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To explore if there is association between vitamin D supplementation through cod liver oil ingestion around the periconceptional period and the risk of developing severe CHD in offspring. Furthermore, we would examine the interaction between vitamin D and folic acid supplementation in the association.
A case–control study was conducted in Shanghai Children’s Medical Center, in which, a total of 262 severe CHD cases versus 262 controls were recruited through June 2016 to December 2017. All children were younger than 2 years. To reduce potential selection bias and to minimise confounding effects, propensity score matching was applied.
After propensity score matching, vitamin D supplementation seemed to be associated with decreased odds ratio of severe CHD (odds ratio = 0.666; 95% confidence intervals: 0.449–0.990) in the multivariable conditional logistic analysis. Furthermore, we found an additive interaction between vitamin D and folic acid supplementation (relative excess risk due to interaction = 0.810, 95% confidence intervals: 0.386–1.235) in the association.
The results suggested that maternal vitamin D supplementation could decrease the risk of offspring severe CHD; moreover, it could strengthen the protective effect of folic acid. The significance of this study lies in providing epidemiological evidence that vitamin D supplementation around the periconceptional period could be a potential nutritional intervention strategy to meet the challenge of increasing CHD.
No studies have reported on how to relieve distress or relax in medical health workers while wearing medical protective equipment in coronavirus disease 2019 (COVID-19) pandemic. The study aimed to establish which relaxation technique, among six, is the most feasible in first-line medical health workers wearing medical protective equipment.
This was a two-step study collecting data with online surveys. Step 1: 15 first-line medical health workers were trained to use six different relaxation techniques and reported the two most feasible techniques while wearing medical protective equipment. Step 2: the most two feasible relaxation techniques revealed by step 1 were quantitatively tested in a sample of 65 medical health workers in terms of efficacy, no space limitation, no time limitation, no body position requirement, no environment limitation to be done, easiness to learn, simplicity, convenience, practicality, and acceptance.
Kegel exercise and autogenic relaxation were the most feasible techniques according to step 1. In step 2, Kegel exercise outperformed autogenic relaxation on all the 10 dimensions among the 65 participants while wearing medical protective equipment (efficacy: 24 v. 15, no space limitation: 30 v. 4, no time limitation: 31 v. 4, no body position requirement: 26 v. 4, no environment limitation: 30 v. 11, easiness to learn: 28 v. 5, simplicity: 29 v. 7, convenience: 29 v. 4, practicality: 30 v. 14, acceptance: 32 v. 6).
Kegel exercise seems a promising self-relaxation technique for first-line medical health workers while wearing medical protective equipment among COVID-19 pandemic.
Toxoplasma gondii rhoptry protein TgROP18 is a polymorphic virulence effector that targets immunity-related GTPases (IRGs) in rodents. Given that IRGs are uniquely diversified in rodents and not in other T. gondii intermediate hosts, the role of TgROP18 in manipulating non-rodent cells is unclear. Here we show that in human cells TgROP18I interacts with the interferon-gamma-inducible protein N-myc and STAT interactor (NMI) and that this is a property that is unique to the type I TgROP18 allele. Specifically, when expressed ectopically in mammalian cells only TgROP18I co-immunoprecipitates with NMI in IFN-γ-treated cells, while TgROP18II does not. In parasites expressing TgROP18I or TgROP18II, NMI only co-immunoprecipitates with TgROP18I and this is associated with allele-specific immunolocalization of NMI on the parasitophorous vacuolar membrane (PVM). We also found that TgROP18I reduces NMI association with IFN-γ-activated sequences (GAS) in the IRF1 gene promoter. Finally, we determined that polymorphisms in the C-terminal kinase domain of TgROP18I are required for allele-specific effects on NMI. Together, these data further define new host pathway targeted by TgROP18I and provide the first function driven by allelic differences in the highly polymorphic ROP18 locus.
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 effect of dietary vitamin D, calcium and dairy products intake on colorectal cancer risk is controversial. This study aims to investigate the associations between dietary vitamin D, calcium, dairy products intake and colorectal cancer risk among Chinese population.
Materials and Methods
During July 2010 to December 2018, 2380 incident, first primary, histologically confirmed colorectal cancer cases and 2389 sex and age-matched (5-year interval) controls were recruited. Dietary intake information was collected by face-to-face interviews using a validated food frequency questionnaire. Energy and other nutrient intakes such as dietary calcium were computed on the basis of the 2002 Chinese Food Composition Table, and the dietary vitamin D intake was calculated according to the United States Department of Agriculture Food Composition Database. Unconditional multivariable logistic regression models were used to calculate the odds ratios (ORs) and 95% confidence interval (CI) after adjusting for various confounders, including socio-demographic characteristics, lifestyle factors, BMI, family history of cancer, energy intake and several nutrient intakes.
The energy-adjusted mean dietary vitamin D, calcium and total dairy products intakes were 5.69μg/d, 406.94mg/d, 4.02g/d for cases and 6.81μg/d, 468.21mg/d, 9.50g/d for controls. Compared with the controls, cases had a lower intake of dietary vitamin D, calcium and total dairy (P < 0.001). A higher intake of dietary vitamin D and calcium was found to be associated with 43% and 51% reduction in colorectal cancer. The ORs of the highest quartile compared with the lowest quartile intake were 0.57 (95% CI: 0.46, 0.70, Ptrend < 0.001) for dietary vitamin D and 0.49 (95% CI: 0.39, 0.61, Ptrend < 0.001) for dietary calcium. We observed a statistically significant inverse association of dairy products intake with colorectal cancer risk. Compared with the lowest tertile, the adjusted ORs for the highest tertile were 0.31 (95% CI: 0.26, 0.38, Ptrend < 0.001) for total dairy. The inverse associations of dietary vitamin D, calcium and dairy products intakes with colorectal cancer risk were observed in both men and women, colon and rectal cancer.
Our study indicated that higher dietary vitamin D, calcium and dairy products intakes were associated with a lower colorectal cancer risk.
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.
Personal protective equipment (PPE) is a necessary item in the period of unknown and high-risk emerging infectious disease. It is not only the necessary requirement of strict isolation, but also the last line of defense to protect medical staff.
Compare the differences between contaminated frequency and sites under two types of PPE doffing.
Recruited 56 health care workers (HCWs) who worked in clinical to follow the different PPE removal guidelines issued by the Chinese Center for Disease Control (CDC) and the World Health Organization (WHO) final resolution for preventing Ebola virus. Eight batches of HCWs were divided to conduct simulations of contaminated PPE removal using fluorescent lotion (Glitter Bug Potion, On Solution Pty Lt). Then we recorded the frequency and sites of contamination of personnel after removal of contaminated PPE by the method of visual observation.
According to China’s CDC process, the parts that are easily contaminated during PPE removal are: left hand and wrist (7 times), left calf (7 times), front chest center and left and right chest (6 times each) and left abdomen (5 times). Contaminated parts of the PPE process in accordance with the WHO process from high to low were: right hand and wrist (13 times), left hand and wrist (12 times), middle of the abdomen (10 times), left chest (9 times), and left abdomen (6 Times). There was no statistical difference between the two kinds of PPE piercing and removal (Z=1.177, P > 0. 05).
Under the guidance of the two processes recommended by China CDC and WHO, there was no significant difference in the frequency of pollution after removing PPE. It is speculated that the PPE recommendation processes issued by WHO and China CDC are effective for personal protection against fulminating infectious diseases.
Proper use of personal protective equipment (PPE) is essential when facing emerging infectious diseases. Proper training methods can promote the use of the PPE correctly.
To explore the effect of the training method of sequential operation training on medical staff to master PPE penetration and removal skills, and to study the memory attenuation after training.
Fifteen medical staff with no experience of PPE operation in a hospital were trained to wear PPE in accordance with WHO standards by illustration and sequential operation method. The training included 30 minutes of theoretical teaching and 60 minutes of practical exercises. At the end of the training and 1 week after the training, the training objects were evaluated for PPE operation. A 2.5 x 2.5 cm fluorescent agent was applied on 6 parts, such as hands, chest, abdomen, and knees, to simulate contamination. After taking the PPE off, the parts of the whole body and the inner layer of clothing that were fluorescently contaminated were recorded. The whole operation process was recorded by video to evaluate whether the operation was correct. The error rates of two operations and the contamination position and frequency were compared.
The error rate of the operating PPE after training was 18.6%, rising to 31.9% after 1 week (Z=16.0, P<0.05). After the training, the average number of contaminated PPE removal was 1.96±1.56, which rose to 2.96±2.03 one month later. The difference was statistically significant (Z=8.92, P<0.05). The main vulnerable sites are the wrist, chest, abdomen, and left calf.
Illustrative sequential operation training is an important means to improve the way for medical staff to wear PPE, but it must be completed more than once to ensure that medical staff can firmly master the skills of wearing and removing PPE.
Personal protective equipment (PPE) is a necessary item in the period of unknown and high risk emerging infectious disease. It is not only the necessary requirement of strict isolation but also the last line of defense to protect medical staff.
To determine the frequency and sites of contamination of personnel during the process of using Chinese PPE.
Recruit 56 health care workers (HCWs) who worked in front-line clinical to test PPE issued by the Chinese Center for Disease Control for preventing Ebola virus. Eight batches of HCWs were divided to conduct simulations of contaminated PPE removal using fluorescent lotion. Then the frequency and sites of contamination of personnel were recorded after removal of contaminated PPE. The method of visual observation was used to determine contamination.
The frequency of easily contaminated parts included: left hand and wrist (7 times), left calf (7 times), front chest center, left and right chest (6 times each), and left abdomen (5 times). Mistakes in the process of wearing PPE included: clothing touching the ground (20.00%), N95 air mask tightness not checked (13.33%), glove air-tightness not checked (4.44%), protective clothing zipper not checked (4.44%). Mistakes in doffing PPE included: clothes touching the ground or the inner surface is polluted (20.00%), the wrong method of removing N95 mask (14.44%), touching the pollution goggles mirror with hands (12.22%), incomplete washing steps, insufficient time and frequency of hand hygiene (11.11%).
It is necessary to carry out training on PPE donning and doffing for Chinese medical workers.
Few studies have examined the association of various types of Fe with colorectal cancer risk. The aim of this study was to investigate different forms and sources of Fe in relation to colorectal cancer risk in a Chinese population. A total of 2138 patients with colorectal cancer and 2144 sex- and age-matched (5-year interval) controls were recruited from July 2010 to November 2017. Dietary information was assessed by face-to-face interviews using a validated FFQ. Multivariable logistic regression was used to estimate the OR and 95 % CI on models. Intake of Fe from plants and Fe from white meat were inversely associated with the risk of colorectal cancer, while haem Fe and Fe from red meat were positively associated with colorectal cancer risk. The multivariable OR for the highest quartile v. the lowest quartile were 0·72 (95 % CI 0·59, 0·87, Ptrend<0·001) for Fe from plants, 0·54 (95 % CI 0·45, 0·66, Ptrend<0·001) for Fe from white meat, 1·26 (95 % CI 1·04, 1·53, Ptrend=0·005) for haem Fe and 1·83 (95 % CI 1·49, 2·24, Ptrend<0·001) for Fe from red meat intake, respectively. However, no significant association was found between the consumption of total dietary Fe, non-haem Fe, Fe from meat and colorectal cancer risk. This study showed that lower intake of Fe from plants and white meat, as well as higher intake of haem Fe and Fe from red meat, were associated with colorectal cancer risk in a Chinese population.
X-ray powder diffraction data, unit-cell parameters and space group for azilsartan, C25H20N4O5, are reported [a = 9.641(3) Å, b = 11.301(9) Å, c = 20.010(8) Å, α = 90°, β = 90.351(5)°, γ = 90°, unit-cell volume V = 2196.735(4) Å3, Z = 4, ρcal = 1.379 g·cm−3, and space group P21/c]. All measured lines were indexed and are consistent with the P21/c space group. No detectable impurities were observed.
Although previous studies have investigated the association of cruciferous vegetable consumption with breast cancer risk, few studies focused on the association between bioactive components in cruciferous vegetables, glucosinolates (GSL) and isothiocyanates (ITC), and breast cancer risk. This study aimed to examine the association between consumption of cruciferous vegetables and breast cancer risk according to GSL and ITC contents in a Chinese population. A total of 1485 cases and 1506 controls were recruited into this case–control study from June 2007 to March 2017. Consumption of cruciferous vegetables was assessed using a validated FFQ. Dietary GSL and ITC were computed by using two food composition databases linking GSL and ITC contents in cruciferous vegetables with responses to the FFQ. The OR and 95 % CI were assessed by unconditional logistic regression after adjusting for the potential confounders. Significant inverse associations were found between consumption of cruciferous vegetables, GSL and ITC and breast cancer risk. The adjusted OR comparing the highest with the lowest quartile were 0·51 (95 % CI 0·41, 0·63) for cruciferous vegetables, 0·54 (95 % CI 0·44, 0·67) for GSL and 0·62 (95 % CI 0·50, 0·76) for ITC, respectively. These inverse associations were also observed in both premenopausal and postmenopausal women. Subgroup analysis by hormone receptor status found inverse associations between cruciferous vegetables, GSL and ITC and both hormone-receptor-positive or hormone-receptor-negative breast cancer. This study indicated that consumption of cruciferous vegetables, GSL and ITC was inversely associated with breast cancer risk among Chinese women.
A carbohydrate-rich diet results in hyperglycaemia and hyperinsulinaemia; it may further induce the carcinogenesis of colorectal cancer. However, epidemiological evidence among Chinese population is quite limited. The aim of this study was to investigate total carbohydrate, non-fibre carbohydrate, total fibre, starch, dietary glycaemic index (GI) and glycaemic load (GL) in relation to colorectal cancer risk in Chinese population. A case–control study was conducted from July 2010 to April 2017, recruiting 1944 eligible colorectal cancer cases and 2027 age (5-year interval) and sex frequency-matched controls. Dietary information was collected by using a validated FFQ. The OR and 95 % CI of colorectal cancer risk were assessed by multivariable logistic regression models. There was no clear association between total carbohydrate intake and colorectal cancer risk. The adjusted OR was 0·85 (95 % CI 0·70, 1·03, Ptrend=0·08) comparing the highest with the lowest quartile. Total fibre was related to a 53 % reduction in colorectal cancer risk (adjusted ORquartile 4 v. 1 0·47; 95 % CI 0·39, 0·58). However, dietary GI was positively associated with colorectal cancer risk, with an adjusted ORquartile 4 v. 1 of 3·10 (95 % CI 2·51, 3·85). No significant association was found between the intakes of non-fibre carbohydrate, starch and dietary GL and colorectal cancer risk. This study indicated that dietary GI was positively associated with colorectal cancer risk, but no evidence supported that total carbohydrate, non-fibre carbohydrate, starch or high dietary GL intake were related to an increased risk of colorectal cancer in a Chinese population.
In north-central China, subsistence practices transitioned from hunting and gathering to millet-based agriculture between the early and middle Holocene. To better understand how ancient environmental changes influenced this shift in subsistence strategies and human activities at regional to local levels, we conducted palynological and lithologic analyses on radiocarbon-dated sediment cores from the Luoyang Basin, western Henan Province. Our palynological results suggest that vegetation shifted from broad-leaved deciduous forest (9230–8850 cal yr BP) to steppe-meadow vegetation (8850–7550 cal yr BP), and then to steppe with sparse trees (7550–6920 cal yr BP). Lithologic analyses also indicate that the stabilization of the Luoyang Basin’s floodplain after ~8370 cal yr BP might have attracted people to move into the basin, promoting the emergence of millet-based agriculture during the Peiligang culture period (8500–7000 cal yr BP). Once agricultural practices emerged, the climatic optimum after ~7550 cal yr BP likely facilitated the expansion of the Yangshao culture (7000–5000 cal yr BP) in north-central China. As agriculture intensified, pollen taxa related to human disturbance, such as Urtica, increased in abundance.
Four isonitrogenous and isoenergetic purified diets containing free arachidonic acid (ARA) or EPA (control group), 0·30 % ARA, 0·30 % EPA and 0·30 % ARA+EPA (equivalent) were designed to feed juvenile grass carp (10·21 (sd 0·10) g) for 10 weeks. Only the EPA group presented better growth performance compared with the control group (P<0·05). Dietary ARA and EPA were incorporated into polar lipids more than non-polar lipids in hepatopancreas but not intraperitoneal fat (IPF) tissue. Fish fed ARA and EPA showed an increase of serum superoxide dismutase and catalase activities, and decrease of glutathione peroxidase activity and malondialdehyde contents (P<0·05). The hepatopancreatic TAG levels decreased both in ARA and EPA groups (P<0·05), accompanied by the decrease of lipoprotein lipase (LPL) activity in the ARA group (P<0·05). Fatty acid synthase (FAS), diacylglycerol O-acyltransferase and apoE gene expression in the hepatopancreas decreased in fish fed ARA and EPA, but only the ARA group exhibited increased mRNA level of adipose TAG lipase (ATGL) (P<0·05). Decreased IPF index and adipocyte sizes were found in the ARA group (P<0·05). Meanwhile, the ARA group showed decreased expression levels of adipogenic genes CCAAT enhancer-binding protein α, LPL and FAS, and increased levels of the lipid catabolic genes PPARα, ATGL, hormone-sensitive lipase and carnitine palmitoyltransferase 1 (CPT-1) in IPF, whereas the EPA group only increased PPARα and CPT-1 mRNA expression and showed less levels than the ARA group. Overall, dietary EPA is beneficial to the growth performance, whereas ARA is more potent in inducing lipolysis and inhibiting adipogenesis, especially in IPF. Meanwhile, dietary ARA and EPA showed the similar preference in esterification and the improvement in antioxidant response.
A stalagmite with high 238U content from Yangkou Cave, China, revealed the evolution of the Asian summer monsoon (ASM) between 49.1 and 59.5 ka, and the δ18O values recorded Dansgaard/Oeschger (D/O) events 13–17. The Yangkou record shows a relatively gradual transition into the D/O 14 and 16 events. The discrepancy between the abrupt and gradual transitions of D/O 14 in the records from northern and southern China, respectively, suggests different responses of the ASM to climate changes in the high northern latitudes. The higher resolution δ18O record and more precise 230Th dating indicate that the timing of D/O 14 and 17 in the Hulu records at 53 and 58 ka should be shifted to 54.3 and 59 ka, respectively. The gradual strengthening of the ASM at the onsets of D/O 16 and 14 in our record is different from the abrupt temperature rise in the northern high latitudes. Some other factors must contribute to this relatively gradual ASM change in southern China, but the actual reason is still unknown.
A “RE-free” and I-phase-containing Mg–8Sn-based alloy system was developed and successfully fabricated through the equal channel angular pressing (ECAP) process. The influence of the Zn/Al mass ratio on the microstructures and mechanical properties of the as-ECAPed Mg–8Sn–(5,6,7)Zn–2(wt%)Al alloys was investigated using an optical microscope, an X-ray diffractometer, a scanning electron microscope, a transmission electron microscope, and a universal testing machine. Grain size, dynamic recrystallization behavior, and texture were found to be greatly affected by the Zn/Al mass ratio. Furthermore, the ultimate tensile strength (250 MPa) and elongation (14.5%) of the alloy with a Zn/Al mass ratio of 3 were considerably increased compared to those of the as-ECAPed alloys with Zn/Al ratios of 2.5 and 3.5 (ultimate tensile strength and elongation of 215 MPa and 13% and 184 MPa and 10%, respectively). This significant enhancement was attributed to extensive grain boundary strengthening, precipitation strengthening, and higher work hardening capacity as well as texture randomization. The strength and ductility of the as-ECAPed alloys are also discussed in terms of the I-phase and Mg2Sn formation.
We propose a characteristic function based test for conditional independence, applicable to both cross-sectional and time series data. We also derive a class of derivative tests, which deliver model-free tests for such important hypotheses as omitted variables, Granger causality in various moments and conditional uncorrelatedness. The proposed tests have a convenient asymptotic null N (0, 1) distribution, and are asymptotically locally more powerful than a variety of related smoothed nonparametric tests in the literature. Unlike other smoothed nonparametric tests for conditional independence, we allow nonparametric estimators for both conditional joint and marginal characteristic functions to jointly determine the asymptotic distributions of the test statistics. Monte Carlo studies demonstrate excellent power of the tests against various alternatives. In an application to testing Granger causality, we document the existence of nonlinear relationships between money and output, which are missed by some existing tests.