Transistor Circuits

Contains research objectives and reports on one research project

Transistor and Diode Studies

Contains reports on two research projects.Lincoln Laboratory (Purchase Order DDL-B187)Department of the ArmyDepartment of the NavyDepartment of the Air Force under Contract AF19(122)-45

Transistor Circuits

Contains research objectives and reports on two research projects

Transistor and Diode Studies

Contains reports on four research projects.Lincoln Laboratory (Purchase Order DDL-B187)United States Department of the ArmyUnited States Department of the NavyUnited States Department of the Air Force (Contract AF19(122)-458

Linguistics

Contains reports on five research projects.National Institute of Mental Health (Grant 5 PO1 MH-13390-04

Physical mechanisms of ESCRT-III-driven cell division

Living systems propagate by undergoing rounds of cell growth and division. Cell division is at heart a physical process that requires mechanical forces, usually exerted by assemblies of cytoskeletal polymers. Here we developed a physical model for the ESCRT-III-mediated division of archaeal cells, which despite their structural simplicity share machinery and evolutionary origins with eukaryotes. By comparing the dynamics of simulations with data collected from live cell imaging experiments, we propose that this branch of life uses a previously unidentified division mechanism. Active changes in the curvature of elastic cytoskeletal filaments can lead to filament perversions and supercoiling, to drive ring constriction and deform the overlying membrane. Abscission is then completed following filament disassembly. The model was also used to explore how different adenosine triphosphate (ATP)-driven processes that govern the way the structure of the filament is changed likely impact the robustness and symmetry of the resulting division. Comparisons between midcell constriction dynamics in simulations and experiments reveal a good agreement with the process when changes in curvature are implemented at random positions along the filament, supporting this as a possible mechanism of ESCRT-III-dependent division in this system. Beyond archaea, this study pinpoints a general mechanism of cytokinesis based on dynamic coupling between a coiling filament and the membrane

Brain structural deficits and working memory fMRI dysfunction in young adults who were diagnosed with ADHD in adolescence.

When adolescents with ADHD enter adulthood, some no longer meet disorder diagnostic criteria but it is unknown if biological and cognitive abnorma lities persist. We tested the hypothesis that people diagnosed with ADHD during adolescence present residual brain abnormalities both in brain structure and in working memory brain function. 83 young adults (aged 20-24 years) from the Northern Finland 1986 Birth Cohort were classified as diagnosed with ADHD in adolescence (adolescence ADHD, n = 49) or a control group (n = 34). Only one patient had received medication for ADHD. T1-weighted brain scans were acquired and processed in a voxel-based analysis using permutation-based statistics. A sub-sample of both groups (ADHD, n = 21; controls n = 23) also performed a Sternberg working memory task whilst acquiring fMRI data. Areas of structural difference were used as a region of interest to evaluate the implications that structural abnormalities found in the ADHD group might have on working memory function. There was lower grey matter volume bilaterally in adolescence ADHD participants in the caudate (p < 0.05 FWE corrected across the whole brain) at age 20-24. Working memory was poorer in adolescence ADHD participants, with associated failure to show normal load-dependent caudate activation. Young adults diagnosed with ADHD in adolescence have structural and functional deficits in the caudate associated with abnormal working memory function. These findings are not secondary to stimulant treatment, and emphasise the importance of taking a wider perspective on ADHD outcomes than simply whether or not a particular patient meets diagnostic criteria at any given point in time.This work was supported by an Academy of Finland Award to Dr Veijola; a Sigrid Juselius Foundation grant to Dr Moilanen; a Medical Research Council fellowship to Dr Murray (G0701911); a NARSAD, the Brain and Behavior Research Fund independent investigator award to Dr Miettunen; an Oon Khye Beng Ch'Hia Tsio Studentships in Preventative Medicine awarded by Downing College, Cambridge to Dr Roman-Urrestarazu together with a Becas Chile Doctoral Grant awarded by CONICYT, an Academy of Finland grant and Finnish Medical Foundation grant to Dr Kiviniemi, and an award from the Signe and Ane Gyllenberg Foundation, Finland, to Dr Mäki.. The work was partially conducted with the University of Cambridge Behavioural and Clinical Neuroscience Centre, supported by a joint award from the Medical Research Council (G1000183) and Wellcome Trust (093875/Z/10Z).This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00787-015-0755-

The implications of policy changes on the uptake of a PMTCT programme in rural Malawi: first three years of experience

Objective: To study how the demand for antenatal care (ANC), HIV testing and hospital delivery was influenced by policy changes among pregnant women in rural Malawi. Design: Retrospective analysis of monthly reports. Setting: Malamulo SDA hospital in Thyolo district, Makwasa, Malawi. Methods: Three hospital-based registers were analysed from 2005 to 2007. These were general ANC, delivery and Prevention of Mother to Child Transmission (PMTCT) registers. Observations were documented regarding the introduction of specific policies and when changes were effected. Descriptive analytical methods were used. Results: The ANC programme reached 4,528 pregnant mothers during the study period. HIV testing among the ANC attendees increased from 52.6 to 98.8% after the introduction of routine (opt-out) HIV testing and 15.6% of them tested positive. After the introduction of free maternity services, ANC attendance increased by 42% and the ratio of hospital deliveries to ANC attendees increased from 0.50:1 to 0.66:1. Of the HIV-tested ANC attendees, 52.6% who tested positive delivered in the hospital and got nevirapine at the time of delivery. Conclusions: Increasing maternity service availability and uptake can increase the coverage of PMTCT programmes. Barriers such as economic constraints that prevent women in poor communities from accessing services can be removed by making maternity services free. However, it is likely, particularly in resource-poor settings, that significant increases in PMTCT coverage among those at risk can only be achieved by substantially increasing uptake of general ANC and delivery services.We thank the Swedish Institute, Sweden for the financial support without which the study would have been a non-starter. We are also grateful for the support given by the unit of Epidemiology and Public Health Sciences, Umea University. Furthermore, we thank the management and staff of Malamulo SDA Hospital, P/Bag 2, Makwasa, Malawi for their support throughout the entire period of carrying out the study. This work was undertaken within the Centre for Global Health at Umea University with support from FAS, the Swedish Council for Working Life and Social Research (grant no. 2006-1512).</p

The effect of cartilage and bone density of mushroom-shaped, photooxidized, osteochondral transplants: an experimental study on graft performance in sheep using transplants originating from different species

BACKGROUND: Differences in overall performance of osteochondral photooxidized grafts were studied in accordance of their species origin and a new, more rigorous cleansing procedure using alcohol during preparation. METHODS: Photooxidized mushroom-shaped grafts of bovine, ovine, human and equine origin were implanted in the femoral condyles of 32 sheep (condyles: n = 64). No viable chondrocytes were present at the time of implantation. Grafts were evaluated at 6 months using plastic embedded sections of non-decalcified bone and cartilage specimens. Graft incorporation, the formation of cyst-like lesions at the base of the cartilage junction as well as cartilage morphology was studied qualitatively, semi-quantitatively using a score system and quantitatively by performing histomorphometrical measurements of percentage of bone and fibrous tissue of the original defects. For statistical analysis a factorial analysis of variance (ANOVA- test) was applied. RESULTS: Differences of graft performance were found according to species origin and cleansing process during graft preparation. According to the score system cartilage surface integrity was best for equine grafts, as well as dislocation or mechanical stability. The equine grafts showed the highest percentage for bone and lowest for fibrous tissue, resp. cystic lesions. The new, more rigorous cleansing process decreased cartilage persistence and overall graft performance. CONCLUSION: Performance of grafts from equine origin was better compared to bovine, ovine and human grafts. The exact reason for this difference was not proven in the current study, but could be related to differences in density of cartilage and subchondral bone between species

Communication aid requirements of intensive care unit patients with transient speech loss

Alert and transiently nonvocal intensive care unit (ICU) patients are dependent on augmentative and alternative communication (AAC). Unfortunately, the literature demonstrates that existent AAC devices have not been widely adopted, and unaided methods are often the primary modalities used despite being insufficient, and frustrating. We present the results of a qualitative semi-structured interview study with 8 ex-ICU patients, 4 ICU patient relatives, and 6 ICU staff, exploring their AAC needs and requirements. Participants identified important AAC hardware, software, and content requirements. Salient factors impacting on AAC adoption in the ICU setting were also highlighted and included the need for staff training and bedside patient assessment. Based on the study results, we propose a series of recommendations regarding the design and implementation of future AAC tools specifically targeted at this group