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Dissipative solitons have been realized in mode-locked fiber lasers in the theoretical framework of the Ginzburg–Landau equation and have significantly improved the pulse energy and peak power levels of such lasers. It is interesting to explore whether dissipative solitons exist in optical parametric oscillators in the framework of three-wave coupling equations in order to substantially increase the performance of optical parametric oscillators. Here, we demonstrate a temporal-filtering dissipative soliton in a synchronously pumped optical parametric oscillator. The temporal-gain filtering of the pump pulse combined with strong cascading nonlinearity and dispersion in the optical parametric oscillator enables the generation of a broad spectrum with a nearly linear chirp; consequently, a significantly compressed pulse and high peak power can be realized after dechirping outside the cavity. Furthermore, we realized, for the first time, dissipative solitons in an optical system with a negative nonlinear phase shift and anomalous dispersion, extending the parameter region of dissipative solitons. The findings may open a new research block for dissipative solitons and provide new opportunities for mid-infrared ultrafast science.
Current studies on inhibitory effects of n-3 PUFA on pro-inflammatory cytokines have inconsistent results. Thus, a meta-analysis of randomised controlled trials was conducted to identify the effects of n-3 PUFA administration on circulating IL-6 and TNF in patients with cancer. Studies that examined the effects of n-3 PUFA administration on circulating IL-6 and TNF in patients with cancer were identified by searching PubMed and EMBASE from January 1975 to February 2021. Differences in n-3 PUFA administration and control conditions were determined by calculating standardised mean differences (SMD) with 95 % CI. Twenty studies involving 971 patients met the inclusion criteria. The overall SMD were 0·485 (95 % CI 0·087, 0·883) for IL-6 and 0·712 (95 % CI 0·461, 0·962) for TNF between n-3 PUFA administration and control conditions. Sources of heterogeneity were not found through subgroup and meta-regression analyses. Publication bias was observed in TNF with a slight contribution to the effect size. n-3 PUFA can reduce circulating IL-6 and TNF levels in patients with cancer. Results supported the recommendation of n-3 PUFA as adjuvant therapy for patients with cancer, possibly excluding head and neck cancer, owing to their anti-inflammatory properties.
Extensive magmatism in NE China, eastern Central Asian Orogenic Belt, has produced multi-stage granitic plutons and accompanying W mineralization. The Narenwula complex in the southwestern Great Xing’an Range provides important insights into the petrogenesis, geodynamic processes and relationship with W mineralization. The complex comprises granodiorites, monzogranites and granite porphyry. Mafic microgranular enclaves are common in the granodiorites, and have similar zircon U–Pb ages as their host rocks (258.5–253.9 Ma), whereas the W-bearing granitoids yield emplacement ages of 149.8–148.1 Ma. Permian granodiorites are I-type granites that are enriched in large-ion lithophile elements and light rare earth elements, and depleted in high field strength elements and heavy rare earth elements. Both the mafic microgranular enclaves and granodiorites have nearly identical zircon Hf isotopic compositions. The results suggest that the mafic microgranular enclaves and granodiorites formed by the mixing of mafic and felsic magmas. W-bearing granitoids are highly fractionated A-type granites, enriched in Rb, Th, U and Pb, and depleted in Ba, Sr, P, Ti and Eu. They have higher W concentrations and Rb/Sr ratios, and lower Nb/Ta, Zr/Hf and K/Rb ratios than the W-barren granodiorites. These data and negative ϵHf(t) values (–6.0 to –2.1) suggest that they were derived from the partial melting of ancient lower crust and subsequently underwent extreme fractional crystallization. Based on the regional geology, we propose that the granodiorites were generated in a volcanic arc setting related to the subduction of the Palaeo-Asian Ocean, whereas the W-bearing granitoids and associated deposits formed in a post-orogenic extensional setting controlled by the Mongol–Okhotsk Ocean and Palaeo-Pacific Ocean tectonic regimes.
We study the asymptotic behaviour of convective heat transfer for turbulent flows in high-porosity fluid-saturated media by two-dimensional high-resolution numerical simulation. The generalized Navier–Stokes equations for incompressible fluid flow and the heat transport equation in porous media at the representative element volume scale are solved by the lattice Boltzmann method, wherein the non-Darcian effects are taken into consideration. The asymptotic behaviour of the Nusselt number $N$ has been revealed for Rayleigh numbers $10^4\leq R\leq 10^{11}$ and Darcy numbers $10^{-6}\leq \xi \leq 10^6$: all the data for various Darcy numbers gradually collapse onto a unique line with increasing Rayleigh number. The asymptote can be well represented by $N=0.146\times R^{0.286}$ for $R>2\times 10^7$, which approaches the relationship for the Rayleigh–Bénard turbulent convection of free fluid flows. The transition can be characterized by a scaling analysis with $R^{}\xi ^{3/2}\sim 1$, below which, however, the data collapse onto the Darcy limit for porous media. The Reynolds number and the Nusselt number both increase with Darcy number above the onset of convection, whereas a premature saturation of the Nusselt number is observed in comparison with that of the Reynolds number. The counter-gradient heat transport by the large-scale flows is quantified, which compensates for the increase of the gradient heat transport with Darcy number. The heat transfer in high-porosity fluid-saturated media with a very small Darcy number $\xi \geq 10^{-6}$ can be comparable to that of free fluid flows for a sufficiently high Rayleigh number $R\geq 10^{11}$.
Individuals with HIV are at increased risk for osteoporosis. A healthy diet with adequate Ca is recommended to promote bone health. However, lengthy nutritional assessments pose barriers to routine screenings in clinical practice. This study aimed to examine the validity and reproducibility of a six-item dietary Ca screening tool among Chinese individuals with HIV.
Design:
We conducted a two time-point study in an outpatient setting. Volunteers self-administered the six-item tool upon enrolment and again at 1-month follow-up. At baseline, participants also completed a validated FFQ and surveys regarding demographic and clinical risk factors.
Setting:
Beijing, China; Shenzhen, Guangdong, China.
Participants:
Upon enrolment, 127 individuals with HIV participated in the study, of whom 83 completed the follow-up screening.
Results:
Mean age of participants was 35·2 (sd 9·3) years, average BMI was 22·8 (sd 3·8) kg/m2 and 89 % were men. Among the participants, 54·7 % reported Ca intake less than 800 mg/d. The six-item tool demonstrated fair-to-moderate relative validity with a correlation of 0·39 and 75·7 % of subjects classified in same/adjacent quartiles as the reference, and moderate-to-good reproducibility with a correlation of 0·60 and 83·1 % of subjects classified in same/adjacent quartiles. Finally, receiver operating characteristic analyses yielded a sensitivity of 87·0 % and a specificity of 39·4 % with optimised cut-off level.
Conclusions:
The six-item tool presented adequate validity and reproducibility to identify individuals with low Ca intake among the target population, providing a convenient instrument for categorising Ca intake in clinical practice, prompting referrals for further assessment, and raising awareness of dietary Ca in bone disease prevention.
Evidence about the impact of the COVID-19 pandemic on the mental health of specific subpopulations, such as university students, is needed as communities prepare for future waves.
Aims
To study the association of proximity of COVID-19 with symptoms of anxiety and depression in university students.
Method
This trend study analysed weekly cross-sectional surveys of probabilistic samples of students from the University of British Columbia for 13 weeks, through the first wave of COVID-19. The main variable assessed was propinquity of COVID-19, defined as ‘knowing someone who tested positive for COVID-19’, which was specified at different levels: knowing someone anywhere globally, in Canada, in Vancouver, in their course or at home. Proximity was included in multivariable linear regressions to assess its association with primary outcomes, including 30-day symptoms of anxiety and/or depression.
Results
Of 1388 respondents (adjusted response rate of 50%), 5.6% knew someone with COVID-19 in Vancouver, 0.8% in their course and 0.3% at home. Ten percent were overwhelmed and unable to access help. Knowing someone in Vancouver was associated with an 11-percentage-point increase in the probability of 30-day anxiety symptoms (s.e. 0.05, P ≤ 0.05), moderated by gender, with a significant interaction of the exposure and being female (coefficient −20, s.e. 0.09, P ≤ 0.05). No association was found with depressive symptoms.
Conclusions
Propinquity of COVID-19 cases may increase the likelihood of anxiety symptoms in students, particularly among men. Most students reported coping well, but additional support is needed for an emotionally overwhelmed minority who report being unable to access help.
The aim of this study was to assess the current status of disease-related knowledge and to analyze the relationship among the general condition, illness perception, and psychological status of patients with coronavirus disease 2019 (COVID-19).
Methods:
A hospital-based cross-sectional study was conducted on 118 patients using convenience sampling. The general questionnaire, disease-related knowledge questionnaire of COVID-19, Illness Perception Questionnaire (IPQ), and Profile of Mood States (POMS) were used to measure the current status of participants.
Results:
The overall average score of the disease-related knowledge of patients with COVID-19 was (79.19 ± 14.25), the self-care situation was positively correlated with knowledge of prevention and control (r = 0.265; P = 0.004) and total score of disease-related knowledge (r = 0.206; P = 0.025); the degree of anxiety was negatively correlated with the knowledge of diagnosis and treatment (r = −0.182; P = 0.049). The score of disease-related knowledge was negatively correlated with negative cognition (volatility, consequences, emotional statements) and negative emotions (tension, fatigue, depression) (P < 0.05); positively correlated with positive cognition (disease coherence) and positive emotion (self-esteem) (P < 0.05).
Conclusions:
It was recommended that we should pay more attention to the elderly and low-income groups, and increase the knowledge about diagnosis and treatment of COVID-19 and self-care in the future health education for patients.
The aim of the present study was to examine whether serum Zn concentrations were associated with metabolic risk factors in Chinese children and adolescents. This was a cross-sectional study including 3241 participants, aged 6 to 17 years, from Jiangsu, China. Metabolic risk factors included fasting glucose (FG), total cholesterol (TC), TAG, HDL-cholesterol, LDL-cholesterol, systolic blood pressure and diastolic blood pressure. Data were analysed using multi-variable linear regression and generalised additive models, which were adjusted for age, sex, high-sensitive C-reactive protein, estimated glomerular filtration rate, BMI and region of residence, to assess the associations of serum Zn concentrations with metabolic risk factors. We observed a negative association between serum Zn concentrations and FG (coefficient = −0·532; 95 % CI −0·569, −0·495; P < 0·001). Moreover, TC (coefficient = 0·175; 95 % CI 0·127, 0·222; P < 0·001), HDL-cholesterol (coefficient = 0·137; 95 % CI 0·082, 0·193; P < 0·001) and LDL-cholesterol (coefficient = 0·195; 95 % CI 0·128, 0·263; P < 0·001) were found to be positively associated with Zn levels. A generalised additive model showed that the negative association between serum Zn and FG was weak at lower serum Zn concentrations and was stronger with the increase in serum Zn concentrations. Additionally, a U-shaped association between serum Zn and TAG was observed. Serum Zn concentrations were associated with FG, TC, TAG, HDL-cholesterol and LDL-cholesterol levels in Chinese children and adolescents. Lower levels of serum Zn were more likely related to a poor metabolic status.
The 2019 coronavirus disease (COVID-19) has spread to most countries around the world, infecting millions of people and resulting in the pandemic. This presents great challenges for dental professionals. It is necessary to explore preventive measures for COVID-19 in dental treatments.
Methods:
In this paper, we outline several measures designed to prevent COVID-19 in dental treatments, such as 3-level pre-examination triage and 2-body temperature tests, 3-level protection for medical personnel, gargling before oral treatment, implementing the 4-hand operation, suctioning saliva during oral treatment, using a rubber dam, and strict enforcement of hand hygiene. These measures include recommendations for medical staff and give practical advice for managing treatment.
Results:
The epidemic has been brought under control, and routine oral examination and treatments have gradually been resumed from March 9, 2020, in Hunan Province, China. From January 24 to March 8, 2020, a total of 4272 patients received oral therapy during the COVID-19 epidemic in our hospital. We followed these guidelines during the COVID-19 epidemic, and none of the clinical dental staff, other workers, or patients were infected with COVID-19.
Conclusions:
These preventive measures for COVID-19 in dental treatments can be used as a reference for oral clinics and stomatological hospitals.
Three-dimensional porous materials with the hydrophobic/oleophilic surface have attracted significant interest in the fields of oil/water separation. In this paper, superhydrophobic magnetic polyurethane sponge was fabricated by the self-polymerization of dopamine to bind the Fe3O4 nanoparticles tightly on the sponge and then soaking in cheap stearic acid aqueous solution. The obtained sponge has the superhydrophobic property and good magnetic property. The surface structure, composition, and properties of the modified sponges were characterized by scanning electron microscopy, energy dispersive spectrometer, Fourier-transform infrared spectrum, and water contact angle (WCA) measurements. The as-prepared superhydrophobic magnetic sponge was able to collect a wide range of oils and organic solvents from oil–water mixture with an absorption capacity up to 16–60 times of its own weight. Under an external magnetic field, it can be guided to a designated area. In addition, combined with the vacuum system, continuous oil separation can be carried out, which is of great significance for removing a good deal of dirty oil on the water surface. Furthermore, the WCA of sponge remains above 141°, and the oil absorption is basically unchanged through repeated cyclic experiments.
Renal fibrosis is common especially in the elderly population. Recently, we found that vitamin D deficiency caused prostatic hyperplasia. This study aimed to investigate whether vitamin D deficiency promotes renal fibrosis and functional impairment. All mice except controls were fed with vitamin D-deficient (VDD) diets, beginning from their early life. The absolute and relative kidney weights on postnatal week 20 were decreased in VDD diet-fed male pups but not in female pups. A mild pathological damage was observed in VDD diet-fed male pups but not in females. Further analysis showed that VDD-induced pathological damage was aggravated, accompanied by renal dysfunction in 40-week-old male pups. An obvious collagen deposition was observed in VDD diet-fed 40-week-old male pups. Moreover, renal α-smooth muscle actin (α-SMA), a marker of epithelial–mesenchymal transition (EMT), and Tgf-β mRNA were up-regulated. The in vitro experiment showed that 1,25-dihydroxyvitamin D3 alleviated transforming growth factor-β1 (TGF-β1)-mediated down-regulation of E-cadherin and inhibited TGF-β1-evoked up-regulation of N-cadherin, vimentin and α-SMA in renal epithelial HK-2 cells. Moreover, 1,25-dihydroxyvitamin D3 suppressed TGF-β1-evoked Smad2/3 phosphorylation in HK-2 cells. These results provide experimental evidence that long-term vitamin D deficiency promotes renal fibrosis and functional impairment, at least partially, through aggravating TGF-β/Smad2/3-mediated EMT in middle-aged male mice.
The frequency division multiple access (FDMA) strategy used in GLONASS causes inter-frequency phase bias (IFPB) and inter-frequency code bias (IFCB) between receivers from different manufacturers. The existence of IFPB and IFCB significantly increases the difficulties of fixing GLONASS ambiguity and limits the accuracy and reliability of GLONASS positioning. Moreover, the initial value of IFPB and IFCB may be unavailable or unreliable with the increasing number of receivers from different manufacturers in recent years. In this study, a real-time and reliable calibration algorithm of IFPB and IFCB based on multi-GNSS assistance is proposed by providing a fixed solution. Real-time IFPB rate and IFCB can be obtained using this algorithm without the initial IFPB and IFCB. The IFPB rate for all GLONASS satellites and IFCB for each GLONASS satellite are estimated due to different characteristics of IFPB and IFCB. IFPB calibration can be divided into constant and real-time IFPB calibrations to meet the different positioning requirements. Results show that constant IFPB rate has only 2 mm difference from the mean value of real-time IFPB rate. The IFPB rate and IFCB estimated by this algorithm have excellent stability, and the change in reference satellite cannot affect the results of IFPB rate and the stability of IFCB. The centimetre-level positioning results can be obtained using two calibration methods, and the positioning results with real-time calibration method are 10%–20% better than those with the constant calibration method. Under satellite-deprived environments, the improvements of multi-GNSS positioning accuracy with constant inter-frequency bias calibration gradually increase as the satellite cut-off elevation angle increases compared with GPS/BDS, which can reach up to 0·9 cm in the vertical direction.
The microbiota–gut–brain axis, especially the microbial tryptophan (Trp) biosynthesis and metabolism pathway (MiTBamp), may play a critical role in the pathogenesis of major depressive disorder (MDD). However, studies on the MiTBamp in MDD are lacking. The aim of the present study was to analyze the gut microbiota composition and the MiTBamp in MDD patients.
Methods
We performed shotgun metagenomic sequencing of stool samples from 26 MDD patients and 29 healthy controls (HCs). In addition to the microbiota community and the MiTBamp analyses, we also built a classification based on the Random Forests (RF) and Boruta algorithm to identify the gut microbiota as biomarkers for MDD.
Results
The Bacteroidetes abundance was strongly reduced whereas that of Actinobacteria was significantly increased in the MDD patients compared with the abundance in the HCs. Most noteworthy, the MDD patients had increased levels of Bifidobacterium, which is commonly used as a probiotic. Four Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologies (KOs) (K01817, K11358, K01626, K01667) abundances in the MiTBamp were significantly lower in the MDD group. Furthermore, we found a negative correlation between the K01626 abundance and the HAMD scores in the MDD group. Finally, RF classification at the genus level can achieve an area under the receiver operating characteristic curve of 0.890.
Conclusions
The present findings enabled a better understanding of the changes in gut microbiota and the related Trp pathway in MDD. Alterations of the gut microbiota may have the potential as biomarkers for distinguishing MDD patients form HCs.
To explore whether and how group cognitive-behavioural therapy (GCBT) plus medication differs from medication alone for the treatment of generalised anxiety disorder (GAD).
Methods:
Hundred and seventy patients were randomly assigned to the GCBT plus duloxetine (n=89) or duloxetine group (n=81). The primary outcomes were Hamilton Anxiety Scale (HAMA) response and remission rates. The explorative secondary measures included score reductions from baseline in the HAMA total, psychic, and somatic anxiety subscales (HAMA-PA, HAMA-SA), the Hamilton Depression Scale, the Severity Subscale of Clinical Global Impression Scale, Global Assessment of Functioning, and the 12-item Short-Form Health Survey. Assessments were conducted at baseline, 4-week, 8-week, and 3-month follow-up.
Results:
At 4 weeks, HAMA response (GCBT group 57.0% vs. control group 24.4%, p=0.000, Cohen’s d=0.90) and remission rates (GCBT group 21.5% vs. control group 6.2%, p=0.004; d=0.51), and most secondary outcomes (all p<0.05, d=0.36−0.77) showed that the combined therapy was superior. At 8 weeks, all the primary and secondary significant differences found at 4 weeks were maintained with smaller effect sizes (p<0.05, d=0.32−0.48). At 3-month follow-up, the combined therapy was only significantly superior in the HAMA total (p<0.045, d=0.43) and HAMA-PA score reductions (p<0.001, d=0.77). Logistic regression showed superiority of the combined therapy for HAMA response rates [odds ratio (OR)=2.12, 95% confidence interval (CI) 1.02−4.42, p=0.04] and remission rates (OR=2.80, 95% CI 1.27−6.16, p=0.01).
Conclusions:
Compared with duloxetine alone, GCBT plus duloxetine showed significant treatment response for GAD over a shorter period of time, particularly for psychic anxiety symptoms, which may suggest that GCBT was effective in changing cognitive style.
The Ordos Basin is the largest and most important intracontinental sedimentary depression in China, and a significant amount of crude oil resources has developed within this Mesozoic formation. High-grade organic-rich shale is prevalent in the large-scale areas of the Chang 7 sedimentary stage and provides essential hydrocarbon resources for abundant oil enrichment in the Mesozoic. This research investigated the geochemical characteristics of Chang 7 shale using core samples and well logs and via laboratory tests. In addition, the microscopic components of the shale organic matter (OM), biological marker compounds, carbon isotopes, enrichment grade of trace elements, and elemental ratio were analysed systematically. Moreover, the aspects related to the shale OM source, sedimentary environment and resource potential were evaluated. Our results revealed that spherical alginate and calcium spherical alginate were predominant in the micropetrological components of the shale. Many biomarkers, including n-alkanes, steranes and terpanes, were detected in the gas chromatography – mass spectrometry spectra. An analysis of n-alkanes, regular sterane shapes (C21−/C22− and C26+C27/C28+C29), odd–even predominance index (OEP) and carbon preference index (CPI) values and carbon isotope distributions showed that OM was produced from aquatic organisms. The indicators of trace elements, such as Sr/Ba and V/V+Ni, combined with the biomarker compound in Pr/Ph and the gammacerane index showed the presence of a semi-deep – deep lake environment containing fresh–brackish water. In addition, the hydrocarbon conversion rate index and shale rock pyrolysis parameters revealed that Chang 7 has a high hydrocarbon generation ability and hydrocarbon expulsion efficiency.
We present the design and experiment of a broadband optical parametric chirped-pulse amplifier (OPCPA) which provides high conversion efficiency and good beam quality at 808 nm wavelength. Using a three-dimensional spatial and temporal numerical model, several design considerations necessary to achieve high conversion efficiency, good beam quality and good output stability are discussed. To improve the conversion efficiency and broaden the amplified signal bandwidth simultaneously, the nonlinear crystal length and OPCPA parameters are analyzed and optimized with the concept of dissipating amplified idler between optical parametric amplification (OPA) of two crystals configuration. In the experiment, an amplifier consisting of two OPCPA stages of ‘L’ type configuration was demonstrated by using the optimized parameters. An amplified signal energy of 160 mJ was achieved with a total pump-to-signal efficiency of 35% (43% efficiency for the OPCPA stage 2). The output bandwidth of signal pulse reached 80 nm and the signal pulse was compressed to 24 fs. The energy stability reached 1.67% RMS at 3% pump energy variation. The optimized OPCPA amplifier operates at a repetition rate of 1 Hz and is used as a front-end injection for the main amplifier of SG-II 5PW laser facility.
Uniformly dispersed ultra-small hollow Co9S8 nanoparticles (<10 nm) (H-Co9S8@C) and solid Co9S8 nanoparticles (S-Co9S8@C) in porous carbon were fabricated separately by solvothermal and sulfur powder sulphurisation using Co-MOF-74 as the template. Owing to significant structural stability and uniform hollow structure of carbon-encapsulated Co9S8, the as-prepared H-Co9S8@C exhibited excellent lithium ion storage performance as an anode material. Worked in the voltage of 0.01–3.0 V, H-Co9S8@C revealed outstanding rate capability (850, 670, 613, 552, 457, and 347 mA h/g at 0.1, 0.2, 0.5, 1, 2, and 3 A/g, respectively), and high reversible capacity (after 250 cycles with a remained capacity of 900.5 mA h/g). Compared with S-Co9S8@C, over 50 cycles, the discharge specific capacity of H-Co9S8@C was still maintained at 655 mA h/g at a current density of 0.5 A/g, whereas the capacity of S-Co9S8@C declined rapidly to 160.4 mA h/g. The results showed that superior capacity, excellent rate performance, and highly stable cycle performance depended mainly on the hollow characteristic of Co9S8.
This work designed a facile preparation for an SiO2/C composite as the anode material for lithium ion battery. Both SiO2 and carbon are amorphous. SiO2 and carbon are mixed uniformly. The SiO2/C composite shows high specific capacity, cycle stability, and rate capability in lithium ion battery charge–discharge test. A stable reversible capacity of 1024 mA h/g at the current density of 100 mA/g is reached. The capacity retains 83% after 100 cycles. The uniform mixture of SiO2 and carbon leads to reduced volume change during the lithiation and delithiation of SiO2, together with the amorphous nature of SiO2 explains the high cycling stability. The carbon coating is a key factor for the high capacity and stability due to the increased electrical conductivity and reduced volume change. The resistance of the solid electrolyte interface film and charge transfer resistance of the SiO2/C composite are much smaller than those of pure carbon, which is a direct proof of the improved conductivity of the material by the carbon coating.