This study aimed to describe diet quality of pregnant women and explore the association between maternal diet and the prevalence of low birth weight (LBW) and small for gestational age (SGA). A total of 3856 participants from a birth cohort in Beijing, China, were recruited between June 2018 and February 2019. Maternal diet in the first and second trimesters was assessed by the Chinese diet balance index for pregnancy (DBI-P), using data collected by the inconsecutive 2-d 24-h dietary recalls. Logistic regressions were performed to explore the independent effects of DBI-P components on LBW and SGA. The prevalence of LBW and SGA was 3·8% and 6·0%, respectively. Dietary intakes of the participants were imbalanced. The proportions of participants having insufficient intake of vegetables (87·3% and 86·6%), dairy product (95·9% and 96·7%) and aquatic foods (80·5% and 85·3%) were high in both trimesters. The insufficiency of fruit intake was more severe in the second (85·2%) than that in the first trimester (22·5%) (P < 0·05). After adjusting for potential confounders, the intake of fruits and dairy in the second trimester was negatively associated with the risk of LBW (OR = 0·850, 95% CI: 0·723, 0·999) and SGA (OR = 0·885, 95% CI: 0·787, 0.996), respectively. Sufficient consumption of fruits and dairy products in pregnancy may be suggested in order to prevent LBW and SGA.

Let $\mathbb {N}$ be the set of all nonnegative integers. For $S\subseteq \mathbb {N}$ and $n\in \mathbb {N}$ , let $R_S(n)$ denote the number of solutions of the equation $n=s_1+s_2$ , $s_1,s_2\in S$ and $s_1<s_2$ . Let A be the set of all nonnegative integers which contain an even number of digits $1$ in their binary representations and $B=\mathbb {N}\setminus A$ . Put $A_l=A\cap [0,2^l-1]$ and $B_l=B\cap [0,2^l-1]$ . We prove that if $C \cup D=[0, m]\setminus \{r\}$ with $0<r<m$ , $C \cap D=\emptyset $ and $0 \in C$ , then $R_{C}(n)=R_{D}(n)$ for any nonnegative integer n if and only if there exists an integer $l \geq 1$ such that $m=2^{l}$ , $r=2^{l-1}$ , $C=A_{l-1} \cup (2^{l-1}+1+B_{l-1})$ and $D=B_{l-1} \cup (2^{l-1}+1+A_{l-1})$ . Kiss and Sándor [‘Partitions of the set of nonnegative integers with the same representation functions’, Discrete Math. 340 (2017), 1154–1161] proved an analogous result when $C\cup D=[0,m]$ , $0\in C$ and $C\cap D=\{r\}$ .

We describe an extraordinarily preserved non-trilobite artiopod Bailongia longicaudata gen. et sp. nov. from the Cambrian Stage 4 Guanshan Biota in Yiliang, Kunming of the Yunnan Province in China. Its exoskeleton consists of a large semi-elliptical cephalon with paired lateral posterior eyes, nine tapering homonomous tergites and a long slender tailspine. Appendages include paired small antennae, at least three pairs of post-antennal cephalic limbs, and trunk biramous limbs consisting of an endopod and an exopod with lamellae. B. longicaudata does not conform to any taxon within Artiopoda, although the eyes invite comparisons with Xandarella spectaculum, Sinoburius lunaris and Phytophilaspis. Parsimony analyses indicate Bailongia is a member of Artiopoda and cannot be readily accommodated within any of the major artiopod clades.

Suppressing nonlinear effects in high-power fiber lasers based on fiber gratings has become a hotspot. At present, research is mainly focused on suppressing stimulated Raman scattering in a high-power fiber laser. However, the suppression of spectral broadening, caused by self-phase modulation or four-wave mixing, is still a challenging attribute to the close distance between the broadened laser and signal laser. If using a traditional fiber grating with only one stopband to suppress the spectral broadening, the signal power will be stripped simultaneously. Confronting this challenge, we propose a novel method based on phase-shifted long-period fiber grating (PS-LPFG) to suppress spectral broadening in a high-power fiber master oscillator power amplifier (MOPA) laser system in this paper. A PS-LPFG is designed and fabricated on 10/130 passive fiber utilizing a point-by-point scanning technique. The resonant wavelength of the fabricated PS-LPFG is 1080 nm, the full width at half maximum of the passband is 5.48 nm, and stopband extinction exceeds 90%. To evaluate the performance of the PS-LPFG, the grating is inserted into the seed of a kilowatt-level continuous-wave MOPA system. Experiment results show that the 30 dB linewidth of the output spectrum is narrowed by approximately 37.97%, providing an effective and flexible way for optimizing the output linewidth of high-power fiber MOPA laser systems.

Stable isotope ratios (δ18O and δD) in Antarctic snow and ice are basic proxy indices of climate in ice core studies. The relation between the ratios has important indicative significance for moisture sources. In general, the fractionation characteristics of the two isotopes vary with different meteorological and topographical conditions. This paper presents the spatial and temporal distribution of meteoric water line (MWL) slopes along a traverse from the Zhongshan Station (ZSS) to Dome A in East Antarctica. It is found that the slopes decrease with the increasing distance inland from the coast and the lowest slope occurred at Dome A, where the long-range transported moisture dominates and clear sky snowing have an influence. The slopes in different layers of the snowpack showed a decreasing trend with depth and this is attributed to the fractionation during the interstitial sublimation and re-condensation processes of the water vapor. Frost flower development on the interior plateau surface can greatly alter the depth evolution of the MWL slope. The coastal snow pits also go through the post-depositional smoothing effect, but their influences are not so significant as the inland regions.

Owing to limited data, we conducted a meta-analysis to re-evaluate the relationship between obesity and coronavirus-2019 (COVID-19). Literature published between 1 January 2020 and 22 August 2020 was comprehensively analysed, and RevMan3.5 was used for data analysis. A total of 50 studies, including data on 18 260 378 patients, were available. Obesity was associated with a higher risk of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV2) infection (odds ratio (OR): 1.39, 95% confidence interval (CI) 1.25–1.54; P < 0.00001) and increased severity of COVID-19 (hospitalisation rate: OR: 2.45, 95% CI 1.78–3.39; P < 0.00001; severe cases: OR: 3.74, 95% CI 1.18–11.87; P: 0.02; need for intensive care unit admission: OR: 1.30, 95% CI 1.21–1.40; P < 0.00001; need for invasive mechanical ventilation: OR: 1.59, 95% CI 1.35–1.88; P < 0.00001 and mortality: OR: 1.65, 95% CI 1.21–2.25; P: 0.001). However, we found a non-linear association between BMI and the severity of COVID-19. In conclusion, we found that obesity could increase the risk of SARS-CoV2 infection and aggregate the severity of COVID-19. Further studies are needed to explore the possible mechanisms behind this association.

CHD is closely related to respiratory system diseases (Mok Q, Front Pediatr 2017; 5: 2296–2360). Flexible fibreoptic bronchoscopy will diagnose anatomical lesions of the trachea and perform interventions at the same time for children with indications. We report a case of pulmonary artery sling with severe tracheostenosis in a 11-month-old boy. Tracheal stents were placed with good prognosis.

Fat-soluble vitamins during pregnancy are important for fetal growth and development. The present study aimed at exploring the association between vitamin A, E and D status during pregnancy and birth weight. A total of 19 640 women with singleton deliveries from a retrospective study were included. Data were collected by the hospital electronic information system. Maternal serum vitamin A, E and D concentrations were measured during pregnancy. Logistic regression was performed to estimate the association between the vitamin status and low birth weight (LBW) or macrosomia. Women with excessive vitamin E were more likely to have macrosomia (OR 1·30, 95 % CI 1·07, 1·59) compared with adequate concentration. When focusing on Z scores, there was a positive association between vitamin E and macrosomia in the first (OR 1·07, 95 % CI 1·00, 1·14), second (OR 1·27, 95 % CI 1·11, 1·46) and third (OR 1·28, 95 % CI 1·06, 1·54) trimesters; vitamin A was positively associated with LBW in the first (OR 1·14, 95 % CI 1·01, 1·29), second (OR 1·31, 95 % CI 1·05, 1·63) and third (OR 2·00, 95 % CI 1·45, 2·74) trimesters and negatively associated with macrosomia in the second (OR 0·79, 95 % CI 0·70, 0·89) and third (OR 0·77, 95 % CI 0·62, 0·95) trimesters. The study identified that high concentrations of vitamin E are associated with macrosomia. Maintaining a moderate concentration of vitamin A during pregnancy might be beneficial to achieve optimal birth weight. Further studies to explore the mechanism of above associations are warranted.

Hepatitis C virus (HCV) infection was frequent in human immunodeficiency virus (HIV) patients in Yunnan province. We studied the epidemic characteristics of HCV in HIV/HCV co-infected patients. Serum from 894 HIV-1 patients was collected, together with basic information and biochemical features. All samples were infected with HIV through injecting drug users (IDUs) and sexual transmission (ST). The NS5B gene was amplified and sequenced to affirm HCV genotype. In total, 202 HIV patients were co-infected with HCV, and most (81.19%) of co-infected patients were IDUs. Genotype 3b was predominant (37.62%) in these samples, and its frequency was similar in patients with IDU and ST. The frequencies of genotypes 1a, 1b, 3a, 6a, 6n, 2a and 6u were 3.96%, 16.34%, 23.76%, 6.93%, 10.40%, 0.50% and 0.50%, respectively. However, genotype 3a showed significantly different frequency in HCV patients with IDU and ST (P = 0.019). When HCV patients were divided into subgroups, the haemoglobin (HGB) level was significantly higher in patients with genotype 3a than in patients with 3b (P = 0.033), 6a (P = 0.006) and 6n (P = 0.007), respectively. Although no difference existed among HCV subgroups, HIV-viral load was identified to be positively correlated with the HGB level and CD4+ cells when dividing HCV/HIV co-infected persons into male and female groups. In conclusion, genotype 3b was the predominant HCV genotype in Yunnan HIV/HCV co-infected persons. The HGB level was higher in patients with genotype 3a than others. HIV-viral load was positively correlated with the HGB level and CD4+ cells in the male or female HCV-infected group.

In this study, we argue that foreign subsidiaries may benefit from the corporate strategies of multinational enterprises (MNEs) in different ways in terms of knowledge transfer and strategic flexibility. From this viewpoint, we explore the relationship between product diversification and financial performance of their subsidiaries under the condition of MNE geographic diversification. Using panel data on foreign subsidiaries in European countries from 2006 to 2011, we find a U-shaped relationship between product diversification and subsidiary performance and the joint effect of product and geographic diversification. Given the importance of transition economies in international business today, we conducted a subsample test contrasting the results based on the transitional (Central and Eastern European) versus Western European countries. The contrasting results provide important implications for other transition economies like China. We validate the relationship in several ways in our robustness tests.

Many components in diet have regulated oxidative stress, inflammatory reaction and even balance oestrogen levels. Because these factors are closely associated with depressive symptoms in postmenopausal women, it is considered that dietary factors are able to prevent and control depressive symptoms. On the other hand, a dietary pattern that considers the correlations and synergies between foods and nutrients is expected to have a greater impact on disease risk. The aim of the present study is to evaluate whether dietary patterns are associated with depressive symptoms in Chinese postmenopausal women. A cross-sectional study of 2051 postmenopausal women (mean age: 58·8 (sd 7·4) years) was conducted in Tianjin, China. Dietary consumption was assessed by a valid self-administered FFQ. Principal component analysis was used to derive three major dietary patterns: ‘healthy’, ‘sweets’ and ‘traditional Tianjin’ from eighty-eight food items. Depressive symptoms were assessed using the Zung Self-Rating Depression Scale, and cut-off point of 48 indicating serious depressive symptoms. The association between quartile of dietary patterns and depressive symptoms was assessed using multiple logistic regression analysis. The multivariable-adjusted OR of having depressive symptoms for increasing quartile of dietary patterns were as follows: healthy, 1·00, 0·79 (95 % CI 0·49, 1·28), 0·62 (95 % CI 0·37, 1·04) and 0·57 (95 % CI 0·33, 0·97); sweets, 1·00, 0·75 (95 % CI 0·42, 1·3), 1·08 (95 % CI 0·64, 1·81) and 1·66 (95 % CI 1·03, 2·71); and traditional Tianjin, 1·00, 1·02 (95 % CI 0·58, 1·79), 0·96 (95 % CI 0·54, 1·71) and 2·53 (95 % CI 1·58, 4·16), respectively. The present study demonstrated that a healthy dietary pattern was inversely associated with depressive symptoms. On the contrary, greater adherence to sweets and traditional Tianjin dietary patterns was associated with a higher prevalence of depressive symptoms.

We aimed to investigate the trends of breast milk lutein concentrations at different times and their relationship with dietary lutein intake during the 12 weeks after delivery. Breast milk samples were collected from thirty-seven mothers at 4, 8 and 12 weeks postpartum. A HPLC detection method was used to measure breast milk lutein concentrations. Dietary intake was assessed using an FFQ, and then dietary lutein intake was calculated. The correlations between dietary lutein intake and breast milk lutein concentrations during lactation were investigated by Pearson’s correlation coefficient. General linear regression models were used to evaluate the optimal regression equation. The mean values of dietary lutein intake at 4, 8 and 12 weeks postpartum were 5·22 (sd 3·60), 7·28 (sd 4·30) and 7·33 (sd 4·24) mg/d, respectively. The mean values of breast milk lutein concentrations at 4, 8 and 12 weeks postpartum were as follows: 46·41 (sd 41·36), 57·96 (sd 40·00) and 62·33 (sd 30·10) μg/l, respectively. Breast milk lutein concentrations were positively associated with dietary lutein intake at 4 weeks postpartum (r 0·527, P < 0·05), which was consistent with the positive correlations observed at 8 and 12 weeks postpartum (r 0·444, P < 0·05; r 0·468, P < 0·05) by the sensitivity analysis. Increased dietary lutein intake can increase the concentration of lutein in the breast milk, and women are recommended to increase their dietary intake of green leafy vegetables and fruits that are rich in lutein during the pregnancy and postpartum periods.

Suppression of stimulated Raman scattering (SRS) by means of chirped and tilted fiber Bragg gratings (CTFBGs) has become a key topic. However, research on high-power systems is still lacking due to two problems. Firstly, after the inscription, there are a large number of hydroxyl compounds and hydrogen molecules in CTFBGs that cause significant heating due to their strong infrared absorption. Secondly, CTFBGs can couple Stokes light from the core to the cladding and the coating, which causes serious heating in the coating of the CTFBG. Aimed at overcoming these bottlenecks, a process that combines constant-low-temperature and variable-high-temperature annealing is used to reduce the thermal slope of the CTFBG. Also, a segmented-corrosion cladding power stripping technology is used on the CTFBG to remove the Stokes light which is coupled to the cladding, which solves the problem of overheating in the coating of the CTFBG. Thereby, a CTFBG with both a kilowatt-level power-carrying load and the ability to suppress SRS in a fiber laser has been developed. Further, we establish a kW-level CW oscillator to test the CTFBG. Experimental results demonstrate that the power-carrying load of the CTFBG is close to 1 kW, the thermal slope is lower than $0.015\,^{\circ }\text{C}/\text{W}$, and the SRS suppression ratio is nearly 23 dB.

From a coopetition perspective, we differentiate between a multinational enterprise's product-similar subsidiary network and product-different subsidiary network in a host country. We argue that the product-similar network will have a curvilinear (inverted U-shaped) effect on foreign subsidiary performance, whereas the product-different network will produce a monotonic (positive) effect. Moreover, we introduce host-country economic advantage and intangible resource of the subsidiary as moderators into the relationship between subsidiary network and performance. Using longitudinal panel data of foreign subsidiaries, we find evidence that when host-country economic advantage is large, and the level of intangible asset intensity is high, the inverted U-shaped effect of product-similar subsidiary network is less pronounced. Moreover, host-country economic advantage and intangible asset intensity both enhance the positive effect of product-different subsidiary network. However, the moderating effect of intangible asset intensity is opposite to our prediction.

In this paper, we review the status of the multifunctional experimental platform at the National Laboratory of High Power Laser and Physics (NLHPLP). The platform, including the SG-II laser facility, SG-II 9th beam, SG-II upgrade (SG-II UP) facility, and SG-II 5 PW facility, is operational and available for interested scientists studying inertial confinement fusion (ICF) and a broad range of high-energy-density physics. These facilities can provide important experimental capabilities by combining different pulse widths of nanosecond, picosecond, and femtosecond scales. In addition, the SG-II UP facility, consisting of a single petawatt system and an eight-beam nanosecond system, is introduced including several laser technologies that have been developed to ensure the performance of the facility. Recent developments of the SG-II 5 PW facility are also presented.

In this paper, we study the initial boundary value problem for a class of fourth order damped wave equations with arbitrary positive initial energy. In the framework of the energy method, we further exploit the properties of the Nehari functional. Finally, the global existence and finite time blow-up of solutions are obtained.

The gastrointestinal tract (GIT) of animals is capable of sensing various kinds of nutrients via G-protein coupled receptor-mediated signaling transduction pathways, and the process is known as ‘gut nutrient chemosensing’. GPR40, GPR41, GPR43 and GPR119 are chemoreceptors for free fatty acids (FFAs) and lipid derivatives, but they are not well studied in small ruminants. The objective of this study is to determine the expression of GPR40, GPR41, GPR43 and GPR119 along the GIT of kid goats under supplemental feeding (S) v. grazing (G) during early development. In total, 44 kid goats (initial weight 1.35±0.12 kg) were slaughtered for sampling (rumen, abomasum, duodenum, jejunum, ileum, cecum, colon and rectum) between days 0 and 70. The expression of GPR41 and GPR43 were measured at both mRNA and protein levels, whereas GPR40 and GPR119 were assayed at protein level only. The effects of age and feeding system on their expression were variable depending upon GIT segments, chemoreceptors and expression level (mRNA or protein), and sometimes feeding system × age interactions (P<0.05) were observed. Supplemental feeding enhanced expression of GPR40, GPR41 and GPR43 in most segments of the GIT of goats, whereas G enhanced expression of GPR119. GPR41 and GPR43 were mainly expressed in rumen, abomasum and cecum, with different responses to age and feeding system. GPR41 and GPR43 expression in abomasum at mRNA level was greatly (P<0.01) affected by both age and feeding system; whereas their expression in rumen and abomasum at protein level were different, feeding system greatly (P<0.05) affected GPR41 expression, but had no effect (P>0.05) on GPR43 expression; and there were no feeding system×age interactions (P>0.05) on GPR41 and GPR43 protein expression. The expression of GPR41 and GPR43 in rumen and abomasum linearly (P<0.01) increased with increasing age (from days 0 to 70). Meanwhile, age was the main factor affecting GPR40 expression throughout the GIT. These outcomes indicate that age and feeding system are the two factors affecting chemoreceptors for FFAs and lipid derivatives expression in the GIT of kids goats, and S enhanced the expression of chemoreceptors for FFAs, whereas G gave rise to greater expression of chemoreceptors for lipid derivatives. Our results suggest that enhanced expression of chemoreceptors for FFAs might be one of the benefits of early supplemental feeding offered to young ruminants during early development.

In high power laser facility for inertial confinement fusion research, final optics assembly (FOA) plays a critical role in the frequency conversion, beam focusing, color separation, beam sampling and debris shielding. The design and performance of FOA in SG-II Upgrade laser facility are mainly introduced here. Due to the limited space and short focal length, a coaxial aspheric wedged focus lens is designed and applied in the FOA configuration. Then the ghost image analysis, the focus characteristic analysis, the B integral control design and the optomechanical design are carried out in the FOA design phase. In order to ensure the FOA performance, two key technologies are developed including measurement and adjustment technique of the wedged focus lens and the stray light management technique based on ground glass. Experimental results show that the design specifications including laser fluence, frequency conversion efficiency and perforation efficiency of the focus spot have been achieved, which meet the requirements of physical experiments well.

The Shen-Guang II Upgrade (SG-II-U) laser facility consists of eight high-power nanosecond laser beams and one short-pulse picosecond petawatt laser. It is designed for the study of inertial confinement fusion (ICF), especially for conducting fast ignition (FI) research in China and other basic science experiments. To perform FI successfully with hohlraum targets containing a golden cone, the long-pulse beam and cylindrical hohlraum as well as the short-pulse beam and cone target alignment must satisfy tight specifications (30 and $20~\unicode[STIX]{x03BC}\text{m}$ rms for each case). To explore new ICF ignition targets with six laser entrance holes (LEHs), a rotation sensor was adapted to meet the requirements of a three-dimensional target and correct beam alignment. In this paper, the strategy for aligning the nanosecond beam based on target alignment sensor (TAS) is introduced and improved to meet requirements of the picosecond lasers and the new six LEHs hohlraum targets in the SG-II-U facility. The expected performance of the alignment system is presented, and the alignment error is also discussed.

The origin and characteristics of near-microcoulomb multi-MeV electrons accelerated by short pulse lasers interacting with near-critical density plasma in self-formed channels are studied using three-dimensional particle-in-cell simulations. According to the analysis on interaction phenomena and electron dynamics, the dominant mechanism turns out to be direct laser acceleration, which ensures the outstanding energy coupling. Additionally, self-channeling is found to be a decisive factor for the acceleration performance, as electrons obtain ultra-high energy through betatron resonance inside the channels. In our findings, by using a relativistic short laser pulse and near-critical plasma, a large amount of energetic electrons can be generated, presenting a promising and accessible route to ultraintense, high-spatial-resolution radiation pulses.