Highly stable gold nanoparticles (Au NPs) functionalized by bidentate N-heterocyclic carbene (NHC) ligands have been synthesized by top-down and bottom-up approaches. A detailed study of the effect ...of alkylation, denticity, and method of synthesis has led to the production of NHC-stabilized nanoparticles with higher thermal stability than bi- and tridentate thiol-protected Au NPs and than monodentate NHC-stabilized NPs. Importantly, bidentate NHC-protected NPs also displayed unprecedented stability to external thiol, which has been an unsolved problem to date with all nanoparticles. Thus, multidentate NHC ligands are an important, and as yet unrecognized, step forward for the preparation of high stability nanomaterials.
Graphene nanoribbons (GNRs), narrow and straight-edged stripes of graphene, attract a great deal of attention because of their excellent electronic and magnetic properties. As of yet, there is no ...fabrication method for GNRs to satisfy both precision at the atomic scale and scalability, which is critical for fundamental research and future technological development. Here, we report a methodology for bulk-scale synthesis of GNRs with atomic precision utilizing a metal–organic framework (MOF). The GNR was synthesized by the polymerization of perylene (PER) or its derivative within the nanochannels of the MOF. Molecular dynamics simulations showed that PER was uniaxially aligned along the nanochannels of the MOF through host–guest interactions, which allowed for regulated growth of the nanoribbons. A series of characterizations of the GNR, including NMR, UV/vis/NIR, and Raman spectroscopy measurements, confirmed the formation of the GNR with well-controlled edge structure and width.
Strong interchain interactions render unsubstituted polythiophene un‐fusible, non‐melting, and insoluble. Therefore, control of the packing structure, which has a profound effect on the optical and ...electronic properties of the polymer, has never been achieved. Unsubstituted polythiophene was prepared in the one‐dimensional channels of La(1,3,5‐benzenetrisbenzoate)n, where polymer chains form unprecedented assembly structures mediated by the host framework. It is noteworthy that the emission and carrier transport properties were drastically changed by varying the number of chains within a particular assembly. The response of the composite to additional guests is also examined as a method to use the composites as low‐concentration sensors. Our findings show that the encapsulation of polymer chains in host materials is a facile method for understanding the intrinsic properties of conjugated polymers, along with controlling and enhancing their functions.
Solitary confinement: The controlled assembly of polythiophene within the channels of a metal–organic framework was carried out. This system was used to demonstrate the assembly packing structure as a way of controlling the optical and electronic properties of the conjugated polymer.
Major depressive disorder (MDD) is a common complex disorder with a partly genetic etiology. We conducted a genome-wide association study of the MDD2000+ sample (2431 cases, 3673 screened controls ...and >1 M imputed single-nucleotide polymorphisms (SNPs)). No SNPs achieved genome-wide significance either in the MDD2000+ study, or in meta-analysis with two other studies totaling 5763 cases and 6901 controls. These results imply that common variants of intermediate or large effect do not have main effects in the genetic architecture of MDD. Suggestive but notable results were (a) gene-based tests suggesting roles for adenylate cyclase 3 (ADCY3, 2p23.3) and galanin (GAL, 11q13.3); published functional evidence relates both of these to MDD and serotonergic signaling; (b) support for the bipolar disorder risk variant SNP rs1006737 in CACNA1C (P=0.020, odds ratio=1.10); and (c) lack of support for rs2251219, a SNP identified in a meta-analysis of affective disorder studies (P=0.51). We estimate that sample sizes 1.8- to 2.4-fold greater are needed for association studies of MDD compared with those for schizophrenia to detect variants that explain the same proportion of total variance in liability. Larger study cohorts characterized for genetic and environmental risk factors accumulated prospectively are likely to be needed to dissect more fully the etiology of MDD.
Sleep disturbance in cancer patients Davidson, Judith R; MacLean, Alistair W; Brundage, Michael D ...
Social science & medicine (1982),
05/2002, Letnik:
54, Številka:
9
Journal Article
Recenzirano
Sleep difficulty is a prominent concern of cancer patients, yet there has been no large study of the prevalence and nature of sleep disturbance in cancer patients. This cross-sectional survey study ...examined: (a) the prevalence of reported sleep problems in patients attending six clinics at a regional cancer centre; (b) sleep problem prevalence in relation to cancer treatment; and (c) the nature of reported insomnia (type, duration, and associated factors). For three months, all patients attending clinics for breast, gastrointestinal, genitourinary, gynecologic, lung, and non-melanoma skin cancers were offered a brief sleep questionnaire. Response rate was 87%; the final sample size was 982. Mean age of respondents was 64.9 years (SD 12.5). The most prevalent problems were excessive fatigue (44% of patients), leg restlessness (41%), insomnia (31%), and excessive sleepiness (28%). Chi square tests showed significant variation among clinics in the prevalence of most sleep problems. The lung clinic had the highest or second-highest prevalence of problems. The breast clinic had a high prevalence of insomnia and fatigue. Recent cancer treatment was associated with excessive fatigue and hypersomnolence. Insomnia commonly involved multiple awakenings (76% of cases) and duration ⩾6 months (75% of cases). In 48% of cases, insomnia onset was reported to occur around the time of cancer diagnosis (falling within the period 6 months pre-diagnosis to 18 months post-diagnosis). The most frequently identified contributors to insomnia were thoughts, concerns, and pain/discomfort. In a multivariate logistic regression analysis, variables associated with increased odds of insomnia were fatigue, age (inverse relationship), leg restlessness, sedative/hypnotic use, low or variable mood, dreams, concerns, and recent cancer surgery. This study provides new information about sleep-related phenomena in cancer patients, information which will be useful in planning supportive care services for cancer patients.
The production of a variety of PMO materials made with 1,1′-biphenylene monomers, and the inclusion of 1,1′-binaphthalene dopants is described. The effect of the point of attachment with regard to ...the biaryl axis was studied, and it was found that the highest level of chirality transfer is obtained when the biaryl axis is not restricted by the polymerization point. In addition, the actual loading of dopant was found to vary considerably depending on the synthesis procedure, and the effect of dopant, even at low level, was magnified under basic conditions when more ordered materials are produced.
We previously reported that laboratory reference strains of Chlamydia trachomatis differing in infection organotropism correlated with inactivating mutations in the pathogen's tryptophan synthase ...(trpBA) genes. Here, we have applied functional genomics to extend this work and find that the paradigm established for reference serovars also applies to clinical isolates -- specifically, all ocular trachoma isolates tested have inactivating mutations in the synthase, whereas all genital isolates encode a functional enzyme. Moreover, functional enzyme activity was directly correlated to IFN- gamma resistance through an indole rescue mechanism. Hence, a strong selective pressure exists for genital strains to maintain a functional synthase capable of using indole for tryptophan biosynthesis. The fact that ocular serovars (serovar B) isolated from the genital tract were found to possess a functional synthase provided further persuasive evidence of this association. These results argue that there is an important host-parasite relationship between chlamydial genital strains and the human host that determines organotropism of infection and the pathophysiology of disease. We speculate that this relationship involves the production of indole by components of the vaginal microbial flora, allowing chlamydiae to escape IFN- gamma -mediated eradication and thus establish persistent infection.
The effects of alcohol ingestion were compared with those of prolonged wakefulness on a simulated driving task. Eighteen healthy, male subjects aged between 19 and 35 years drove for 30 min on a ...simulated driving task at blood alcohol concentrations of 0.00, 0.05 and 0.08%. Subjective sleepiness was assessed before and after the driving task. Driving performance was measured in terms of the mean and standard deviation (S.D.) of lane position (tracking); the mean and S.D. of speed deviation (the difference between the actual speed and the posted speed limit); and the number of off-road occurrences. Ratings of sleepiness increased with increasing blood alcohol concentration, and were higher following the driving task. With increasing blood alcohol concentration, tracking variability, speed variability, and off-road events increased, while speed deviation decreased, the result of subjects driving faster. The results were compared with a previous study examining simulated driving performance during one night of prolonged wakefulness Arnedt, J.T., MacLean A.W., 1996. Effects of sleep loss on urban and motorway driving stimulation performance. Presented at the Drive Alert… Arrive Alive International Forum, Washington DC, using an approach adopted by Dawson and Reid Dawson, D., Reid, K., 1997. Fatigue, alcohol and performance impairment. Nature 388, 23. For mean tracking, tracking variability, and speed variability 18.5 and 21 h of wakefulness produced changes of the same magnitude as 0.05 and 0.08% blood alcohol concentration, respectively. Alcohol consumption produced changes in speed deviation and off-road occurrences of greater magnitude than the corresponding levels of prolonged wakefulness. While limited to situations in which there is no other traffic present, the findings suggest that impairments in simulated driving are evident even at relatively modest blood alcohol levels, and that wakefulness prolonged by as little as 3 h can produce decrements in the ability to maintain speed and road position as serious as those found at the legal limits of alcohol consumption.
Omega-3 fatty acids are purported to reduce the risk of cancer. Studies have reported mixed results.
To synthesize published and unpublished evidence to determine estimates of the effect of omega-3 ...fatty acids on cancer risk in prospective cohort studies.
Articles published from 1966 to October 2005 identified through MEDLINE, PREMEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and CAB Health; unpublished literature sought through letters to experts in the neutraceutical industry.
A total of 38 articles with a description of effects of consumption of omega-3 fatty acids on tumor incidence, prospective cohort study design, human study population; and description of effect of omega-3 among groups with different levels of exposure in the cohort were included. Two reviewers independently reviewed articles using structured abstraction forms; disagreements were resolved by consensus.
Two reviewers independently abstracted detailed data about the incidence of cancer, the type of cancer, the number and characteristics of the patients, details on the exposure to omega-3 fatty acids, and the elapsed time between the intervention and outcome measurements. Data about the methodological quality of the study were also abstracted.
Across 20 cohorts from 7 countries for 11 different types of cancer and using up to 6 different ways to categorize omega-3 fatty acid consumption, 65 estimates of the association between omega-3 fatty acid consumption were reported. Among these, only 8 were statistically significant. The high degree of heterogeneity across these studies precluded pooling of data. For breast cancer 1 significant estimate was for increased risk (incidence risk ratio IRR, 1.47; 95% confidence interval CI, 1.10-1.98) and 3 were for decreased risk (RR, 0.68-0.72); 7 other estimates did not show a significant association. For colorectal cancer, there was 1 estimate of decreased risk (RR, 0.49; 95% CI, 0.27-0.89) and 17 estimates without association. For lung cancer one of the significant associations was for increased cancer risk (IRR, 3.0; 95% CI, 1.2-7.3), the other was for decreased risk (RR, 0.32; 95% CI, 0.13-0.76), and 4 other estimates were not significant. For prostate cancer, there was 1 estimate of decreased risk (RR, 0.43; 95% CI, 0.22-0.83) and 1 of increased risk (RR, 1.98; 95% CI, 1.34-2.93) for advanced prostate cancer; 15 other estimates did not show a significant association. The study that assessed skin cancer found an increased risk (RR, 1.13; 95% CI, 1.01-1.27). No significant associations between omega-3 fatty acid consumption and cancer incidence were found for aerodigestive cancer, bladder cancer, lymphoma, ovarian cancer, pancreatic cancer, or stomach cancer.
A large body of literature spanning numerous cohorts from many countries and with different demographic characteristics does not provide evidence to suggest a significant association between omega-3 fatty acids and cancer incidence. Dietary supplementation with omega-3 fatty acids is unlikely to prevent cancer.
Although repeat induced abortion is common, data concerning characteristics of women undergoing this procedure are lacking. We conducted this study to identify the characteristics, including history ...of physical abuse by a male partner and history of sexual abuse, of women who present for repeat induced abortion.
We surveyed a consecutive series of women presenting for initial or repeat pregnancy termination to a regional provider of abortion services for a wide geographic area in southwestern Ontario between August 1998 and May 1999. Self-reported demographic characteristics, attitudes and practices regarding contraception, history of relationship violence, history of sexual abuse or coercion, and related variables were assessed as potential correlates of repeat induced abortion. We used chi2 tests for linear trend to examine characteristics of women undergoing a first, second, or third or subsequent abortion. We analyzed significant correlates of repeat abortion using stepwise multivariate multinomial logistic regression to identify factors uniquely associated with repeat abortion.
Of the 1221 women approached, 1145 (93.8%) consented to participate. Data regarding first versus repeat abortion were available for 1127 women. A total of 68.2%, 23.1% and 8.7% of the women were seeking a first, second, or third or subsequent abortion respectively. Adjusted odds ratios for undergoing repeat versus a first abortion increased significantly with increased age (second abortion: 1.08, 95% confidence interval CI 1.04-1.09; third or subsequent abortion: 1.11, 95% CI 1.07-1.15), oral contraceptive use at the time of conception (second abortion: 2.17, 95% CI 1.52-3.09; third or subsequent abortion: 2.60, 95% CI 1.51-4.46), history of physical abuse by a male partner (second abortion: 2.04, 95% CI 1.39-3.01; third or subsequent abortion: 2.78, 95% CI 1.62-4.79), history of sexual abuse or violence (second abortion: 1.58, 95% CI 1.11-2.25; third or subsequent abortion: 2.53, 95% CI 1.50-4.28), history of sexually transmitted disease (second abortion: 1.50, 95% CI 0.98-2.29; third or subsequent abortion: 2.26, 95% CI 1.28-4.02) and being born outside Canada (second abortion: 1.83, 95% CI 1.19-2.79; third or subsequent abortion: 1.75, 95% CI 0.90-3.41).
Among other factors, a history of physical or sexual abuse was associated with repeat induced abortion. Presentation for repeat abortion may be an important indication to screen for a current or past history of relationship violence and sexual abuse.
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