Based on bound water characteristics study of microporosity characteristics and mechanical properties evolution of copper-contaminated laterite.

The potential impact of heavy metal ion infiltration on macroscopic and microscopic soil properties is a subject of academic interest. Laterite has an extensive distribution in southern China and is extensively utilized as a vertical containment wall for landfills. Consequently, there is a need to investigate how heavy metal ions affect laterite's microstructure and mechanical properties. To examine the impact of Cu2+ on laterite's microporous characteristics and mechanical properties, laboratory tests were conducted on the permeability, shear strength, microporous characteristics, and strong absorbed water content of Cu2+-contaminated laterite. The results show that Cu2+ hydrolysis generates an acidic environment, which leads to erosion of the cementing substance between the laterite particles, increasing the laterite's porosity and decreasing the soil's cohesive strength, thus affecting the shear strength and permeability of the laterite. When the concentration of Cu2+ is 5.0 g/L, the laterite demonstrated the most significant decrease in shear strength, 43.01%, while the permeability coefficient increased from 3.24 × 10-8 cm/s to 1.32 × 10-7 cm/s. Meanwhile, Cu2+ changes the content of strong absorbed water in laterite. The change of strong absorbed water content will affect the Van der Waals between laterite particles, promote the evolution of soil micropore structure, and lead to a decrease in the proportion of intra-aggregate pores (d < 1 µm) and an increase in the proportion of inter-aggregate pores (1 µm < d < 10 µm), which in turn affects the macroscopic shear strength and permeability. This study has improved our understanding of the mechanisms underlying the microporosity and mechanical property evolution of laterite when subjected to heavy metal attack.

Delayed versus immediate cord clamping in dichorionic twins <32 weeks: a retrospective study.

OBJECTIVES: Strong evidence imply that delayed cord clamping (DCC) provides significant benefits for singleton neonates. However, there is little information about the safety or efficacy of DCC in twins to recommend for or against DCC in twins in guidelines. We aimed to determine the effect of DCC on dichorionic twins born at <32 weeks of gestation. STUDY DESIGN: This is a retrospective cohort study comparing the neonatal and maternal outcomes of immediate cord clamping (ICC) [<15 second (s)] versus DCC (at 60 s). Generalized estimating equations models were performed accounting for twin correlation. RESULTS: A total of 82 pairs of twins (DCC: 41; ICC: 41) were included in analysis. The primary outcome of death before discharge occurred in 3.66% of twins in the DCC group and 7.32% in the ICC group, without a significant difference between the groups. Compared to ICC group, DCC was associated with increased hemoglobin levels [ß1 coefficient 6.51; 95% confidence interval (CI) 0.69-12.32. ß2 coefficient 5.80; 95% CI 0.07-11.54] at 12-24 h of life. There were no significant differences between the groups in neonatal death, neonatal major morbidities and maternal bleeding complications, although DCC was associated with higher estimated maternal blood loss in the cesarean section group (p = .005). CONCLUSIONS: DCC for 60 s in dichorionic twins born at <32 weeks of gestation was associated with increased neonatal hemoglobin levels, when compared with ICC. The finding of a higher estimated maternal blood loss by cesarean section in the DCC group calls for further trials to assess maternal safety of this procedure in this patient population.

Cord blood 25(OH)D3, cord blood total immunoglobulin E levels, and food allergies in infancy: A birth cohort study in Chongqing, China.

Background: Food allergy (FA) in infants has become a common disease worldwide. There are many controversies surrounding the relationships among levels of cord blood 25-hydroxy vitamin D3 [25(OH)D3], total immunoglobulin E (IgE), and FA. Methods: In this study, we recruited pregnant women in the third trimester undergoing obstetric examination in Chongqing City, Western China. Healthy full-term singleton births between May to August 2018 and November 2018 to January 2019 were included in the summer-birth and winter-birth cohorts, respectively. Questionnaires on vitamin D status in pregnancy and family allergies were used to investigate the pregnant women. The levels of <12 ng/mL, 12～20 ng/mL, and >20 ng/mL 25(OH)D3 in cord blood detected by liquid chromatography tandem mass spectrometry were considered deficient, insufficient, and sufficient, respectively. The electrochemiluminescence method was used to detect the total lgE levels in cord blood, classified into low-IgE (<0.35 IU/mL) and high-IgE (≥0.35 IU/mL) levels, respectively. Within postnatal 6 months, allergic symptoms in infants were investigated using questionnaire during the infants' monthly physical examinations. Suspected cases of FA underwent a history inquiry, skin prick test, food elimination test, and open-food challenge for diagnosis of FA. Multivariate logistic regression was used to analyze the risk factors of FA in infants. Results: In this study, we recruited 741 pairs of pregnant women and infants, including 343 infants in the summer-birth cohort and 398 infants in the winter-birth cohort. The incidence of FA within postnatal 6 months was 6.88%, showing significantly higher incidence of FA in the winter-birth cohorts than in the summer-birth cohorts (10.3% vs. 2.9%, χ2 = 15.682, P = 0.000). Among the 741 infants, 47.1%, 27.5%, and 13.8% of infants had deficient, insufficient, and sufficient 25(OH)D3, respectively, in the cord blood; 81.5% and 18.5% of infants had total low-IgE and total high-IgE levels, respectively, in the cord blood. No significant correlation was found between the 25(OH)D3 and IgE levels (r = -0.038, P = 0.300). Logistic regression analysis showed that winter birth [odds ratio (OR) 95% confidence interval (CI): 4.292 (2.003～8.359)] compared with infants in summer birth group, and sufficient (>20 ng/mL) 25(OH)D3 levels in cord blood [OR (95% CI): 2.355 (1.129～4.911) compared with infants in the deficient group (<12 ng/mL) and 3.782 (1.680～8.514) compared with infants in the insufficient group (12～20 ng/mL)] were independent risk factors for FA in infants within postnatal 6 months. Conclusions: Winter birth and sufficient 25(OH)D3 levels in infant cord blood were independent risk factors for FA in infants. 25(OH)D3 and total IgE levels in cord blood cannot be used as predictors of FA in early infancy.

With or Without Nasal Continuous Positive Airway Pressure During Delayed Cord Clamping in Premature Infants <32 Weeks: A Randomized Controlled Trial Using an Intention-To-Treat Analysis.

Objective: To assess whether providing nasal continuous positive airway pressure (nCPAP) during delayed cord clamping is beneficial for preterm infants <32 weeks. Study Design: A randomized controlled trial was performed from March 2020 to May 2021. Premature infants (<32 weeks of gestational age; n = 160) were allocated to receive at least 60 s of delayed cord clamping with nCPAP (DCC+nCPAP; n = 80) or without nCPAP (DCC only; n = 80). For both groups, after the umbilical cord was clamped, the infants were carried immediately to the resuscitation room to continue receiving standard transition. The primary outcome was the mechanical ventilation (MV) rate within 24 h of life. The measurements related to early respiratory support effect before cord clamping including positive end-expiratory pressure (PEEP) and FiO2 during transition/leaving the delivery room, intubation rate during transition, pulmonary surfactant (PS) administration ≥2 times after birth, extubation failure, and incidence of bronchopulmonary dysplasia (BPD) were collected as the secondary outcomes. Furthermore, other neonatal short-term outcomes and safety assessment were also included. Results: The measurements were calculated using intention-to-treat analysis. The median time for cord clamping were 60 s with interquartile range (IQR) (60.00-60.00 vs. 60.00-70.00) in both groups. There were no difference in the primary outcome of MV rate within 24 h of life (p = 0.184). The arterial blood gas pH at 1 h after birth in the DCC+nCPAP group was 7.28 ± 0.08 vs. 7.25 ± 0.07 in the control group (mean difference = 0.01, 95% CI: -0.01-0.05, p = 0.052), which approached statistical significance. There was no significant statistical difference in the other short-term neonatal outcomes and the safety indicators between the two groups. Conclusions: Our study showed that delayed cord clamping with nCPAP was feasible and safe in preterm infants with gestational age <32 weeks. Although there was a trend toward a higher arterial blood gas pH at 1 h after birth in the DCC+nCPAP group, DCC+nCPAP neither resulted in a corresponding measurable clinical improvement nor did it reduce subsequent neonatal morbidity. A larger multi-center study including more infants with gestational age <28 weeks is needed to evaluate the full effects of DCC in combination with nCPAP in preterm infants.

Serum levels of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 in children with autism spectrum disorder. / å­¤ç‹¬ç—‡è°±ç³»éšœç¢å„¿ç«¥çš„è¡€æ¸ èƒ°å²›ç´ æ ·ç”Ÿé•¿å› å­-1å’Œèƒ°å²›ç´ æ ·ç”Ÿé•¿å› å­ç»“åˆè›‹ç™½-3æ°´å¹³ç ”ç©¶.

OBJECTIVES: To study the serum levels of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) in children with autism spectrum disorder (ASD) and their association with the core symptoms of ASD. METHODS: A total of 150 ASD children aged 2-7 years (ASD group) and 165 healthy children matched for age and sex (control group) who were recruited at the outpatient service of Chongqing Health Center for Women and Children were enrolled as subjects. Autism Behavior Checklist (ABC) and Childhood Autism Rating Scale (CARS) were used to evaluate the core symptoms of the ASD children. Chemiluminescence was used to measure the serum levels of IGF-1 and IGFBP-3 in both groups. RESULTS: The ASD group had a significantly lower serum level of IGF-1 than the control group (P<0.05). The children with severe ASD had significantly lower serum levels of IGF-1 and IGFBP-3 than those with mild-to-moderate ASD (P<0.001). For the children aged 2-3 years, the ASD group had a significantly lower serum level of IGF-1 than the control group (P<0.05). Boys had a significantly lower serum level of IGF-1 than girls in both ASD and control groups (P<0.05). The serum levels of IGF-1 and IGFBP-3 were negatively correlated with the total score of CARS (r=-0.32 and -0.40 respectively, P<0.001). CONCLUSIONS: The reduction in serum IGF-1 level in early childhood may be associated with the development of ASD, and the serum levels of IGF-1 and IGFBP-3 are associated with the core symptoms of ASD children.

Analysis of longitudinal follow-up data of physical growth in singleton full-term small for gestational age infants.

OBJECTIVE: This study aimed to investigate the catch-up growth pattern of singleton full-term small for gestational age (SGA) infants in the first year after birth. METHODS: A single-center retrospective cohort study was performed to assess singleton full-term SGA infants. Weight, length, and head circumference were measured at birth, and at 1, 3, 6, and 12 months of age. RESULTS: Two hundred ten SGA infants were included in this study. Boys (n = 90) and girls (n = 120) showed a similar gestational age, birth weight, and body length. Weight, length, and head circumference in SGA infants in all age groups increased with age, with the fastest growth stage from birth to 3 months. The speed of weight and head circumference catch-up was higher than that of body length. At 12 months, significant associations of height in boys with height of the fathers, mothers, and both parents combined appeared. The height of girls showed associations with the mothers' and the parents' height. CONCLUSIONS: Full-term SGA infants grow rapidly after birth, with the fastest growth rate in the first 3 months, as examined by weight, body length, and head circumference. However, the catch-up speed of weight and body length were not balanced in this study.

A prospective cohort study of cord blood 25(OH)D3 and food allergies in 6-month-old Chinese infants.

BACKGROUND: Vitamin D is closely related to childhood allergic diseases, such as food allergies, atopic dermatitis, and asthma. However, it is unclear whether vitamin D status in the cord blood from mothers is related to food allergies in infants. OBJECTIVE: We performed a prospective cohort study on the relationship between the cord blood vitamin D [i.e., 25-hydroxyvitamin D3(25(OH)D3)] level and infant food allergies. METHODS: This study selected 741 newborns to observe until 6 months of age and used open oral food challenges (OFCs) to diagnose their food allergies. Cord blood and 6-month serum 25(OH)D3 levels of the infants were measured by liquid chromatography-tandem mass spectrometry. RESULTS: The proportion of children with cord blood 25(OH)D3 deficiency (< 20 ng/mL) was 86.27%. Cord blood vitamin D was positively correlated with the supplementation frequency of egg yolk, multivitamins, calcium, and docosahexaenoic acid (DHA) during pregnancy and the mother's age. No significant difference was found in the cord blood 25(OH)D3 level between summer born and winter born infants (p = 0.465). After adjusting for seasonal factors, the risk of food allergies in the 25(OH)D3 non-deficiency group was 2.72 times that of the 25(OH)D3 deficiency group. Infants in the 25(OH)D3 non-deficiency group ≥20 ng/mL) had a higher risk of allergies compared with the deficiency group (< 20 ng/mL) (RR = 2.49). CONCLUSIONS: Cord blood 25(OH)D3 is associated with infant food allergies. Maintaining 25(OH)D3 in maternal cord blood at a low level may be conducive to the prevention of infant food allergies.

Characteristics influencing high-risk sexual behaviours in elderly men.

With the objective of investigating the characteristics influencing high-risk sexual behaviours in elderly men (60-74 years of age) in Chongqing, China, a total of 1433 healthy elderly men with sexual intercourse frequencies of one to six times/month who were willing to participate in the questionnaires were studied at four hospitals. We measured serum testosterone levels and performed follow-ups every six months, with a total of 1128 elderly men followed up after two years. We also investigated socio-economic and demographic characteristics (age, education, income, location, marital status and number of marriages), types of sexual partners, age differences with fixed sexual partners, frequency of sexual intercourse, combined basic age-related diseases, sexually transmitted infections (STIs) education, elderly self-care ability and high-risk sexual behaviours (frequency of sexual intercourse and number of sexual partners) using questionnaires. We analysed the influencing factors of high-risk sexual behaviours in elderly men using a univariate analysis, multivariate logistic regression analysis, BP neural network prediction and cluster analysis. Finally, we found that serum total testosterone, age, types of sexual partners, age differences with fixed partners and frequency of sexual intercourse are five factors that influence high-risk sexual behaviours in elderly men.

Adherence to pre-exposure prophylaxis among men who have sex with men: A prospective cohort study.

OBJECTIVE: To evaluate adherence to pre-exposure prophylaxis (PrEP) in a clinical trial of a population of men who have sex with men (MSM), to explore the influence of social psychology and objective factors (e.g., forgetting, too busy) on adherence, and to provide evidence for subsequent PrEP research. METHODS: This study analyzed the data from the daily medication group within a PrEP study (a randomized placebo-controlled trial of oral tenofovir among MSM in Western China from April 2013 to March 2015). A total of 331 participants were analyzed. PrEP adherence was self-reported by the subjects at every 3-month follow-up visit for 24 months. AIDS-related information including HIV prevention, transmission, and treatment knowledge, as well as PrEP-related motivation (including personal and social motivation) and behavior skills, i.e., self-efficacy, were collected using questionnaires. The objective reasons for non-adherence were collected during face-to-face follow-up visits every 3 months. A theoretical model of information motivation behavior skills (IMB) was constructed. Then confirmatory factor analysis was performed to test the fit of each IMB construct. Finally, the structure equation model was used to evaluate the IMB model. RESULTS: The median adherence rate was 64.29%. During the follow-up period, the percentage of high adherence (adherence ≥80%) was 32.33%, intermediate adherence (adherence 40-80%) was 38.97%, and low adherence (adherence ≤40%) was 28.70%. The final IMB model showed that there was no significant correlation between adherence to PrEP and the psychological constructs: information, motivation, and behavior skills. The main objective reasons for non-adherence were 'forgetting to take medicine' (70.21%), 'too busy' (29.08%), 'worrying about side effects' (28.01%), and 'too much trouble' (18.44%). CONCLUSIONS: This study found no association between PrEP adherence and social psychological factors, and the main objective factor in non-adherence was forgetting to take the medicine. In the future, the MSM population could be reminded to take their medicine regularly using electronic devices, which may improve PrEP adherence to some extent and may further reduce the incidence of HIV. The strategy to improve PrEP adherence requires further study.