ZIF-8 shows good stability in a humid atmosphere and has also been studied for applications in aqueous solutions. However, inconsistent results were reported about the stability of ZIF-8 in aqueous ...solutions. To clarify these inconsistent reports, ZIF-8 water stability tests were conducted using ZIF-8 crystallites of different size prepared by different methods. High crystallinity ZIF-8 crystallites were immersed in pure water at different ZIF-8/water ratio for 24 hours under ambient conditions. The solid powders obtained by evaporation of all the tested ZIF-8/water samples at 40 °C show the presence of a new substance of crystalline structure with a dense, leaf-like morphology. The conversion of ZIF-8 to this substance increases from about 20% to 100% as ZIF-8/water decreases from 6 wt.% to 0.02 wt.%. The solid powder and supernatant were also obtained from the tested ZIF-8/water samples by filtration. Such collected solid powder composes mainly of ZIF-8. The solid powder from the supernatant after evaporation at 40 °C has the same morphology and structure of the new substance discussed above. The results show that ZIF-8 crystallites are not stable in water under ambient conditions. The amount of ZIF-8 crystallites that get dissolved depends on ZIF-8/water ratio and contact time. The solid sample collected by filtration may contain residual ZIF-8, which is responsible for the confusion in the literature about the water stability of ZIF-8. The dissolved zinc and imidazolate ions in aqueous solution, upon condensation by evaporation, form the new substance which is not ZIF-8.
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•ZIF-8 structure is not stable in water under ambient conditions.•ZIF-8 undergoes phase shift to a substance with crystalline, dense structure and a leaf-like morphology.•Conversion ratio of ZIF-8 to new substance depends on ZIF-8/water ratio, independent of crystal size and synthesis method.•Sample collection method is responsible for inconsistent reports on water stability in the literature.
There are two ways to unify gravitational field and gauge field. One is to represent gravitational field as principal bundle connection, and the other is to represent gauge field as affine ...connection. Poincaré gauge theory and metric-affine gauge theory adopt the first approach. This paper adopts the second. In this approach, (i) gauge field and gravitational field can both be represented by affine connection; they can be described by a unified spatial frame. (ii) Time can be regarded as the total metric with respect to all dimensions of internal coordinate space and external coordinate space. On-shell can be regarded as gradient direction. Quantum theory can be regarded as a geometric theory of distribution of gradient directions. Hence, gauge theory, gravitational theory, and quantum theory all reflect intrinsic geometric properties of manifold. (iii) Coupling constants, chiral asymmetry, PMNS mixing, and CKM mixing arise spontaneously as geometric properties in affine connection representation, so they are not necessary to be regarded as direct postulates in the Lagrangian anymore. (iv) The unification theory of gauge fields that are represented by affine connection can avoid the problem that a proton decays into a lepton in theories such as SU5. (v) There exists a geometric interpretation to the color confinement of quarks. In the affine connection representation, we can get better interpretations to the above physical properties; therefore, to represent gauge fields by affine connection is probably a necessary step towards the ultimate theory of physics.
Thin-walled parts processed by five-axis CNC machine tools are widely used in aerospace and other fields due to their excellent performance. However, due to the weak rigidity of thin-walled parts, ...they are prone to deformation during milling, which poses great difficulties for efficient and precise machining of thin-walled parts. This paper introduces the classification and corresponding machining methods of thin-walled parts. By analyzing the causes and evolution mechanisms of errors in the machining process of thin-walled parts, and combining modeling methods with factors such as milling force, residual stress, and cutting chatter, the current research status of domestic and foreign scholars on deformation factors is summarized. At the same time, two deformation control methods, adaptive machining and error compensation, were introduced. Finally, the overall research status of thin-walled parts machining was summarized, and prospects for efficient and precise machining of thin-walled parts were proposed based on actual machining conditions.
Background and purpose
Having good collaterals is associated with better clinical outcomes in patients undergoing endovascular thrombectomy. This study aims to evaluate whether the effect of ...collateral status on functional outcomes is modified by volemia at admission.
Methods
This is a single‐center, retrospective analysis of patients who had acute proximal anterior circulation occlusion and underwent endovascular thrombectomy between January 2019 and June 2022. Volemia at admission, evaluated by blood urea nitrogen‐to‐creatinine ratio, was used to dichotomize patients into dehydrated and hydrated groups. The primary outcome was functional independence (90‐day modified Rankin Scale score = 0–2). Secondary outcomes were the rates of successful reperfusion, 24‐h symptomatic intracranial hemorrhage, and 90‐day all‐cause mortality. Multivariable logistic regression analysis was used to assess the interaction between collateral status and volemia at admission on outcomes.
Results
A total of 290 patients were enrolled, among whom having good collaterals was associated with functional independence (adjusted odds ratio OR = 2.71, 95% confidence interval CI = 1.41–5.22, p = 0.003). Having good collaterals benefited dehydrated patients (adjusted OR = 3.33, 95% CI = 1.45–7.63, p = 0.004) but not hydrated patients (adjusted OR = 2.21, 95% CI = 0.73–6.68, p = 0.161). However, an interaction between collaterals and volemia at admission on functional independence was not observed (p = 0.319). The rates of successful reperfusion, symptomatic intracerebral hemorrhage, and all‐cause mortality were similar between those with good and poor collaterals in both dehydrated and hydrated patients.
Conclusions
The effect of collateral status on the functional independence of patients undergoing thrombectomy is not modified by volemia at admission.
Lung cancer (LC) is one of the most serious malignant tumors, which has the fastest growing morbidity and mortality worldwide. A role of the lung microbiota in LC pathogenesis has been analyzed, but ...a comparable role of the gut microbiota has not yet been investigated. In this study, the gut microbiota of 30 LC patients and 30 healthy controls were examined via next-generation sequencing of 16S rRNA and analyzed for diversity and biomarkers. We found that there was no decrease in significant microbial diversity (alpha diversity) in LC patients compared to controls (
observed = 0.1422), while the composition (beta diversity) differed significantly between patients and controls (phylum stress = 0.153, class stress = 0.16, order stress = 0.146, family stress = 0.153). Controls had a higher abundance of the bacterial phylum
and genus
, while patients with LC showed elevated levels of
. These bacteria were found as possible biomarkers for LC. A decline of normal function of the gut microbiome in LC patients was also observed. These results provide the basic guidance for a systematic, multilayered assessment of the role of the gut microbiome in LC, which has a promising potential for early prevention and targeted intervention.
is obligate parasitic nematode with a wide variety of hosts that causes huge economic losses every year. In an effort to identify novel bacterial biocontrols against
, the nematicidal activity of
...strain Bv-25 obtained from cucumber rhizosphere soil was measured. Strain Bv-25 could inhibit the egg hatching of
and had strong nematicidal activity, with the mortality rate of second-stage
juveniles (J2s) at 100% within 12 h of exposure to Bv-25 fermentation broth. The
genes
,
, and
were suppressed by Bv-25 fumigation treatment after 48 h. Strain Bv-25 could colonize cucumber roots, with 5.94 × 10
colony-forming units/g attached within 24 h, effectively reducing the infection rate with J2s by 98.6%. The bacteria up-regulated the expression levels of cucumber defense response genes
,
, and
and induced resistance to
in split-root trials. Potted trials showed that Bv-25 reduced cucumber root knots by 73.8%. The field experiment demonstrated that disease index was reduced by 61.6%, cucumber height increased by 14.4%, and yield increased by 36.5% in Bv-25-treated plants compared with control. To summarize,
strain Bv-25 strain has good potential to control root-knot nematodes both when colonizing the plant roots and through its volatile compounds.
Metal-organic frameworks (MOFs) have presented potential for detection of specific species and catalytic application due to their diverse framework structures and functionalities. In this work, two ...novel pillar-layered MOFs Cd6(DPA)2(NTB)4(H2O)4n·n(DPA·5DMA·H2O) (1) and Cu2(DPA)(OBA)2n·n(2.5DMF·H2O) (2) DPA = 2,5-di(pyridin-4-yl)aniline, H3NTB = 4,4′,4′′-nitrilotribenzoic acid, H2OBA = 4,4′-oxydibenzoic acid, DMA = N,N-dimethylacetamide, DMF = N,N-dimethylformamide were successfully synthesized and structurally characterized. Both 1 and 2 have three-dimensional framework structures. The fluorescent property of 1 makes it possible for sensing specific amino acid such as L-glutamic acid (Glu) and L-aspartic acid (Asp). While MOF 2 was found to be suitable for photocatalytic degradation of Rhodamine B (RhB) in the presence of H2O2. The results imply that MOFs are versatile and metal centers are important in determining their properties.
To systematically evaluate the relationship between the neutrophil-to-lymphocyte ratio (NLR) and the risk of all-cause mortality or cardiovascular events in patients with chronic kidney disease ...(CKD).
PubMed, Embase, and Web of Science databases were searched for cohort studies that were published since the databases were launched, until 1 April 2020. We selected papers according to specific inclusion and exclusion criteria, extracted data, and evaluated the quality of the citations. Data from eligible studies were used to calculate the combined hazard ratios (HRs) and 95% confidence intervals (CI).
The search identified 1048 potentially eligible records, and 10 studies (n = 1442) were selected. Eight studies reported all-cause mortality, and two studies reported cardiovascular events. The combined HR of all-cause mortality was 1.45 (95% CI 1.20-1.75) and the HR of cardiovascular events was 1.52 (95% CI 1.33-1.72) when NLR was considered as a categorical variable. Similarly, the association between NLR and all-cause mortality was confirmed (HR 1.35; 95% CI 1.23-1.48) when NLR was used as a continuous variable.
NLR is a predictor of all-cause mortality and cardiovascular events in patients with chronic kidney disease.
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