In recent decades, hydrogen-rich compounds are promising candidates for room-temperature superconductors under extremely high pressure. Remarkably, the theory-oriented finding of covalent hydride H
3
...S and a class of clathrate hydrides, such as YH
9
and LaH
10
, with high superconducting critical temperature (
T
c
) above 240 K, which give rise to the hope of searching for room-temperature superconductivity among hydrogen-rich compounds under high pressure. In this paper, we focus on the research progress of binary and ternary hydrides, provide the introduction of conventional phonon-mediated superconductivity theory and the physical mechanism of high-temperature superconductivity briefly, and offer an outlook on the challenge of discovering room-temperature superconductors among hydrogen-rich compounds in the future.
Abstract
Pulsar timing arrays aim to detect nanohertz-frequency gravitational waves (GWs). A background of GWs modulates pulsar arrival times and manifests as a stochastic process, common to all ...pulsars, with a signature spatial correlation. Here we describe a search for an isotropic stochastic gravitational-wave background (GWB) using observations of 30 millisecond pulsars from the third data release of the Parkes Pulsar Timing Array (PPTA), which spans 18 yr. Using current Bayesian inference techniques we recover and characterize a common-spectrum noise process. Represented as a strain spectrum
h
c
=
A
(
f
/
1
yr
−
1
)
α
, we measure
A
=
3.1
−
0.9
+
1.3
×
10
−
15
and
α
= −0.45 ± 0.20, respectively (median and 68% credible interval). For a spectral index of
α
= −2/3, corresponding to an isotropic background of GWs radiated by inspiraling supermassive black hole binaries, we recover an amplitude of
A
=
2.04
−
0.22
+
0.25
×
10
−
15
. However, we demonstrate that the apparent signal strength is time-dependent, as the first half of our data set can be used to place an upper limit on
A
that is in tension with the inferred common-spectrum amplitude using the complete data set. We search for spatial correlations in the observations by hierarchically analyzing individual pulsar pairs, which also allows for significance validation through randomizing pulsar positions on the sky. For a process with
α
= −2/3, we measure spatial correlations consistent with a GWB, with an estimated false-alarm probability of
p
≲ 0.02 (approx. 2
σ
). The long timing baselines of the PPTA and the access to southern pulsars will continue to play an important role in the International Pulsar Timing Array.
The neocortex consists of a vast number of diverse neurons that form distinct layers and intricate circuits at the single-cell resolution to support complex brain functions
. Diverse cell-surface ...molecules are thought to be key for defining neuronal identity, and they mediate interneuronal interactions for structural and functional organization
. However, the precise mechanisms that control the fine neuronal organization of the neocortex remain largely unclear. Here, by integrating in-depth single-cell RNA-sequencing analysis, progenitor lineage labelling and mosaic functional analysis, we report that the diverse yet patterned expression of clustered protocadherins (cPCDHs)-the largest subgroup of the cadherin superfamily of cell-adhesion molecules
-regulates the precise spatial arrangement and synaptic connectivity of excitatory neurons in the mouse neocortex. The expression of cPcdh genes in individual neocortical excitatory neurons is diverse yet exhibits distinct composition patterns linked to their developmental origin and spatial positioning. A reduction in functional cPCDH expression causes a lateral clustering of clonally related excitatory neurons originating from the same neural progenitor and a significant increase in synaptic connectivity. By contrast, overexpression of a single cPCDH isoform leads to a lateral dispersion of clonally related excitatory neurons and a considerable decrease in synaptic connectivity. These results suggest that patterned cPCDH expression biases fine spatial and functional organization of individual neocortical excitatory neurons in the mammalian brain.
Purpose
Based on natural-resource-based view (NRBV), the purpose of this paper is to clarify the dimensions of green procurement and the mechanisms involved in the relationship between green ...procurement and firm performance.
Design/methodology/approach
Secondary data were to measure all the variables in 206 Chinese A-share companies’ annual reports, social responsibility reports, environmental reports, and sustainability reports, which were published by Guotai Junan Securities Co., Ltd and Wind Information Co., Ltd.
Findings
The results indicate that although both product-based and process-based green procurement have a positive effect on firm performance, these Chinese companies focus on the impact of product-based green procurement on their operational efficiency as well as the moderating role played by stakeholder satisfaction.
Originality/value
Although studies on green procurement have increased in recent years, issues such as how to measure green purchasing behaviors and how green procurement affects firms’ operational and financial performance are still unexplored. Based on previous literature, two dimensions have been defined for green procurement in this study to develop corresponding measurements, namely, product-based green procurement and process-based green procurement. Besides, this study considers operational efficiency as the mediator and stakeholder satisfaction as the moderator when constructing a new conceptual model to illustrate the relationship between green procurement and firm performance.
Chemical acaricides are mainly used in traditional tick control, which leads to the emergence of tick resistance and concurrently results in environmental pollution. In the present study, the ...chemical constituents of essential oils (EOs) from Thymus mongolicus, Cinnamomum verum, and Origanum vulgare was analyzed, and their potential application was evaluated to control the vector tick Haemaphysalis longicornis, which is widely distributed over vast areas of Eurasia, Australia, and New Zealand. Gas chromatography-mass spectrometry analysis revealed that the phenols thymol and carvacrol accounted for 34.66% and 75.72% of the EOs of T. mongolicus and O. vulgare, respectively, whereas trans-cinnamaldehyde (49.42%) was the main constituent of C. verum EO. Immersion tests showed that the EOs of C. verum and O. vulgare had significant acaricidal activity against larval H. longicornis, with the 50% lethal concentration (LC50) being 16.07 and 18.02 mg/mL, respectively, and the 95% lethal concentration (LC95) being 120.37 and 130.09 mg/mL, respectively. The EOs of O. vulgare and T. mongolicus showed significant acaricidal activity against unfed adult H. longicornis, with LC50 being 43.50 and 44.21 mg/mL, respectively, and LC95 being 113.66 and 137.99 mg/mL, respectively. The fumigant toxicity test showed significant acaricidal activity of the three EOs against both unfed and engorged nymphal and adult H. longicornis. Enzyme assays revealed that the EOs of both C. verum and O. vulgare significantly inhibited glutathione S-transferase activity (P < 0.05). In contrast, the activities of carboxylesterase and multifunction oxidases were significantly inhibited by EOs extracted from all three plants (P < 0.05). Taken together, these findings suggest that plant EOs may serve as an environment-friendly alternative for synthetic acaricides in future tick control.
•Thymol, carvacrol and trans-cinnamaldehyde were found the main compounds in the three Eos.•EOs of C. verum and O. vulgare had significant acaricidal activity against larval H. longicornis.•EOs of O. vulgare and T. mongolicus showed significant acaricidal activity to adult H. longicornis.•The activity of carboxylesterase and multifunction oxidases were significantly inhibited by Eos.
Background
Although video-assisted breast surgery is gaining popularity, endoscopic reconstruction after mastectomy is still facing lots of problems, bring about that endoscopic method has not yet ...become a standard procedure for breast cancer reconstruction. Here, we introduce a novel surgical technique of video-assisted transaxillary nipple-sparing mastectomy and immediate implant-based breast reconstruction and describe the detailed surgical procedure using this technique.
Methods
Detailed steps of surgical procedure, the patient characteristics and the mean operative time of this new technique were described in this article. All patients were asked to score their satisfaction with their reconstructed breasts preoperatively, 1 month, 3 months, 6 months and 12 months postoperatively using the BREAST-Q.
Results
At first, we used our “conventional method” and performed on 10 patients from April 2017 to June 2020; the operative time was 324.80 ± 66.39 minutes. After improving several procedures of the technique, the “optimized method” was performed on 14 cases from July 2020 to November 2020; the operative time decreased to 193.71 ± 28.75 minutes with shortest was 133 minutes; the optimized method was novel and easy to learn and be generalized. Most of the patients were satisfied with the reconstruction results. There was no significant difference between preoperative scores and scores at 3 months, 6 months and 12 months (
p
= 0.364). Since there is no wound on the breast dome, no obvious postoperative complications were observed except for one patient presented with infection.
Conclusions
This new technique has allowed surgeons to achieve excellent and reproducible outcomes in a single-stage procedure and represents an excellent technique for patients who wish to have a scarless and aesthetically pleasing appearance after mastectomy for breast cancer. This article also highlights the mean operative time (193.71 ± 28.75 minutes) that has been made possible with this new technique.
Level of Evidence V
This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors
http://www.springer.com/00266
.
Glutathione S-transferases (GSTs) are a superfamily of multifunctional enzymes in living organisms with metabolic and detoxification functions, which can detoxify exogenous and endogenous compounds ...and thereby reduce the damage caused by toxic substances to the body. Ticks are obligate blood-sucking ectoparasites that can transmit various pathogens, and the characterization of tick-derived GSTs may help improve current understanding of the molecular mechanism of tick resistance to insecticides. In this study, a novel GST gene, named HrGSTm1, was identified from Hyalomma rufipes.
Sequence analysis was performed by using bioinformatics techniques. A prokaryotic expression system was used to obtain the recombinant expression protein rHrGSTm1. Detection of spatiotemporal expression patterns of target genes and their response to the toxicity of cyhalothrin on female H. rufipes was performed by using a quantitative PCR platform. The optimal enzymological parameters of rHrGSTm1 using glutathione as substrate were calculated. The antioxidant capacity of the recombinant protein was evaluated by DPPH• (1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl). Knockdown of the HrGSTm1 genes through RNA interference was used to analyze their effects on the physiological parameters of ticks. The changes in HrGSTm1 messenger RNA expression patterns under cypermethrin stress were analyzed.
The complementary DNA sequence of HrGSTm1 contained a 672-bp open reading frame, which potentially encoded 223 amino acids. The predicted molecular weight was 25.62 kDa, and the isoelectric point 8.22. HrGSTm1 is a Mu-class GST, belonging to the cytoplasmic GSTs with no signal peptide observed. The V
and K
of rHrGSTm1 were 3.367 ± 0.81 uM and 2.208 ± 0.76 uM, respectively, and its activities were dependent on different temperatures and pH conditions; the scavenging rate of rHrGSTm1 to DPPH• reached 76.4% at 1.25 mg/ml. Variable expressions of HrGSTm1 were observed under various treatment periods and in different tissues, with the highest appearing in eggs (analysis of variance ANOVA, F
= 279.9, P < 0.0001) and Malpighian tubules (ANOVA, F
= 290.5, P < 0.0001). After knockdown of HrGSTm1, compared with the control group, the mortality in the treatment group was increased by 16.7%, the average oviposition rate decreased by 33.9%, the average engorged body weight decreased by 287.38 mg and egg weight decreased by 127.46 mg, although only the engorged body weight was significantly different (t-test, t
= 2.886, P = 0.006). After exposure to three sublethal concentrations (LC
, LC
, LC
) of cyhalothrin, the expression level of HrGSTm1 in the midgut, ovary and salivary gland was upregulated, whereas in Malpighian tubules, it showed a trend of upregulation at first and then downregulation, implying different functions during the detoxification in different tissues.
In this study, a novel GST of the Mu-class was successfully isolated from H. rufipes and systematically subjected to bioinformatic analysis and recombination identification. The variation trend of HrGSTm1 expression level in different tissues suggests that the gene has different detoxification functions in different tissues. The potential function of this gene was analyzed to provide basic research for further investigation of its detoxification mechanism.
Obstructive hypertrophic cardiomyopathy (obstructive HCM) is a hereditary disease characterized by septal hypertrophy and dynamic left ventricular outflow tract (LVOT) obstruction. Other than septal ...hypertrophy, mitral valve abnormalities are also quite common in patients with obstructive HCM, which may contribute to systolic anterior motion (SAM) of the mitral valve and LVOT obstruction. Surgical myectomy is the standard treatment to achieve anatomic correction of obstructive HCM, but controversies remain on whether and how the mitral valve procedures should be performed at the same time. In this review, we first described the mitral valve abnormalities in patients with obstructive HCM and their surgical corrections, we then explained the controversies based on current clinical studies, and we finally made a brief introduction on our surgical strategy and results.Obstructive hypertrophic cardiomyopathy (obstructive HCM) is a hereditary disease characterized by septal hypertrophy and dynamic left ventricular outflow tract (LVOT) obstruction. Other than septal hypertrophy, mitral valve abnormalities are also quite common in patients with obstructive HCM, which may contribute to systolic anterior motion (SAM) of the mitral valve and LVOT obstruction. Surgical myectomy is the standard treatment to achieve anatomic correction of obstructive HCM, but controversies remain on whether and how the mitral valve procedures should be performed at the same time. In this review, we first described the mitral valve abnormalities in patients with obstructive HCM and their surgical corrections, we then explained the controversies based on current clinical studies, and we finally made a brief introduction on our surgical strategy and results.
PDF
