A novel avian influenza A(H7N9) virus causing human infection emerged in February 2013 in China. To elucidate the mechanism of interspecies transmission, we compared the signature amino acids of avian influenza A(H7N9) viruses from human and non-human hosts and analysed the reassortants of 146 influenza A(H7N9) viruses with full genome sequences. We propose a genetic tuning procedure with continuous amino acid substitutions and reassorting that mediates host adaptation and interspecies transmission. When the early influenza A(H7N9) virus, containing ancestor haemagglutinin (HA) and neuraminidase (NA) genes similar to A/Shanghai/05 virus, circulated in waterfowl and transmitted to terrestrial poultry, it acquired an NA stalk deletion at amino acid positions 69 to 73. Then, receptor binding preference was tuned to increase the affinity to human-like receptors through HA G186V and Q226L mutations in terrestrial poultry. Additional mammalian adaptations such as PB2 E627K were selected in humans. The continual reassortation between H7N9 and H9N2 viruses resulted in multiple genotypes for further host adaptation. When we analysed a potential association of mutations and reassortants with clinical outcome, only the PB2 E627K mutation slightly increased the case fatality rate. Genetic tuning may create opportunities for further adaptation of influenza A(H7N9) and its potential to cause a pandemic. www.eurosurveillance.org Methods Virus sampling and isolation Specimens as well as clinical and epidemiological information were collected from human cases. Environmental samples and avian samples were collected in the area where human cases identified. Virus isolation was conducted by Chinese National Influenza Center (CNIC) in a biosafety level 3 facility using nineday-old specific pathogen-free (SPF) embryonated chicken eggs and incubated at 37 °C for 48-72 hours. The allantoic fluid was harvested, aliquoted and stored at-80 ºC until use. RNA extraction and genome sequencing Viral RNA was extracted using QIAamp Viral RNA Mini Kit (Qiagen, Hilden, Germany). Gene segments were amplified using the Qiagen OneStep RT-PCR Kit. A total of 48 primer pairs were used to generate PCR amplicons between 378 and 1,123 bp in length for full genome sequencing. Primer sequences are available from the authors on request. Amplified PCR products were purified using ExoSAP-IT reagent (USB, Cleveland, US). Complete genome sequencing was performed with an ABI 3730XL automatic DNA analyser (Applied Biosystems, Foster City, US) using the ABI BigDye Terminator v3.1 cycle sequencing kit (Applied Biosystems; Foster City, US). HA: haemagglutinin; NA: neuraminidase. Red dots represent the common ancestor of the novel H7N9 virus. A/Shanghai/5/2013 and A/Shanghai/1/2013 are highlighted in pink and green, respectively. Schematic unrooted trees of HA and NA genes are shown in lower left boxes. The authors gratefully acknowledge the originating and submitting laboratories who contributed sequences used in the phylogenetic analysis to GISAID, and recognise in ...

Through thermal annealing above the glass transition temperature, a supertoughened binary blend with the highest notched Izod impact strength of 98 KJ/m 2 was achieved, which was about 52 times of that of neat polylactide (PLA; 1.9 KJ/m 2 ). The binary blend was composed of biocompatible and biodegradable PLA and ethylene−acrylic ester−glycidyl methacrylate terpolymer (EGMA) elastomer at the composition of 80/20 PLA/EGMA. For one toughened binary blend with the notched Izod impact strength of 94 KJ/ m 2 , its tensile elongation at break was kept above 120%. Moreover, this supertoughened binary blend also displayed a much higher heat deflection temperature for application. Thermal annealing induced crystallization of the PLA matrix in the blend, and a linear correlation between the notched Izod impact strength and crystallinity was revealed. The possible toughening mechanism for the PLA/EGMA 80/20 blend with thermal annealing was analyzed from the viewpoint of negative pressure effects, as imposed on EGMA elastomeric particles during the quench process and thermal annealing thereafter. Decreases of the glass transition temperatures for the EGMA elastomeric particles in the blend were observed for both the quench and thermal annealing processes, which originated from asymmetric thermal shrinkages between the EGMA elastomeric phase and PLA matrix phase.

Inorganic nanofillers are often added into polymer/elastomer blends as a third component to modify their performance. This work aims to clarify the role of interface-localized spherical nanoparticles in determining the impact toughness of polymer blends. The selective distribution of titanium dioxide (TiO2) nanoparticles in poly(L-lactide)/poly(ether) urethane (PLLA/PU) blends was investigated by using scanning electron microscope. It is interesting to find that, regardless of the method of TiO2 introduction, nano-TiO2 particles are always selectively localized at the phase interface between PLLA and PU, leading to a significant improvement in notched Izod impact toughness. The moderately weakened interfacial adhesion induced by the interfacially-localized nano-TiO2 particles is believed to be the main reason for the largely enhanced impact toughness

Background: Novel coronavirus disease (COVID-19) is spreading rapidly, which poses great challenges to patients on maintenance hemodialysis. Here we report the clinical features of 66 hemodialysis patients with laboratory confirmed COVID-19 infection. Design, setting, participants, and measurements: Retrospective, single-center case series of the 66 hemodialysis patients with confirmed COVID-19 from 1 January to 5 March 2020; the final date of follow-up was 25 March 2020. Results: The clinical data were collected from 66 hemodialysis patients with confirmed COVID-19. The incidence of COVID-19 in our center was 11.0% (66/602), of which 18 patients died. According to different prognosis, hemodialysis patients with COVID-19 were divided into the survival and death group. A higher incidence of fever and dyspnea was found in the death group compared with the survival group. Meanwhile, patients in the death group were often accompanied by higher white blood cell count, prolonged PT time, increased D-dimer (p < .05). More patients in the death group showed hepatocytes and cardiomyocytes damage. Furthermore, logistic regression analysis suggested that fever, dyspnea, and elevated D-dimer were independent risk factors for death in hemodialysis patients with COVID-19 (OR, 1.077; 95% CI, 1.014 to 1.439; p ¼ .044; OR, 1.146; 95% CI, 1.026 to 1.875; p ¼ .034, OR, 4.974; 95% CI, 3.315 to 6.263; p ¼ .007, respectively). Conclusions: The potential risk factors of fever, dyspnea, and elevated D-dimer could help clinicians to identify hemodialysis patients with poor prognosis at an early stage of COVID-19 infection.

Two pairs of positive-and negative-parity doublet bands together with eight strong electric dipole transitions linking their yrast positive-and negative-parity bands have been identified in 78 Br. They are interpreted as multiple chiral doublet bands with octupole correlations, which is supported by the microscopic multidimensionally-constrained covariant density functional theory and triaxial particle rotor model calculations. This observation reports the first example of chiral geometry in octupole soft nuclei. DOI: 10.1103/PhysRevLett.116.112501 Spontaneous symmetry breaking is a fundamental concept in nature. As a many-body quantum system, the atomic nucleus carries a wealth of information on fundamental symmetries and symmetry breaking. As one example, chiral symmetry breaking in atomic nuclei has attracted considerable attention and intensive discussion since it was first predicted by Frauendorf and Meng [1]. They pointed out that, in the intrinsic frame of the rotating triaxial nucleus, the total angular momentum vector may lie outside the three principal planes, referred to as chiral geometry. The spontaneous chiral symmetry breaking in the laboratory frame may give rise to pairs of nearly degenerate ΔI ¼ 1 bands with the same parity, i.e., chiral doublet bands. Such chiral doublet bands were first observed in N ¼ 75 isotones [2]. So far, more than 30 experimental candidates have been reported in the A ∼ 80, 100, 130, and 190 mass regions [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].Based on constrained triaxial covariant density functional theory (CDFT) calculations, it has been suggested that multiple chiral doublet (MχD) bands can exist in a single nucleus [21][22][23][24][25][26]. The theoretical prediction of MχD bands stimulated lots of experimental efforts [27][28][29][30][31]. The first experimental evidence for MχD bands was reported in 133 Ce [27], which confirmed the manifestation of triaxial shape coexistence in this nucleus. Later, Kuti et al. reported a novel type of MχD bands with the same configuration in 103 Rh [29], which showed that chiral geometry can be robust against the increase of the intrinsic excitation energy.Compared to the A ∼ 130 and 100 mass regions, the A ∼ 80 mass region is a relatively new and less studied territory for the investigation of chiral symmetry breaking in rotating nuclei, with only one report of chiral doublet bands based on the πg 9=2 ⊗ νg 9=2 configuration in odd-odd 80 Br [18]. In 78 Br, the πg 9=2 ⊗ νg 9=2 band was suggested to have an obvious triaxial shape [32], which is suitable for the construction of chiral doublet bands.

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A series of long-chain branched polylactide (LCB PLA)/poly­(D-lactic acid) (PDLA) blends with different low amounts of PDLA were prepared by a solution blending method. The formation of stereocomplex (SC) crystallites in LCB PLA/PDLA blends during a quenching process was proved by differential scanning calorimetry (DSC) and dynamic rheological frequency sweep, and the content of SC crystallites increased as the PDLA composition increased. The morphological evolution of LCB PLA/PDLA blends during crystallization at 130 °C was traced by polarized optical microscopy (POM), disclosing the separate growths of SC crystallites and PLA homocrystallites. The crystallization kinetics of LCB PLA/PDLA blends was investigated by rheometry, which was accelerated dramatically with increasing PDLA composition mainly due to the nucleation density enhancement. In particular, a two-stage crystallization process was found for LCB PLA/PDLA blends with PDLA compositions of 5 and 10 wt %, evidenced by the two plateaus in the storage modulus–time curves, which were apparently related to the existence of an LCB structure. The DSC result further confirmed that both SC crystallites and homocrystallites of PLA coexisted in LCB PLA/PDLA blends, with homocrystallites appearing much later as compared to SC crystallites, even after the complete crystallization of SC crystallites.

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