High-Pressure Induced Continuous Structural Evolution of Kagome Antiferromagnet MgMn3(OH)6Cl2: A Structural Analogue to Quantum Spin Liquid Herbertsmithite.

MgMn3(OH)6Cl2 serves readily as the classical Heisenberg kagome antiferromagnet lattice spin frustration material, due to its similarity to herbertsmithite in composition and crystal structure. In this work, nanosheets of MgMn3(OH)6Cl2 are synthesized through a solid-phase reaction. Low-temperature magnetic measurements revealed two antiferromagnetic transitions, occurring at ∼8 and 55 K, respectively. Utilizing high-pressure synchrotron radiation X-ray diffraction techniques, the topological structural evolution of MgMn3(OH)6Cl2 under pressures up to 24.8 GPa was investigated. The sample undergoes a second-order structural phase transition from the rhombohedral phase to the monoclinic phase at pressures exceeding 7.8 GPa. Accompanying the disappearance of the Fano-like line shape in the high-pressure Raman spectra were the emergence of new Raman active modes and discontinuities in the variations of Raman shifts in the high-frequency region. The phase transition to a structure with lower symmetry was attributed to the pressure-induced enhancement of cooperative Jahn-Teller distortion, which is caused by the mutual substitution of Mn2+ ions from the kagome layer and Mg2+ ions from the triangular interlayer. High-pressure ultraviolet-visible absorption measurements support the structural evolution. This research provides a robust experimental approach and physical insights for further exploration of classical geometrical frustration materials with kagome lattice.

[Risk factors for bronchopulmonary dysplasia in twin preterm infants: a multicenter study]. / åŒèƒŽæ—©äº§å„¿æ”¯æ°”ç®¡è‚ºå‘è‚²ä¸è‰¯å±é™©å› ç´ åˆ†æžï¼šä¸€é¡¹å¤šä¸­å¿ƒç ”ç©¶.

OBJECTIVES: To investigate the risk factors for bronchopulmonary dysplasia (BPD) in twin preterm infants with a gestational age of <34 weeks, and to provide a basis for early identification of BPD in twin preterm infants in clinical practice. METHODS: A retrospective analysis was performed for the twin preterm infants with a gestational age of <34 weeks who were admitted to 22 hospitals nationwide from January 2018 to December 2020. According to their conditions, they were divided into group A (both twins had BPD), group B (only one twin had BPD), and group C (neither twin had BPD). The risk factors for BPD in twin preterm infants were analyzed. Further analysis was conducted on group B to investigate the postnatal risk factors for BPD within twins. RESULTS: A total of 904 pairs of twins with a gestational age of <34 weeks were included in this study. The multivariate logistic regression analysis showed that compared with group C, birth weight discordance of >25% between the twins was an independent risk factor for BPD in one of the twins (OR=3.370, 95%CI: 1.500-7.568, P<0.05), and high gestational age at birth was a protective factor against BPD (P<0.05). The conditional logistic regression analysis of group B showed that small-for-gestational-age (SGA) birth was an independent risk factor for BPD in individual twins (OR=5.017, 95%CI: 1.040-24.190, P<0.05). CONCLUSIONS: The development of BPD in twin preterm infants is associated with gestational age, birth weight discordance between the twins, and SGA birth.

Structural phase transformation of quantum spin liquid herbertsmithite via pressure induced enhancement of the cooperative Jahn-Teller effect and antisite disorder.

Herbertsmithite, Cu3Zn(OH)6Cl2, serves as one of the most promising candidates for quantum spin liquids with a perfect quantum kagome Heisenberg antiferromagnetic system. It can comprise an ideal model system for studying the compression response of the unique structure as well as exotic properties of kagome quantum spin liquid materials, which is of fundamental importance from both scientific and technological viewpoints. In this work, the structural evolution of herbertsmithite was investigated via in situ X-ray diffraction and Raman scattering techniques up to 30 GPa. The trigonal herbertsmithite structure transformed into a monoclinic clinoatacamite-like structure at 12.6 GPa. High pressure seems to act in a reverse way as Zn-doping for herbertsmithite, with the distortion degree of the system changing continuously. The occurrence of the displacive and reversible phase transition between the polymorphs is a consequence of the interplay between the external pressure and cooperative Jahn-Teller (JT) effect, aided by the presence of antisite mutual substitution of magnetic Cu2+ ions and nonmagnetic Zn2+ ions between the kagome layer and interlayer sites.

[Impact of assisted reproductive technology on birth weight discordance in twins]. / è¾ åŠ©ç”Ÿæ®–æŠ€æœ¯å¯¹åŒèƒŽå‡ºç”Ÿä½“é‡ä¸ä¸€è‡´çš„å½±å“.

OBJECTIVES: To explore the association between assisted reproductive technology (ART) and birth weight discordance in twins (BWDT). METHODS: A retrospective analysis was conducted on twin infants born between January 2011 and December 2020 at the Third Affiliated Hospital of Guangzhou Medical University, with complete basic birth data. The impact of ART on the occurrence of BWDT was identified by the multivariate logistic regression analysis. RESULTS: A total of 3 974 pairs of twins were included, with 1 431 conceived naturally and 2 543 through ART. Neonates in the ART group had higher birth weights than those in the naturally conceived group (P<0.001). The incidence of BWDT was lower in the ART group compared to the naturally conceived group (16.17% vs 21.09%, P<0.001). The multivariate logistic regression analysis, adjusting for confounding factors such as maternal age, parity, pre-pregnancy body mass index, gestational diabetes, hypothyroidism, gestational age, and chorionic properties, showed no significant difference in the risk of BWDT between the ART and naturally conceived groups (P>0.05). CONCLUSIONS: ART is not associated with the risk of BWDT.

Interplay between External High Pressure and Intrinsic Jahn-Teller Effect in the Compression Behavior of Clinoatacamite.

Clinoatacamite (γ-Cu2(OH)3Cl) possesses a geometrically frustrated kagome lattice for the S = 1/2 antiferromagnetic spin system. Thus, it is deemed as the mother compound of many promising quantum spin liquid materials. Here, we synthesized clinoatacamite consisting of homogeneous octahedron-like particles with an average size of 1-2 µm via a hydrothermal strategy. Clinoatacamite crystallizes in a monoclinic lattice composed of Jahn-Teller distorted Cu(OH)6 and Cu(OH)4Cl2 octahedrons. The bonding nature of clinoatacamite is characterized using Raman scattering and FTIR absorption spectroscopies, which reveal the existence of trimeric hydrogen bonds. The magnetic measurements indicate that at temperatures below about 6 K, the magnetic response of the prepared samples is dominated by weak ferromagnetic contributions. The compression behavior is investigated by in situ high-pressure synchrotron radiation X-ray diffraction and Raman scattering spectroscopy. An isostructural phase transition is observed at about 8.4 GPa, which is evidenced by the anomalies in the variation curves of the lattice parameters and Raman scattering frequencies with pressure. The occurrence of the isostructural phase transition is attributed to the competition and cooperation of the external pressure and intrinsic Jahn-Teller effect, together with the interplay of intrastructural hydrogen bonding.

[Sex differences in clinical outcomes of extremely preterm infants/extremely low birth weight infants: a propensity score matching study]. / è¶ æ—©äº§å„¿/è¶ ä½Žå‡ºç”Ÿä½“é‡å„¿ä¸´åºŠç»“å±€çš„æ€§åˆ«å·®å¼‚ï¼šä¸€é¡¹å€¾å‘æ€§è¯„åˆ†åŒ¹é ç ”ç©¶.

OBJECTIVES: To study the effect of sex on the clinical outcome of extremely preterm infants (EPIs)/extremely low birth weight infants (ELBWIs) by propensity score matching. METHODS: A retrospective analysis was performed for the medical data of 731 EPIs or ELBWIs who were admitted from January 1, 2011 to December 31, 2020. These infants were divided into two groups: male and female. A propensity score matching analysis was performed at a ratio of 1:1. The matching variables included gestational age, birth weight, percentage of withdrawal from active treatment, percentage of small-for-gestational-age infant, percentage of use of pulmonary surfactant, percentage of 1-minute Apgar score ≤3, percentage of mechanical ventilation, duration of mechanical ventilation, percentage of antenatal use of inadequate glucocorticoids, and percentage of hypertensive disorders in pregnancy. The two groups were compared in the incidence rate of main complications during hospitalization and the rate of survival at discharge. RESULTS: Before matching, compared with the female group, the male group had significantly higher incidence rates of neonatal respiratory distress syndrome, bronchopulmonary dysplasia (BPD), severe intraventricular hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, and patent ductus arteriosus (P<0.05), while after matching, the male group only had a significantly higher incidence rate of BPD than the female group (P<0.05). There was no significant difference in the rate of survival at discharge between the two groups before and after matching (P>0.05). CONCLUSIONS: Male EPIs/ELBWIs have a higher risk of BPD than female EPIs/ELBWIs, but male and female EPIs/ELBWIs tend to have similar outcomes.

Incidence of extrauterine growth retardation and its risk factors in very preterm infants during hospitalization: a multicenter prospective study. / ä½é™¢æžæ—©äº§å„¿å®«å¤–ç”Ÿé•¿è¿Ÿç¼“åŠç›¸å ³å› ç´ çš„å¤šä¸­å¿ƒå‰çž»æ€§ç ”ç©¶.

OBJECTIVES: To investigate the incidence of extrauterine growth retardation (EUGR) and its risk factors in very preterm infants (VPIs) during hospitalization in China. METHODS: A prospective multicenter study was performed on the medical data of 2 514 VPIs who were hospitalized in the department of neonatology in 28 hospitals from 7 areas of China between September 2019 and December 2020. According to the presence or absence of EUGR based on the evaluation of body weight at the corrected gestational age of 36 weeks or at discharge, the VPIs were classified to two groups: EUGR group (n=1 189) and non-EUGR (n=1 325). The clinical features were compared between the two groups, and the incidence of EUGR and risk factors for EUGR were examined. RESULTS: The incidence of EUGR was 47.30% (1 189/2 514) evaluated by weight. The multivariate logistic regression analysis showed that higher weight growth velocity after regaining birth weight and higher cumulative calorie intake during the first week of hospitalization were protective factors against EUGR (P<0.05), while small-for-gestational-age birth, prolonged time to the initiation of total enteral feeding, prolonged cumulative fasting time, lower breast milk intake before starting human milk fortifiers, prolonged time to the initiation of full fortified feeding, and moderate-to-severe bronchopulmonary dysplasia were risk factors for EUGR (P<0.05). CONCLUSIONS: It is crucial to reduce the incidence of EUGR by achieving total enteral feeding as early as possible, strengthening breastfeeding, increasing calorie intake in the first week after birth, improving the velocity of weight gain, and preventing moderate-severe bronchopulmonary dysplasia in VPIs.

Clinical treatment outcomes and their changes in extremely preterm twins: a multicenter retrospective study in Guangdong Province, China. / è¶ æœªæˆç†ŸåŒèƒŽå„¿ä¸´åºŠæ•‘æ²»ç»“å±€åŠå˜åŒ–åˆ†æžï¼šä¸€é¡¹å¹¿ä¸œçœå¤šä¸­å¿ƒå›žé¡¾æ€§ç ”ç©¶.

OBJECTIVES: To investigate the clinical treatment outcomes and the changes of the outcomes over time in extremely preterm twins in Guangdong Province, China. METHODS: A retrospective analysis was performed for 269 pairs of extremely preterm twins with a gestational age of <28 weeks who were admitted to the department of neonatology in 26 grade A tertiary hospitals in Guangdong Province from January 2008 to December 2017. According to the admission time, they were divided into two groups: 2008-2012 and 2013-2017. Besides, each pair of twins was divided into the heavier infant and the lighter infant subgroups according to birth weight. The perinatal data of mothers and hospitalization data of neonates were collected. The survival rate of twins and the incidence rate of complications were compared between the 2008-2012 and 2013-2017 groups. RESULTS: Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of severe asphyxia and smaller head circumference at birth (P<0.05). The mortality rates of both of the twins, the heavier infant of the twins, and the lighter infant of the twins were lower in the 2013-2017 group compared with the 2008-2012 group (P<0.05). Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of pulmonary hemorrhage, patent ductus arteriosus (PDA), periventricular-intraventricular hemorrhage (P-IVH), and neonatal respiratory distress syndrome (NRDS) and a higher incidence rate of bronchopulmonary dysplasia (P<0.05). CONCLUSIONS: There is a significant increase in the survival rate over time in extremely preterm twins with a gestational age of <28 weeks in the 26 grade A tertiary hospitals in Guangdong Province. The incidences of severe asphyxia, pulmonary hemorrhage, PDA, P-IVH, and NRDS decrease in both the heavier and lighter infants of the twins, but the incidence of bronchopulmonary dysplasia increases. With the improvement of diagnosis and treatment, the multidisciplinary collaboration between different fields of fetal medicine including prenatal diagnosis, obstetrics, and neonatology is needed in the future to jointly develop management strategies for twin pregnancy.

[Effect of weight growth velocity in the early stage after birth on neurodevelopment of preterm infants at the corrected age of 12 months].

OBJECTIVE: To study the effect of weight growth velocity in the early stage after birth on the neurodevelopment of preterm infants at the corrected age of 12 months. METHODS: Related data were collected from the preterm infants who were discharged from the Department of Neonatology, Third Affiliated Hospital of Guangzhou Medical University, from July 1, 2015 to December 31, 2019 and were followed up at the outpatient service of high-risk infants. According to the weight growth velocity from birth to the corrected gestational age of 40 weeks, the infants were divided into two groups: low velocity [< 10 g/(kg·d); n=21] and high velocity [≥10 g/(kg·d); n=87]. At the corrected ages of 3, 6, and 12 months, Gesell Developmental Schedules were used to evaluate and compare neurodevelopment between the two groups. RESULTS: At the corrected age of 12 months, the low velocity group had a significantly lower score of fine motor (P < 0.05) and a significantly higher abnormal rate of language ability score compared with high velocity (P < 0.05). For the preterm infants with a birth weight of < 1 500 g or ≥1 500 g, the low velocity group had a significantly lower score of fine motor than the high velocity group (P < 0.05); for the preterm infants with a birth weight of ≥1 500 g, the low velocity group had a significantly higher abnormal rate of language ability score than the high velocity group (P < 0.05). CONCLUSIONS: The weight growth velocity from birth to the corrected age of 40 weeks affects the development of fine motor and language in preterm infants at the corrected age of 12 months; however it needs to be further verified by large-sample studies.

Pressure-induced reversible phase transition in thiourea dioxide crystal.

The effect of high pressure on the crystal structure of thiourea dioxide has been investigated by Raman spectroscopy and angle-dispersive X-ray diffraction (ADXRD) in a diamond anvil cell up to 10.3 GPa. The marked changes in the Raman spectra at 3.7 GPa strongly indicated a structural phase transition associated with the distortions of hydrogen bonding. There were no further changes up to the maximum pressure of 10.3 GPa and the observed transition was completely reversible when the system was brought back to ambient pressure. This transition was further confirmed by the changes of ADXRD spectra. The high-pressure phase was indexed and refined to an orthorhombic structure with a possible space group Pbam. The results from the first-principles calculations suggested that this phase transition was mainly related to the changes of hydrogen-bonded networks in thiourea dioxide.

Reduced expression of IA channels is associated with postischemic seizures in hyperglycemic rats.

Poststroke seizures are considered to be the major cause of epilepsy in the elderly. The mechanisms of poststroke seizures remain unclear. A history of diabetes mellitus has been identified as an independent predictor of acute poststroke seizures in stroke patients. The present study sought to reveal the mechanisms for the development of postischemic seizures under hyperglycemic conditions. Transient forebrain ischemia was produced in adult Wistar rats by using the four-vessel occlusion method. At the normal blood glucose level, seizures occurred in ∼50% of rats after 25 min of ischemia. However, in rats with hyperglycemia, the incidence rate of postischemic seizures was significantly increased to 100%. The occurrence of postischemic seizures was not correlated with the severity of brain damage in hyperglycemic rats. Mannitol, an osmotic diuretic agent, could neither prevent postischemic seizures nor alleviate the exacerbated brain damage in the presence of hyperglycemia. K(+) channels play a critical role in controlling neuronal excitability. The expression of A-type K(+) channel subunit Kv4.2 in the hippocampus and the cortex was significantly reduced in hyperglycemic rats with seizures compared with those without seizures. These results suggest that the reduction of Kv4.2 expression could contribute to the development of postischemic seizures in hyperglycemia.

Pressure-driven variations of hydrogen bonding energy in ammonium azide (NH4N3): IR absorption and Raman scattering studies.

In this study, high pressure infrared (IR) absorption and Raman scattering studies for ammonium azide (NH4N3) were carried out at room temperature up to 20 GPa and 22 GPa, respectively. For comparison and further assignment, the vibrational spectra at ambient conditions were calculated using CASTEP code, particularly for the far- and mid-IR modes. The recorded vibrational data consistently indicated a pressure-induced phase transition at 2.9 GPa. All observed vibrational modes maintained their identities at the high pressure phase, indicating that NH4N3 was still presented in the form of ammonium cations and azide anions linked by the hydrogen bond (N-H⋯N). Above 2.9 GPa, the relative magnitude of the torsional mode weakened and the N-H symmetric stretch displayed a redshift, indicating strengthened hydrogen bonding energy. The opposite effects were observed above 12 GPa, where the relative magnitude of the torsional mode strengthened and the N-H symmetric stretch reverted to a blueshift, indicating weakened hydrogen bonding energy. It can be concluded that the hydrogen bonding energy exhibited a weakening (0-2.9 GPa), strengthening (2.9-12 GPa), and then again weakening (12-22 GPa) phenomena with the increasing of compression. The hydrogen bonding energy changing with the increase of pressure can be ascribed to a phase transition at 2.9 GPa and a rotational or bending behavior of azide ions at 12 GPa.

[Comparative analysis of risk factors for preterm and small-for-gestational-age births].

OBJECTIVE: To compare the risk factors between preterm and small-for-gestational-age (SGA) births. METHODS: A total of 1 270 newborns who had no obstetric risk factors or maternal diseases were enrolled in this study. Their mothers' stature, body weight, passive smoking, and history of abnormal pregnancy were investigated using the self-designed questionnaire. The infants were divided into four groups: preterm, appropriate-for-gestational-age (AGA), SGA, and term infants. Multivariate logistic regression analysis was performed to compare the risk factors between preterm and SGA births. RESULTS: A weight gain less than 9 kg during pregnancy increased the risks of preterm (OR=1.63, 95% CI: 1.12-2.07) and SGA (OR=1.92, 95% CI: 1.56-2.58). The histories of abortion (OR=1.46, 95% CI: 1.09-1.93) and preterm birth (OR=2.63, 95% CI: 1.81-3.92) were independent risk factors for preterm births, while low pre-pregnancy body mass index (<18.5) (OR=2.16, 95% CI: 1.53-3.16), short stature (<1.55 m) (OR=2.46, 95% CI: 1.78-3.48), and passive smoking (OR=2.24, 95% CI: 1.65-2.98) were independent risk factors for SGA births. CONCLUSIONS: Due to different risk factors between preterm and SGA births, specific preventive measures should be taken pertinently to reduce the incidence of the two bad pregnancy outcomes.

[Effects of feeding patterns after hospital discharge on increase rates of growth indices in preterm and low-birth-weight infants within 3 months after birth].

OBJECTIVE: To study the effects of post-discharge formula (PDF) for preterm infants, breast milk (BM) and term infant formula (TF) on increase rates of body weight, length and head circumference in preterm and low-birth-weight infants (PLBWIs) from discharge to 3 months after birth, and to provide a reference for the choice of feeding pattern for PLBWIs. METHODS: A total of 407 PLBWIs discharged from the newborn departments of ten hospitals in Guangzhou City and Foshan City in Guangdong Province, China were chosen for this study. According to feeding pattern, they were assigned to three groups: PDF-fed (n=258), BM-fed (n=58) and TF-fed (n=91). Their body weight, length and head circumference were measured at 3 months after birth, and the increase rates of growth indices relative to baseline values (at birth) were calculated and compared. RESULTS: At 3 months after birth, the PDF-fed group had significantly greater body weight, length and head circumference than the BM-fed and TF-fed groups (P<0.05). The increase rates of body weight and length were significantly higher in the PDF-fed group than in the BM-fed and TF-fed groups (P<0.05). CONCLUSIONS: Compared with those fed with BM and TF after discharge, the PDF-fed PLBWIs have higher increase rates of body weight and length and show greater body weight and length at 3 months after birth. However, further study is needed to investigate the long-term effects.

The injection-production performance of an enhanced geothermal system considering fracture network complexity and thermo-hydro-mechanical coupling in numerical simulations.

The effect of fracture networks on EGS performance remains worth further investigation to guide the formulation of geothermal extraction strategy. We established models that account for thermo-hydraulic-mechanical (THM) coupling and that are based on the framework of discrete fracture network (DFN) to evaluate the heat extraction performance in deep-seated fractured reservoir. Our numerical results reveal that the zones of temperature, pressure, and stress perturbation diffuse asynchronously during the circulation of injection-production, and the stress perturbation always lags behind the other two. Furthermore, the effects of the fracture network characteristics including randomness, geometry, length, aperture, and injection parameters on the heat production are quantitatively investigated. Under the same number of fractures, different network geometry leads to different EGS production performance, the network with horizontal fracture set shows better thermal extraction performance but poor injection performance, which is because the fracture dip affects the thermal evolution on the horizontal plane. The effect of fracture length on EGS performance highly depends on its orientation, the excessive increase of fracture length towards injection-production wells is detrimental to heat extraction. The fracture aperture affects the working fluid transport and thus the EGS performance, the fractured reservoir with smaller fracture aperture shows the worse fluid flow performance but the better geothermal extraction performance, thus we believe that the optimal fracture aperture should be kept at a level of 0.5-1.0 mm in a self-propping fractured granitic system. The main influence of injection parameters on thermal extraction from the fractured reservoirs is the injection mass rate, because a high injection rate results in significant solid responses, including failure stress concentration, decreased safety factor, and increased permeability, which occur in those fractures that are originally connected to the injection well. These results of our research and the insights obtained have important implications for deep geothermal geoengineering activities.

Efficacy of inhaled nitric oxide in preterm infants ≤ 34 weeks: a systematic review and meta-analysis of randomized controlled trials.

Background: The effect of inhaled nitric oxide (iNO) in neonates >34 weeks on improving respiration is well documented. However, the efficacy of iNO in preterm infants ≤34 weeks remains controversial. Objectives: The main purpose of this review is to assess the effectiveness and safety of iNO treatment in preterm infants ≤34 weeks. Search methods: We systematically searched PubMed, Embase and Cochrane Libraries from their inception to 1 June 2023. We also reviewed the reference lists of retrieved studies. Selection criteria: Our study involved randomized controlled trials on preterm infants ≤34 weeks, especially those receiving iNO treatment, and mainly assessed outcomes such as bronchopulmonary dysplasia (BPD) and mortality. Two authors independently reviewed these trials, extracted data, and evaluated study biases. Disagreements were resolved by consensus. We used the GRADE method to assess evidence quality. Results: Our research included a total of 17 studies involving 4,080 neonates and 7 follow-up studies. The synthesis of results showed that in neonates, iNO treatment reduced the incidence of BPD (RR: 0.92; 95% CI: 0.86-0.98). It also decreased the composite outcome of death or BPD (RR: 0.94; 95% CI: 0.90-0.98), without increasing the risk of short-term (such as intraventricular hemorrhage, periventricular leukomalacia) and long-term neurological outcomes (including Bayley mental developmental index <70, cerebral palsy and neurodevelopmental impairment). Furthermore, iNO did not significantly affect other neonatal complications like sepsis, pulmonary hemorrhage, necrotizing enterocolitis, and symptomatic patent ductus arteriosus. Subgroup analysis revealed that iNO significantly reduced BPD incidence in neonates at 36 weeks under specific intervention conditions, including age less than 3 days, birth weight over 1,000 g, iNO dose of 10 ppm or higher, or treatment duration exceeding 7 days (p < 0.05). Conclusion: Inhaled NO reduced the incidence of BPD in neonates at 36 weeks of gestation, and the effect of the treatment depended on neonatal age, birth weight, duration and dose of iNO. Therefore, iNO can be considered a promising treatment for the potential prevention of BPD in premature infants. More data, however, would be needed to support nitric oxide registration in this specific patient population, to minimize its off-label use.

The acoustic velocity, refractive index, and equation of state of liquid ammonia dihydrate under high pressure and high temperature.

High-pressure and high-temperature Brillouin scattering studies have been performed on liquid of composition corresponding to the ammonia dihydrate stoichiometry (NH(3)·2H(2)O) in a diamond anvil cell. Using the measured Brillouin frequency shifts from 180° back- and 60° platelet-scattering geometries, the acoustic velocity, refractive index, density, and adiabatic bulk modulus have been determined under pressure up to freezing point along the 296, 338, 376, and 407 K isotherms. Along these four isotherms, the acoustic velocities increase smoothly with increasing pressure but decrease with the increased temperature. However, the pressure dependence of the refractive indexes on the four isotherms exhibits a change in slope around 1.5 GPa. The bulk modulus increases linearly with pressure and its slope, dB/dP, decreases from 6.83 at 296 K to 4.41 at 407 K. These new datasets improve our understanding of the pressure- and temperature-induced molecular structure changes in the ammonia-water binary system.

[Analysis of de novo copy number variations in a family affected with autism spectrum disorders using high-resolution array-based comparative genomic hybridization].

OBJECTIVE: To analyze de novo copy number variations (CNVs) in a Chinese family affected with autism spectrum disorders (ASD). METHODS: Affymetrix Cytogenetics Whole Genome 2.7M Array assay was performed to identify potential CNVs in four members from the family. RESULTS: A total of 89 de novo CNV regions were identified in the autistic siblings. The CNV regions in total have exceeded 1/1000 of the lengths of chromosomes 5, 11 and 14. In addition, de novo CNV regions were also identified at 3p26.1, 4q22.2, and 5p15.2, which encompassed 10 genes associated with nerve development including GRM7, GRID2 and CTNND2. CONCLUSION: A number of nerve development associated genes were at the de novo CNV sites, which may provide new clues for genetic research of ASD. High-resolution array-comparative genomic hybridization is an effective method for detecting submicroscopic chromosomal imbalances.

Increased Risk for Respiratory Complications in Male Extremely Preterm Infants: A Propensity Score Matching Study.

Background: Many factors can affect the clinical outcome of extremely premature infants (EPIs), but the effect of sex is paradoxical. This study used propensity score matching to adjust baseline information to reassess the clinical outcome of EPIs based on sex. Methods: A retrospective analysis was performed on EPIs admitted in the Department of Neonatology of the Third Affiliated Hospital of Guangzhou Medical University from 2011 to 2020. A propensity score matching (PSM) analysis was used to adjust the confounding factors including gestational age, birth weight, 1-minute Apgar score ≤ 3, withholding or withdrawing life-sustaining treatment(WWLST), mechanical ventilation, duration of mechanical ventilation, the mother with advanced age (≥35 years old), complete-course antenatal steroid therapy and hypertensive disorders of pregnancy. The survival rate at discharge and the incidence of major complications were evaluated between the male and female groups. Results: A total of 439 EPIs were included, and 240 (54.7%) infants were males. After matching the nine confounding factors, 148 pairs of infants were finally enrolled. There was no significant difference in the survival rate at discharge, as well as the mortality of activating treatment or WWLST between the two groups (all P>0.05). However, the incidence of respiratory distress syndrome, bronchopulmonary dysplasia (BPD), and moderate to severe BPD in the male group was significantly increased (all P<0.01), especially at birth weight between 750 and 999 grams. Conclusions: The male EPIs have a higher risk of respiratory complications than females, particularly at 750 to 999 grams of birth weight.

The inhibition of enterocyte proliferation by lithocholic acid exacerbates necrotizing enterocolitis through downregulating the Wnt/ß-catenin signalling pathway.

OBJECTIVES: Necrotizing enterocolitis (NEC) is a catastrophic gastrointestinal emergency in preterm infants, whose exact aetiology remains unknown. The role of lithocholic acid (LCA), a key component of secondary bile acids (BAs), in NEC is unclear. METHODS: Clinical data were collected to analyse the changes of BAs in NEC patients. In vitro studies, the cell proliferation and cell death were assessed. In vivo experiments, the newborn rats were administered with low or high dose of LCA and further induced NEC. RESULTS: Clinically, compared with control group, total BAs in the NEC patients were significantly higher when NEC occurred. In vitro, LCA treatment significantly inhibited the cell proliferation through arresting cell cycle at G1/S phase without inducing apoptosis or necroptosis. Mechanistically, the Wnt/ß-catenin pathway was involved. In vivo, LCA inhibited intestinal cell proliferation leading to disruption of intestinal barrier, and thereby increased the severity of NEC. Specifically, LCA supplementation caused higher levels of FITC-labelled dextran in serum, reduced PCNA expression and inhibited the activity of Wnt/ß-catenin pathway in enterocytes. The LC-MS/MS test found that LCA was significantly higher in intestinal tissue of NEC group, and more obviously in the NEC-L and NEC-H group compared with the DM group. CONCLUSION: LCA exacerbates NEC by inhibiting intestinal cell proliferation through downregulating the Wnt/ß-catenin pathway.