all surrogate markers, transfer by hands occurred at significantly lower rates in the gloves-alone group (OR, 0.02; P < .001) and the gloves-plus-gown group (OR, 0.06; P = .002). Transfer by stethoscope diaphragms was common in all groups and was reduced by wiping the stethoscope between simulations (OR, 0.06; P < .001). Compared to the no-barriers group, wearing a cover gown and gloves resulted in reduced contamination of clothing (OR, 0.15; P < .001), but wearing gloves alone did not.
Wearing gloves alone or gloves plus gowns reduces hand transfer of pathogens but may not address transfer by devices such as stethoscopes. Cover gowns reduce the risk of contaminating the clothing of personnel.
Critical shortages of personal protective equipment, especially N95 respirators, during the coronavirus disease 2019 (COVID-19) pandemic continues to be a source of concern. Novel methods of N95 filtering face-piece respirator decontamination that can be scaled-up for in-hospital use can help address this concern and keep healthcare workers (HCWs) safe.
A multidisciplinary pragmatic study was conducted to evaluate the use of an ultrasonic room high-level disinfection system (HLDS) that generates aerosolized peracetic acid (PAA) and hydrogen peroxide for decontamination of large numbers of N95 respirators. A cycle duration that consistently achieved disinfection of N95 respirators (defined as ≥6 log10 reductions in bacteriophage MS2 and Geobacillus stearothermophilus spores inoculated onto respirators) was identified. The treated masks were assessed for changes to their hydrophobicity, material structure, strap elasticity, and filtration efficiency. PAA and hydrogen peroxide off-gassing from treated masks were also assessed.
The PAA room HLDS was effective for disinfection of bacteriophage MS2 and G. stearothermophilus spores on respirators in a 2,447 cubic-foot (69.6 cubic-meter) room with an aerosol deployment time of 16 minutes and a dwell time of 32 minutes. The total cycle time was 1 hour and 16 minutes. After 5 treatment cycles, no adverse effects were detected on filtration efficiency, structural integrity, or strap elasticity. There was no detectable off-gassing of PAA and hydrogen peroxide from the treated masks at 20 and 60 minutes after the disinfection cycle, respectively.
The PAA room disinfection system provides a rapidly scalable solution for in-hospital decontamination of large numbers of N95 respirators during the COVID-19 pandemic.
On coronavirus disease 2019 (COVID-19) wards, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid was frequently detected on high-touch surfaces, floors, and socks inside patient rooms. Contamination of floors and shoes was common outside patient rooms on the COVID-19 wards but decreased after improvements in floor cleaning and disinfection were implemented.
Ticks display a distinct type of host-seeking behaviour called questing. It has been proposed that the questing behaviour of Ixodes scapularis explains the geographic variation in Lyme disease (LD) risk in the eastern USA because the northern population has been shown to quest more often than the southern population. The height at which questing occurs is variable and this study aimed to characterize questing height for I. scapularis. Ticks were collected from a northern and southern state (i.e. Maryland and Texas) and bioassays were conducted. We report that nymphs from Texas quested at lower heights compared to nymphs from Maryland. In addition, only Texas nymphs exhibited a behaviour we call ‘hiding behaviour’. These results may reflect the different composition of hosts between these two areas as the south has a higher abundance of lizards. In contrast, there was no significant difference in questing height between Maryland adults and Texas adults which was to be expected since adults are feeding on white-tailed deer in both locations. If all southern I. scapularis nymphs are questing at lower heights, this might make them less likely to come into contact with humans and this may be contributing to the geographical difference in LD prevalence.
Microvascular health is a main determinant of coronary blood flow reserve and myocardial vascular resistance. Extracardiac capillary abnormality has been reported in subjects at increased coronary heart disease risk, such as prehypertension, hypertension, diabetes, hyperlipidemia, and atherosclerosis. We have reported cardiovascular dysfunction in a cohort of maternal nutrient reduction (MNR)-induced intrauterine growth restriction (IUGR) baboon offspring. Here we test the hypothesis that there is oral capillary rarefaction associated with MNR-induced IUGR. Capillary density was quantified using in vivo high-power capillaroscopy on seven middle-aged (~10.7 yr; human equivalent ~40 yr) male IUGR baboons and seven male age-matched controls in the lateral buccal and inferior labial mucosa. While no difference was found between groups in either area by fraction area or optical density for these vascular beds derived from fetal preductal vessels, further studies are needed on post-ductal vascular beds, retina, and function.
In this paper, the generation of relativistic electron mirrors (REM) and the reflection of an ultra-short laser off the mirrors are discussed, applying two-dimension particle-in-cell simulations. REMs with ultra-high acceleration and expanding velocity can be produced from a solid nanofoil illuminated normally by an ultra-intense femtosecond laser pulse with a sharp rising edge. Chirped attosecond pulse can be produced through the reflection of a counter-propagating probe laser off the accelerating REM. In the electron moving frame, the plasma frequency of the REM keeps decreasing due to its rapid expansion. The laser frequency, on the contrary, keeps increasing due to the acceleration of REM and the relativistic Doppler shift from the lab frame to the electron moving frame. Within an ultra-short time interval, the two frequencies will be equal in the electron moving frame, which leads to the resonance between laser and REM. The reflected radiation near this interval and corresponding spectra will be amplified due to the resonance. Through adjusting the arriving time of the probe laser, a certain part of the reflected field could be selectively amplified or depressed, leading to the selective adjustment of the corresponding spectra.
For patients with methicillin-resistant Staphylococcus aureus (MRSA) colonization, a traditional fist-bump greeting did not significantly reduce MRSA transfer in comparison to a handshake. However, transfer was reduced with a modified fist bump that minimized the surface area of contact and when hand hygiene was performed before the handshake.
We report two cases of respiratory toxigenic Corynebacterium diphtheriae infection in fully vaccinated UK born adults following travel to Tunisia in October 2019. Both patients were successfully treated with antibiotics and neither received diphtheria antitoxin. Contact tracing was performed following a risk assessment but no additional cases were identified. This report highlights the importance of maintaining a high index of suspicion for re-emerging infections in patients with a history of travel to high-risk areas outside Europe.
To determine the clinical significance of arachnoid cysts.
The scans of 6978 patients undergoing magnetic resonance imaging of the internal acoustic meatus for unilateral cochleovestibular symptoms were retrospectively reviewed. We identified the scans with arachnoid cysts, and assessed the statistical associations between the laterality, location and size of the arachnoid cyst, the laterality of symptoms, the patients’ age and gender.
In a total of 37 arachnoid cysts identified in 36 patients (0.5 per cent), no associations were identified between the laterality of symptoms and the laterality of the arachnoid cyst, regardless of its size or location. There were no significant associations between the location of the arachnoid cyst and the age (p = 0.99) or gender of the patient (p = 0.13), or size (p = 0.656) or side of the cyst (p = 0.61). None of the cysts with repeat imaging scans (17 cysts) demonstrated growth.
Our results suggest that most, if not all, arachnoid cysts are of no clinical significance. Given their indolent behaviour, even serial imaging is not essential.
A critical region of PTSD is the medial prefrontal cortex, which may be impaired in this disorder. Neuroimaging studies have reported reduced cortical volumes and neuronal integrity, as well as decreased function in medial prefrontal structures in this disorder.
The aim of this study is to find whether mPFC neurons have cell apoptosis, which may lead to the dysfunction of mPFC of PTSD.
The group to test apotosis was divided into SPS after1d, 4d, 7d, 14d and control group. Expression of caspase-9 and caspase-3 were detected by immunohistochemistry, immunofluorescence, western blotting and RT-PCR.
Caspase-3 was located in cytoplasm. Evaluation of Caspase-3 immunohistochemistry showed a significant increased in the SPS-1d, SPS-4d and SPS-7d compared with the normal control group, then gradually decreased in SPS-14d. Caspase-9-positive cells were expressed in the control group and the SPS groups, The positive expression was green fluorescence, which in cell body, membrane, and processes. The mRNA levels of Caspase-9 in the SPS rats were significant increased on days 1d and 4d then gradually decreased. The Caspase-3 mRNA levels peaked at SPS-7d, then decreased on SPS-14d.
The mPFC neuronal apoptosis through mintochodrial pathway would play an important role in the dysfunction of mPFC in post traumatic stress disorder patients.
The aim of this study was to reveal the possible mechanisms involved in apoptosis induced by single prolonged stress (SPS) in hippocampus of post-traumatic stress disorder (PTSD) rats.
SPS is one of the animal models proposed for PTSD. Wistar rats were killed at 1, 4, 7, 14 and 28days after exposure to SPS. Expression of caspase-9, caspase-3, cytochrome c, Bcl-2 and Bax was detected by immunohistochemistry, immunofluorescence, western blotting and electron microscopy. Apoptotic cells were assessed by TUNEL method.
Our results showed apoptotic cells were significantly increased in hippocampus of SPS rats, accompanied by release of cytochrome c from the mitochondria into the cytosol, increase of caspase-9 and caspase-3 expression and decrease of the Bcl-2 / Bax ratio.
The results indicate that SPS induced apoptosis in hippocampus of PTSD rats, and the mitochondrial pathway was involved in the process of SPS induced apoptosis. *National Natural Science Foundation of China
To compare therapeutic efficacy, social function, discontinue rate, relapse and recurrence rate of the depression outpatients with first episode between Venlafaxine extended release and Fluoxertine hydrochloride treatment. Methods In this 48 week natural parallel follow-up study, total 188 patients who meet ICD-10 criteria for a major depressive episode were admitted and assigned to receive either Venlafaxine Extended Release (Venlafaxine XR group) (n=89) or Fluoxertine hydrochloride(Fluoxertine group) (n=99).At baseline,week2,8,12,16,24,32,48,Hamilton Rating Scale for Depression (HAMD)-17 item was used to value disease severity, and Social Disability Screening Schedule(SDSS)for social disability, and the discontinue, relapse and recurrence rates were compared. Results (1) At week 24 Venlafaxine XR group had much lower HAMD17 total score than Fluoxertine group (P<0.05). (2)The remission rate and response rate between two groups had no statistical difference (P>0.05). (3) At week 12, Venlafaxine XR group had a higher SDSS score than Fluoxertine group (P<0.05).(4)At week 12, 16, 24, 32,48,Venlafaxine XR group displayed lower discontinue rates (P<0.05). Venlafaxine XR group had a longer treatment course than Fluoxertine did [(30.99±15.98) weeks vs. [(22.57±15.26) weeks] (P<0.01). (5) The relapse and recurrence rates of two groups had no statistical difference (P>0.05). Conclusions In the acute phase, Venlafaxine XR has a better effect for social function and treatment adherence than Fluoxertine hydrochloride. In the continued phase and sustained phase, Venlafaxine XR performs better for symptoms relief and treatment adherence.Venlafaxine XR has parallel performance with Fluoxertine hydrochloride by the terms of therapeutic efficacy, social function restore, relapse and recurrence rate.
There are strong links between circadian disturbance and some of the most characteristic symptoms of clinical major depressive disorder (MDD). However there are no published studies of changes in expression of clock genes or of other neuropeptides related to circadian-rhythm regulation, which may influence recurrent susceptibility after treatment with antidepressant in MDD.
Blood samples were collected from twelve healthy controls and twelve male major depressive patients pre- and post- treated with escitalopram for eight weeks at 4-hour intervals for 24 hours. Outcome measures were the relative expression of mRNA of clock genes (hPERIOD1, hPERIOD2, hPERIOD3, hCRY1, hBMAL1, hNPAS2 and hGSK-3beta) and the levels of serum melatonin, Vasoactive Intestinal Peptide (VIP), cortisol, Adrenocorticotropic Hormone (ACTH), Insulin-like Growth Factor-1(IGF-1) and growth hormone (GH) in twelve healthy controls and twelve pre- and post- treated MDD patients.
Compared with healthy controls, MDD patients showed disruptions in diurnal rhythms of expression of hPERIOD1, hPERIOD2, hCRY1, hBMAL1, hNPAS2 and hGSK-3beta, along with disruptions in diurnal rhythms of release of melatonin, VIP, cortisol, ACTH, IGF-1, and GH. Several of these disruptions (hPER1, hCRY1, melatonin, VIP, cortisol, ACTH, and IGF-1) persisted after eight weeks escitalopram treatment, as did elevation of 24-hour levels of VIP and decreases in 24-hour levels of cortisol and ACTH.
These persisted neurobiological changes may play a role in MDD symptoms that are thought to contribute to recurrence vulnerability and in maintenance therapy for a long term.
Post-traumatic stress disorder (PTSD) is a significant problem,The medial prefrontal cortex (mPFC) is known to be significantly involved in emotional adjustment.
To discuss the issue of post-traumatic stress disorder (PTSD) rat apoptosis-related genes Bcl-2, Bax and medial prefrontal cortex (mPFC) neuronal apoptosis, and to provide experimental evidence to reveal PTSD pathogenesis.
The single-prolonged stress(SPS) method was used to set up the rat PTSD models There were five groups after SPS 1 day 4 days 7 days 14 days groups and control group Serum corticosterone level was determined with chemiluminescence, mPFC neuronal apoptosis changes and detection of apoptotic index were detected with transmission electron microscopy, hoechst 33342 staining and in situ nick end labeling method (TUNEL) staining. Immunohistochemistry, immunofluorescence, RT-PCR and western blotting were used to detect the expressions of Bcl-2 and Bax in the medial prefrontal cortex neuronal.
PTSD rat mPFC neuron cell apoptosis, the number of apoptotic cells gradually increased with time and reached a peak at 7 days after SPS stimulates. Bcl-2 expression reached a peak at 4d and Bax expression reached a peak at 7d after SPS stimulates, Bcl-2/Bax ratio transient increased and then gradually decreased, reached a lowest point in seventh days after SPS stimulates.
The expression of apoptosis related genes Bcl-2 and Bax increase and their ratio imbalances are likely to be one of the reasons that lead to PTSD in rat mPFC neurons apoptosis, which may provide the pathophysiology basis for PTSD.
The debates about depressive disorder and cognition impairment are supported by controversial data.
We launched the study to investigate cognitive change in first onset depressive patients over a 6 year period.
A prospective cohort was performed. Participants included 206 cases of first onset depressive Chinese outpatient aged from 17 to 60 year old and followed from Apr. 2003-Feb. 2004 to Apr. 2009-Feb. 2010 in Shanghai. During the first 48 weeks, case management service was delivered. Participants were assessed by 17-HAMD and HAMA scale at baseline, week 12, week 32, week 48, and year 6. Cognitive changes were assessed using the WMS-RC, WAIS-RC, and WCST at baseline (n = 116), week 12 (n = 80) and year 6 (n = 24), 41 normal participants as control.
(1) During the first depressive onset, cognitive performance deteriorated comparing with those of control group (P < 0.01).
(2) At week 12,effective medication could relieve symptom and improve cognition function (P < 0.05), cognitive performance compared between patient and control with no obvious difference (P > 0.05). While patient group had a significantly larger proportion (whose Memory Quotient below 85) than control group did (χ2 = 5.66, P < 0.05).
(3) Using a general linear mixed model to estimate cognitive change,patients with more severe depressive retardation and lower education had a worse short-term memory over 6 years (estimate = -1.65, SE = 0.80, P < 0.05;estimate=1.63, SE = 0.30, P < 0.01), adjusting for demographics and medical status.
The first onset depressive patient has cognitive defects. Memory does not full recovery after symptom relief. Short-term memory impairment persists over 6 years with relative factors.