A strategy called ultramicroporous building unit (UBU) is introduced. It allows the creation of hierarchical bi‐porous features that work in tandem to enhance gas uptake capacity and separation. ...Smaller pores from UBUs promote selectivity, while larger inter‐UBU packing pores increase uptake capacity. The effectiveness of this UBU strategy is shown with a cobalt MOF (denoted SNNU‐45) in which octahedral cages with 4.5 Å pore size serve as UBUs. The C2H2 uptake capacity at 1 atm reaches 193.0 cm3 g−1 (8.6 mmol g−1) at 273 K and 134.0 cm3 g−1 (6.0 mmol g−1) at 298 K. Such high uptake capacity is accompanied by a high C2H2/CO2 selectivity of up to 8.5 at 298 K. Dynamic breakthrough studies at room temperature and 1 atm show a C2H2/CO2 breakthrough time up to 79 min g−1, among top‐performing MOFs. Grand canonical Monte Carlo simulations agree that ultrahigh C2H2/CO2 selectivity is mainly from UBU ultramicropores, while packing pores promote C2H2 uptake capacity.
Hole to differentiate, and hole to accommodate. Two types of pores can mingle together using a strategy called UBU (ultramicroporous building unit). This strategy results in a promising gas absorbent for excellent C2H2 storage capacity and top‐level C2H2/CO2 separation ability.
AbstractObjectiveTo examine the protective effects of appropriate personal protective equipment for frontline healthcare professionals who provided care for patients with coronavirus disease 2019 ...(covid-19).DesignCross sectional study.SettingFour hospitals in Wuhan, China.Participants420 healthcare professionals (116 doctors and 304 nurses) who were deployed to Wuhan by two affiliated hospitals of Sun Yat-sen University and Nanfang Hospital of Southern Medical University for 6-8 weeks from 24 January to 7 April 2020. These study participants were provided with appropriate personal protective equipment to deliver healthcare to patients admitted to hospital with covid-19 and were involved in aerosol generating procedures. 77 healthcare professionals with no exposure history to covid-19 and 80 patients who had recovered from covid-19 were recruited to verify the accuracy of antibody testing.Main outcome measuresCovid-19 related symptoms (fever, cough, and dyspnoea) and evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, defined as a positive test for virus specific nucleic acids in nasopharyngeal swabs, or a positive test for IgM or IgG antibodies in the serum samples.ResultsThe average age of study participants was 35.8 years and 68.1% (286/420) were women. These study participants worked 4-6 hour shifts for an average of 5.4 days a week; they worked an average of 16.2 hours each week in intensive care units. All 420 study participants had direct contact with patients with covid-19 and performed at least one aerosol generating procedure. During the deployment period in Wuhan, none of the study participants reported covid-19 related symptoms. When the participants returned home, they all tested negative for SARS-CoV-2 specific nucleic acids and IgM or IgG antibodies (95% confidence interval 0.0 to 0.7%).ConclusionBefore a safe and effective vaccine becomes available, healthcare professionals remain susceptible to covid-19. Despite being at high risk of exposure, study participants were appropriately protected and did not contract infection or develop protective immunity against SARS-CoV-2. Healthcare systems must give priority to the procurement and distribution of personal protective equipment, and provide adequate training to healthcare professionals in its use.
Aerogels, a type of fascinating material with very low density and high surface area, show many unique properties and unlimited applications. To boost their practical applications, it is necessary to ...develop efficient, controllable, and low‐cost methods to produce high‐performance aerogels on a large‐scale, preferably in a sustainable way. Here, a general strategy is reported for controllable fabrication of a family of carbonaceous nanofiber aerogels (CNFAs) by biomass‐derived nanofibers template‐directed hydrothermal carbonization method. Abundant functional groups are exposed on the surface of the prepared carbonaceous nanofibers. Importantly, in contrast to traditional nature biopolymer‐based aerogels, a superior combination of good recoverability and high strength is achieved for the CNFAs by adjusting the synthetic parameters. The successful synthesis of such fascinating materials provides an excellent platform for design and construction of devices for fast water treatment. The synthetic strategy and sustainable concept presented in this work will open a new way to prepare advanced aerogels with unique properties for wide applications.
Biomass‐derived nanofibers, including amyloid nanofibrils, aminated cellulose nanofibers, and deacetylated chitin nanofibers, are used as templates to direct the hydrothermal carbonization of glucose. The obtained carbonaceous nanofiber aerogels with rigid 3D cross‐linked structures provide an excellent platform for design and construction of powerful devices for fast water purification.
Phagocytosis is an ancient, highly conserved process in all multicellular organisms, through which the host can protect itself against invading microorganisms and environmental particles, as well as ...remove self-apoptotic cells/cell debris to maintain tissue homeostasis. In crustacean, phagocytosis by hemocyte has also been well-recognized as a crucial defense mechanism for the host against infectious agents such as bacteria and viruses. In this review, we summarized the current knowledge of hemocyte-mediated phagocytosis, in particular focusing on the related receptors for recognition and internalization of pathogens as well as the downstream signal pathways and intracellular regulators involved in the process of hemocyte phagocytosis. We attempted to gain a deeper understanding of the phagocytic mechanism of different hemocytes and their contribution to the host defense immunity in crustaceans.
The design and implementation of a GaN stacked distributed 2-19GHz monolithic microwave integrated circuit (MMIC) power amplifier (PA) is presented in this paper. The PA architecture uses six ...distributed cells, each containing a stack of three transistors. A design method that employs capacitance compensation is presented and applied to a 5-10-W PA design for the 2-19-GHz range in a 100-nm GaN on Si technology. The resulting measured performance at 28-V supply shows a gain flatness of 20.5 ± 1.5 dB, with an output power of 37.4-40.9 dBm and corresponding poweradded efficiency of 22%-49% over the entire frequency range. To the best of the authors' knowledge, this is the first demonstration of a GaN on Si stacked distributed MMIC PA, with a die size of <inline-formula> <tex-math notation="LaTeX">2.8\times1.7 </tex-math></inline-formula> mm 2 and with a maximum power density of 2.58 W/mm 2 over chip area.
Enveloped virus usually utilizes the receptor-mediated multiple endocytic routes to enter permissive host cells for successful infection. Cellular receptors are cell surface molecules, either by ...helping viral attachment to cell surface followed by internalization or by triggering antiviral immunity, participate in the viral-host interaction. White spot syndrome virus (WSSV), the most lethally viral pathogen with envelope and double strand DNA genome in crustacean farming, including shrimp and crayfish, has been recently found to recruit various endocytic routes for cellular entry into host cells. Meanwhile, other than the typical pattern recognition receptors for recognition of WSSV, more and more putative cellular receptors have lately been characterized to facilitate or inhibit WSSV entry. In this review, recent findings on the endocytosis-dependent WSSV entry, viral entry mediated by putative cellular receptors, the molecular interplay between WSSV and cellular receptors, and the following anti-WSSV immunity are summarized and discussed, which may provide us a better understanding of the WSSV pathogenesis and further possible antiviral control of white spot disease in crustacean farming.
•Recent findings on the putative cellular receptors-mediated recognition and entry of WSSVare summarized.•Advances in cellular receptors-mediated sensing of WSSV and triggering of anti-WSSV immunity are discussed.•IgSF receptors, Integrin, Laminin receptor, Chitin-binding protein and glucose transporter 1 mediate WSSV entry.•Toll-like receptors, C-type lectins and Scavenger receptors sense WSSV and trigger antiviral immunity.
Abstract Background Large cohort studies provide conflicting evidence regarding the potential for oral macrolide antibiotics to increase the risk of serious cardiac events. Objectives This study ...performed a meta-analysis to examine the link between macrolides and risk of sudden cardiac death (SCD) or ventricular tachyarrhythmias (VTA), cardiovascular death, and death from any cause. Methods We performed a search of published reports by using MEDLINE (January 1, 1966, to April 30, 2015) and EMBASE (January 1, 1980, to April 30, 2015) with no restrictions. Studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) for the associations of interest were included. Results Thirty-three studies involving 20,779,963 participants were identified. Patients taking macrolides, compared with those who took no macrolides, experienced an increased risk of developing SCD or VTA (RR: 2.42; 95% CI: 1.61 to 3.63), SCD (RR: 2.52; 95% CI: 1.91 to 3.31), and cardiovascular death (RR: 1.31; 95% CI: 1.06 to 1.62). No association was found between macrolides use and all-cause death or any cardiovascular events. The RRs associated with SCD or VTA were 3.40 for azithromycin, 2.16 for clarithromycin, and 3.61 for erythromycin, respectively. RRs for cardiovascular death were 1.54 for azithromycin and 1.48 for clarithromycin. No association was noted between roxithromycin and adverse cardiac outcomes. Treatment with macrolides is associated with an absolute risk increase of 118.1 additional SCDs or VTA, and 38.2 additional cardiovascular deaths per 1 million treatment courses. Conclusions Administration of macrolide antibiotics is associated with increased risk for SCD or VTA and cardiovascular death but not increased all-cause mortality.
Metal–organic frameworks (MOFs) are very promising self‐sacrificing templates for the large‐scale fabrication of new functional materials owing to their versatile functionalities and tunable ...porosities. Most conventional metal oxide electrodes derived from MOFs are limited by the low abundance of incorporated metal elements. This study reports a new strategy for the synthesis of multicomponent active metal oxides by the pyrolysis of polymetallic MOF precursors. A hollow N‐doped carbon‐coated ZnO/ZnCo2O4/CuCo2O4 nanohybrid is prepared by the thermal annealing of a polymetallic MOF with ammonium bicarbonate as a pore‐forming agent. This is the first report on the rational design and preparation of a hybrid composed of three active metal oxide components originating from MOF precursors. Interestingly, as a lithium‐ion battery anode, the developed electrode delivers a reversible capacity of 1742 mAh g−1 after 500 cycles at a current density of 0.3 mA g−1. Furthermore, the material shows large storage capacities (1009 and 667 mAh g−1), even at high current flow (3 and 10 A g−1). The remarkable high‐rate capability and outstanding long‐life cycling stability of the multidoped metal oxide benefits from the carbon‐coated integrated nanostructure with a hollow interior and the three active metal oxide components.
Hollow N‐doped carbon‐coated ZnO/ZnCo2O4/CuCo2O4 nanohybrids are prepared via thermal annealing of a polymetallic metal–organic framework in the presence of ammonium bicarbonate as a pore‐forming agent. The multidoped metal oxide components feature hollow nanostructures composed of an N‐dopant and a carbon‐coated layer. As an anode material for lithium–ion batteries, the multidoped three active metal oxide components deliver remarkable high‐rate and long‐life cycling stability.
Both methane (CH4) and acetylene (C2H2) are important energy source and raw chemicals in many industrial processes. The development of an energy-efficient and environmentally friendly separation and ...purification strategy for CH4 and C2H2 is necessary. Ultramicroporous metal–organic framework (MOF) materials have shown great success in the separation and purification of small-molecule gases. Herein, the synergy effect of tritopic polytetrazolate and ditopic terephthalate ligands successfully generates a series of isoreticular ultramicroporous cadmium tetrazolate–carboxylate MOF materials (SNNU-13–16) with excellent CH4 and C2H2 purification performance. Except for the uncoordinated tetrazolate N atoms serving as Lewis base sites, the pore size and pore surface of MOFs are systematically engineered by regulating dicarboxylic acid ligands varying from OH-BDC (SNNU-13) to Br-BDC (SNNU-14) to NH2-BDC (SNNU-15) to 1,4-NDC (SNNU-16). Benefiting from the ultramicroporous character (3.8–5.9 Å), rich Lewis base N sites, and tunable pore environments, all of these ultramicroporous MOFs exhibit a prominent separation capacity for carbon dioxide (CO2) or C2 hydrocarbons from CH4 and C2H2. Remarkably, SNNU-16 built by 1,4-NDC shows the highest ideal adsorbed solution theory CO2/CH4, ethylene (C2H4)/CH4, and C2H2/CH4 separation selectivity values, which are higher than those of most famous MOFs with or without open metal sites. Dynamic breakthrough experiments show that SNNU-16 can also efficiently separate the C2H2/CO2 mixtures with a gas flow rate of 4 mL min–1 under 1 bar and 298 K. The breakthrough time (18 min g–1) surpasses most best-gas-separation MOFs and nearly all other metal azolate–carboxylate MOF materials under the same conditions. The above prominently CH4 and C2H2 purification abilities of SNNU-13–16 materials were further confirmed by the Grand Canonical Monte Carlo (GCMC) simulations.
The COVID-19 outbreak can be seen as a 'big test' for China; a summative assessment of its preparedness on multiple fronts, including medical education. Being intimately involved in the coordinated ...response, the First Affiliated Hospital of Sun Yat-sen University has been a first-hand witness to the strengths and weaknesses of the current medical education system in China. On the one hand, we believe that the distinguished contributions in disease containment efforts by healthcare professionals indicated that our medical education system has achieved its intended outcomes and is socially accountable. On the other hand, we have also identified three major issues that need to be addressed from an educational standpoint: insufficient emphasis on public health emergency preparedness; unsophisticated mechanisms for interdisciplinary cooperation; and inadequate guidance in medical ethics. Whilst these reflections might be seen in its summative form, we would suggest changing it to that of a formative process, where we learn from our assessment through observation and feedback of the gaps, upon which improvement of our present situation can be made. We hope that these lessons may be helpful to our colleagues in the rest of China and around the world, who are engaged in medical educational reform.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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