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 firstname.lastname@example.org
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.
Schizophrenia is associated with robust hippocampal volume deficits but subregion volume deficits, their associations with cognition, and contributing genes remain to be determined.
Hippocampal formation (HF) subregion volumes were obtained using FreeSurfer 6.0 from individuals with schizophrenia (n = 176, mean age ± s.d. = 39.0 ± 11.5, 132 males) and healthy volunteers (n = 173, mean age ± s.d. = 37.6 ± 11.3, 123 males) with similar mean age, gender, handedness, and race distributions. Relationships between the HF subregion volume with the largest between group difference, neuropsychological performance, and single-nucleotide polymorphisms were assessed.
This study found a significant group by region interaction on hippocampal subregion volumes. Compared to healthy volunteers, individuals with schizophrenia had significantly smaller dentate gyrus (DG) (Cohen's d = −0.57), Cornu Ammonis (CA) 4, molecular layer of the hippocampus, hippocampal tail, and CA 1 volumes, when statistically controlling for intracranial volume; DG (d = −0.43) and CA 4 volumes remained significantly smaller when statistically controlling for mean hippocampal volume. DG volume showed the largest between group difference and significant positive associations with visual memory and speed of processing in the overall sample. Genome-wide association analysis with DG volume as the quantitative phenotype identified rs56055643 (β = 10.8, p < 5 × 10−8, 95% CI 7.0–14.5) on chromosome 3 in high linkage disequilibrium with MOBP. Gene-based analyses identified associations between SLC25A38 and RPSA and DG volume.
This study suggests that DG dysfunction is fundamentally involved in schizophrenia pathophysiology, that it may contribute to cognitive abnormalities in schizophrenia, and that underlying biological mechanisms may involve contributions from MOBP, SLC25A38, and RPSA.
The role that changes in the crystal temperature and the doping concentration play in shaping the character of the steady-state and transient transport response of electrons within bulk wurtzite zinc oxide will be examined. Monte Carlo electron transport simulations are drawn upon for the purposes of this analysis. We find that both the crystal temperature and the doping concentration greatly influence the character of the steady-state and transient electron transport response. In particular, for the case of steady-state electron transport, the peak drift velocity decreases by 30% as the crystal temperature is increased from 100 to 700 K, this decrease in velocity being only 20% as the doping concentration is increased from 1015 to 1019 cm-3. The impact on the transient electron drift velocity is not as acute.
To identify the intracochlear electrode position in cochlear implant recipients and determine the correlation to speech perception for two peri-modiolar electrode arrays.
Post-operative cone-beam computed tomography images of 92 adult recipients of the ‘CI512’ electrode and 18 adult recipients of the ‘CI532’ electrode were analysed. Phonemes scores were recorded pre-implantation, and at 3 and 12 months post-implantation.
All CI532 electrodes were wholly within scala tympani. Of the 79 CI512 electrodes intended to be in scala tympani, 58 (73 per cent) were in scala tympani, 14 (17 per cent) were translocated and 7 (9 per cent) were wholly in scala vestibuli. Thirteen CI512 electrodes were deliberately inserted into scala vestibuli. Speech perception scores for post-lingual recipients were higher in the scala tympani group (69.1 per cent) compared with the scala vestibuli (54.2 per cent) and translocation (50 per cent) groups (p < 0.05). Electrode location outside of scala tympani independently resulted in a 10.5 per cent decrease in phoneme scores.
Cone-beam computed tomography was valuable for demonstrating electrode position. The rate of scala tympani insertion was higher in CI532 than in CI512 electrodes. Scala vestibuli insertion and translocation were associated with poorer speech perception outcomes.
We present some recently acquired results corresponding to the nature of the electron transport that occurs within bulk alloys of zinc-magnesium-oxide. These results are obtained using three-valley ensemble semi-classical Monte Carlo electron transport simulations. The impact that the magnesium content plays in shaping the form of the electron transport related characteristics associated with this alloy system is explored. Both steady-state and transient electron transport results are examined. The device implications of these results are then commented upon.
Schizophrenia (SZ) is a severe neuropsychiatric disorder associated with disrupted connectivity within the thalamic-cortico-cerebellar network. Resting-state functional connectivity studies have reported thalamic hypoconnectivity with the cerebellum and prefrontal cortex as well as thalamic hyperconnectivity with sensory cortical regions in SZ patients compared with healthy comparison participants (HCs). However, fundamental questions remain regarding the clinical significance of these connectivity abnormalities.
Resting state seed-based functional connectivity was used to investigate thalamus to whole brain connectivity using multi-site data including 183 SZ patients and 178 matched HCs. Statistical significance was based on a voxel-level FWE-corrected height threshold of p < 0.001. The relationships between positive and negative symptoms of SZ and regions of the brain demonstrating group differences in thalamic connectivity were examined.
HC and SZ participants both demonstrated widespread positive connectivity between the thalamus and cortical regions. Compared with HCs, SZ patients had reduced thalamic connectivity with bilateral cerebellum and anterior cingulate cortex. In contrast, SZ patients had greater thalamic connectivity with multiple sensory-motor regions, including bilateral pre- and post-central gyrus, middle/inferior occipital gyrus, and middle/superior temporal gyrus. Thalamus to middle temporal gyrus connectivity was positively correlated with hallucinations and delusions, while thalamus to cerebellar connectivity was negatively correlated with delusions and bizarre behavior.
Thalamic hyperconnectivity with sensory regions and hypoconnectivity with cerebellar regions in combination with their relationship to clinical features of SZ suggest that thalamic dysconnectivity may be a core neurobiological feature of SZ that underpins positive symptoms.
To investigate the effectiveness and usability of automated procedural guidance during virtual temporal bone surgery.
Two randomised controlled trials were performed to evaluate the effectiveness, for medical students, of two presentation modalities of automated real-time procedural guidance in virtual reality simulation: full and step-by-step visual presentation of drillable areas. Presentation modality effectiveness was determined through a comparison of participants’ dissection quality, evaluated by a blinded otologist, using a validated assessment scale.
While the provision of automated guidance on procedure improved performance (full presentation, p = 0.03; step-by-step presentation, p < 0.001), usage of the two different presentation modalities was vastly different (full presentation, 3.73 per cent; step-by-step presentation, 60.40 per cent).
Automated procedural guidance in virtual temporal bone surgery is effective in improving trainee performance. Step-by-step presentation of procedural guidance was engaging, and therefore more likely to be used by the participants.
We examine how stress has the potential to shape the character of the electron transport that occurs within ZnO. In order to narrow the scope of this analysis, we focus on a determination of the velocity-field characteristics associated with bulk wurtzite ZnO. Monte Carlo simulations of the electron transport are pursued for the purposes of this analysis. Rather than focusing on the impact of stress in of itself, instead we focus on the changes that occur to the energy gap through the application of stress, i.e., energy gap variations provide a proxy for the amount of stress. Our results demonstrate that stress plays a significant role in shaping the form of the velocity-field characteristics associated with ZnO. This dependence could potentially be exploited for device application purposes.
To investigate the importance of anatomical variation in acquiring skills in virtual reality cochlear implant surgery.
Eleven otolaryngology residents participated in this study. They were randomly allocated to practice cochlear implant surgery on the same specimen or on different specimens for four weeks. They were then tested on two new specimens, one standard and one challenging. Videos of their performance were de-identified and reviewed independently, by two blinded consultant otolaryngologists, using a validated assessment scale. The scores were compared between groups.
On the standard specimen, the round window preparation score was 2.7 ± 0.4 for the experimental group and 1.7 ± 0.6 for the control group (p = 0.01). On the challenging specimen, instrument handling and facial nerve preservation scores of the experimental group were 3.0 ± 0.4 and 3.5 ± 0.7 respectively, while the control group received scores of 2.1 ± 0.8 and 2.4 ± 0.9 respectively (p < 0.05).
Training on temporal bones with differing anatomies is beneficial in the development of expertise.
A single question (SQ) and a twenty-eight-item FFQ to measure takeaway meal intake were compared with two 7-d estimated food records (EFR; reference method). Test methods were completed after the reference period and repeated 6–8 d later for repeatability. The SQ asked about intake of high-SFA takeaway meals. FFQ items included low- and high-SFA meals. Test methods were compared with EFR for sensitivity, specificity, and positive and negative predictive values, using a goal of ≤1 high-SFA weekly takeaway meals. Bland–Altman analyses were used to check agreement between measurement approaches, the κ coefficient was used to summarise the observed level of agreement, and Spearman’s correlation was used to assess the degree to which instruments ranked individuals. Young adults were recruited from two universities, and 109 participants (61 % female) completed the study. The mean age was 24·4 (sd 4·9) years, and the mean BMI was 23·5 (sd 3·7) kg/m2. The SQ and the FFQ had a sensitivity of 97 and 83 % and a specificity of 46 and 92 %, respectively. Both methods exhibited moderate correlation for measuring total and high-SFA takeaway meal intakes (rs ranging from 0·64 to 0·80). Neither instrument could measure precise, absolute intake at the group or individual level. Test methods ranged from fair (κw=0·24) to moderate agreement (κw=0·59). The repeatability for all was acceptable. The FFQ identified excessive high-SFA takeaway meal intake and measured individuals’ category for total and high-SFA takeaway intakes. Both methods are suitable for ranking individuals for total or high-SFA takeaway meal intakes.
Zinc oxide has recently been touted as a material that may prove useful for high-power and high-frequency electron device applications. Unfortunately, at the present moment at least, zinc oxide’s electron transport results are based upon material parameter selections that remain disputed, i.e., their exact values have yet to be satisfactorily resolved. In order to establish how the expected range of disputed material parameter values influence the corresponding electron transport results, this paper assesses the sensitivity of the electron transport results associated with zinc oxide to variations in these disputed material parameters. The disputed material parameters that we focus on for the purposes of this particular analysis include the non-parabolicity coefficient associated with the lowest energy conduction band valley, the conduction band inter-valley energy separation, and the effective mass associated with the electrons in the upper energy conduction band valleys. For the purposes of this analysis, steady-state electron transport results are the focus of this sensitivity analysis, the velocity-field characteristic associated with zinc oxide being the principal metric of concern. We find that increases in the non-parabolicity coefficient associated with the lowest energy conduction band valley lead to increases in the peak field of the velocity-field characteristic and initially an increase and then a decrease in the peak electron drift velocity of this material. Increases in the conduction band inter-valley energy separation are instead found to result in increases in the peak field and concomitant increases in the peak electron drift velocity. Finally, increases in the effective mass associated with the electrons in the upper energy conduction band valleys are found to lead to a sharpening of the slope of the velocity-field characteristic in the region beyond the peak field, greater effective mass leading to a greater magnitude slope. Based on the magnitude of these variations, we conclude that zinc oxide may indeed be considered as a material for high-power and high-frequency electron device applications even when the variations in these disputed material parameters have been accounted for.
The Durban Diabetes Study (DDS) is a population-based cross-sectional survey of an urban black population in the eThekwini Municipality (city of Durban) in South Africa. The survey combines health, lifestyle and socioeconomic questionnaire data with standardised biophysical measurements, biomarkers for non-communicable and infectious diseases, and genetic data. Data collection for the study is currently underway and the target sample size is 10 000 participants. The DDS has an established infrastructure for survey fieldwork, data collection and management, sample processing and storage, managed data sharing and consent for re-approaching participants, which can be utilised for further research studies. As such, the DDS represents a rich platform for investigating the distribution, interrelation and aetiology of chronic diseases and their risk factors, which is critical for developing health care policies for disease management and prevention. For data access enquiries please contact the African Partnership for Chronic Disease Research (APCDR) at email@example.com or the corresponding author.
At the present moment, zinc oxide is primarily being used as an electronic material for low-field thin-film transistor and transparent conducting oxide device applications. In this paper, we present some recent results on the steady-state electron transport within zinc oxide suggesting that this material may also be considered as an alternative material to gallium nitride for high-power and high-frequency electron device applications. The expected device performance that may be obtained from zinc oxide-based devices is then projected and contrasted with that expected from gallium nitride-based devices. It is shown that zinc oxide-based devices have a slight advantage when compared with the case of gallium nitride.
Hospitalizations for acute bacterial skin and skin structure infection (ABSSSI) are common. Optimizing antibiotic use for ABSSSIs requires an understanding of current management. The objective of this study was to evaluate antibiotic prescribing practices and factors affecting prescribing in a diverse group of hospitals
Multicenter, retrospective cohort study.
Seven community and academic hospitals.
Children and adults hospitalized between June 2010 and May 2012 for cellulitis, wound infection, or cutaneous abscess were eligible. The primary endpoint was a composite of 2 prescribing practices representing potentially avoidable antibiotic exposure: (1) use of antibiotics with a broad spectrum of activity against gram-negative bacteria or (2) treatment duration greater than 10 days.
A total of 533 cases were included: 320 with nonpurulent cellulitis, 44 with wound infection or purulent cellulitis, and 169 with abscess. Of 492 cases with complete prescribing data, the primary endpoint occurred in 394 (80%) cases and varied significantly across hospitals (64%–97%; P < .001). By logistic regression, independent predictors of the primary endpoint included wound infection or purulent cellulitis (odds ratio [OR], 5.12 [95% confidence interval (CI)], 1.46–17.88), head or neck involvement (OR, 2.83 [95% CI, 1.17–6.82]), adult cases (OR, 2.20 [95% CI, 1.18–4.11]), and admission to a community hospital (OR, 1.90 [95% CI, 1.05–3.44]).
Among patients hospitalized for ABSSSI, use of antibiotics with broad gram-negative activity or treatment courses longer than 10 days were common. There may be substantial opportunity to reduce antibiotic exposure through shorter courses of therapy targeting gram-positive bacteria.
Infect Control Hosp Epidemiol 2014;35(10):1241–1250
We examine the electron transport that occurs within a zinc-oxide-based two-dimensional electron gas using Monte Carlo simulations. The sensitivity of the results to variations in the lowest energy conduction band valley electron effective mass is examined. Increased values of the electron effective mass result in diminished electron drift velocities and reduced sensitivity to the free electron concentration. In agreement with our previous studies for a fixed value of the electron effective mass , we find that the reduced scattering due to the screening of the impurity and polar optical scattering leads to a slightly higher mobility of the 2DEG at low-fields but reduces the peak velocity, since gaining a higher energy due to the reduced polar optical phonon scattering enhances the effects of the non-parabolicity within this material.
To assess the epidemiology of vestibular vertigo, including the new entity of vestibular migraine, in a neuro-otology clinic population in the biggest public hospital in Thailand.
Study design and setting:
A prospective study involving all patients presenting to the neuro-otology clinic in the Rajavithi Hospital in Bangkok between November 2007 and November 2008.
Subjects and methods:
The population studied consisted of adults referred to the neuro-otology clinic. Accepted international criteria and standardised otological and, when necessary, psychiatric assessment were applied to establish each diagnosis. The association between diagnoses and potential triggers was explored.
Of the 167 patients assessed, the most prevalent conditions encountered were benign paroxysmal positional vertigo and vestibular migraine. The prevalence of vestibular migraine was 29.3 per cent. No cases of Ménière's disease were encountered. An association was found between vestibular migraine and inadequate sleep, insomnia and changes of head position.
This study provides current data on the epidemiology of vestibular vertigo in a Thai neuro-otology out-patient population. The results include data on the prevalence of the new diagnostic entity of vestibular migraine, and on its association with potential triggers.
We employ Monte Carlo simulations of the electron transport that occurs within the two-dimensional electron gas formed at a ZnO/ZnMgO heterojunction. Steady-state and transient electron transport results are presented. We find that at high fields, increases in the free electron concentration result in decreases in the electron drift velocities.