The collapse of an initially spherical cavitation bubble near a free surface leads to the formation of two jets: a downward jet into the liquid, and an upward jet penetrating the free surface. In this study, we examine the surprising interaction of a bubble trapped in a stable cavitating vortex ring approaching a free surface. As a result, a single fast and tall liquid jet forms. We find that this jet is observed only above critical Froude numbers ($Fr$) and Weber numbers ($We$) when ${Fr}^2 (1.6-2.73/{We}) > 1$, illustrating the importance of inertia, gravity and surface tension in accelerating this novel jet and thereby reaching heights several hundred times the radius of the vortex ring. Our experimental results are supported by numerical simulations, revealing that the underlying mechanism driving the vortex ring acceleration is the disruption of the equilibrium of high-pressure regions at the front and rear of the vortex ring caused by the free surface. Quantitative analysis based on the energy relationships elucidates that the velocity ratio between the maximum velocity of the free-surface jet and the translational velocity of the vortex ring is relatively stable yet is attenuated by surface tension when the jet is mild.

The aeolian loess-paleosol sequences in the Chinese Loess Plateau (CLP) are an excellent archive of variations in atmospheric circulation in the geological past. However, there is no consensus regarding the roles of the East Asian winter monsoon and westerly winds in transporting the dust responsible for loess deposition during glacial and interstadial periods. We conducted detailed measurements of the anisotropy of magnetic susceptibility (AMS) on two parallel loess profiles covering the most recent 130 ka in the western CLP to determine paleowind directions. Results show that the magnetic lineations of the loess and paleosol units in both sections are significantly clustered along the northwest to southeast direction. These observations demonstrate that the prevailing wind system responsible for dust transport in the western CLP was the northwesterly winter monsoon, rather than the westerly winds. The AMS-derived dust-bearing wind direction was relatively stable during the last glacial and interglacial cycle in the western CLP, consistent with sedimentary and AMS evidence from the eastern CLP. Accordingly, it is reasonable to conclude that large areas of deserts and Gobi deserts areas located in the upwind direction were the dominant sources for the aeolian deposits of the Loess Plateau.

A 53-year-old male presents with cough, fever, and myalgias for 7 days. Vitals include temperature, 38.0°C; heart rate, 110; blood pressure, 118/70 mm Hg; respiration rate, 28; and oxygen saturation 83% on room air. His only past medical history is hypertension. Your community is in the midst of the coronavirus disease 2019 (COVID-19) pandemic. The patient is hypoxic but responds to oxygen supplementation with nasal cannula and a face mask. His chest x-ray demonstrates multifocal infiltrates. Are there any therapeutic agents currently available for COVID-19?

Intestinal barrier inflammatory damage is commonly accompanied by hypoxia. The hypothesis that dietary Acanthopanax senticosus polysaccharides (ASPS) might modulate the hypoxia-inducible factor-1α (HIF-1α) signalling pathway and contribute to attenuate intestinal injury was tested in lipopolysaccharide (LPS)-challenged piglets. Thirty-six weaned pigs were randomly allocated to one of the following three groups: (1) basal diet + saline challenge; (2) basal diet + LPS challenge; (3) basal diet with 800 mg/kg ASPS + LPS challenge. LPS was injected at 15, 18 and 21 d, and intestinal sections were sampled following blood collection at 21 d . The results showed ASPS reversed (P < 0·05) LPS-induced decrease in average daily feed intake and rise (P < 0·05) of diarrhoea incidence and index. Biochemical index reflecting gut barrier damage and function involving ileal pro-inflammatory cytokines (TNF-α and IL-1β) and enzyme activity (diamine oxidase and lactase), as well as circulatory d-xylose, was normalised (P < 0·05) in LPS-challenged piglets receiving ASPS. ASPS also ameliorated intestinal morphological deterioration of LPS-challenged piglets, proved by elevated ileal villus height (P < 0·05) and improved appearance of epithelial villus and tight junction ultrastructure. Moreover, ASPS prevented LPS-induced amplification of inflammatory mediators, achieved by depressed ileal mRNA abundance of TNF-α, inducible NO synthase and IL-1β concentration. Importantly, ileal protein expressions of HIF-1α, cyclo-oxygenase-2 (COX-2) and NFκB p65 were also suppressed with ASPS administration (P < 0·05). Collectively, these results suggest the improvement of mucosal inflammatory damage and diarrhoea in immune stress piglets is possibly associated with a novel finding where HIF-1α/COX-2 pathway down-regulation is involved in NFκB p65-inducible releasing of inflammatory cytokines by dietary ASPS.

Structural distortions at the nanoscale are delicately linked with many exotic properties for ferroic thin films. Based on advanced aberration corrected scanning transmission electron microscopy, we observe BiFeO3 thin films with variant tensile strain states and demonstrate at an atomic scale the interplay of intrinsic spontaneous structural distortions with external constraints. Structural parameters (the rhombohedral distortion and domain wall shear distortion) under zero (BiFeO3/GdScO3) and 1.5% (BiFeO3/PrScO3) lateral strain states are quantitatively analyzed which are suppressed within a few unit cells near the film/substrate interfaces. In particular, an interfacial layer with asymmetrical lattice distortions (enhanced and reduced out-of-plane lattice spacing) on the two sides of 109° domain wall is resolved. These structural distortions near the film/substrate interface in ferroic thin films reveal intense tanglement of intrinsic distortions of BiFeO3 with external boundary conditions, which could provide new insights for the development of nanoscale ferroelectric devices.

Objectives: Huntington’s disease (HD) is a debilitating genetic disorder characterized by motor, cognitive and psychiatric abnormalities associated with neuropathological decline. HD pathology is the result of an extended chain of CAG (cytosine, adenine, guanine) trinucleotide repetitions in the HTT gene. Clinical diagnosis of HD requires the presence of an otherwise unexplained extrapyramidal movement disorder in a participant at risk for HD. Over the past 15 years, evidence has shown that cognitive, psychiatric, and subtle motor dysfunction is evident decades before traditional motor diagnosis. This study examines the relationships among subcortical brain volumes and measures of emerging disease phenotype in prodromal HD, before clinical diagnosis. Methods: The dataset includes 34 cognitive, motor, psychiatric, and functional variables and five subcortical brain volumes from 984 prodromal HD individuals enrolled in the PREDICT HD study. Using cluster analyses, seven distinct clusters encompassing cognitive, motor, psychiatric, and functional domains were identified. Individual cluster scores were then regressed against the subcortical brain volumetric measurements. Results: Accounting for site and genetic burden (the interaction of age and CAG repeat length) smaller caudate and putamen volumes were related to clusters reflecting motor symptom severity, cognitive control, and verbal learning. Conclusions: Variable reduction of the HD phenotype using cluster analysis revealed biologically related domains of HD and are suitable for future research with this population. Our cognitive control cluster scores show sensitivity to changes in basal ganglia both within and outside the striatum that may not be captured by examining only motor scores. (JINS, 2017, 23, 159–170)

The pure and Er3+-modified binary Pb(Zn1/3Nb2/3)O3–9PbTiO3 (PZN–9PT) single crystals were grown by using the flux method. The phase structure of the as-grown single crystals at room temperature was confirmed by the x-ray diffraction analysis. The effect of Er3+ addition on the electrical properties and upconversion luminescence of PZN–9PT was investigated. The rhombohedral to tetragonal phase transition temperature and the Curie temperature of the Er3+-modified PZN–9PT single crystals were 370 and 451 K, respectively. The coercive field E C at room temperature was evidently higher by 11.6 kV/cm than that of the PZN–9PT single crystals (E C, ∼3.5 kV/cm). Furthermore, the green and red upconversion emission bands were obtained under the 980 nm excitation, which are related to (2H11/2, 4S3/2) → 4I15/2 and 4F9/2 → 4I15/2 transitions.

The oxidation of CO to CO2 is necessary in the operation of Proton Exchange Membrane Fuel Cells (PEMFCs) since even a small amount of CO that is formed when the PEMFC is operated under ambient conditions is sufficient to poison the Pt catalyst in the electrodes and degrade the performance. Operation using higher loads of Pt catalysts or increasing the purity of the H2 input gas significantly adds to the cost, adversely impacting the commercial development of PEMFCs. We combined graphene oxide (GO) with metallic salts and partially reduced the mixture with sodium borohydride, yielding a metallized form of partially reduced graphene oxide (prGO) platelets that remained in solution. When these platelets were coated on the Nafion membrane of a PEMFC, a 72% increase in the power output was observed, whereas a 62% increase was observed when the membrane was coated with partially reduced graphene oxide without the metallic salts. Results will be presented for AuGO/prGO, PtGO/prGO, and AuPtGO/prGO combinations.

The studies of differences in life history and suitability of both water temperatures and trophic levels among rotifer sibling species improve our understanding of speciation, sibling species coexistence and possible niche differentiation over space and time, and consequences for the functioning of ecosystems induced by climate change and eutrophication. We collected Brachionus calyciflorus from Lake Baixiang and Lake Kongque, two tropical shallow lakes, in Xishuangbanna city, Yunnan, China, clonally cultured them in laboratory, and found that the B. calyciflorus complex contains two sibling species named sibling species BNA13 and BNB3 by phylogenetic analysis, and investigated the life-table parameters of the two sibling species BNA13 and BNB3 at four temperatures (16, 20, 24 and 28°C) and four algal densities (0.5, 1.0, 2.0 and 4.0×106 cells.mL−1). The results showed that the responses to increasing temperature and algal density for each of the life-table parameters differed with rotifer sibling species. Sibling species, temperature, algal density and their interactions almost all significantly affected the durations of juvenile period, embryonic development, reproductive period, post-reproductive period, mean lifespan, net reproductive rate, generation time and intrinsic rate of population growth. Sibling species significantly affected the age-specific survivorship. Temperature, algal density and their interaction and the interaction of sibling species and temperature significantly affected the age-specific fecundity. Regardless of the effects of temperature and algal density, the durations of juvenile period, embryonic development, reproductive period, post-reproductive period and mean lifespan, age-specific survivorship, net reproductive rate and generation time of the B. calyciflorus sibling species BNA13 were greater than those of BNB3, but the intrinsic rate of population growth of BNA13 was lower than those of BNB3. This suggests that the two B. calyciflorus sibling species adopted variable life history strategies, low population growth and high survivorship for sibling species BNA13, and high population growth and low survivorship for sibling species BNB3. Both the intrinsic rates of population growth of BNA13 and BNB3 were the highest at 28°C and 4.0×106 cells.mL−1 algal density, indicating that some adaptations of the B. calyciflorus sibling species BNA13 and BNB3 in tropical shallow lakes to water temperatures and trophic levels were similar, and they have the potential for coexistence in single waterbody of higher temperature and higher trophic level.

Intense broad absorption bands centered around 1.7, 2.5, 3.1, and 3.7 eV take place in Er3+-diffused layer formed near MgO (5 mol%)-doped LiNbO3 crystal surface by in-diffusion of Er metal under Li-poor atmosphere. These bands are tentatively attributed to the defect absorption of small polarons, bipolarons, F-centers, and Q-polarons created due to Er3+ in-diffusion and Li2O loss from the crystal. It is interesting that the number, type, area, and peaking position of the bands can be controlled by the diffusion temperature and further oxidation treatment. Such material is a promising medium for data storage based upon two-color holography.

In the filled gallium-germanium clathrates, R8Ga16Ge30, where R is Ba, Sr, or Eu, the guests are located in two large cages and are weakly bound to the crystalline clathrate framework. The caged guests exhibit a localized “rattling” vibrational mode that provides an efficient mechanism for reducing the thermal conductivity. Inelastic neutron scattering and nuclear inelastic scattering measurements have yielded the phonon density of states in R8Ga16Ge30; the line width of the localized vibrational modes is found to be an important parameter in determining the lattice thermal conductivity. Neutron diffraction studies on R8Ga16Ge30 have shown that the guests in the larger cage are located off-center, and it was proposed that their jumping about the four off-center locations is responsible for the observed glass-like thermal conductivity at temperatures below 10 K. The detection of such slow guest motion is challenging because the typical time and energy scales involved are ca. 4 ns and 1 µeV, respectively. We have studied the slow europium tunneling dynamics in Eu4Sr4Ga16Ge30 by both Mössbauer and microwave absorption spectroscopy.

While its electrochemical oxidation is difficult, Cgg is readily oxidized in protic superacidic media. In order to exploit the reactive nature of the radical cations thus formed for the purpose of generating novel fullerene derivatives, a method involving nucleophilic trapping of oxidized Cgg has been developed. Thus, trapping oxidized Cgg with alcohols and aromatics results in the formation of alkoxylated and arylated C60, respectively, while trapping oxidized CgQ with x, y-diols results in the formation of x, y-difulleroxyalkanes (earmuff ethers).

The paper deals with equivalent norms and Schauder bases in anisotropic Besov spaces where 1≦p <∞, = (s1,…, sn), and 0 < sk <1.