Host density is a key regulatory factor in parasite transmission. The goldfish (Carassius auratus)-Gyrodactylus kobayashii model was used to investigate effects of host density on population growth of gyrodactylids. A donor fish infected by five gravid gyrodactylids was mixed with 11 parasite-free goldfish at five host densities. There was a significant positive correlation between host density and mean abundance of G. kobayashii throughout the 58-day experiment. During early infection (days 15–24), mean abundance in medium high (0.5 fish L−1) and high host density groups (1 and 2 fish L−1) was significantly higher than that in the low host density groups (0.125 and 0.25 fish L−1). At high host density, prevalence increased more rapidly, and the peak prevalence was higher. Fitting of an exponential growth model showed that the population growth rate of the parasite increased with host density. A hypothesis was proposed that higher host density contributed to increased reinfection of detached gyrodactylids. A reinfection experiment was designed to test this hypothesis. Both mean abundance and prevalence at a host density of 1 fish L−1 were significantly higher than those at 0.25 fish L−1 on days 1 and 3, which suggested that more reinfections of G. kobyashii occurred at the higher host density. Density-dependent transmission during the early infection was an important contributor of population growth of G. kobayashii, as well as density-dependent reinfection of the detached gyrodactylids.

Sarcopenic obesity is regarded as a risk factor for the progression and development of non-alcoholic fatty liver disease (NAFLD). Since male sex is a risk factor for NAFLD and skeletal muscle mass markedly varies between the sexes, we examined whether sex influences the association between appendicular skeletal muscle mass to visceral fat area ratio (SVR), that is, an index of skeletal muscle mass combined with abdominal obesity, and the histological severity of NAFLD. The SVR was measured by bioelectrical impedance in a cohort of 613 (M/F = 443/170) Chinese middle-aged individuals with biopsy-proven NAFLD. Multivariable logistic regression and subgroup analyses were used to test the association between SVR and the severity of NAFLD (i.e. non-alcoholic steatohepatitis (NASH) or NASH with the presence of any stage of liver fibrosis). NASH was identified by a NAFLD activity score ≥5, with a minimum score of 1 for each of its categories. The presence of fibrosis was classified as having a histological stage ≥1. The SVR was inversely associated with NASH in men (adjusted OR 0·62; 95 % CI 0·42, 0·92, P = 0·017 for NASH, adjusted OR 0·65; 95 % CI 0·43, 0·99, P = 0·043 for NASH with the presence of fibrosis), but not in women (1·47 (95 % CI 0·76, 2·83), P = 0·25 for NASH, and 1·45 (95 % CI 0·74, 2·83), P = 0·28 for NASH with the presence of fibrosis). There was a significant interaction for sex and SVR (Pinteraction = 0·017 for NASH and Pinteraction = 0·033 for NASH with the presence of fibrosis). Our findings show that lower skeletal muscle mass combined with abdominal obesity is strongly associated with the presence of NASH only in men.

Steam jet milling was applied for the first time to ultra-fine grind the filter cake (moisture content 23.80%) produced by a kaolin concentrator. The material was dehydrated and dried simultaneously during grinding, and the final ground sample met the moisture content requirement for powder products of <2%. The particle size of the ground kaolin samples decreased and the particle-size distribution was more concentrated, indicating that the steam jet milling was more effective for kaolin processing than the conventional dry grinding process. In addition, steam jet milling can improve the whiteness and decrease the crystal order of the samples, thus improving the kaolin properties in follow-up applications.

In glaciology, snow–firn temperature at 10 m is considered a representation of the mean annual air temperature at the surface (MAAT) of the studied site. Although MAAT is an important parameter in ice-sheet investigations, it has not been widely measured in Antarctica. To measure the 10 m snow–firn temperature in Antarctica, a shallow hot-point drill system is designed. In this simple and lightweight system, a hot-point drill can melt boreholes with a diameter of 34 mm in the snow–firn to a depth of 30 m and a temperature sensors string can measure the borehole temperature precisely. In the 2018/19 field season, 16 boreholes along the Zhongshan–Dome A traverse were drilled, and the borehole temperature was measured. Although certain problems existed pertaining to the hot-point drill, a total depth of ~244 m was successfully drilled at an average penetration rate of ~10 m h−1. After borehole drilling, ~12–15 h were generally required for the borehole to achieve thermal equilibrium with the surroundings. Preliminary results demonstrated that the 10 m snow–firn temperature along the traverse route was affected by the increasing altitude and latitude, and it decreased gradually with an increase in the distance from Zhongshan station.

Drug-induced liver injury (DILI) is a common adverse drug reaction leading to the interruption of tuberculosis (TB) therapy. We aimed to identify whether the hepatitis B virus (HBV) infection would increase the risk of DILI during first-line TB treatment. A meta-analysis of cohort studies searched in PubMed, Web of Science and China National Knowledge Infrastructure was conducted. Effect sizes were reported as risk ratios (RRs) and 95% confidence intervals (CIs) and calculated by R software. Sixteen studies with 3960 TB patients were eligible for analysis. The risk of DILI appeared to be higher in TB patients co-infected with HBV (RR 2.66; 95% CI 2.13–3.32) than those without HBV infection. Moreover, patients with positive hepatitis B e antigen (HBeAg) were more likely to develop DILI (RR 3.42; 95% CI 1.95–5.98) compared to those with negative HBeAg (RR 2.30; 95% CI 1.66–3.18). Co-infection with HBV was not associated with a higher rate of anti-TB DILI in latent TB patients (RR 4.48; 95% CI 0.80–24.99). The effect of HBV infection on aggravating anti-TB DILI was independent of study participants, whether they were newly diagnosed with TB or not. Besides, TB and HBV co-infection patients had a longer duration of recovery from DILI compared to non-co-infected patients (SMD 2.26; 95% CI 1.87–2.66). To conclude, the results demonstrate that HBV infection would increase the risk of DILI during TB therapy, especially in patients with positive HBeAg, and close liver function monitoring is needed for TB and HBV co-infection patients.

The FNDC5 gene encodes the fibronectin type III domain-containing protein 5 that is a membrane protein mainly expressed in skeletal muscle, and the FNDC5 rs3480 polymorphism may be associated with liver disease severity in non-alcoholic fatty liver disease (NAFLD). We investigated the influence of the FNDC5 rs3480 polymorphism on the relationship between sarcopenia and the histological severity of NAFLD. A total of 370 adult individuals with biopsy-proven NAFLD were studied. The association between the key exposure sarcopenia and the outcome liver histological severity was investigated by binary logistic regression. Stratified analyses were undertaken to examine the impact of FNDC5 rs3480 polymorphism on the association between sarcopenia and the severity of NAFLD histology. Patients with sarcopenia had more severe histological grades of steatosis and a higher prevalence of significant fibrosis and definite non-alcoholic steatohepatitis than those without sarcopenia. There was a significant association between sarcopenia and significant fibrosis (adjusted OR 2·79, 95 % CI 1·31, 5·95, P = 0·008), independent of established risk factors and potential confounders. Among patients with sarcopenia, significant fibrosis occurred more frequently in the rs3480 AA genotype carriers than in those carrying the FNDC5 rs3480 G genotype (43·8 v. 17·2 %, P = 0·031). In the association between sarcopenia and liver fibrosis, there was a significant interaction between the FNDC5 genotype and sarcopenia status (P value for interaction = 0·006). Sarcopenia is independently associated with significant liver fibrosis, and the FNDC5 rs3480 G variant influences the association between sarcopenia and liver fibrosis in patients with biopsy-proven NAFLD.

Sugarcane brown rust, caused by Puccinia melanocephala, is one of the main diseases of sugarcane in China. The identification and discovery of new resistance genes have important theoretical and practical significance for preventing outbreaks of brown rust and ensuring the sustainable production of sugarcane. To screen for polymorphic simple-sequence repeat (SSR) molecular markers for localization of brown rust resistance genes, we used two populations that are suitable for genetic linkage map construction and mapping of new resistance genes to construct resistant and susceptible genetic pools. We then screened 449 pairs of primers to identify polymorphic SSR markers in the parental lines and the resistant/susceptible genetic pools. The results showed that 25 pairs of primers directed amplification of polymorphic DNA fragments between the parents of the cross combination ‘Yuetang 03-393’ × ‘ROC 24’, and 16 pairs of primers amplified polymorphic fragments between the parents of the cross combination ‘Liucheng 03-1137’ × ‘Dezhe 93-88’. Four pairs of primers (SMC236CG, SCESSR0928, SCESSR0636 and SCESSR2551) amplified polymorphic DNA fragments between the parental lines and the resistant/susceptible genetic pools in ‘Yuetang 03-393’ × ‘ROC 24’. The results of this study will establish a solid foundation for the mapping of new brown rust resistance genes, genetic linkage map construction and the development of closely-associated molecular markers in sugarcane.

For a wide range of insect species, the microbiota has potential roles in determining host developmental programme, immunity and reproductive biology. The tea geometrid moths Ectropis obliqua and E. grisescens are two closely related species that mainly feed on tea leaves. Although they can mate, infertile hybrids are produced. Therefore, these species provide a pair of model species for studying the molecular mechanisms of microbiotal involvement in host reproductive biology. In this study, we first identified and compared the compositions of microbiota between these sibling species, revealing higher microbiotal diversity for E. grisescens. The microbiota of E. obliqua mainly comprised the phyla Firmicutes, Proteobacteria and Cyanobacteria, whereas that of E. grisescens was dominated by Proteobacteria, Actinobacteria and Firmicutes. At the genus level, the dominant microbiota of E. grisescens included Wolbachia, Enterobacter and Pseudomonas and that of E. obliqua included Melissococcus, Staphylococcus and Enterobacter. Furthermore, we verified the rate of Wolbachia to infect 80 samples from eight different geographical populations, and the results supported that only E. grisescens harboured Wolbachia. Taken together, our findings indicate significantly different microbiotal compositions for E. obliqua and E. grisescens, with Wolbachia possibly being a curial factor influencing the reproductive isolation of these species. This study provides new insight into the mechanisms by which endosymbiotic bacteria, particularly Wolbachia, interact with sibling species.

The Antarctic subglacial drilling rig (ASDR) is designed to recover 105 mm-diameter ice cores up to 1400 m depth and 41.5 mm-diameter bedrock cores up to 2 m in length. In order to ensure safe and convenient drilling, drilling auxiliaries are designed to support fieldwork and servicing. These auxiliaries are subdivided into several systems for power supply, drill tripping in the borehole, ice core and chip processing, and drill servicing and maintenance. The required equipment also includes two generators, a drilling winch with a cable, logging winch with a cable, control desk, pipe handler with a fixed clamp, chip chamber vibrator, centrifuge, emergency devices and fitting and electrical tools. Additionally, several environmental protective measures such as a new liquid-tight casing with a thermal casing shoe and a bailing device for recovering drilling fluid from the borehole were designed. Most of the auxiliaries were tested during the summer of 2018–2019 near Zhongshan Station, East Antarctica while drilling to the bedrock to a depth of 198 m.

A new, modified version of the cable-suspended Ice and Bedrock Electromechanical Drill (IBED) was designed for drilling in firn, ice, debris-rich ice and rock. The upper part of the drill is almost the same for all drill variants and comprises four sections: cable termination, a slip-ring section, an antitorque system and an electronic pressure chamber. The lower part of the IBED comprises an auger core barrel, reamers, a core barrel for ice/debris-ice drilling and a conventional geological single-tube core barrel or custom-made double-tube core barrel. First, the short and full-scale field versions of the IBED were tested at an outdoor testing stand and a testing facility with a 12.5 m-deep ice well. Then, in the 2018–2019 summer season, the IBED was tested in the field at a site ~12 km south of Zhongshan Station, East Antarctica, and a ~6 cm bedrock core was recovered from a 198 m-deep borehole. A total of 18 d was required to penetrate the ice sheet. The retrieved core samples of blue ice, basal ice and bedrock provided valuable information regarding the Earth's paleo-environment.

Cruciferous vegetables contain high levels of glucosinolates (GSL) and isothiocyanates (ITC). ITC are known to induce glutathione S-transferases (GST) and thus exert their anticarcinogenic effects. This study explored the combined effects of cruciferous vegetable, GSL and ITC intake and GST polymorphisms on breast cancer risk. A total of 737 breast cancer cases and 756 controls were recruited into this case–control study. OR and 95 % CI were assessed by multivariable logistic regression. Higher cruciferous vegetable, GSL and ITC intakes were inversely associated with breast cancer risk, with adjusted OR of 0·48 (95 % CI 0·35, 0·65), 0·54 (95 % CI 0·40, 0·74) and 0·62 (95 % CI 0·45, 0·84), respectively. Compared with women carrying the GSTP1 rs1695 wild AA genotype and high cruciferous vegetable, GSL or ITC intake, carriers of the AA genotype with low cruciferous vegetable, GSL and ITC intake had greater risk of breast cancer, with adjusted OR of 1·43 (95 % CI 1·01, 1·87), 1·34 (95 % CI 1·02, 1·75) and 1·37 (95 % CI 1·05, 1·80), respectively. Persons with the GSTM1-null genotype and lower intake of cruciferous vegetables, GSL and ITC had higher risk of breast cancer than those with the GSTM1-present genotype and higher intake, with OR of 1·42 (95 % CI 1·04, 1·95), 1·43 (95 % CI 1·05, 1·96) and 1·45 (95 % CI 1·06, 1·98), respectively. Among women possessing the GSTT1-present genotype, low intake of cruciferous vegetables, GSL or ITC was associated with higher risk of breast cancer. But these interactions were non-significant. This study indicated that there were no significant interactions between cruciferous vegetable, GSL or ITC intake and GST polymorphisms on breast cancer risk.

B vitamins (including folate, vitamin B2, vitamin B6 and vitamin B12) and methionine are essential for methylation reactions, nucleotide synthesis, DNA stability and DNA repair. However, epidemiological evidence among Chinese populations is limited. The objective of this study was to evaluate B vitamins and methionine in relation to colorectal cancer risk in a Chinese population. A case–control study was conducted from July 2010 to April 2019. A total of 2502 patients with colorectal cancer were recruited along with 2538 age- (5-year interval) and sex-matched controls. Dietary data were collected using a validated FFQ. Multivariable logistic regression was used to assess OR and 95 % CI. The intake of folate, vitamin B2, vitamin B6 and vitamin B12 was inversely associated with colorectal cancer risk. The multivariable OR for the highest quartile v. the lowest quartile were 0·62 (95 % CI 0·51, 0·74; Ptrend < 0·001) for folate, 0·46 (95 % CI 0·38, 0·55; Ptrend < 0·001) for vitamin B2, 0·55 (95 % CI 0·46, 0·76; Ptrend < 0·001) for vitamin B6 and 0·72 (95 % CI 0·60, 0·86; Ptrend < 0·001) for vitamin B12. No statistically significant association was found between methionine intake and colorectal cancer risk. Stratified analysis by sex showed that the inverse associations between vitamin B12 and methionine intake and colorectal cancer risk were found only among women. This study indicated that higher intake of folate, vitamin B2, vitamin B6 and vitamin B12 was associated with decreased risk of colorectal cancer in a Chinese population.

The effects of dietary vitamin D, Ca and dairy products intakes on colorectal cancer risk remain controversial. The present study investigated the association between these dietary intakes and the risk of colorectal cancer in Guangdong, China. From July 2010 to December 2018, 2380 patients with colorectal cancer and 2389 sex- and age-matched controls were recruited. Dietary intake data were collected through face-to-face interviews using a validated FFQ. Unconditional multivariable logistic regression models were used to calculate the OR and 95 % CI after adjusting for various confounders. Higher dietary vitamin D and Ca intakes were associated with 43 and 52 % reductions in colorectal cancer risk, with OR of 0·57 (95 % CI 0·46, 0·70) and 0·48 (95 % CI 0·39, 0·61), respectively, for the highest quartile (v. the lowest quartile) intakes. A statistically significant inverse association was observed between total dairy product intake and colorectal cancer risk, with an adjusted OR of 0·32 (95 % CI 0·27, 0·39) for the highest v. the lowest tertile. Subjects who drank milk had a 48 % lower risk of colorectal cancer than those who did not (OR 0·52, 95 % CI 0·45, 0·59). The inverse associations of dietary vitamin D, Ca, total dairy products and milk intakes with the risk of colorectal cancer were independent of sex and cancer site. Our study supports the protective effects of high dietary vitamin D, Ca and dairy products intakes against colorectal cancer in a Chinese population.

The present study was conducted to evaluate the effects of glucose, soya oil or glutamine on jejunal morphology, protein metabolism and protein expression of the mammalian target of rapamycin complex 1 (mTORC1) signalling pathway in jejunal villus or crypt compartment of piglets. Forty-two 21 d-weaned piglets were randomly allotted to one of the three isoenergetic diets formulated with glucose, soya oil or glutamine for 28 d. On day 14 or 28, the proteins in crypt enterocytes were analysed with isobaric tags for relative and absolute quantification and proteins involved in mTORC1 signalling pathway in villus or crypt compartment cells were determined by Western blotting. Our results showed no significant differences (P > 0·05) in jejunal morphology among the three treatments on day 14 or 28. The differentially expressed proteins mainly took part in a few network pathways, including antimicrobial or inflammatory response, cell death and survival, digestive system development and function and carbohydrate metabolism. On day 14 or 28, there were higher protein expression of eukaryotic initiation factor-4E binding protein-1 in jejunal crypt compartment of piglets supplemented with glucose or glutamine compared with soya oil. On day 28, higher protein expression of phosphor-mTOR in crypt compartment was observed in piglets supplemented with glucose compared with the soya oil. In conclusion, the isoenergetic glucose, soya oil or glutamine did not affect the jejunal morphology of piglets; however, they had different effects on the protein metabolism in crypt compartment. Compared with soya oil, glucose or glutamine may be better energy supplies for enterocytes in jejunal crypt compartment.