| 41. |
- Xu, Chao-Qun, et al.
(författare)
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Genome sequence of Malania oleifera, a tree with great value for nervonic acid production
- 2019
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Ingår i: GigaScience. - : Oxford University Press. - 2047-217X. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- Background Malania oleifera, a member of the Olacaceae family, is an IUCN red listed tree, endemic and restricted to the Karst region of southwest China. This tree's seed is valued for its high content of precious fatty acids (especially nervonic acid). However, studies on its genetic makeup and fatty acid biogenesis are severely hampered by a lack of molecular and genetic tools. Findings We generated 51 Gb and 135Gb of raw DNA sequences, using Pacific Biosciences (PacBio) single-molecule real-time and 10x Genomics sequencing, respectively. A final genome assembly, with a scaffold N50 size of 4.65 Mb and a total length of 1.51Gb, was obtained by primary assembly based on PacBio long reads plus scaffolding with 10x Genomics reads. Identified repeats constituted approximate to 82% of the genome, and 24,064 protein-coding genes were predicted with high support. The genome has low heterozygosity and shows no evidence for recent whole genome duplication. Metabolic pathway genes relating to the accumulation of long-chain fatty acid were identified and studied in detail. Conclusions Here, we provide the first genome assembly and gene annotation for M. oleifera. The availability of these resources will be of great importance for conservation biology and for the functional genomics of nervonic acid biosynthesis.
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| 42. |
- Xu, Guangwei, et al.
(författare)
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Synthesis, properties, and top-gated metal-oxide-semiconductor field-effect transistors of p-type GaSb nanowires
- 2013
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:43, s. 19834-19839
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Tidskriftsartikel (refereegranskat)abstract
- High-quality GaSb nanowires (NWs) have been synthesized via chemical vapor deposition. The as-synthesized NWs have a zinc-blende structure with growth direction along a < 011 > direction. Raman spectrum of the GaSb NWs consists of two peaks, corresponding to the LO and TO phonon modes, respectively. The temperature dependence of the photoluminescence spectra shows a blue-shift as the temperature decreases from 300 to 13 K. The electrical properties of the GaSb NWs are investigated over a wide range of temperatures from 25 mK to 291 K. The results show that the GaSb NWs exhibit excellent p-type transistor performance at low temperatures (<40 K). The room-temperature hole density and mobility were found to be similar to 2.2 x 10(18) cm(-3) and similar to 14.2 cm(2) V-1 s(-1), respectively. The Schottky contact characteristics were observed and the barrier height was found to be similar to 14 meV. Our results show that the GaSb NWs could be used as building blocks for emerging p-type nanoelectronic devices in extremely low temperature environments.
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| 43. |
- Xu, Hui, et al.
(författare)
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Association of Lifespan Cognitive Reserve Indicator With Dementia Risk in the Presence of Brain Pathologies
- 2019
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149 .- 2168-6157. ; 76:10, s. 1184-1191
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Tidskriftsartikel (refereegranskat)abstract
- Importance Evidence on the association of lifespan cognitive reserve (CR) with dementia is limited, and the strength of this association in the presence of brain pathologies is unknown.Objective To examine the association of lifespan CR with dementia risk, taking brain pathologies into account.Design, setting, and participants This study used data from 2022 participants in the Rush Memory and Aging Project, an ongoing community-based cohort study with annual follow-up from 1997 to 2018 (mean follow-up, 6 years; maximum follow-up, 20 years). After excluding 420 individuals who had prevalent dementia, missing data on CR, or dropped out, 1602 dementia-free adults were identified at baseline and evaluated to detect incident dementia. During follow-up, 611 died and underwent autopsies. Data were analyzed from May to September 2018.Exposures Information on CR factors (education; early-life, midlife, and late-life cognitive activities; and social activities in late life) was obtained at baseline. Based on these factors, lifespan CR scores were captured using a latent variable from a structural equation model and was divided into tertiles (lowest, middle, and highest).Main outcomes and measures Dementia was diagnosed following international criteria. Neuropathologic evaluations for Alzheimer disease and other brain pathologies were performed in autopsied participants. The association of lifespan CR with dementia or brain pathologies was estimated using Cox regression models or logistic regression.Results Of the 1602 included participants, 1216 (75.9%) were women, and the mean (SD) age was 79.6 (7.5) years. During follow-up, 386 participants developed dementia (24.1%), including 357 participants with Alzheimer disease-related dementia (22.3%). The multiadjusted hazards ratios (HRs) of dementia were 0.77 (95% CI, 0.59-0.99) for participants in the middle CR score tertile and 0.61 (95% CI, 0.47-0.81) for those in the highest CR score tertile compared with those in the lowest CR score tertile. In autopsied participants, CR was not associated with most brain pathologies, and the association of CR with dementia remained significant after additional adjustment for brain pathologies (HR, 0.60; 95% CI, 0.42-0.86). The highest CR score tertile was associated with a reduction in dementia risk, even among participants with high Alzheimer disease pathology (HR, 0.57; 95% CI, 0.37-0.87) and any gross infarcts (HR, 0.34; 95% CI, 0.18-0.62).Conclusions and relevance High lifespan CR is associated with a reduction in dementia risk, even in the presence of high brain pathologies. Our findings highlight the importance of lifespan CR accumulation in dementia prevention.
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| 44. |
- Xu, Hui, et al.
(författare)
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Association of lifespan cognitive reserve indicator with the risk of mild cognitive impairment and its progression to dementia
- 2020
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Ingår i: Alzheimer's & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 16:6, s. 873-882
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The association of lifespan cognitive reserve (CR) with mild cognitive impairment (MCI) remains controversial. We aimed to examine the association of lifespan CR indicator with the risk of MCI and its progression to dementia, taking brain pathologies into account.Methods: In a community-based cohort study (mean age, 79 years) with annual followup (median, 5.16 years; maximum, 20 years), a cognitively intact group (n = 1182) and an MCI group (n = 420) were identified at baseline. During the follow-up, 611 participants died and underwent autopsies. CR indicator encompassing education, early life to late-life cognitive and social activities were obtained and tertiled.Results: The multi-adjusted hazard ratio (HR) of MCI was 0.72 (95% confidence interval [CI] 0.58 to 0.90) in the cognitively intact group, and the HR of dementia was 0.66 (95% CI 0.45 to 0.97) in the MCI group for participants with the highest CR indicator (reference: the lowest CR indicator). Among MCI participants with brain pathologies, dementia incidence was about 50% lower in people with the highest CR indicator than the lowest CR indicator.Discussion: High lifespan CR indicator reduces risk of MCI, and delays its progression to dementia.
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| 45. |
- Xu, Hui, et al.
(författare)
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Impact of Pore Structure on Two-Electron Oxygen Reduction Reaction in Nitrogen-Doped Carbon Materials : Rotating Ring-Disk Electrode vs. Flow Cell
- 2022
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 15:5
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Tidskriftsartikel (refereegranskat)abstract
- The impact of pore structure on the two-electron oxygen reduction reaction (ORR) in nitrogen-doped carbon materials is currently under debate, and previous studies are mainly limited to the rotating ring-disk electrode (RRDE) rather than the practical flow cell (FC) system. In this study, assisted by a group of reliable pore models, the impact of two pore structure parameters, that is, Brunauer–Emmett–Teller surface area (SBET) and micropore surface fraction (fmicro), on ORR activity and selectivity are investigated in both RRDE and FC. The ORR mass activity correlates positively to the SBET in the RRDE and FC because a higher SBET can host more active sites. The H2O2 selectivity is independent of fmicro in the RRDE but correlates negatively to fmicro in the FC. The inconsistency results from different states of the electrode in the RRDE and the FC. These insights will guide the design of carbon materials for H2O2 synthesis.
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| 46. |
- Xu, Hui, et al.
(författare)
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Osteoporosis and Osteopenia Among Patients With Type 2 Diabetes Aged >= 50 : Role of Sex and Clinical Characteristics
- 2020
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Ingår i: Journal of clinical densitometry. - : Elsevier BV. - 1094-6950 .- 1559-0747. ; 23:1, s. 29-36
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Tidskriftsartikel (refereegranskat)abstract
- Introduction/Background: Although some studies have explored the association of adiposity and life habits (such as smoking) with osteoporosis and osteopenia among type 2 diabetes mellitus (T2DM) patients, the association between diabetic clinical characteristics (especially hypoglycemic drug use) and osteoporosis/ osteopenia remains unclear. This study aimed to investigate the relationship of clinical characteristics with osteoporosis and osteopenia among T2DM patients by sex. Methods: A total of 1222 T2DM patients aged >= 50 were included in the present study. Information on demographic, anthropometric and clinical characteristics was collected from medical records. Bone mineral density was assessed by dual-energy X-ray absorptiometry densitometer. Multiple adjusted logistic regression analyses were performed to estimate the odds ratio (OR) and 95% confidence interval (CI) of osteoporosis and osteopenia related to clinical characteristics. Results: Of all participants, the prevalence of osteoporosis and osteopenia was 9.2% and 41.3%, respectively, and they were higher in females (14.7% and 48.5%) than in males (2.8% and 33%). After adjustment for potential confounders, the results showed that overweight (OR = 0.59; 95 % CI, 0.42-0.81) and obesity (OR = 0.35; 95% CI, 0.24-0.50) were related to decreased odds of osteoporosis and osteopenia in both male and female T2DM patients, poor glycemic control (OR = 1.63; 95% CI, 1.08-2.47) was associated with increased odds of osteoporosis and osteopenia in males, and metformin treatment (OR = 0.65; 95% CI, 0.43-0.99) was associated with decreased odds of osteoporosis and osteopenia in females. Conclusions: Better glycemic management and rational choice of antidiabetic medication might be promising to prevent osteoporosis in T2DM patients. Further longitudinal studies are warranted to explore the association between antidiabetic treatment and osteoporosis.
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| 47. |
- Xu, Hong-Tao, et al.
(författare)
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Effects of fucosylated milk of goat and mouse on Helicobacter pylori binding to Lewis b antigen
- 2004
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Ingår i: World Journal of Gastroenterology. - Beijing : WJG Press. - 1007-9327 .- 2219-2840. ; 10:14, s. 2063-2066
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Tidskriftsartikel (refereegranskat)abstract
- Aim:To evaluate the effects of animal milk containing fucosylated antigens on Helicobacter pylori (H pylon) binding to Lewis b antigen. Methods:A mammary gland expression vector containing human α1-3/4-fucosyltransferase cDNA sequences was constructed. Transient expression of human(α1-3/4-fucosyltransferase cDNA in goat mammary cell and establishment of transgenic mice were performed. The adhesion inhibitory properties of milk samples were analyzed by using Hpylori. Results: Goat milk samples were found to inhibit bacterial binding to Lewis b antigen. The highest inhibition was observed 42 h after injection of the plasmid. The binding activity of Hpylori to Lewis b antigen reduced mostly, by 83%, however milk samples from transgenic mice did not inhibit Hpylori binding to Lewis b antigen. Conclusion: The use of “humanized“ animal milk produced by the transgenic introduction of fucosylated antigen can perhaps provide an alternative therapy and preventive measure for Hpylori infection.
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| 48. |
- Xu, Jie, et al.
(författare)
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UV-B-induced molecular mechanisms of stress physiology responses in the major northern Chinese conifer Pinus tabuliformis Carr
- 2021
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Ingår i: Tree Physiology. - : Oxford University Press. - 0829-318X .- 1758-4469. ; 41:7, s. 1247-1263
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Tidskriftsartikel (refereegranskat)abstract
- During their lifetimes, plants are exposed to different abiotic stress factors eliciting various physiological responses and triggering important defense processes. For UV-B radiation responses in forest trees, the genetics and molecular regulation remain to be elucidated. Here, we exposed Pinus tabuliformis Carr., a major conifer from northern China, to short-term high-intensity UV-B and employed a systems biology approach to characterize the early physiological processes and the hierarchical gene regulation, which revealed a temporal transition from primary to secondary metabolism, the buildup of enhanced antioxidant capacity and stress-signaling activation. Our findings showed that photosynthesis and biosynthesis of photosynthetic pigments were inhibited, while flavonoids and their related derivates biosynthesis, as well as glutathione and glutathione S-transferase mediated antioxidant processes, were enhanced. Likewise, stress-related phytohormones (jasmonic acid, salicylic acid and ethylene), kinase and reactive oxygen species signal transduction pathways were activated. Biological processes regulated by auxin and karrikin were, for the first time, found to be involved in plant defense against UV-B by promoting the biosynthesis of flavonoids and the improvement of antioxidant capacity in our research system. Our work evaluated the physiological and transcriptome perturbations in a conifer's response to UV-B, and generally, highlighted the necessity of a systems biology approach in addressing plant stress biology.
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| 49. |
- Xu, Weili, et al.
(författare)
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Detection of Prediabetes and Undiagnosed Type 2 Diabetes : A Large Population-Based Study
- 2012
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Ingår i: Canadian Journal of Diabetes. - : Elsevier BV. - 1499-2671. ; 36:3, s. 108-113
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Prediabetes and undiagnosed diabetes have been commonly ignored. We aimed to investigate the prevalence of prediabetes and undiagnosed type 2 diabetes mellitus, and to verify the hypothesis that vascular risk factors (VRFs) may indicate prediabetes and undiagnosed type 2 diabetes.Methods: A total of 7567 adults, who were 20 to 79 years of age, and living in Tianjin, China, participated in this study. Type 2 diabetes was assessed based on medical history, hypoglycemic drugs use, fasting plasma glucose level >= 7.0 mmol/L, or postprandial 2-hour plasma glucose level >= 11.1 mmol/L. Undiagnosed type 2 diabetes was defined among subjects with type 2 diabetes when neither a medical history of diabetes nor hypoglycemic drugs use was present. Prediabetes was ascertained as fasting plasma glucose level of 6.1 to 6.9 mmol/L, or postprandial 2-hour plasma glucose level of 7.8 to 11.0 mmol/L (WHO 1999) among diabetes-free participants. Data were analyzed using multinomial logistic regression with adjustment for potential confounders.Results: Of all participants, 655 (8.7%) had prediabetes, and 721 (9.5%) were patients with type 2 diabetes, including 321 (4.2%) undiagnosed type 2 diabetes accounting for 44.5% patients with diabetes. The prevalence of prediabetes and undiagnosed type 2 diabetes increased with age, and was higher in women than in men. In a fully adjusted multinomial logistic regression model, hypertension, overweight, obesity, central obesity, and family history of diabetes were significantly associated with prediabetes and undiagnosed diabetes, whereas physical inactivity was independently related to undiagnosed diabetes.Conclusion: The prevalence of prediabetes and undiagnosed diabetes is approximately 13%, and almost 45% of patients with diabetes are undiagnosed. VRFs, such as hypertension, high adiposity, and family history of diabetes can be indicators for detecting prediabetes and undiagnosed diabetes.
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| 50. |
- Yang, Rongrong, et al.
(författare)
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A healthy lifestyle mitigates the risk of heart disease related to type 2 diabetes : a prospective nested case-control study in a nationwide Swedish twin cohort
- 2021
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 64, s. 530-539
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis We aimed to examine the association between type 2 diabetes and major subtypes of heart disease, to assess the role of genetic and early-life familial environmental factors in this association and to explore whether and to what extent a healthy lifestyle mitigates the risk of heart disease related to type 2 diabetes.Methods In this prospective nested case-control study based on the Swedish Twin Registry, 41,463 twin individuals who were aged >= 40 and heart disease-free were followed up for 16 years (from 1998 to 2014) to detect incident heart disease. Type 2 diabetes was ascertained from self-report, the National Patient Registry and glucose-lowering medication use. Heart disease diagnosis (including coronary heart disease, cardiac arrhythmias and heart failure) and onset age were identified from the National Patient Registry. Healthy lifestyle-related factors consisted of being a non-smoker, no/mild alcohol consumption, regular physical activity and being non-overweight. Participants were divided into three groups according to the number of lifestyle-related factors: (1) unfavourable (participants who had no or only one healthy lifestyle factor); (2) intermediate (any two or three); and (3) favourable (four). Generalised estimating equation models for unmatched case-control design and conditional logistic regression for co-twin control design were used in data analyses.Results Of all participants, 2304 (5.5%) had type 2 diabetes at baseline. During the observation period, 9262 (22.3%) had any incident heart disease. In unmatched case-control analyses and co-twin control analyses, the multi-adjusted OR and 95% CI of heart disease related to type 2 diabetes was 4.36 (3.95, 4.81) and 4.89 (3.88, 6.16), respectively. The difference in ORs from unmatched case-control analyses vs co-twin control analyses was statistically significant (OR 1.57; 95% CI 1.42, 1.73; p < 0.001). In stratified analyses by type 2 diabetes, compared with an unfavourable lifestyle, an intermediate lifestyle or a favourable lifestyle was associated with a significant 32% (OR 0.68; 95% CI 0.49, 0.93) or 56% (OR 0.44; 95% CI 0.30, 0.63) decrease in heart disease risk among patients with type 2 diabetes, respectively. There were significant additive and multiplicative interactions between lifestyle and type 2 diabetes on heart disease.Conclusions/interpretation Type 2 diabetes is associated with more than fourfold increased risk of heart disease. The association still remains statistically significant, even after fully controlling for genetic and early-life familial environmental factors. However, greater adherence to a healthy lifestyle may significantly mitigate the risk of heart disease related to type 2 diabetes.
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