A Liquid Biopsy Signature for the Early Detection of Gastric Cancer in Patients.

BACKGROUND & AIMS: Diagnosing gastric cancer (GC) while the disease remains eligible for surgical resection is challenging. In view of this clinical challenge, novel and robust biomarkers for early detection thus improving prognosis of GC are necessary. The present study is to develop a blood-based long noncoding RNA (LR) signature for the early-detection of GC. METHODS: The present 3-step study incorporated data from 2141 patients, including 888 with GC, 158 with chronic atrophic gastritis, 193 with intestinal metaplasia, 501 healthy donors, and 401 with other gastrointestinal cancers. The LR profile of stage I GC tissue samples were analyzed using transcriptomic profiling in discovery phase. The extracellular vesicle (EV)-derived LR signature was identified with a training cohort (n = 554) and validated with 2 external cohorts (n = 429 and n = 504) and a supplemental cohort (n = 69). RESULTS: In discovery phase, one LR (GClnc1) was found to be up-regulated in both tissue and circulating EV samples with an area under the curve (AUC) of 0.9369 (95% confidence interval [CI], 0.9073-0.9664) for early-stage GC (stage I/II). The diagnostic performance of this biomarker was further confirmed in 2 external validation cohorts (Xi'an cohort, AUC: 0.8839; 95% CI: 0.8336-0.9342; Beijing cohort, AUC: 0.9018; 95% CI: 0.8597-0.9439). Moreover, EV-derived GClnc1 robustly distinguished early-stage GC from precancerous lesions (chronic atrophic gastritis and intestinal metaplasia) and GC with negative traditional gastrointestinal biomarkers (CEA, CA72-4, and CA19-9). The low levels of this biomarker in postsurgery and other gastrointestinal tumor plasma samples indicated its GC specificity. CONCLUSIONS: EV-derived GClnc1 serves as a circulating biomarker for the early detection of GC, thus providing opportunities for curative surgery and improved survival outcomes.

Local OAM manipulation of a terahertz wave from the air filament by chirping the few-cycle vortex pump laser.

We propose a scheme to manipulate the local orbital angular momentum (OAM) of the ultra-broadband (0.1-30 THz) terahertz (THz) waves from the laser-induced short air filament via chirping the few-cycle vortex laser pump. The simulation results show that either the THz vortex pulses with linear azimuth-dependent phases or the THz angular accelerating vortex beams (AAVBs) with nonlinear azimuth-dependent phases can be produced by tuning the chirp parameter of the pump. Thus, the dominant physical mechanism for THz generation can be determined. The THz temporal and transverse spatial distributions can be also controlled by the chirp parameter. Furthermore, their local OAM density distributions present very complex structures because most of the modulated azimuthal intensity and the corresponding local angular helicity distributions are not able to cancel out completely. Via analyzing the simulated THz results at the different pump intensities, we classify the initial pump intensity into three cases. For the low intensity case, the Kerr effect comes into prominence, so the generated THz radiation shall be vortex pulses. While for the high intensity case, the leading plasma effect dominates. In contrast, when the pump intensity is at the medium level, the Kerr nonlinearity and the plasma effect may be comparable and competitive. Basically, THz AAVBs are generated for both high and medium intensity cases. Our study will provide the possibility for studying the optically induced rotation technology more intuitively from the perspective of angular momentum transfer.

The abdominal-transhiatal surgical approach versus the thoracoabdominal surgical approach in Siewert type II adenocarcinoma of the esophagogastric junction: protocol for a multicenter prospective, open, parallel, and randomized controlled trial.

BACKGROUND: To date, Siewert type II adenocarcinoma of the esophagogastric junction (ST-II AEG) can be removed radically utilizing either the abdominal-transhiatal (TH) or the right thoracoabdominal (RTA) approaches. Because of a paucity of high-quality direct evidence, the appropriate surgical approach for ST-II AEG remains debatable. In the present, only several retrospective studies are available, representing ambiguous results. Thus, prospective randomized clinical trials are demanded to compare the survival, oncological outcomes, safety and efficiency and life quality between the TH and RTA approach in patients with resectable AEG of Siewert type II. METHODS: A prospective, multicenter, open, randomized, and parallel controlled study named S2AEG will be conducted. Three hundred and twelve patients who match the inclusion criteria but not the exclusion criteria will be participating in the trial and randomly divided into the TH (156) and RTA (156) cohorts. The primary efficacy endpoint is the 3-year disease-free survival (DFS) following the operation. The rate of R0-resection, the number and site of lymph nodes infiltrated and dissected, postoperative complications, hospital days and life quality are the second endpoints. DISCUSSION: This study is the first prospectively randomized controlled trial aiming to compare the surgical outcomes between TH and RTA approaches in patients with resectable ST-II AEG. It is hypothesized that patients in the TH cohort would harvest equivalent oncological results and survival while maintaining acceptable life quality when compared to patients in the RTA cohort. Our findings will provide high-level clinical evidence for clinical decision-making on the appropriate surgical approach for patients with ST-II AEG. Embarked in November 2019, this research will be completed 3 years after the final participant's enrolment date. TRIAL REGISTRATION: Clinical Trial.gov ID: NCT04910789 May 29, 2021. Name: S2AEG.

Associations of genetic variants of lysophosphatidylcholine metabolic enzymes with levels of serum lipids.

OBJECTIVE: Metabolic disturbance of lysophosphatidylcholine (LPC) is related with dyslipidemia. Therefore, eight single-nucleotide polymorphisms (SNPs) were selected from LPC metabolic enzymes to study their associations with obesity and serum levels of lipids. METHODS: A total of 3305 children were recruited from four independent studies. Eight SNPs of LPC metabolic enzymes were selected and genotyped with the matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). The multivariable linear regression model was applied to detect the associations of eight SNPs with obesity-related phenotypes and levels of lipids in each study. Meta-analyses were used to combine the results of four studies. RESULTS: Only SNP rs4420638 of APOC-1 gene was associated with serum lipids even after Bonferroni correction. The rs4420638 was positively associated with TC (ß = 0.15, P = 8.59 × 10-9) and low-density-lipoprotein-cholesterol (LDL-C, ß = 0.16, P = 9.98 × 10-14) individually. CONCLUSION: The study firstly revealed the association between APOC-1/rs4420638 and levels of serum lipids in Chinese children, providing evidence for susceptible gene variants of dyslipidemia.

Red meat consumption and all-cause and cardiovascular mortality: results from the UK Biobank study.

PURPOSE: To investigate the prospective associations between red meat consumption and all-cause and cardiovascular diseases (CVD) mortality, and to assess the modification effects of lifestyle and genetic risk factors. METHODS: 180,642 individuals free of CVD or cancer were enrolled from 2006 to 2010 and followed up to 2018 in the UK Biobank. Information on demographics, lifestyles, and medical history was collected through a baseline touchscreen questionnaire. The information on diet was collected through a single touchscreen food-frequency questionnaire. A total of ten single-nucleotide polymorphisms were used to calculate the genetic risk score (GRS) of trimethylamine N-oxide (TMAO), a gut microbiota metabolite from red meat. Adjusted Cox proportional hazard regression models were used to assess the association of red meat consumption with mortality. RESULTS: We documented 3596 deaths [655 CVD deaths, 285 coronary heart disease (CHD) deaths, and 149 stroke deaths] during median 8.6 years of follow-up. Compared with the lowest red meat intake (< 1.5 times/week), the highest red meat intake (≥ 3.0 times/week) was associated with a 20%, 53%, and 101% elevated risk for CVD, CHD, and stroke mortality (P for trend = 0.04, 0.007, and 0.02, respectively), but not all-cause mortality. We found that the associations between red meat intake and mortality were not modified by dietary and lifestyle factors, as well as TMAO GRS. In addition, substitution analyses showed that a decrease in red meat consumption and an increase in the consumption of poultry or cereal was significantly associated with 9%-16% lower CVD or CHD mortality risk. CONCLUSION: Our results indicated that red meat consumption was associated with higher risks of CVD, CHD, and stroke mortality, and the associations were not modified by lifestyle and genetic risk factors. Replacing red meat by poultry or cereal was related to lower risks of CVD and CHD mortality.

Influences of gestational diabetes mellitus on the oral microbiota in offspring from birth to 1 month old.

BACKGROUND: Maternal gestational diabetes mellitus (GDM) had long-term influences on the health of their children. However, the influences of GDM on the oral microbiota, which was closely related to oral and systemic health in offspring, were less documented. The present study aimed to explore the oral microbiota of neonates born to mothers with GDM is differentially colonized compared with those born to mothers without GDM, and whether any such differences persist to 1 month of age. METHODS: Oral samples were collected from children of mothers with (n = 20) and without GDM (n = 34) at birth and again at an average age of 1 month. The oral microbiota was characterized by 16S rRNA sequencing (V3-V4). Differences in diversity and composition according to maternal GDM status were assessed, and different metabolic functional pathways and microbial ecological networks were also analyzed. RESULTS: Although no significant differences were observed in diversity metrics between GDM and non-GDM groups (P > 0.05), we found significant differences in the taxonomic composition of oral microbiota from phylum to genus level between the two groups, with the GDM group exhibiting less abundance of Veillonella in both "Day 1" (P < 0.001) and "Day 30" (P < 0.05) phases. Metabolic pathways analysis showed that 5-aminoimidazole ribonucleotide biosynthesis and inosine-5'-phosphate biosynthesis were enriched in GDM subjects in the "Day 30" phase. Moreover, ecological network analysis revealed apparent differences between GDM and control groups, with the non-GDM group containing more high-degree nodes and microbial interactions compared with the GDM group. CONCLUSION: Maternal GDM was associated with an altered oral microbial composition in neonates, although the distinct difference between GDM and non-GDM groups diminished in infancy. The oral microbiota functions and ecological networks differed dramatically between the two groups, highlighting the importance of maternal GDM status on initial oral microbiota in offspring.

Generation and evolution of different terahertz singular beams from long gas-plasma filaments.

We theoretically and numerically investigate the generation and evolution of different pulsed terahertz (THz) singular beams with an ultrabroad bandwidth (0.1-40 THz) in long gas-plasma filaments induced by a shaped two-color laser field, i.e., a vortex fundamental pulse (ω0) and a Gaussian second harmonic pulse (2ω0). Based on the unidirectional propagation model under group-velocity moving reference frame, the simulating results demonstrate that three different THz singular beams, including the THz necklace beams with a π-stepwise phase profile, the THz angular accelerating vortex beams (AAVBs) with nonlinear phase profile, and the THz vortex beams with linear phase profile, are generated. The THz necklace beams are generated first at millimeter-scale length. Then, with the increase of the filament length, THz AAVBs and THz vortex beams appear in turn almost periodically. Our calculations confirm that all these different THz singular beams result from the coherent superposition of the two collinear THz vortex beams with variable relative amplitudes and conjugated topological charges (TCs), i.e., +2 and -2. These two THz vortex beams could come from the two four-wave mixing (FWM) processes, respectively, i.e., ω0+ω0-2ω0→ωTHz and -(ω0+ω0) + 2ω0→ωTHz. The evolution of the different THz singular beams depends on the combined effect of the pump ω0-2ω0 time delay and the separate, periodical, and helical plasma channels. And the TC sign of the generated THz singular beams can be easily controlled by changing the sign of the ω0-2ω0 time delay. We believe that these results will deepen the understanding of the THz singular beam generation mechanism and orbital angular momentum (OAM) conversion in laser induced gas-filamentation.

Enhance terahertz radiation and its polarization- control with two paralleled filaments pumped by two-color femtosecond laser fields.

We present experimentally an obvious enhancement of the terahertz (THz) radiation with two paralleled filaments pumped by two-color laser fields for a full use of a high laser power, compared with single filament. By mapping the 3-dimensional electric trajectories of generated THz fields with a (111) ZnTe crystal, we observe that the total THz polarization from two filaments can be manipulated by varying the time delay between the two orthogonally polarized pumps, which agrees well with the simulations under the photocurrent model. Notably, the power and spectrum of the THz field almost keep unchanged while manipulating the ellipticity of the THz polarization, which is important for a polarization-controllable THz source.

Genetic variants in the FAM3C gene are associated with lipid traits in Chinese children.

BACKGROUND: Previous studies have related FAM3C gene with childhood bone health, and the regulation of lipid metabolism in hepatocytes. The present case-control study aimed to analyze the association of FAM3C genetic variants with overweight/obesity and lipid traits among Chinese children. METHODS: Two genetic variants (rs7776725 and rs7793554) within the FAM3C gene were genotyped in 3305 Chinese children aged 6-18 years. RESULTS: In the whole study population, the T-allele of rs7776725 and A-allele of rs7793554 within the FAM3C gene were associated with 40.2% (95% CI: 11.6-76.1%; P = 0.004) and 29.1% (6.9-56.0%; P = 0.008) increased risk of dyslipidemia, higher triglyceride (P = 0.014 and P = 0.001) and lower HDL-C (P = 0.015 and P = 0.003). In addition, we found that rs7776725 interacted with sex on dyslipidemia (Pfor interaction = 0.004), and sex-stratified analyses showed that it was significantly associated with dyslipidemia only in girls (P = 8.78 × 10-5). The variant also showed nominally significant interactions with sex on total cholesterol and LDL-C (Pfor interaction = 0.012 and 0.008). CONCLUSION: We found that FAM3C genetic variants were associated with dyslipidemia and lipid traits among Chinese children. In addition, we found significant gene-by-sex interactions. Our findings provided evidence supporting the role of FAM3C gene in regulating lipid metabolism in humans. IMPACT: FAM3C genetic variants were associated with dyslipidemia and lipid traits among Chinese children. In addition, we found significant gene-by-sex interactions. FAM3C/rs7776725 was associated with dyslipidemia and lipid traits only in girls. Our findings provided evidence supporting the role of FAM3C gene in regulating lipid metabolism in humans.

High-order above-threshold dissociation of molecules.

Electrons bound to atoms or molecules can simultaneously absorb multiple photons via the above-threshold ionization featured with discrete peaks in the photoelectron spectrum on account of the quantized nature of the light energy. Analogously, the above-threshold dissociation of molecules has been proposed to address the multiple-photon energy deposition in the nuclei of molecules. In this case, nuclear energy spectra consisting of photon-energy spaced peaks exceeding the binding energy of the molecular bond are predicted. Although the observation of such phenomena is difficult, this scenario is nevertheless logical and is based on the fundamental laws. Here, we report conclusive experimental observation of high-order above-threshold dissociation of H2 in strong laser fields where the tunneling-ionized electron transfers the absorbed multiphoton energy, which is above the ionization threshold to the nuclei via the field-driven inelastic rescattering. Our results provide an unambiguous evidence that the electron and nuclei of a molecule as a whole absorb multiple photons, and thus above-threshold ionization and above-threshold dissociation must appear simultaneously, which is the cornerstone of the nowadays strong-field molecular physics.

Assessment of growth pattern of preterm infants up to a corrected age of 24 months. / æ—©äº§å„¿æ ¡æ­£24æœˆé¾„å† ç”Ÿé•¿è½¨è¿¹ç ”ç©¶.

OBJECTIVES: To assess the growth of preterm infants up to a corrected age of 24 months, and to understand the growth trend and pattern of preterm infants. METHODS: A preterm infant follow-up database was established based on the Internet Plus follow-up system. A total of 3 188 preterm infants who were born from April 2018 to April 2021 were enrolled. Their length, weight, and head circumference were recorded at birth and at the corrected ages of 1, 3, 6, 12, 18, and 24 months. The preterm infants were grouped by perinatal factors. The growth curves of these infants were plotted and compared with the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st) standard and World Health Organization (WHO) standard. RESULTS: The weight, length, and head circumference curves of each group of preterm infants grouped by various perinatal factors all rose rapidly within the corrected age of 6 months, but the growth rate slowed down after the corrected age of 6 months. Based on the actual age for the groups of preterm infants with different gestational ages (<28 weeks, 28-31+6 weeks, 32-33+6 weeks, and 34-36+6 weeks), the length curve gradually coincided with the WHO curve after the actual age of 9 months (P=0.082), while for the preterm infants with a gestational age of <32 weeks, the weight and head circumference curves were significantly lower than the WHO curves (P<0.001). Based on the corrected age, the physical growth curve of preterm infants with different gestational ages (<28 weeks, 28-31+6 weeks, 32-33+6 weeks, and 34-36+6 weeks) basically coincided with each other (P>0.05). For the infants with extremely low birth weight and the small-for-gestational-age infants, the length, weight, and head circumference curves were significantly lower than those of the INTERGROWTH-21st standard and the WHO standard (P<0.05). CONCLUSIONS: The physical growth rate of preterm infants is faster within the corrected age of 6 months, and the growth rate slows down after the corrected age of 6 months. Preterm infants with a smaller gestational age need longer time to catch up in weight and head circumference. More attention should be paid to the physical growth of extremely preterm infants, extremely low birth weight infants, and small-for-gestational-age infants.

Causal associations of body mass index and waist-to-hip ratio with cardiometabolic traits among Chinese children: A Mendelian randomization study.

BACKGROUND AND AIMS: Body mass index (BMI) and waist-to-hip ratio (WHR) have been reported to be causally associated with cardiometabolic diseases in adults in European populations. However, this causality was less explored in East Asian populations and in children. Our study aimed to explore and compare the causal associations of general obesity (measured by BMI) and central obesity (measured by WHR) with cardiometabolic traits. METHODS AND RESULTS: We performed a Mendelian randomization (MR) analysis in 2030 unrelated children from two independent case-control studies in Beijing, China. BMI-associated single nucleotide polymorphisms (SNPs) and WHR-SNPs identified by previous genome-wide association studies were used as genetic instruments to examine the casual associations of BMI and WHR with cardiometabolic traits, including glycemic traits, blood lipids, and blood pressure. Each 1-SD increase in BMI and WHR were significantly associated with 0.111 mmol/L and 0.110 mmol/L increase in log-transformed fasting insulin (FINS), 0.049 and 0.060 increase in log-transformed HOMA-ß, 0.112 and 0.108 increase in log-transformed HOMA-IR, 0.009 mmol/L and 0.015 mmol/L increase in log-transformed triglyceride, and 15.527 mmHg and 7.277 mmHg increase in systolic blood pressure, respectively (all P < 0.05). The receiver operating characteristic curves showed that WHR had a stronger effect on FINS, HOMA-ß, HOMA-IR, and triglyceride than BMI (all P < 0.05). CONCLUSIONS: Using the MR method, we found that the genetic predisposition to higher BMI or WHR was associated with altered cardiometabolic traits in Chinese children. When compared with general obesity, central obesity might have stronger effects on glycemic traits and blood lipids among children.

Breastfeeding Practices and Overweight/Obesity Among Children Under 5 Years of Age: A Multistage Random Sampling Survey in Central and Western China.

OBJECTIVES: To describe the prevalence of overweight and obesity among children under 5 years old, assess the indicators of breastfeeding practices, and explore the associations between breastfeeding practices and early childhood overweight/obesity. METHODS: The survey was conducted in 20 counties in central and western China in 2016. All children under 5 years old were physically measured for anthropometric data and their breastfeeding practices were obtained through a face-to-face questionnaire interview. We performed logistic regressions to assess the associations of different breastfeeding practices with overweight/obesity. RESULTS: The prevalence of overweight and obesity among children under 5 years old were 8.7% and 2.6%, respectively. Overall, 93.6% of children were breastfed, while only 20.7% had exclusive breastfeeding under 6 months of age and about half of the children under 5 years old were weaned at 12 months. Compared with children with a duration of breastfeeding ≥ 12 months, children who have been breastfed for < 6 months were significantly associated with a 97% increased risk of overweight/obesity (OR 1.97, 95% CI 1.34-2.88, P = 0.001). CONCLUSIONS FOR PRACTICE: The present study showed that overweight and obesity among children under 5 years old in central and western China remained an important childhood health concern. The rates of most indicators of breastfeeding practices were low, which needed more public attention. Moreover, we found that a shorter duration of breastfeeding was associated with an increased risk of overweight/obesity among children in central and western China.

Generation of terahertz vortex pulses without any need of manipulation in the terahertz region.

Converting a Gaussian mode to a vortex beam is much more inconvenient in the terahertz (THz) region than in the near-infrared (NIR) region due to underdevelopment of THz components and strong THz diffraction. This Letter reports the direct generation of THz vortex pulses by optical difference-frequency between two NIR chirped pulses with different topological charges (TCs). By designing a passive and transmissive device for a collinear NIR pulse pair with conjugated TCs, we have experimentally obtained stable THz vortex pulses with a TC value of 2 or -2. The process needs no THz components and so is flexible to be realized and has promising applications in the THz field.

Interaction between lifestyle behaviors and genetic polymorphism in SCAP gene on blood pressure among Chinese children.

BACKGROUNDS: Previous studies had revealed that sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP) rs12487736 polymorphism was associated with blood pressure (BP), but whether rs12487736 could interact with lifestyle behaviors on BP is unknown. METHODS: A case-control study with 1092 Chinese children was conducted. RESULTS: We found an interaction between rs12487736 and high calorie foods intake (fried chips/cakes/cookies) on systolic blood pressure (SBP) (Pinteraction = 0.027), and rs12487736 was associated with SBP in the subgroup having high calorie foods at least once in the last week (b = 2.19, P = 0.025), but not in the subgroup not having high calorie foods. Also, interaction between protein intake (meat/fish/soy beans/egg) and rs12487736 on diastolic BP (DBP) was identified (Pinteraction = 0.049); rs12487736 was associated with DBP in the subgroup consuming protein (meat/fish/soy beans/egg)

Physical activity attenuates the association between the IRS1 genotype and childhood obesity in Chinese children.

BACKGROUND AND AIMS: The insulin receptor substrate 1 (IRS1) rs2943650 was found to be associated with obesity in adults, but the association has not been evaluated in children. The present study aimed to examine whether IRS1 rs2943650 was associated with obesity in Chinese children and investigate the interaction between rs2943650 and physical activity. METHODS AND RESULTS: IRS1 rs2943650 was genotyped in 3303 Chinese children aged 6-18 years recruited from four independent studies. Logistic regression and linear regression were performed to examine associations. Meta-analyses were conducted to pool the results of the four independent studies. The C-allele carriers of rs2943650 showed a 29% higher risk of obesity than noncarriers (OR (95% CI) = 1.29 (1.05, 1.58), P = 0.02) and a 0.41 kg/m2 increase in BMI (ß (95% CI) = 0.41 (0.05, 0.78) kg/m2, P = 0.02). We also observed significant interactions between rs2943650 and physical activity/sedentary behaviors on obesity (Pforinteraction<0.05). Compared with the physically active children (physical activity ≥1 h/d and sedentary behaviors <2 h/d), the risk allele (C) of rs2943650 was significantly associated with a 241% increased risk of obesity among inactive children who participated in physical activity <1 h/d and sedentary behaviors ≥2 h/d (OR (95% CI) = 3.41 (1.45, 8.01), P = 0.005). CONCLUSIONS: We found that IRS1 rs2943650 was significantly associated with BMI and risk of childhood obesity. Additionally, we also found significant interaction between IRS1 rs2943650 polymorphism and physical activity/sedentary behaviors on childhood obesity. Our study would provide novel insights into the function of the IRS1 gene and the implementation of effective intervention strategies of childhood obesity.

Quality of care and suspected developmental delay among children aged 1-59 months: a cross-sectional study in 8 counties of rural China.

BACKGROUND: The data about quality of care of more than 70 countries were available from UNICEF but little was known about China. We examined the status about quality of care and explored its associations with developmental outcomes in Chinese children. METHODS: A cross-sectional study with probability proportional to size sampling method was conducted in 8 counties of rural China. A total 1927 children were assessed on development status using Ages and Stages Questionnaires-Chinese (ASQ-C) based on Chinese normative data. Nutritional status was derived from the anthropometric method following WHO guidelines. Caregivers were interviewed through household questionnaires from UNICEF's 5th Multiple Indicator Cluster Survey to understand the quality of care, including the status of availability of children's books, availability of playthings, support for learning, fathers' support for learning and inadequate care. Moreover, quality of care was explored to be categorized into three levels (poor, medium and good) for overall assessment. Multivariable logistic regression model was applied to estimate the odds ratios and 95% confidence intervals between quality of care and suspected developmental delay (SDD) after adjustment for potential confounding variables. RESULTS: The proportions of availability of children's books, playthings, support for learning, fathers' support for learning and inadequate care were 36.8, 91.3, 83.1, 16.4 and 4.9%, respectively. When compared to available data of more than 70 countries and areas, the quality of care in rural China was in the middle to upper level. After adjustment for potential confounding variables, multivariable analysis showed that SDD in overall ASQ remained negatively associated with availability of children's books (odds ratio [OR] and 95% confidence interval [CI]: 1.64 [1.27-2.12]), playthings (OR and 95% CI: 2.23 [1.52-3.27]) and support for learning (OR and 95% CI: 1.81 [1.06-3.10]). When compared with children under good quality of care, children under medium and poor quality of care had higher prevalence of SDD in overall ASQ (OR and 95% CI: 1.59 [1.21-2.07]; 3.05 [1.96-4.74]). CONCLUSIONS: Quality of care in rural China still had scope for improvement. Better quality of care had negative associations with SDD.

Orientation-dependent strong-field dissociative single ionization of CO.

The dissociative ionization of CO in orthogonally polarized femtosecond laser pulses are studied in a pump-probe scheme. The ionization of CO by the pump pulse and the dissociation of the created CO+ by the probe pulse can be fully disentangled by identifying the photoelectron momentum distributions. Different from the dissociative ionization by a single pulse in which the CO molecule mostly breaks along the field polarization, in this pump-probe strategy, the CO+ ion created from ionization by the pump pulse is favored to dissociate when it orients orthogonal to the polarization direction of the probe pulse. It is attributed to the laser-coupling of various electronic states of the molecular ion in the dissociation process, supported by the numerical simulation of a modeled time-dependent Schrödinger equation.

Rotated echoes of molecular alignment: fractional, high order and imaginary.

We report experimental observations of rotated echoes of alignment induced by a pair of time-delayed and polarization-skewed femtosecond laser pulses interacting with an ensemble of molecular rotors. Rotated fractional echoes, rotated high order echoes and rotated imaginary echoes are directly visualized by using the technique of coincident Coulomb explosion imaging. We show that the echo phenomenon not only exhibits temporal recurrences but also spatial rotations determined by the polarization of the time-delayed second pulse. The dynamics of echo formation is well described by the laser-induced filamentation in rotational phase space. The quantum-mechanical simulation shows good agreements with the experimental results.

Energy-Resolved Ultrashort Delays of Photoelectron Emission Clocked by Orthogonal Two-Color Laser Fields.

A phase-controlled orthogonal two-color (OTC) femtosecond laser pulse is employed to probe the time delay of photoelectron emission in the strong-field ionization of atoms. The OTC field spatiotemporally steers the emission dynamics of the photoelectrons and meanwhile allows us to unambiguously distinguish the main and sideband peaks of the above-threshold ionization spectrum. The relative phase shift between the main and sideband peaks, retrieved from the phase-of-phase of the photoelectron spectrum as a function of the laser phase, gradually decreases with increasing electron energy, and becomes zero for the fast electron which is mainly produced by the rescattering process. Furthermore, a Freeman resonance delay of 140±40 attoseconds between photoelectrons emitted via the 4f and 5p Rydberg states of argon is observed.