Antibiotic rank the most powerful weapons against bacterial infection, but their use is often limited by antibiotic-associated diarrhea (AAD). Here we reported that glutamine deficiency might act as a new link between clindamycin-induced dysbiosis and intestinal barrier dysfunction during AAD progression. Using a mouse model, we demonstrated that glutamine became a conditionally essential amino acid upon persistent therapeutic-dose clindamycin expose, evidenced by a dramatic decrease in intestinal glutamine level and glutaminase expression. Mechanistically, clindamycin substantially confounded the abundance of butyrate-producing strains, lead to the deficiency of fecal butyrate which is normally a fundamental fuel for enterocytes, and in turn increased compensatory use of glutamine. In addition to its pivotal roles in colonic epithelial cell turnover, glutamine was required for nitric oxide (NO) production in classic macrophage-driven host defense facilitating pathogen removal. Importantly, oral administration of glutamine effectively attenuated clindamycin-induced dysbiosis and restored intestinal barrier dysfunction in mice. Collectively, this study highlighted the importance of gut microbiota in host energy homeostasis, and provided a rationale for introducing glutamine supplementation to patients receiving long-term antibiotic treatment.

Near-interface colloidal monolayers are often used as model systems for research on hydrodynamics in biophysics systems and in the chemical industry. Using microrheological methods, the correlated diffusion of particles is experimentally measured in colloidal monolayers near a water–air interface. The results show that the scaling lengths $({\chi _{||}},{\chi _ \bot })$ of such colloidal monolayers are anisotropic in two orthogonal directions within the monolayer, which are parallel and perpendicular to the line connecting the centres of a particle pair. The former $({\chi _{||}})$ is the Saffman length of the monolayer, while the latter $({\chi _ \bot })$ is a function of both the Saffman length and the radius of the colloids. The size of the colloids is involved in ${\chi _ \bot }$ but not ${\chi _{||}}$ , which reflects the discrete nature of the monolayer in the transverse direction and the continuous nature of the monolayer in the longitudinal direction. From the scaling lengths, the viscosities of the colloidal monolayers are obtained, which agree with those obtained from the single-particle diffusion coefficients. The influence of the boundary condition imposed by the nearby interface on the hydrodynamic interactions is in a power-law behaviour of the distance z.

Lead-free ferroelectric electrocaloric ceramics that could convert electrical energy into heat are the promising candidate for environment-friendly cooling devices. For refrigeration devices, a large temperature change (ΔT) and good temperature stability are required, which are highly related to the phase structure and the applied electric field. In this work, a diffused ferroelectric–paraelectric (FP) phase transition is formed in (K, Na)NbO3 (KNN) by using appropriate composition engineering. The relaxor ferroelectrics in this work present both a large ΔT of 1.24 K and a high ΔT/ΔE of 0.19 K mm/kV. In addition, a wide temperature span exceeds 55 °C at the high electrocaloric effect (ECE) criterion (ΔT ≥ 0.5 K) could also be observed. This work not only opens a new strategy for obtaining high-performance ceramics for refrigeration devices but also extends the application area of the KNN-based lead-free ferroelectrics from sensors, actuators and energy harvesting to solid-state cooling applications.

The Ginzburg–Landau equation (GLE) can phenomenologically model several key features of non-equilibrium systems including those in fluid mechanics. Its validity in real flows, however, remains questionable. Here, we show that the linear GLE can be formulated such that it has the same Wentzel–Kramers–Brillouin (WKB) approximation as for the linear global stability problem in open shear flows. We use the GLE to model the linear global modes of three different wakes and find that it can accurately capture the linear growth rate and frequency to first order in the WKB approximation. Furthermore, we find that it can also provide the shapes of the direct and adjoint eigenvectors and the regions of maximal structural sensitivity. The proposed model requires only the basic flow as input, but gives robust predictions and is computationally inexpensive. As well as opening up new possibilities for GLE-based control strategies, the proposed model makes accurate stability calculations possible, even for some computationally intractable open shear flows.

The construction of halloysite spherical capsules (halloysite aerogels) was reported for the first time in our previous work. The excellent performance of the microcapsule in functional carrying was also found in our further research. In this work, the anti-icing surface was fabricated by using halloysite nanotubes and halloysite spherical microcapsules. The fabrication of the anti-icing coating was investigated, and the ice nucleation behavior of droplet on the coating surface was studied. The modified halloysite nanotubes (F-HNTs) and the modified halloysite microcapsules (F-HAs) were characterized by Fourier-transform infrared spectroscopy, thermal gravimetric, and pore size distribution. The results show that the introduction of F-HNTs and F-HAs have successfully formed a micro-nano structure on the coating surface with superhydrophobicity performance. The icing temperature of the coating has decreased 2.3 °C compared with bare glass, and the ice adhesion strength has decreased 82%. According to the ice dynamic mechanics, the ice nucleation rate on the coating is significantly reduced, thus the halloysite microcapsule coating has good icephobic performance.

Stratospheric airships are promising aircraft, usually designed as a non-rigid airship. As an essential part of the non-rigid airship, the envelope plays a significant role in maintaining its shape and bearing the external force load. Generally, the envelope material of a flexible airship consists of plain-weave fabric, composed of warp and weft fibre yarn. At present, biaxial tensile experiments are the primary method used to study the stress–strain characteristics of such flexible airship materials. In this work, biaxial tensile testing of UN-5100 material was carried out. The strain on the material under unusual stress and the stress ratio were obtained using Digital Image Correlation (DIC) technology. Also, the stress–strain curve was corrected by polynomial fitting. The slope of the stress–strain curve at different points, the Membrane Structures Association of Japan (MSAJ) standard and the Radial Basis Function (RBF) model were compared to identify the stress–strain characteristics of the materials. Some conclusions on the mechanical properties of the flexible airship material can be drawn and will play a significant role in the design of such envelopes.

Iridium (Ir) has an extremely high melting point (2443 °C), high chemical stability and is one of the most promising high-temperature materials. However, Ir is more difficult to process compared with other face-centered cubic metals, such as Ni and Al, which limits its applications. To solve this problem, we study the effect of 32 alloying elements (X) on stacking fault energy of dilute Ir-based alloys generated by shear deformation using the first-principles calculations. The investigation reveals that there are many alloying elements studied herein decrease the stacking fault energy of face-centered cubic (fcc) Ir, and the most effective element in reducing stacking fault energy of fcc Ir is Zn. The microscopic mechanism is caused by electron redistribution in the local stacking fault area. These results are expected to provide valuable guidance for the further design and application of Ir-based alloys.

The Shuangjianzishan vein-type Ag-Pb-Zn deposit in the southern Great Xing’an Range (GXR), NE China, is hosted in the slate of the Lower Permian Dashizhai Formation intruded by granite porphyry. In this paper, U–Pb zircon ages and bulk-rock and isotope (Sr, Nd, Pb and Hf) compositions are reported to investigate the derivation, evolution and geodynamic setting of this granite porphyry. It is closely associated with Pb-Zn-Ag mineralization in the southern GXR and contains important geological information relating to regional tectonic evolution. Laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) zircon U–Pb dating yields an emplacement age of 131 ± 1 Ma for the granite porphyry. Bulk-rock analyses show that the Shuangjianzishan granite porphyry is characterized by high Si, Na and K contents but low Mg and Fe contents, and that the enrichment of Zr, Y and Ga suggests an A-type granite affinity. Most of the studied samples have relatively low 87Sr/86Sr values (0.70549–0.70558), with positive ϵNd(t) (0.71–0.88) and ϵHf(t) (4.9–6.9) values. The Sr–Nd isotope modelling results, in combination with the young TDM2 ages of Nd and Hf (850–864 and 668–778 Ma, respectively), reveal that the Shuangjianzishan granite porphyry may be derived from the melting of mantle-derived juvenile component, with minor lower crustal components; this finding is also supported by Pb isotopic compositions. Considering the widespread presence of granitoids with coeval volcanic rocks and regional geology data, we propose that the Shuangjianzishan granite porphyry formed in a post-orogenic extensional environment related to the upwelling of asthenospheric mantle following the closure of the Mongol–Okhotsk Ocean.

We investigate the three-dimensional surface pattern and nonlinear dynamics of a condensing liquid layer suspended from a cooled substrate and in contact with a mixture of its vapour and an inert gas below. A vapour boundary layer (VBL) is introduced, to which the changes in gaseous composition and temperature are assumed to be confined. An interfacial transport equation is derived, which incorporates the physical effects of convection and diffusion of vapour within the VBL, coupled with a long-wave evolution equation for the location of the free surface. This work extends the study of Kanatani (J. Fluid Mech., vol. 732, 2013, pp. 128–149) on a sessile evaporating film to the Rayleigh–Taylor unstable condensing/evaporating case with nonlinear analyses which also accounts for the effect of vapour recoil due to mass transfer on interfacial evolution and that of gravity combined with buoyancy on the internal convection of pendent drops in a condensate layer. The coupled nonlinear evolutionary system is referred to as a $1.5$ -sided model. It can be reduced to the conventional one-sided model when phase change is limited by processes in the liquid. An extended basic state is obtained, whose stability is investigated with pseudo-steady linear theory and time-dependent nonlinear simulations. With the one-sided model, the influences of vapour recoil and Marangoni effects are illustrated with three representative cases. In the one-sided simulations with a random perturbation, the interface is prone to finite-time rupture and the surface patterns feature isolated droplets when vapour recoil is significant, while it becomes more regular and even without rupture as vapour recoil is weakened relative to the Marangoni effect. This suggests that, in the absence of the convection and diffusion of vapour, the destabilizations of vapour recoil and negative gravity could prevail over the stabilizations of thermocapillarity, capillarity, viscous dissipation and mass gain. With an unsaturated initial interface concentration, $\tilde {x}_{A,I0}$ , the $1.5$ -sided model indicates that the liquid layer can be stabilized to a quasi-hexagon pattern and the Rayleigh–Taylor-driven rupture can be suppressed with the effects of vapour convection and diffusion near the interface. However, the initial dynamics is in contrast to the case with a saturated $\tilde {x}_{A,I0}$ , where transition from weak evaporation to a condensation-dominated regime is seen in the later stage. The viewpoint of stability competition offers vital evidence for an induced Marangoni stabilization, which is a quintessential characteristic of the $1.5$ -sided model. Comparisons of the theory and simulations with available experiments are included throughout.

In this paper, dual-band and tri-band bandpass filters (BPFs) with fully independent and controllable passbands based on multipath-embedded resonators are presented. The dual-band BPF consists of two double open-ended stub-loaded terminal-shorted resonators (DOESL-TSRs) with a common via-hole connected along the symmetric plane of the filter. Based on DOESL-TSRs, a triple open-ended stub-loaded terminal-shorted resonator (TOESL-TSR) is proposed in the design of tri-band BPFs. The resonant characteristics of DOESL-TSR/TOESL-TSR are analyzed by the numerical calculation method. The measured results of the dual-band BPF show that the center frequencies (CFs) are located at 2.595 and 5.75 GHz, respectively, with 3 dB fraction bandwidth (FBWs) of 15 and 12.8%. The measured CFs of the tri-band BPF are located at 2.545, 3.775, and 5.95 GHz, respectively, with 3 dB FBWs of 9.8, 9.3, and 5.5%. Both of the filters exhibit the merits of fully independent and controllable passbands, high selectivity, and compact size.