To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This paper presents the results of an experimental campaign to measure thruster-relevant parameters for a high-power (180kW) inductive propulsion system utilising Ar,
as propellants. Results from the investigation show that inductive thrusters can make use of these propellants without the severe degradation seen in other electric propulsion systems. Furthermore, the collection of experimental data at powers greater than 100kW provides a reference of performance for the high-power electric propulsion devices intended for missions in the near future. Thrust and specific impulse in inductive systems can be improved by preferentially combining the chemical properties of atomic and molecular propellants. The maximum thrust recorded during these experiments was 7.9N, obtained using a combination of argon and oxygen (0.68 Ar + 0.32
). The combination of argon and molecular propellants also decreased thermal losses within the discharge volume. Specific impulse can be doubled for the same input electric power by combining propellants, and future modifications to the thruster geometry and acceleration mechanism can be used to further improve the performance of such systems.
Individuals with posttraumatic stress disorder (PTSD) are at increased risk of various chronic diseases. One hypothesized pathway is via changes in diet quality. This study evaluated whether PTSD was associated with deterioration in diet quality over time.
Data were from 51 965 women in the Nurses' Health Study II PTSD sub-study followed over 20 years. Diet, assessed at 4-year intervals, was characterized via the Alternative Healthy Eating Index-2010 (AHEI). Based on information from the Brief Trauma Questionnaire and Short Screening Scale for DSM-IV PTSD, trauma/PTSD status was classified as no trauma exposure, prevalent exposure (trauma/PTSD onset before study entry), or new-onset (trauma/PTSD onset during follow-up). We further categorized women with prevalent exposure as having trauma with no PTSD symptoms, trauma with low PTSD symptoms, and trauma with high PTSD symptoms, and created similar categories for women with new-onset exposure, resulting in seven comparison groups. Multivariable linear mixed-effects spline models tested differences in diet quality changes by trauma/PTSD status over follow-up.
Overall, diet quality improved over time regardless of PTSD status. In age-adjusted models, compared to those with no trauma, women with prevalent high PTSD and women with new-onset high PTSD symptoms had 3.3% and 3.6% lower improvement in diet quality, respectively, during follow-up. Associations remained consistent after adjusting for health conditions, sociodemographics, and behavioral characteristics.
PTSD is associated with less healthy changes in overall diet quality over time. Poor diet quality may be one pathway linking PTSD with a higher risk of chronic disease development.
Although the science of team science is no longer a new field, the measurement of team science and its standardization remain in relatively early stages of development. To describe the current state of team science assessment, we conducted an integrative review of measures of research collaboration quality and outcomes.
Collaboration measures were identified using both a literature review based on specific keywords and an environmental scan. Raters abstracted details about the measures using a standard tool. Measures related to collaborations with clinical care, education, and program delivery were excluded from this review.
We identified 44 measures of research collaboration quality, which included 35 measures with reliability and some form of statistical validity reported. Most scales focused on group dynamics. We identified 89 measures of research collaboration outcomes; 16 had reliability and 15 had a validity statistic. Outcome measures often only included simple counts of products; publications rarely defined how counts were delimited, obtained, or assessed for reliability. Most measures were tested in only one venue.
Although models of collaboration have been developed, in general, strong, reliable, and valid measurements of such collaborations have not been conducted or accepted into practice. This limitation makes it difficult to compare the characteristics and impacts of research teams across studies or to identify the most important areas for intervention. To advance the science of team science, we provide recommendations regarding the development and psychometric testing of measures of collaboration quality and outcomes that can be replicated and broadly applied across studies.
The resection of a subaortic membrane remains far from a curative operation. We sought to examine factors associated with reoperation and the degree of aortic valve regurgitation as a potential long-term source for reoperation.
All patients who underwent resection of an isolated subaortic membrane between 1995 and 2018 were included. Patients who underwent other procedures were excluded. Paired categorical data were compared using McNemar’s test. Univariate time-to-event analyses were performed using Kaplan–Meier methods with log-rank tests for categorical variables and univariate Cox models for continuous variables.
A total of 84 patients (median age 6.6, 31% females) underwent resection of isolated subaortic membrane. At a median follow-up of 9.3 years (interquartile range 0.6–22.5), 12 (14%) patients required one reoperation and 1 patient required two reoperations. Median time to first reoperation was 4.6 years. The degree of aortic valve regurgitation improved post-operatively from pre-operatively (p = 0.0007); however, the degree of aortic valve regurgitation worsened over the course of follow-up (p = 0.010) to equivalence with pre-operative aortic valve regurgitation (p = 0.18). Performance of a septal myectomy was associated with longer freedom from reoperation (p = 0.004).
In patients with isolated subaortic membranes, performance of a septal myectomy can minimise risk for reoperation. Patients should be serially monitored for degradation of the aortic valve, even if aortic regurgitation is not present post-operatively.
A simple and facile stereolithography 3D printing technique was utilized to fabricate piezoelectric photopolymer-based polyvinylidene fluoride (PVDF) blends. Different process variables, such as solvent (N,N-dimethylformamide, DMF) to PVDF ratio and PVDF solution to photopolymer resin (PR) ratio, were engineered to enhance the dispersion of the PVDF into the PR so as to achieve the maximum piezoelectric coupling coefficient. Our results demonstrate that a ratio of 1:10 (PVDF:DMF) and 2 wt%-PVDF/PR was optimal for the best dissolution of the PVDF, 3D printability, and piezoelectric properties. Under these conditions, the blend generated ±0.121 nA under 80 N dynamic loading excitation. We believe that the findings of this work would promote many further studies on the mass production of flexible piezoelectric polymer blends with higher quality finished surface and design flexibility.
Fermented feeds are being considered as practical alternatives to antimicrobial growth promoters (AGP) supplemented in nursery pig diets. This study aimed to investigate health-promoting effects of fermented barley in weaned pigs challenged with Escherichia coli K88 +. A total of 37 piglets were weaned at 21 ± 1 day of age (6.41 ± 0.47 kg of BW) and assigned to either of the following five treatment groups: (1) unchallenged control (UCC; n = 7), (2) challenged control (CC; n = 7), (3) AGP (CC + 0.1% AGP; n = 7), (4) Ferm1 (challenged and fed homofermentative Lactobacillus plantarum (Homo)-fermented barley; n = 8) and (5) Ferm2 (challenged and fed heterofermentative L. buchneri (Hetero)-fermented barley; n = 8). The control diet included unfermented barley. Barley was fermented with either Homo or Hetero for 90 days under anaerobic conditions. On day 10, all pigs except those in UCC group were orally inoculated with E. coli K88 + (6 × 109 colony forming units/ml). The pre-planned orthogonal test was performed to compare (1) UCC and CC, (2) CC and AGP, (3) CC and Ferm1 + Ferm2, as well as (4) Ferm1 and Ferm2. Challenged control pigs showed shorter (P < 0.05) villus height (VH) in the duodenum and deeper (P < 0.05) crypt depth (CD) in the jejunum than UCC pigs. The AGP group had higher (P < 0.05) VH and lower (P < 0.05) IL-6 gene expression in the jejunum compared with CC group. Compared to CC, Ferm1 and Ferm2 had decreased (P < 0.05) CD in the duodenum, IL-6 gene expression in the jejunum and rectal temperature at 24 h post-challenge. Pigs fed fermented barley diets showed greater (P < 0.05) faecal abundance of Clostridium Cluster IV and Lactobacilli than those fed UCC diet. Ferm2-fed pigs showed lower (P < 0.05) concentrations of band cells, eosinophils and lymphocytes at 6, 24 and 48 h after challenge, respectively, and lower (P < 0.05) faecal abundance of Enterobacteriaceae 24 h after challenge than the Ferm1-fed pigs. In conclusion, the substitution of unfermented barley with fermented barley in a nursery diet showed similar results as those shown by AGP supplementation in terms of enhancing the intestinal morphology and modulating faecal microbiota composition, as well as down-regulating the pro-inflammatory cytokines; therefore, fermented barley can be a possible nutritional strategy for managing nursery pigs fed diets without in-feed AGP.
To determine the baseline individual characteristics that predicted symptom recovery and functional recovery at 10-years following the first episode of psychosis.
AESOP-10 is a 10-year follow up of an epidemiological, naturalistic population-based cohort of individuals recruited at the time of their first episode of psychosis in two areas in the UK (South East London and Nottingham). Detailed information on demographic, clinical, and social factors was examined to identify which factors predicted symptom and functional remission and recovery over 10-year follow-up. The study included 557 individuals with a first episode psychosis. The main study outcomes were symptom recovery and functional recovery at 10-year follow-up.
At 10 years, 46.2% (n = 140 of 303) of patients achieved symptom recovery and 40.9% (n = 117) achieved functional recovery. The strongest predictor of symptom recovery at 10 years was symptom remission at 12 weeks (adj OR 4.47; CI 2.60–7.67); followed by a diagnosis of depression with psychotic symptoms (adj OR 2.68; CI 1.02–7.05). Symptom remission at 12 weeks was also a strong predictor of functional recovery at 10 years (adj OR 2.75; CI 1.23–6.11), together with being from Nottingham study centre (adj OR 3.23; CI 1.25–8.30) and having a diagnosis of mania (adj OR 8.17; CI 1.61–41.42).
Symptom remission at 12 weeks is an important predictor of both symptom and functional recovery at 10 years, with implications for illness management. The concepts of clinical and functional recovery overlap but should be considered separately.
Item 9 of the Patient Health Questionnaire-9 (PHQ-9) queries about thoughts of death and self-harm, but not suicidality. Although it is sometimes used to assess suicide risk, most positive responses are not associated with suicidality. The PHQ-8, which omits Item 9, is thus increasingly used in research. We assessed equivalency of total score correlations and the diagnostic accuracy to detect major depression of the PHQ-8 and PHQ-9.
We conducted an individual patient data meta-analysis. We fit bivariate random-effects models to assess diagnostic accuracy.
16 742 participants (2097 major depression cases) from 54 studies were included. The correlation between PHQ-8 and PHQ-9 scores was 0.996 (95% confidence interval 0.996 to 0.996). The standard cutoff score of 10 for the PHQ-9 maximized sensitivity + specificity for the PHQ-8 among studies that used a semi-structured diagnostic interview reference standard (N = 27). At cutoff 10, the PHQ-8 was less sensitive by 0.02 (−0.06 to 0.00) and more specific by 0.01 (0.00 to 0.01) among those studies (N = 27), with similar results for studies that used other types of interviews (N = 27). For all 54 primary studies combined, across all cutoffs, the PHQ-8 was less sensitive than the PHQ-9 by 0.00 to 0.05 (0.03 at cutoff 10), and specificity was within 0.01 for all cutoffs (0.00 to 0.01).
PHQ-8 and PHQ-9 total scores were similar. Sensitivity may be minimally reduced with the PHQ-8, but specificity is similar.
Intake of the plant-derived n-3 fatty acid α-linolenic acid (ALA) has been associated with anti-atherosclerotic properties. However, information on the association between ALA intake and development of peripheral artery disease (PAD) is lacking. In this follow-up study, we investigated the association between dietary intake of ALA and the rate of PAD among middle-aged Danish men and women enrolled into the Danish Diet, Cancer and Health cohort between 1993 and 1997. Incident PAD cases were identified through the Danish National Patient Register. Intake of ALA was assessed using a validated FFQ. Statistical analyses were performed using Cox proportional hazard regression allowing for separate baseline hazards among sexes and adjusted for established risk factors for PAD. During a median of 13·6 years of follow-up, we identified 950 valid cases of PAD with complete information on covariates. The median energy-adjusted ALA intake within the cohort was 1·76 g/d (95 % central range: 0·94–3·28). In multivariable analyses, we found no statistically significant association between intake of ALA and the rate of PAD (P = 0·339). Also, no statistically significant associations were observed in analyses including additional adjustment for co-morbidities and in sex-specific analyses. In supplemental analyses with additional adjustment for potential dietary risk factors, we found a weak inverse association of PAD with ALA intake above the median, but the association was not statistically significant (P = 0·314). In conclusion, dietary intake of ALA was not consistently associated with decreased risk of PAD.
With increasing numbers of children growing up with conditions that are associated with acquired brain injury, efficient neuropsychological screening for cognitive deficits is pivotal. Brief self-report measures concerning daily complaints can play an important role in such screening. We translated and adapted the pediatric perceived cognitive functioning (PedsPCF) self- and parent-report item bank to Dutch. This study presents (1) psychometric properties, (2) a new short form, and (3) normative data for the short form.
A general population sample of children and parents was recruited. Dimensionality of the PedsPCF was assessed using confirmatory factor analyses and exploratory bifactor analyses. Item response theory (IRT) modeling was used to evaluate model fit of the PedsPCF, to identify differential item functioning (DIF), and to select items for the short form. To select short-form items, we also considered the neuropsychological content of items.
In 1441 families, a parent and/or child participated (response rate 66% at family level). Assessed psychometric properties were satisfactory and the predominantly unidimensional factor structure of the PedsPCF allowed for IRT modeling using the graded response model. One item showed meaningful DIF. For the short form, 10 items were selected.
In this first study of the PedsPCF outside the United States, studied psychometric properties of the translated PedsPCF were satisfactory, and allowed for IRT modeling. Based on the IRT analyses and the content of items, we proposed a new 10-item short form. Further research should determine the relation of PedsPCF outcomes with neurocognitive measures and its ability to facilitate neuropsychological screening in clinical practice.
Given the challenges in accurately identifying unexposed controls in case–control studies of diarrhoea, we examined diarrhoea incidence, subclinical enteric infections and growth stunting within a reference population in the Global Enteric Multicenter Study, Kenya site. Within ‘control’ children (0–59 months old without diarrhoea in the 7 days before enrolment, n = 2384), we examined surveys at enrolment and 60-day follow-up, stool at enrolment and a 14-day post-enrolment memory aid for diarrhoea incidence. At enrolment, 19% of controls had ⩾1 enteric pathogen associated with moderate-to-severe diarrhoea (‘MSD pathogens’) in stool; following enrolment, many reported diarrhoea (27% in 7 days, 39% in 14 days). Controls with and without reported diarrhoea had similar carriage of MSD pathogens at enrolment; however, controls reporting diarrhoea were more likely to report visiting a health facility for diarrhoea (27% vs. 7%) or fever (23% vs. 16%) at follow-up than controls without diarrhoea. Odds of stunting differed by both MSD and ‘any’ (including non-MSD pathogens) enteric pathogen carriage, but not diarrhoea, suggesting control classification may warrant modification when assessing long-term outcomes. High diarrhoea incidence following enrolment and prevalent carriage of enteric pathogens have implications for sequelae associated with subclinical enteric infections and for design and interpretation of case–control studies examining diarrhoea.