It has been confirmed that the coronavirus disease 2019 (COVID-19) can transmit through droplets created when an infected human coughs or sneezes. Accordingly, 1.83-m (6-feet) social distancing is ...advised to reduce the spread of the disease among humans. This is based on the assumption that no air circulation exists around people. However, it is not well investigated whether the ambient wind and relative humidity (RH) will cause SARS-CoV-2 laden droplets to transport farther in the air, and make the current social distancing policy insufficient. To provide evidence and insight into the “social distancing” guidelines, a validated computational fluid-particle dynamics (CFPD) model was employed to simulate the transient transport, condensation/evaporation, and deposition of SARS-CoV-2 laden droplets emitted by coughs, with different environmental wind velocities and RHs. Initial droplet diameters range from 2 to 2000 μm, and the wind velocities range from 0 to 16 km/h, representing different wind forces from calm air to moderate breeze. The comparison between a steady-state wind and a gust with a constant frequency has also been performed. Ambient RHs are 40% and 99.5%. The distances between the two virtual humans are 1.83 m and 3.05 m (6 feet and 10 feet). The facial covering effect on reducing the airborne transmission of the cough droplets has also been evaluated. Numerical results indicate that the ambient wind will enhance the complexity of the secondary flows with recirculation between the two virtual humans. Microdroplets follow the airflow streamlines well and deposit on both human bodies and head regions, even with the 3.05-m (10-feet) separation distance. The rest of the microdroplets can transport in the air farther than 3.05 m (10 feet) due to wind convection, causing a potential health risk to nearby people. High RH will increase the droplet sizes due to the hygroscopic growth effect, which increases the deposition fractions on both humans and the ground. With the complex environmental wind and RH conditions, the 6-feet social distancing policy may not be sufficient to protect the inter-person aerosol transmission, since the suspending micro-droplets were influenced by convection effects and can transport from the human coughs/sneezes to the other human in less than 5 seconds. Due to the complex real-world environmental ventilation conditions, a social distance longer than 1.83 m (6 feet) needs to be considered. Wearing masks should also be recommended for both infected and healthy humans to reduce the airborne cough droplet numbers.
•Air transmission of cough droplets with condensation and evaporation effects are modeled between two virtual humans.•Relative humidity (RH) has a noticeable influence on droplet size change dynamics.•High RH (99.5%) lead to higher deposition fractions of cough droplets on both virtual humans than low RH (40%).•Six-feet social distancing policy for COVID-19 may not be sufficient with ambient wind.
To systematically review the epidemiologic relationship between periodontitis and type 2 diabetes mellitus (T2DM).
Four electronic databases were searched up until December 2018. The manual search ...included the reference lists of the included studies and relevant journals. Observational studies evaluating the relationship between T2DM and periodontitis were included. Meta-analyses were conducted using STATA.
A total of 53 observational studies were included. The Adjusted T2DM prevalence was significantly higher in periodontitis patients (OR = 4.04, p = 0.000), and vice versa (OR = 1.58, p = 0.000). T2DM patients had significantly worse periodontal status, as reflected in a 0.61 mm deeper periodontal pocket, a 0.89 mm higher attachment loss and approximately 2 more lost teeth (all p = 0.000), than those without T2DM. The results of the cohort studies found that T2DM could elevate the risk of developing periodontitis by 34% (p = 0.002). The glycemic control of T2DM patients might result in different periodontitis outcomes. Severe periodontitis increased the incidence of T2DM by 53% (p = 0.000), and this result was stable. In contrast, the impact of mild periodontitis on T2DM incidence (RR = 1.28, p = 0.007) was less robust.
There is an evident bidirectional relationship between T2DM and periodontitis. Further well-designed cohort studies are needed to confirm this finding. Our results suggest that both dentists and physicians need to be aware of the strong connection between periodontitis and T2DM. Controlling these two diseases might help prevent each other's incidence.
Purpose
Severe geometric distortions induced by tissue susceptibility, water–fat chemical shift, and eddy currents pose a substantial obstacle in single‐shot EPI, especially for high‐resolution ...imaging at ultrahigh field. View angle tilting (VAT)‐EPI can mitigate in‐plane distortion. However, the accompanied strong image blurring prevented its widespread applications. On the other hand, point‐spread function mapping (PSF)‐EPI can correct distortion and blurring accurately but requires prolonged scan time. We present fused VAT‐PSF‐EPI and possibilities for acceleration.
Methods
MR signal equations were explicitly derived to quantify image blurring in VAT‐EPI and the maximum acceleration capacity in VAT‐PSF‐EPI. To validate the theoretical prediction, phantom measurements with varying in‐plane parallel imaging factors, slice thicknesses, and RF pulses were conducted at 7 Tesla. In addition, in vivo human brain scans were acquired with T
2
and diffusion weighting to assess distortion and blurring correction.
Results
VAT can effectively suppress distortion, and the introduced image blurring is corrected through PSF encoding. Up to fourfold acceleration (only 5 shots) in VAT‐PSF‐EPI was achieved compared with standard PSF‐EPI without VAT. VAT‐induced signal loss was mitigated by adjusting the sequence parameters and EPI resolution. In vivo T
2
‐weighted EPI data with 1.4 mm
3
resolution demonstrate immunity to water–fat chemical shift‐induced distortion. Very high‐spatial resolution diffusion‐weighted EPI (0.7 × 0.7 × 2.8 mm
3
and 1.2 mm
3
) demonstrates the immunity to eddy current‐induced distortion.
Conclusion
VAT‐PSF‐EPI is a novel spin‐echo EPI‐based sequence for fast high‐resolution diffusion imaging at ultrahigh field.
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Background and Purpose
Atopic dermatitis is a common chronic pruritic inflammatory disease of the skin involving neuro‐immune communication. Neuronal mechanism‐based therapeutic treatments remain ...lacking. We investigated the efficacy of intravenous lidocaine therapy on atopic dermatitis and the underlying neuro‐immune mechanism.
Experimental Approach
Pharmacological intervention, immunofluorescence, RNA‐sequencing, genetic modification and immunoassay were performed to dissect the neuro‐immune basis of itch and inflammation in atopic dermatitis‐like mouse model and in patients.
Key Results
Lidocaine alleviated skin lesions and itch in both atopic dermatitis patients and calcipotriol (MC903)‐induced atopic dermatitis model by blocking subpopulation of sensory neurons. QX‐314, a charged NaV blocker that enters through pathologically activated large‐pore ion channels and selectivity inhibits a subpopulation of sensory neurons, has the same effects as lidocaine in atopic dermatitis model. Genetic silencing NaV1.8‐expressing sensory neurons was sufficient to restrict cutaneous inflammation and itch in the atopic dermatitis model. However, pharmacological blockade of TRPV1‐positive nociceptors only abolished persistent itch but did not affect skin inflammation in the atopic dermatitis model, indicating a difference between sensory neuronal modulation of skin inflammation and itch. Inhibition of activity‐dependent release of calcitonin gene‐related peptide (CGRP) from sensory neurons by lidocaine largely accounts for the therapeutic effect of lidocaine in the atopic dermatitis model.
Conclusion and Implications
NaV1.8+ sensory neurons play a critical role in pathogenesis of atopic dermatitis and lidocaine is a potential anti‐inflammatory and anti‐pruritic agent for atopic dermatitis. A dissociable difference for sensory neuronal modulation of skin inflammation and itch contributes to further understanding of pathogenesis in atopic dermatitis.
Aims
The emerging of drug resistant Pseudomonas aeruginosa is a critical challenge and renders an urgent action to discover innovative antimicrobial interventions. One of these interventions is to ...disrupt the pseudomonas quinolone signal (pqs) quorum sensing (QS) system, which governs multiple virulence traits and biofilm formation. This study aimed to investigate the QS inhibitory activity of a series of new PqsR inhibitors bearing a quinoline scaffold against Ps. aeruginosa.
Methods and Results
The results showed that compound 1 suppressed the expression of QS‐related genes and showed the best inhibitory activity to the pqs system of wild‐type Ps. aeruginosa PAO1 with an IC50 of 20.22 μmol L−1. The virulence factors including pyocyanin, total protease, elastase and rhamnolipid were significantly suppressed in a concentration‐dependent manner with the compound. In addition, compound 1 in combination with tetracycline inhibited synergistically the bacterial growth and suppressed the biofilm formation of PAO1. The molecular docking studies also suggested that compound 1 could potentially interact with the ligand‐binding domain of the Lys‐R type transcriptional regulator PqsR as a competitive antagonist.
Conclusions
The quinoline‐based derivatives were found to interrupt the quorum sensing system via the pqs pathway and thus the production of virulence factors was inhibited and the antimicrobial susceptibility of Ps. aeruginosa was enhanced.
Significance and Impact of Study
The study showed that the quinoline‐based derivatives could be used as an anti‐virulence agent for treating Ps. aeruginosa infections.
Glassy and liquid state metal–organic frameworks (MOFs) are emerging type of materials subjected to intense research for their rich physical and chemical properties. In this report, we obtained the ...first glassy MOF that involves metal‐carboxylate cluster building units via multi‐stage structural transformations. This MOF is composed of linear Mn3(COO)6 node and flexible pyridyl‐ethenylbenzoic linker. The crystalline MOF was first perturbed by vapor hydration and thermal dehydration to give an amorphous state, which can go through a glass transition at 505 K into a super‐cooled liquid. The super‐cooled liquid state is stable through a wide temperature range of 40 K and has the largest fragility index of 105, giving a broad processing window. Remarkably, the super‐cooled liquid can not only be quenched into glass, but also recrystallize into the initial MOF when heated to a higher temperature above 558 K. The mechanism of the multi‐stage structural transformations was studied by systematic characterizations of in situ X‐ray diffraction, calorimetry, rheological, spectroscopic and pair‐distribution function analysis. These multi‐stage transformations not only represent a rare example of high temperature coordinative recognition and self‐assembly, but also provide new MOF processing strategy through crystal‐amorphous‐liquid‐crystal transformations.
The first MOF glass composed of metal‐carboxylate cluster building units is vitrified by multi‐stage transformations: The crystalline MOF is amorphized by vapor hydration and thermal dehydration, goes through a glass transition to enter a super‐cooled liquid state, and recrystallizes into the initial structure. These multi‐stage transformations are a rare example of high‐temperature coordinative recognition and self‐assembly.
Despite that some approved drugs and genetically engineered vaccines against hepatitis B virus (HBV) are available for HBV patients, HBV infection is still a severe public health problem in the ...world. All the approved therapeutic drugs (including interferon-alpha and nucleoside analogues) have their limitations. No drugs or therapeutic methods can cure hepatitis B so far. Therefore, it is urgently needed to discover and develop new anti-HBV drugs, especially non-nucleoside agents. Naturally originated compounds with enormous molecular complexity and diversity offer a great opportunity to find novel anti-HBV lead compounds with specific antiviral mechanisms. In this review, the natural products against HBV are discussed according to their chemical classes such as terpenes, lignans, phenolic acids, polyphenols, lactones, alkaloids and flavonoids. Furthermore, novel mode of action or new targets of some representative anti-HBV natural products are also discussed. The aim of this review is to report new discoveries and updates pertaining to anti-HBV natural products in the last 20 years, especially novel skeletons and mode of action. Although many natural products with various skeletons have been reported to exhibit potent anti-HBV effects to date, scarcely any of them are found in the list of conventional anti-HBV drugs worldwide. Additionly, in anti-HBV mechanism of action, only a few references reported new targets or novel mode of action of anti-HBV natural products.
Morphology evolution of sulfonic acid functionalized organosilica nanohybrids (Si(Et)Si‐Pr/ArSO3H) with a 1D tubular structure (inner diameter of ca. 5 nm), a 2D hexagonal mesostructure (pore ...diameter of ca. 5 nm), and a 3D hollow spherical structure (shell thickness of 2–3 nm and inner diameter of ca. 15 nm) was successfully realized through P123‐templated sol–gel cocondensation strategies and fine‐tuning of the acidity followed by aging or a hydrothermal treatment. The Si(Et)Si‐Pr/ArSO3H nanohybrids were applied in synthesis of alkyl levulinates from the esterification of levulinic acid and ethanolysis of furfural alcohol. Hollow spherical Si(Et)Si‐Pr/ArSO3H and hexagonal mesoporous analogues exhibited the highest and lowest catalytic activity, respectively, among three types of nanohybrids; additionally, the activity was influenced by the SO3H loading. The activity differences are explained in terms of different Brønsted acid and textural properties, reactant/product diffusion, and mass transfer rate, as well as accessibility of SO3H sites to the reactant molecules. The reusability of the nanohybrids was also evaluated.
Control the power within: Si(Et)Si‐Pr/ArSO3H nanohybrids with a hollow spherical structure, a tubular structure, and a periodic mesostructure were prepared controllably by a cocondensation route (see figure). These nanohybrids exhibited excellent heterogeneous acid catalytic activity in the synthesis of biomass‐derived alkyl levulinates; moreover, the morphology clearly influenced the catalytic activity.
Adding small molecular plasticizers is the most common route to tailor the stretchability of poly(vinyl alcohol) (PVA). However, how the plasticization along with the nature of the plasticizer ...governs the structural homogeneity during stretching remains an open question to answer. Herein, two representative plasticizers, glycerol (GLY) and water, are chosen to endow the PVA films with ductility. It is found that large strain cavitations cause obvious stress whitening in the PVA/H2O films; on the contrary, most of the PVA/GLY films maintain transparent undergoing tensile deformation. Through a combination of experimental inspections and molecular dynamic simulation, it is revealed that partial water molecules that behave as free water will aggregate into microdomains, which serve as mechanical defects responsible for yielding voids. Whereas, the GLY plasticizer homogeneously disperses at a molecular level and interacts with PVA chains through strong hydrogen bonds. More interestingly, it is illustrated that the dispersion and bound states of plasticizers are closely related to the mechanical character of the plasticized PVA films. These findings offer new insight into the working mechanism of plasticization on the structural stability during stretching, and guide the design of PVA/plasticizer system to obtain excellent comprehensive mechanics.
The structural stability of plasticized PVA films during stretching strongly relies on the dispersion and bound states of plasticizers. A molecule‐level dispersion of glycerol and its tight interaction with PVA chains endow the PVA film with a facile reformation of H‐bonds after breakage. Whereas, freezable bound water and free water aggregate into microdomains responsible for forming cavitations.
Childhood trauma has been linked to increased risk of schizophrenia and social dysfunction, and oxytocin and its receptor gene have been implicated in regulating social behavior. This study ...investigated the potential role of oxytocin and oxytocin receptor gene (OXTR) in mediating the effects of childhood trauma on social functioning in schizophrenia.
The study consisted of 382 patients with schizophrenia and 178 healthy controls who were assessed using the Taiwanese version of the Childhood Trauma Questionnaire (CTQ-SF), the Social Functioning Scale (SFS), and plasma oxytocin levels. DNA was extracted to genotype the OXTR and ten single-nucleotide polymorphisms (SNPs; rs2254298, rs237885, rs237887, rs237899, rs53576, rs9840864, rs13316193, rs7632287, rs1042778, and rs237895) were selected.
Patients with schizophrenia showed higher CTQ-SF scores (
= 12.549,
< 0.001), lower SFS scores (
= -46.951,
< 0.001), and lower plasma oxytocin levels (
= -5.448,
< 0.001) compared to healthy controls. The study also found significant differences in OXTR SNPs between both groups, with risk alleles being more prevalent in patients with schizophrenia (
= 2.734,
= 0.006). Results indicated a significant moderated mediation effect, with oxytocin and the OXTR SNPs partially mediating the relationship between childhood trauma exposure and social functioning in patients with schizophrenia (index of mediation = 0.038, 95% CI 0.033-0.044).
The findings suggest that oxytocin and its receptor gene may be promising targets for interventions aimed at improving social functioning in patients with a history of childhood trauma and schizophrenia. However, further research is needed to fully understand these effects and the potential of oxytocin-based interventions in this population.
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