Immune signatures underlying post-acute COVID-19 lung sequelae

[Figure: see text].

Biofunctional magnesium-coated Ti6Al4V scaffolds promote autophagy-dependent apoptosis in osteosarcoma by activating the AMPK/mTOR/ULK1 signaling pathway

The recurrence of osteosarcoma (OS) after reconstruction using Ti6Al4V prostheses remains a major problem in the surgical treatment of OS. Modification of the surfaces of Ti6Al4V prostheses with antitumor functions is an important strategy for improving therapeutic outcomes. Magnesium (Mg) coating has been shown to be multifunctional: it exhibits osteogenic and angiogenic properties and the potential to inhibit OS. In this study, we determined the proper concentration of released Mg²⁺ with respect to OS inhibition and biosafety and evaluated the anti-OS effects of Mg-coated Ti6Al4V scaffolds. We found that the release of Mg²⁺ during short-term and long-term degradation could significantly inhibit the proliferation and migration of HOS and 143B cells. Increased cell apoptosis and excessive autophagy were also observed, and further evidence of AMPK/mTOR/ULK1 signaling pathway activation was obtained both in vitro and in vivo, which suggested that the biofunctional scaffolds induce OS inhibition. Our study demonstrates the ability of an Mg coating to inhibit OS and may contribute to the further application of Mg-coated Ti6Al4V prostheses.

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Multifunctional Mg coating is considerable surface modification for Ti6Al4V prostheses.

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Mg²⁺ releasing by the scaffolds could significantly inhibit the proliferation and migration of OS cells.

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The biofunctional scaffolds could inhibit OS by activating autophagy-dependent apoptosis.

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The AMPK/mTOR/ULK-1 pathway was involved in autophagy-depended apoptosis induced by the scaffolds.

Prevalence and influencing risk factors of eczema among preschool children in Urumqi city: a cross-sectional survey

Background

Eczema is a chronic inflammatory disease associated with impaired quality of life. We identified indoor environmental risk factors, to provide strong evidence for the prevention and control of eczema in preschool children.

Methods

Using a cross-sectional study with stratified random cluster sampling, we conducted a self-administered questionnaire survey among 8153 parents of children aged 2–8 years in 60 kindergartens in six districts of Urumqi city during August 2019.

Results

Among 8153 preschool children, 12.0% of the children have been diagnosed with eczema. Multivariate logistic regression analysis showed that caesarean section (odds ratio [OR] = 1.18, 95% confidence interval [CI]: 1.03–1.36), being an only child (OR = 1.36, 95% CI: 1.18–1.57), presence of mould or moisture in the mother’s home before pregnancy (OR = 1.53, 95% CI: 1.17–2.00), presence of flies or mosquitoes in the dwelling currently (OR = 1.31, 95% CI: 1.10–1.55), pets kept in the child’s home currently (OR = 1.23, 95% CI: 1.01–1.51), presence of pets during child’s first year (OR = 1.45, 95% CI: 1.14–1.85), and family history of eczema (OR = 3.53, 95% CI: 2.98–4.19) are the risk factors for the development of eczema, whereas ethnicity other than the Han Chinese (OR = 0.77, 95% CI: 0.61–0.96) is a protective factor for eczema.

Conclusion

Preschool children in Urumqi are at a high risk of eczema, particularly those of the Han Chinese ethnicity. Parents should be attentive to the indoor living environment of children and take actions to reduce indoor humidity, pest control and elimination, and avoid raising pets to reduce the risk of development of eczema in children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02819-5.

A cryptic long-chain 3-ketoacyl-ACP synthase in the Pseudomonas putida F1 unsaturated fatty acid synthesis pathway

The Pseudomonas putida F1 genome contains five genes annotated as encoding 3-ketoacyl-acyl carrier protein (ACP) synthases. Four are annotated as encoding FabF (3-ketoacyl-ACP synthase II) proteins, and the fifth is annotated as encoding a FabB (3-ketoacyl-ACP synthase I) protein. Expression of one of the FabF proteins, FabF2, is cryptic in the native host and becomes physiologically important only when the repressor controlling fabF2 transcription is inactivated. When derepressed, FabF2 can functionally replace FabB, and when expressed from a foreign promoter, had weak FabF activity. Complementation of Escherichia coli fabB and fabF mutant strains with high expression showed that P. putida fabF1 restored E. coli fabF function, whereas fabB restored E. coli fabB function and fabF2 restored the functions of both E. coli fabF and fabB. The P. putida ΔfabF1 deletion strain was almost entirely defective in synthesis of cis-vaccenic acid, whereas the ΔfabB strain is an unsaturated fatty acid (UFA) auxotroph that accumulated high levels of spontaneous suppressors in the absence of UFA supplementation. This was due to increased expression of fabF2 that bypasses loss of fabB because of the inactivation of the regulator, Pput_2425, encoded in the same operon as fabF2. Spontaneous suppressor accumulation was decreased by high levels of UFA supplementation, whereas competition by the P. putida β-oxidation pathway gave increased accumulation. The ΔfabB ΔfabF2 strain is a stable UFA auxotroph indicating that suppressor accumulation requires FabF2 function. However, at low concentrations of UFA supplementation, the ΔfabF2 ΔPput_2425 double-mutant strain still accumulated suppressors at low UFA concentrations.

[Clinical and genetic studies on 76 patients with hydrocephalus caused by methylmalonic acidemia combined with homocysteinuria]

Objective: To analyze the clinical features, genetic characteristics, treatment and follow-up results of patients with hydrocephalus caused by methylmalonic acidemia combined with homocysteinuria, and to discuss the optimal strategies for assessing and treating such patients. Methods: From January 1998 to December 2020, 76 patients with hydrocephalus due to methylmalonic acidemia combined with homocysteinuria in the Department of Pediatrics in 11 hospitals including Peking University First Hospital were diagnosed by biochemical, genetic analysis and brain imaging examination. The patients were divided into operation-group and non-operation-group according to whether they underwent ventriculoperitoneal shunt. The clinical features, laboratory examinations, genotype, and follow-up data were retrospectively analyzed. Data were compared between the two groups using rank sum test, and categorical data were compared using χ² test. Results: Among the 76 patients (51 male, 25 female), 5 were detected by newborn screening, while 71 were diagnosed after clinical onset, 68 cases (96%) had early-onset, 3 cases (4%) had late-onset. The most common clinical manifestations of 74 cases with complete data were psychomotor retardation in 74 cases (100%), visual impairment in 74 cases (100%), epilepsy in 44 cases (59%), anemia in 31 cases (42%), hypotonia or hypertonia in 21 cases (28%), feeding difficulties in 19 cases (26%) and disturbance of consciousness in 17 cases (23%). Genetic analysis was performed in 76 cases, all of whom had MMACHC gene variations, including 30 homozygous variations of MMACHC c.609G>A. The most common variations were c.609G>A (94, 62.7%), followed by c.658_660del (18, 12.0%), c.567dupT (9, 6.0%) and c.217C>T (8, 5.3%). Therapy including cobalamin intramuscular injection, L-carnitine and betaine were initiated immediately after diagnosis. A ventriculoperitoneal shunt operation was performed in 41 cases (operation group), and 31 patients improved after metabolic intervention (non-operation group). There was no significant difference in the age of onset, the age of diagnosis, the blood total homocysteine, methionine, and urinary methylmalonic acid concentration between the two groups (all P>0.05). The symptoms of psychomotor development, epilepsy, and visual impairments improved gradually after a long-term follow-up in the operation group. Conclusions: Hydrocephalus is a severe complication of methylmalonic acidemia combined with homocysteinuria. The most common clinical manifestations are psychomotor retardation, visual impairment, and epilepsy. It usually occurs in early-onset patients. Early diagnosis and etiological treatment are very important. Hydrocephalus may improve after metabolic intervention in some patients. For patients with severe ventricular dilatation, prompt surgical intervention can improve the prognosis.

Temperature regulation of membrane composition in the Firmicute, Enterococcus faecalis, parallels that of Escherichia coli

Both Enterococcus faecalis and Escherichia coli can undergo abrupt temperature transitions in nature. E. coli changes the composition of its phospholipid acyl chains in response to shifts growth temperature. This is mediated by a naturally temperature sensitive enzyme, FabF (3-ketoacyl-acyl carrier protein synthase II), that elongates the 16 carbon unsaturated acyl chain palmitoleate to the 18 carbon unsaturated acyl chain, cis-vaccenate. FabF is more active at low temperatures resulting in increased incorporation of cis-vaccenoyl acyl chains into the membrane phospholipids. This response to temperature is an intrinsic property of FabF and does not require increased synthesis of the enzyme. We report that the FabF of the very divergent bacterium, E. faecalis, has properties very similar to E. coli FabF and is responsible for changing E. faecalis membrane phospholipid acyl chain composition in response to temperature. Moreover, expression E. faecalis FabF in an E. coli ∆fabF strain restores temperature regulation to the E. coli strain.

[Establishment of animal models of epidermal growth factor receptor inhibitor-related rashes]

OBJECTIVE

To establish animal models epidermal growth factor receptor inhibitor-related skin rashes using cetuximab, gefitinib or erlotinib.

OBJECTIVE

Female SCID mice were randomly divided into blank control group and high-, moderate-, and low-dose cetuximab groups. The mice in control group received intraperitoneal injection of saline, and those in the 3 cetuximab groups were injected with 80, 40, and 20 mg/kg cetuximab (3 times a week for 4 weeks), respectively. The general skin appearance and skin pathologies of the mice were observed. Female BN rats were randomly divided into blank group, ovalbumin group, gefitinib group and erlotinib group, and in the latter 3 groups, the rats were given ovalbumin (1 mg), gefitinib (37.5 mg/kg), and erlotinib (23.5 mg/kg) by lavage once daily for 45 days, respectively. Skin pathologies of the rats were observed, and serum levels of TNF-α, IL-6 and other inflammatory factors were detected using ELISA.

OBJECTIVE

Intraperitoneal injection of cetuximab did not induce typical skin rashes, scabs or obvious skin inflammation in the mice. In female BN rats, lavage of gefitinib caused obvious skin rashes, scabs and exudation, and obvious inflammatory cell infiltration, keratinosis, spinous layer release and epidermal thickening were observed in the skin. No obvious skin inflammation were observed in the rats in the control, ovalbumin or erlotinib groups. While IgE (P=0.061) and TNF-α concentrations (P=0.057) did not differ significantly among the groups, serum levels of IL-6 was significantly higher in gefitinib group than in the blank control group (P=0.016) but similar between erlotinib group and the blank group (P=0.910).

OBJECTIVE

Intraperitoneal injection of cetuximab can not induce epidermal growth factor receptor inhibitor-related skin rashes in SCID mice. Lavage of gefitinib, but not erlotinib, can be used to establish models of epidermal growth factor receptor inhibitor-related rashes in BN rats.

Environmental damage cost assessment from municipal solid waste treatment based on LIME3 model

Environmental damage cost can measure the impact of pollution caused by human activity on final safeguard subjects from endpoint perspective. Application of environmental damage cost to municipal solid waste (MSW) management is still rare. To fill such a research gap, this study established a MSW environmental damage cost assessment method using Life Cycle Impact Assessment Method based on Endpoint (LIME) model. Four types of environmental damage cost, namely, primary productivity, social assets, biodiversity and human health for waste treatment were investigated in the city of Shanghai. Results show that the environmental damage cost was 113.7, 116.9, 140.0, 144.0 and 170.8 million dollars in Shanghai from 2014 to 2018, respectively. Damage cost of social assets was the dominant component, accounting for about 55%. Landfill mainly caused social assets damage cost, while incineration mainly caused human health damage cost. Scenarios analysis further revealed that after implementing MSW separation, the total environmental damage cost could be reduced by about 1/3. The best MSW treatment method is fermentation, followed by compost, incineration and landfill, with unit environmental damage cost being 0.22, 4.51, 16.04 and 23.47 USD/ton, respectively.

The significance of phase reversion-induced nanograined/ultrafine-grained (NG/UFG) structure on the strain hardening behavior and deformation mechanism in copper-bearing antimicrobial austenitic stainless steel

The unique concept of phase reversion involving severe deformation of parent austenite into martensite, followed by annealing for a short duration, whereby the strain-induced martensite reverts to austenite, was adopted to obtain nano-grained/ultrafine-grained (NG/UFG) structure in a Cu-bearing biomedical austenitic stainless steel resulting in high strength-high ductility combination. Work hardening and accompanying deformation mechanism are two important aspects that govern the mechanical behavior of biomedical devices. Thus, post-mortem electron microscopy of the strained region was carried out to explore the differences in the deformation mechanisms induced by grain refinement, while the strain hardening behavior was analyzed by Crussard-Jaoul (C-J) analysis of the tensile stress-strain data. The strain hardening behavior consisted of four stages and was strongly affected by grain structure. Twinning-induced plasticity (TWIP) was the governing deformation mechanism in the NG/UFG structure and contributed to good ductility. In striking contrast, transformation-induced plasticity (TRIP) contributed to high ductility in the coarse-grained (CG) counterpart and was the governing strain hardening mechanism. When the grain size is less than ~1 μm, the increase in the strain energy and the austenite stability significantly reduce the possibility of strain-induced martensite transformation such that there is a distinct transition in deformation mechanism from nanoscale twinning in the NG/UFG structure to strain-induced martensite in CG structure. The differences in the deformation mechanisms are explained in terms of austenite stability - strain energy relationship.

Analysis of factors leading to lid wiper epitheliopathy

OBJECTIVE

Lid wiper epitheliopathy (LWE) has received more attention during the diagnosis and treatment of the dry eye. However, its causes and pathogenesis remain unclear. We aimed to explore the etiology of LWE by analyzing the association between the severity of LWE and different anatomical and tissue morphological examination characteristics using confocal microscopy on eyes with dry eye syndrome.

PATIENTS AND METHODS

We recruited 350 patients with LWE and dry eye syndrome (350 eyes). We examined the eyes with lid-wiper staining, conjunctival staining, a comprehensive ocular surface exam using the OCULUS keratography 5M, conjunctival impression cytology, and confocal microscopy observations. We analyzed the associations between each indicator and the LWE staining score.

RESULTS

According to the Spearman's analysis, the LWE staining score was weakly associated with thickness of the lipid layer (r=0.1737, p=0.0005) and severity of Meibomian gland dysfunction (r=0.2026, p<0.0001); and strongly associated with staging of conjunctival impression cytology (r= -0.7694, p<0.0001). Pearson's correlation analysis indicated that, LWE staining score was moderately associated with age (r=0.4165, p<0.0001), tear meniscus height (r=0 -0.4019, p<0.0001), and NIKBUT-first (noninvasive keratography tear film breakup time) (r= -0.5108, p<0.0001); and strongly associated with NIKBUT-average (r= -0.7820, p<0.0001) and ocular staining score (r=0.6113, p<0.00001). Some patients presented abnormal blinking. We observed deeper lesion depths and more holes and fissures in the lid wipers of patients with more severe LWE than in patients with milder LWE.

CONCLUSIONS

Abnormal friction factors caused by insufficient lubrication between the lid wiper area and the ocular surface seem to influence the development and/or the severity of LWE. Aggravation of LWE further increases the frictional damage between the lid wiper and the ocular surface.

Greenhouse gas emission mitigation potential from municipal solid waste treatment: A combined SD-LMDI model

Fast urbanization and economic prosperity generate huge amount of municipal solid waste (MSW). It is therefore critical to identify the determinants of greenhouse gas (GHG) emissions from MSW treatment and prepare potential GHG mitigation measures. A combined System Dynamics - Logarithmic Mean Divisia Index model is developed to identify the driving forces of GHG emission generated from MSW treatment and explore the mitigation potentials. Shanghai, a typical megacity in China is selected as a case study. Results showed that economic development, population scale and emission intensity were driving forces to induce GHG emissions from MSW treatment, while generation intensity and treatment structure were the factors to mitigate GHG emissions from MSW during 2000-2017. Scenario analysis further revealed that landfill gas utilization and MSW separation improvement were the most effective measures in reducing GHG emissions from MSW treatment, leading to about 88.07% and 85.48% of reduction compared with the business-as-usual scenario in 2050. Scenarios of improving incineration rate, reducing per capita MSW generation and restricting population growth will reduce GHG emissions by 72.29%, 30.06% and 0.30%, respectively. Utilizing landfill gas, improving MSW separation and promoting green behaviors are suggested to mitigate GHG emissions from MSW treatment.

Correction: Analysis of the effects of acoustic levitation to simulate the microgravity environment on the development of early zebrafish embryos

Correction for ‘Analysis of the effects of acoustic levitation to simulate the microgravity environment on the development of early zebrafish embryos’ by Li Li et al., RSC Adv., 2020, 10, 44593–44600, DOI: 10.1039/D0RA07344J.

Comparative genome-wide methylation analysis of longissimus dorsi muscles in Yorkshire and Wannanhua pigs

DNA methylation was one of the earliest discovered epigenetic modifications in vertebrates, and is an important epigenetic mechanism involved in the expression of genes in many biological processes, including muscle growth and development. Its effects on economically important traits are evidenced in reported differences in meat quality traits between Chinese indigenous pig breeds (Wannanhua pig) and Western commercial pig breeds (Yorkshire pig), and this presents a unique model for analyzing the effects of DNA methylation on these traits. In the present study, a whole genome DNA methylation analysis was performed on the two breeds using methylated DNA immunoprecipitation. GO functional enrichment and pathway enrichment analyses identified differentially methylated genes primarily associated with fatty acid metabolism, biological processes of muscle development and signaling pathways related to muscle development and pork quality. Differentially methylated genes were verified by sodium pyrosequencing, and the results were consistent with the sequencing results. The results of the integrative analysis between DNA methylation and gene expression revealed that the DNA methylation levels showed a significantly negative correlation with gene expression levels around the transcription start site of genes. In total, 41 genes were both differentially expressed and methylated; these genes were related to fat metabolism, lipid metabolism and skeletal muscle development. This study could help further explore the molecular mechanisms and phenotypic differences in pig growth and development among different breeds.

DLSR: a solution to the parallax artefact in X-ray diffraction computed tomography data

A new tomographic reconstruction algorithm is presented, termed direct least-squares reconstruction (DLSR), which solves the well known parallax problem in X-ray-scattering-based experiments. The parallax artefact arises from relatively large samples where X-rays, scattered from a scattering angle 2θ, arrive at multiple detector elements. This phenomenon leads to loss of physico-chemical information associated with diffraction peak shape and position (i.e. altering the calculated crystallite size and lattice parameter values, respectively) and is currently the major barrier to investigating samples and devices at the centimetre level (scale-up problem). The accuracy of the DLSR algorithm has been tested against simulated and experimental X-ray diffraction computed tomography data using the TOPAS software.

An overview of the municipal solid waste management modes and innovations in Shanghai, China

Municipal solid waste (MSW) management and recycling has become an emerging issue in developing countries. Shanghai, the largest megacity in China, is well-known nationwide due to leading China's MSW separation and recycling. Therefore, this paper introduces the Shanghai mode for MSW management and its current situation to enrich existing MSW management studies. Results show that the total generation volume of MSW and amount of MSW generation per capita were 9.00 million tons and 372.16 kg in 2017, increased approximately eight-fold and four-fold compared with the data in 1978, respectively. The MSW treatment rate reached 100% since 2014, with incineration rate increased to 48.56% in 2017. The cost of MSW management after implementing MSW sorting regulation is increased to 985 CNY/ton, including 390 CNY/ton of MSW sorting cost. Then three key features and innovative MSW management modes, namely, mandatory MSW sorting legislation, Green Account program, and the Combined Network program are introduced. Meanwhile, two main challenges are urgent to be responded, including inadequate collecting vehicles and limited wet waste treatment capacity. Finally, policy recommendations on strengthening MSW recycling process, constructing complete terminal treatment industry, and making systematic policies were provided to respond existing challenges.

[Research progress of non-alcoholic fatty liver disease in postmenopausal women]

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease with a risk of developing non-alcoholic hepatitis, cirrhosis and liver cancer. Postmenopausal women have an increased risk of developing metabolic diseases including NAFLD under the influence of various factors such as aging, endocrine and metabolic changes. This article summarizes the latest research of NAFLD in postmenopausal women to elaborate and analyze the epidemiological characteristics, correlation between NAFLD and postmenopause, possible pathogenesis as well as feasible prevention and treatment methods.

Hollow Plasma Acceleration Driven by a Relativistic Reflected Hollow Laser

In order to address the present difficulty in experimentally generating the relativistic Laguerre-Gaussian laser, primarily due to damage caused to optical modulators, a high-reflectivity phase mirror is applied in the femtosecond petawatt laser system to generate a relativistic hollow laser at the highest intensity of 6.3×10^{19}  W/cm^{2} for the first time. A simple optical model is used to verify that the vortex laser may be generated in this new scheme; using such a relativistic vortex laser, the hollow plasma drill and acceleration are achieved experimentally and proven by particle-in-cell simulations. With the development of the petawatt laser, this scheme opens up possibilities for the convenient production of the relativistic hollow laser at high repetition and possible hollow plasma acceleration, which is important for a wide range of applications such as the generation of radiation sources with orbital angular momentum, fast ignition for inertial confinement fusion, and jet research in the astrophysical environment.

[The phenotypes and genotypes in 314 patients with isolated methylmalonic acidemia]

Objectives: To summarize the clinical and genetic characteristics of the patients with isolated methylmalonic acidemia and investigate the strategies for the diagnosis, treatment and prevention. Methods: Three hundred and fourteen patients (180 males, 134 females) with isolated methylmalonic acidemia were ascertained from 26 provinces or cities across the mainland of China during January 1998 to March 2020. Genetic analysis was performed by Sanger sequencing, gene panel sequencing, whole exome sequencing, multiplex ligation-dependent probe amplification or quantitative PCR. According to the age of onset, the patients were divided to early-onset group (≤12 months of age) and the late-onset group (>12 months of age). They were treated by cobalamin, L-carnitine and (or) special diet and symptomatic treatment. Statistical analysis was done using Chi-square test. Results: Fifty-eight of 314 (18.5%) patients were detected by Newborn screening using liquid chromatography tandem mass spectrometry. Five cases (1.6%) had a postmortem diagnosis. Two hundred and fifty-one patients (79.9%) were clinically diagnosed with an age of onset ranged from 3 hours after birth to 18 years. One hundred and fifty-nine patients (71.0%) belonged to early-onset groups, 65 patients (29.0%) belonged to the late-onset group. The most common symptoms were metabolic crises, psychomotor retardation, epilepsy, anemia and multiple organ damage. Metabolic acidosis and anemia were more common in early-onset patients than that in late-onset patients (20.8%(33/159) vs. 9.2% (6/65), 34.6% (55/159) vs. 16.9% (11/165), χ(2)=4.261, 6.930, P=0.039, 0.008). Genetic tests were performed for 236 patients (75.2%), 96.2%(227/236) had molecular confirmation. One hundred and twenty-seven variants were identified in seven genes (MMUT, MMAA, MMAB, MMADHC, SUCLG1, SUCLA2, and MCEE), of which 49 were novel. The mut type, caused by the deficiency of methylmalonyl-CoA mutase, was the most common (n=211, 93%) cause of this condition. c.729_730insTT, c.1106G>A and c.914T>C were the three most frequent mutations in MMUT gene. The frequency of c.914T>C in early-onset patients was significantly higher than that in late-onset patients (8.3% (18/216) vs. 1.6% (1/64), χ(2)=3.859, P=0.037). Metabolic crisis was more frequent in mut type than the other types (72.6% (114/157) vs. 3/13, χ(2)=13.729, P=0.001),developmental delay and hypotonia were less frequent in mut type (38.2% (60/157) vs. 9/13, 25.5% (40/157) vs. 8/13, χ(2)=4.789, 7.705, P=0.030, 0.006). Of the 58 patients identified by newborn screening, 44 patients (75.9%) who were treated from asymptomatic phase developed normally whereas 14 patients (24.1%) who received treatment after developing symptoms exhibited varying degrees of psychomotor retardation. Conclusions: The characteristics of phenotypes and genotypes among Chinese patients with isolated methylmalonic acidemia were analyzed. Expanded the mutation spectrum of the associated genes. Because of the complex clinical manifestations and severe early onset of isolated methylmalonic acidemia, Newborn screening is crucial for early diagnosis and improvement of prognosis. MMUT gene is recommended for carrier screening as an effort to move the test earlier as a part of the primary prevention of birth defects.

Ultrasound-assisted cyanide extraction of gold from gold concentrate at low temperature

A sonochemical reactor was developed to study the ultrasound-assisted cyanide extraction of gold from gold ore at low temperature. The effects of ultrasound on gold leaching in low temperature and conventional conditions were investigated. At the low temperature of 10 °C, ultrasound-assisted extraction increased extraction rate of gold by 0.6%-0.8% and reduced the gold content of cyanide tailings to 0.28 g/t in the leaching of gold concentrate and cyanide tailings, respectively. At the conventional temperature of 25 °C, ultrasound-assisted extraction obtained a 0.1% higher extraction rate of gold compared with conventional extraction, with the unit consumption of NaCN reduction of 15%. The analysis of kinetic model also demonstrated that sonication indeed improved the reaction of gold leaching greatly. The mineralogy and morphology of ore were further analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and particle size analyzer to explore the strengthening mechanism of gold leaching. The results showed that the ore particles were smashed, the ore particle surface was peeled, the passive film was destroyed and the reaction resistance decreased under ultrasonic processing. Therefore, the extraction rate of gold was improved and the extraction time was shortened significantly in ultrasound-assisted cyanide extraction.

Grey water footprint evaluation and driving force analysis of eight economic regions in China

The grey water footprint (GWF) can be used to connect wastewater quality and quantity, making it a powerful tool for policy makers and those responsible for managing wastewater systems. As a supplementary to existing GWF research, this study explores the GWF evolution of eight economic regions in China by taking into consideration the GWF of livestock feeding. In addition, we use the logarithmic mean division index method to study the background driving forces of GWF in primary industry for eight economic regions. Results show that the overall GWF in China fluctuates from 6082 billion m³ to 6238 billion m³ between the years 2003 and 2015. Primary industry contributes most to the GWF because of livestock feeding, particularly for the northwest economic region, accounting for 84.81% in 2015. The southwest economic region has the highest total GWF, and east coast region has the lowest total GWF. An analysis of driving forces shows that economic scale and industrial structure are the driving forces that best explain the GWF for the East coast, middle of Yellow River, Northwest, and Southwest economic regions. The effects of economic scale and pollution producing intensity are driving the GWF in the Northeast Regions. For the North coast and middle Yangtze River Regions, economic scale, industrial structure, and pollution producing intensity are driving forces for GWF. While for the South coast region, population is an important contributor apart from economic scale and industrial structure. Policy implications from perspective of the agriculture GWF and endowment of different regions were finally discussed.

Behavioural, social and structural-level risk factors for developing AIDS among HIV-positive people who use injection drugs in a Canadian setting, 1996-2017

People who use injection drugs (PWID) experience high rates of HIV acquisition and, as a result of lower rates of optimal access and adherence to combination antiretroviral therapy (ART), experience worse HIV treatment outcomes than other key affected populations. However, the incidence and risk factors for the development of AIDS among HIV-positive PWID have not been completely described. We used data from a community-recruited prospective cohort of HIV-positive PWID in Vancouver, Canada, a setting with universal no-cost ART and a comprehensive clinical monitoring registry. We used multivariable extended Cox models to identify factors associated with time to AIDS. Between 1996 and 2017, 396 participants, including 140 (35.4%) women, were followed for a median of 39.0 months (interquartile range: 16.6-76.2), among whom 165 (41.7%) developed AIDS. In a multivariable model, homelessness (Adjusted Hazard Ratio [AHR] = 1.76 (1.18-2.61)) and injection drug use within the preceding six months (AHR = 1.74 (1.17-2.58)) were independently associated with a higher risk of developing AIDS. Despite widespread scale-up of programmes to improve ART utilization, significant risk factors for the development of AIDS remain among HIV-positive PWID in this setting.

[Mechanism of transcriptional regulation of Meox1 by transforming growth factor β (1) and its effect on cell migration of adult human dermal fibroblasts]

Objective: To explore the transcriptional regulation mechanism of transforming growth factor β(1) (TGF-β(1)) on Meox1 and its effect on cell migration of adult human dermal fibroblasts (HDF-a). Methods: (1) HDF-a cells were cultured in RPMI 1640 complete medium (hereinafter referred to as routinely cultured). The cells were divided into TGF-β(1) stimulation group and blank control group. The cells in TGF-β(1) stimulation group were stimulated with 10 μL TGF-β(1) in the mass concentration of 1 mg/μL, while the cells in blank control group were stimulated with the equal volume of phosphate buffer solution. After 72 hours in culture, partial cells in both groups were collected for transcriptome sequencing. The genes with differential expression ratio greater than or equal to 2 and P<0.01 between the two groups were selected to perform enrichment analysis and analysis of metabolic pathways of the Kyoto Gene and Genome Encyclopedia with, and the expression value of Meox1 per million transcripts (TPM) was recorded (n=3). Partial cells from the two groups were used to detect the Meox1 mRNA expression by real-time fluorescent quantitative reverse transcription polymerase chain reaction (RT-PCR) (n=3). (2) Cultured HDF-a cells in the logarithmic growth phase (the same growth phase of cells below) were divided into empty plasmid group, Smad2 overexpression (OE) group, Smad3 OE group, and Smad4 OE group, which were transfected respectively with 2 μg empty pcDNA3.1 plasmid and pcDNA3.1 plasmids separately carrying Smad2, Smad3, and Smad4 for 6 hours, and then were routinely cultured for 48 hours. The Meox1 mRNA expression in the transfected cells of each group was detected by real-time fluorescent quantitative RT-PCR (n=3). (3) HDF-a cells were routinely cultured and grouped the same as in experiment (1). After 72 hours in culture, the enrichment of Smad2, Smad3, and Smad4 protein on the Meox1 promoter in the cells of each group was detected by chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) (n=3). (4) HDF-a cells were routinely cultured and divided into negative interference group, small interference RNA (siRNA)-Smad2 group, siRNA-Smad3 group, siRNA-Smad4 group, empty plasmid group, Smad2 OE group, Smad3 OE group, and Smad4 OE group, which were transfected respectively with 50 μmol/L random siRNA, siRNA-Smad2, siRNA-Smad3, siRNA-Smad4, 2 μg empty pcDNA3.1 plasmid and pcDNA3.1 plasmids separately carrying Smad2, Smad3, and Smad4 for 6 hours and then routinely cultured for 48 hours. The enrichment of Smad2, Smad3, and Smad4 protein on the Meox1 promoter in the cells of corresponding group was detected by ChIP-qPCR (n=3). (5) Two batches of HDF-a cells were cultured and divided into negative interference group, siRNA-Meox1 group, empty plasmid group, and Meox1 OE group, which were transfected respectively with 50 μmol/L random siRNA, siRNA-Meox1, 2 μg empty pcDNA3.1 plasmid and pcDNA3.1 plasmid carrying Meox1 for 6 hours and then routinely cultured for 24 hours. One batch of cells were subjected to scratch test with the scratch width being observed 24 hours after scratching and compared with the initial width for scratch wound healing; the other batch of cells were subjected to Transwell assay, in which the migrated cells were counted after being routinely cultured for 24 hours (n=3). (6) From January 2018 to June 2019, 3 hypertrophic scar patients (2 males and 1 female, aged 35-56 years) were admitted to the First Affiliated Hospital of Army Medical University (the Third Military Medical University) 8-12 months after burns. The scar tissue and normal skin tissue along the scar margin resected during surgery were taken, and immunohistochemical staining was performed to observe the distribution of Meox1 protein expression. Data were statistically analyzed with one-way analysis of variance and independent sample t test. Results: (1) After 72 hours in culture, a total of 843 genes were obviously differentially expressed between the two groups, being related to tissue repair, cell migration, inflammatory cell chemotaxis induction process and potential signaling pathways such as tumor necrosis factor, interleukin 17, extracellular matrix receptor. The TPM value of Meox1 in the cells of blank control group was 45.9±1.9, which was significantly lower than 163.1±29.5 of TGF-β(1) stimulation group (t=6.88, P<0.01) with RNA-sequencing. After 72 hours in culture, the Meox1 mRNA expression levels in the cells of blank control group was 1.00±0.21, which was significantly lower than 11.00±3.61 of TGF-β(1) stimulation group (t=4.79, P<0.01). (2) After 48 hours in culture, the Meox1 mRNA expression levels in the cells of Smad2 OE group, Smad3 OE group, and Smad4 OE group were 198.70±11.02, 35.47±4.30, 20.27±2.50, respectively, which were significantly higher than 1.03±0.19 of empty plasmid group (t=31.07, 13.80, 13.12, P<0.01). (3) After 72 hours in culture, the enrichment of Smad2, Smad3, and Smad4 protein on the promoter of Meox1 in the cells of TGF-β(1) stimulation group was significantly higher than that of blank control group respectively (t=12.99, 41.47, 29.10, P<0.01). (4) After 48 hours in culture, the enrichment of Smad2 protein on the promoter of Meox1 in the cells of negative interference group was (0.200 000±0.030 000)%, significantly higher than (0.000 770±0.000 013)% of siRNA-Smad2 group (t=11.67, P<0.01); the enrichment of Smad2 protein on the promoter of Meox1 in the cells of empty plasmid group was (0.200 000±0.040 000)%, significantly lower than (0.700 000±0.090 000)% of Smad2 OE group (t=8.85, P<0.01). The enrichment of Smad3 protein on the promoter of Meox1 in the cells of negative interference group was (0.500 0±0.041 3)%, significantly higher than (0.006 0±0.001 3)% of siRNA-Smad3 group (t=17.79, P<0.01); the enrichment of Smad3 protein on the promoter of Meox1 in the cells of empty plasmid group was (0.470 0±0.080 0)%, which was significantly lower than (1.100 0±0.070 0)% of Smad3 OE group (t=9.93, P<0.01). The enrichment of Smad4 protein on the promoter of Meox1 in the cells of negative interference group was similar to that of siRNA-Smad4 group (t=2.11, P>0.05); the enrichment of Smad4 protein on the promoter of Meox1 in the cells of empty plasmid group was similar to that of Smad4 OE group (t=0.60, P>0.05). (5) Twenty-four hours after scratching, the scratch healing width of cells in siRNA-Meox1 group was narrower than that of negative interference group, while that of Meox1 OE group was wider than that of empty plasmid group. After 24 hours in culture, the number of migration cells in negative interference group was significantly higher than that in siRNA-Meox1 group (t=9.12, P<0.01), and that in empty plasmid group was significantly lower than that in Meox1 OE group (t=8.99, P<0.01). (6) The expression of Meox1 protein in the scar tissue was significantly higher than that in normal skin of patients with hypertrophic scars. Conclusions: TGF-β(1) transcriptionally regulates Meox1 expression via Smad2/3 in HDF-a cells, thus promoting cell migration.

Towed Overhauser marine magnetometer for weak magnetic anomaly detection in severe ocean conditions

A towed Overhauser marine geomagnetic magnetometer used for weak magnetic anomaly detection in severe ocean conditions is studied to investigate means to reduce the negative effect of dynamic behavior and magnetic noise associated with ocean waves. For the dynamic effect, a continuous polarization workflow is proposed to enhance the free-induction-decay signal, and then, a multi-angle pickup coil and a self-tracking programmable amplifier are used to further reduce the adverse effect caused by uncontrollable changes in the towfish attitude on the signal quality. Furthermore, to achieve adaptive suppression of magnetic noise in different ocean conditions and areas, a modified adaptive Kalman algorithm is assessed. In addition, an optimized Overhauser sensor and a towfish were developed. Overall, the experimental results show that the sensor can effectively suppress the dynamic effect and magnetic noise. Regarding the magnetic sensitivity, uncertainty and range are 12 pT/Hz^1/2@1Hz and 0.21 nT and 20 000 nT-100 000 nT, respectively. Moreover, underwater testing was performed to verify the function and the detection of the magnetic anomaly.