DFT/NEGF study of discrete dopants in Si/III-V 3D FET.

In this work, electron densities around dopants in Si and GaAs have been calculated using density functional theory (DFT) calculations. These extracted densities have been used to describe dopants in an in-house non-equilibrium Green functions device simulator. The transfer characteristics of nanowire gate all around field effect transistor have been calculated using DFT electron densities. These transport calculations were compared with those using a point charge model of the dopant. The dopants are located in the middle of the channel of the device. Specifically, DFT calculations of a 512 atom Si supercell with a single impurity atom have been carried out, both phosphorous and boron atoms have been used as donor and acceptor impurities respectively. The calculations were repeated on a gallium arsenide supercell, where the silicon atom substituted gallium and arsenide to act as donor and acceptor respectively. We found that for donors and acceptors, the DFT charge distribution extends similarly in both materials. In addition, the relaxed structure produces a 50% larger spread of electronic charge as compared with unrelaxed Si and GaAs. The extracted current voltage characteristics of the devices are altered significantly using the charge density obtained by DFT. At 0.7 V the current in Si is 20% larger using the DFT charge density compared to the point charge model for donors. Whereas the current using the point charge model in GaAs is 2.5 times larger than the distributed charge. Devices exhibit substantial tunnelling currents for donors and acceptors irrespective of the model of the dopant considered. In GaAs, this was 76% using a point charge and 78% using the distributed charge when using a donor; 61% and 68% in Si respectively. The tunnelling current using acceptors for Si was 100% and 99% using GaAs for both models.

Mass spectrometric evidence for the modification of small molecules in a cobalt-60-irradiated rodent diet.

The purpose of this study was to investigate the effect of radiation on the content of animal diet constituents using global metabolomics. Aqueous methanolic extracts of control and cobalt-60-irradiated Teklad 7001 diets were comprehensively analyzed using nano-liquid chromatography-MS/MS. Among the over 2000 ions revealed by XCMS followed by data preprocessing, 94 positive and 143 negative metabolite ions had greater than 1.5-fold changes and p-values <0.01. Use of MetaboAnalyst statistical software demonstrated complete separation of the irradiated and non-radiated diets in unsupervised principal components analysis and supervised partial least squares discriminant analysis. Irradiation led to an increase in the content of phytochemicals such as glucosinolates and oxidized lipids in the diet. Twenty-eight metabolites that were significantly changed in the irradiated samples were putatively identified at the level of molecular formulae by MS/MS. MS/MSALL analysis of chloroform-methanol extracts of the irradiated diet showed increased levels of a number of unique linoleic acid-derived branched fatty acid esters of hydroxy fatty acids. These data imply that gamma irradiation of animal diets causes chemical changes to dietary components, which in turn may influence the risk of mammary cancer. Copyright © 2017 John Wiley & Sons, Ltd.

Standards of prescription writing in a long-term psychogeriatric unit: a series of clinical audits.

OBJECTIVE: The aim of this study was to improve the quality of prescription writing in a long-term psychogeriatric inpatient unit by a combination of serial audits and interventions designed to address the identified deficiencies. METHODS: We undertook three clinical audits of the prescription sheets used in an inpatient unit providing continuing care for residents with severe and enduring mental illness and dementia. Based on the findings of the first audit a set of prescribing guidelines was implemented into the ward. Following the second audit a new prescription sheet was developed. The format of the new prescription sheet was designed to account for the needs of the unit and to adhere to Irish and UK best practise guidelines. Two months after its introduction we undertook a third audit. RESULTS: Completion of the drug sensitivity box increased from 25% at audit one to 100% at audit three. Other specific aspects of prescription writing that had been poor at the beginning of the audit cycle also showed improvement: prescribing of generic psychotropic drugs increased by 69% and inclusion of the prescribers Medical Council Registration Number increased by 78%. However, some basic aspects of prescription writing remained weak such as frequency of drug administration and documentation of the stop/review date for 'as required' medication. CONCLUSION: The results of this study suggest that clinical audit and feedback can improve the quality of prescriptions in an in-patient setting.

Mental health professionals and information sharing: carer perspectives.

BACKGROUND: The important role played by carers of those with mental health problems is frequently undervalued among healthcare professionals. AIMS: To identify the difficulties encountered by carers in relation to obtaining information from mental health teams. METHODS: Participants in the study included carers or family members of persons with mental illness who were affiliated with a support group in Ireland. Information was gathered using an 18-item self-report questionnaire. This is an amended version of the Carer Well-Being and Support Questionnaire for carers of people with a mental health problem or dementia. RESULTS: One-hundred and fifty-nine carers complete the questionnaire. On average respondents stated that they have been in the role of a carer for someone with a mental health problem for 14.4 years, spending a median of 20-h caring each week. Despite most carers maintaining that they are generally satisfied with the support offered to them from medical and/or care staff, the majority (56.3%) of respondents stated that they have specifically encountered difficulties accessing information from the treating mental health team. The main reasons given to them by the mental health team for withholding information include: lack of patient consent (46.2%) and unavailability of a team member (46.2%). From a carer perspective, respondents stated that the main reason they feel there is difficulty in accessing information is a lack of concern for their role as a carer in the patient's management (60.5%). More than 75% of all respondents are afraid of negative consequences for them or for the person in their care as a result of information being withheld by the treating team. CONCLUSIONS: Carer involvement is essential for the complete and effective management of individuals with mental illness. Confidentiality should not be used as a reason for completely excluding carers.

Who gets admitted? Study of referrals and admissions to an adolescent psychiatry inpatient facility over a 6-month period.

BACKGROUND: Child and adolescent psychiatry services have historically been neglected in Ireland, in terms of resource provision and research. AIM: To describe referral and admission patterns to an adolescent inpatient unit in Ireland. METHODS: We studied reasons for referral and admission decisions relating to all adolescents referred to St. Joseph's Adolescent Inpatient Unit (AIPU), Dublin in the first 6 months following its establishment in 2009. RESULTS: Forty-one adolescents were referred during the study period; 46 % were admitted. There was no difference between those admitted and not admitted in terms of gender (two-thirds were female), age (mean age 16.2 years), most common reason for referral (depression, in almost one-in-two) and suicidality (present in one-in-two). Amongst those referred, 46 % were resident in the primary catchment area. While a majority of admissions occurred within 5 days of referral (53 %), a significant minority were not admitted until over 20 days after referral (16 %). CONCLUSIONS: The demographic and clinical characteristics of adolescents referred and admitted to St. Joseph's AIPU are consistent with national and international patterns. At national level, the opening of additional beds for adolescents (such as St. Joseph's AIPU) has had positive effects on admission patterns; our findings indicate a need to further educate referrers about referral criteria, to optimise benefits derived from these new resources. Future studies could examine the potential roles of intensive support services in the community to further maximise use of scarce resources for this patient group.

Modelling the cost-effectiveness of sentinel lymph node mapping and adjuvant interferon treatment for stage II melanoma.

Clinical studies have demonstrated that high dose adjuvant interferon therapy improves disease-free and overall survival among high risk (stage IIb and III) melanoma patients. Sentinel lymph node mapping (SLM) has been shown to accurately detect micrometastasis and may be used to identify higher risk stage II patients, who might benefit most from adjuvant interferon therapy. We modelled the cost-effectiveness of first testing with SLM and then treating with adjuvant interferon (IFN) therapy for stage II melanoma. We used a decision analytical model to compare four strategies for stage II patients after surgical excision of their melanoma: (1) treat all with low dose IFN; (2) test first with SLM and then treat only those with positive micrometastasis with high dose IFN; (3) test first with SLM and treat positives with high dose IFN and negatives with low dose IFN (test and treat appropriately); and (4) surgery only. Treatment, toxicity, follow-up and relapse costs were included over a 5 year time period. The primary outcome was cost per quality-adjusted relapse-free life year saved. Our analysis shows that, compared with the current surgery-only strategy, all three treatment strategies provide incremental benefits. The test and treat appropriately strategy is the most effective, with an incremental improvement of 0.64 quality-adjusted life-years (QALY). The cost-effectiveness of test and treat some with high dose IFN compared with the surgery-only strategy is $18,700/QALY. The test and treat appropriately strategy is also cost-effective compared with test and treat some at $31,100/QALY. In conclusion appropriate dosing of IFN therapy based on the results of SLM is a cost-effective strategy for stage II melanoma patients.

Model of estimated rates of colorectal cancer from polyp growth by year of surveillance.

OBJECTIVE: Most studies show protective effects of non-steroidal anti-inflammatory drugs (NSAIDs) against polyps and colorectal cancers (CRCs) of up to 50%. Current models are unable to directly estimate changes in effects of chemoprevention on CRCs. The purpose is to develop a model to examine effects of changes in growth rates of polyps on surveillance intervals and risk of CRC. METHODS: The growth model simulates 500 people after polypectomy, estimating number and size of polyps annually over 10 years. Each polyp is assigned a random growth rate consistent with distributions of empirically observed growth assumed to follow a log linear model. Rates of CRC were calculated from largest polyps distributed to people. RESULTS: Simulated distributions of polyps and CRCs closely match empirical estimates which confirms the usefulness of the model. If polyp growth is 25% of normal, the number of cancers by year 10 after index colonoscopy decrease from 146 to only 57/100 000 for those in risk group 0 (no polyps at index colonoscopy) and from 840 to 124/100 000 for those of risk group 3 (4 or more polyps). CONCLUSIONS: This is the first model based on polyp growth rates. The CRC rates suggest that for those with no polyps on index colonoscopy, surveillance may be as for people of average risk (7-10 years), whereas those with one polyp or more need more surveillance (2-5 years). The use of the model is the indication that surveillance intervals could be increased by as much as 2-10 years if the growth rates of polyps are slowed.

Foot and ankle injuries in motor vehicle accidents.

BACKGROUND: We studied foot and ankle (F/A) injuries that occurred in motor vehicle accidents treated in a Level 1 trauma center. METHODS: The records of F/A injuries of 2248 consecutive orthopedic patients were reviewed to find foot and ankle injuries. RESULTS: Pilon fractures were common. Motor Vehicle Accident (MVA) occupants with F/A injuries had a higher injury Severity Score than those without (17.9 vs. 11.6, p <. 001). MVA F/A injury risk was higher without restraint [relative risk ratio (rrr) 1.68, p <. 0032] than with restraint except for air bagged drivers who were similar to unrestrained drivers (rrr 1.18, p > .05, NS). CONCLUSION: Patients with F/A injuries may have serious associated injuries. Air bags may not protect feet.

Longitudinal assessment of economic burden and clinical outcomes in acromegaly.

OBJECTIVE: To determine costs and outcomes over time for surgical and various medical regimens in the management of patients with acromegaly. METHODS: We studied a sample of 53 consecutive Canadian patients with acromegaly who underwent a transsphenoidal pituitary surgical procedure only (N = 27) or in conjunction with medical therapy (N = 26). Outcomes were analyzed as person-months spent in various health state outcomes, which were defined on the basis of growth hormone and insulin-like growth factor I levels. Costs are reported in 1998 Canadian dollars. RESULTS: The mean duration of follow-up was 49 months. Of the 53 patients, 25 (47%) had microadenomas at admission. Patients spent as much as 65% of the time in "uncured" health states. Patients with less extensive disease had better outcomes. The mean annual cost per patient was $8,111 (95% confidence interval, $5,848 to $10,374). Medications were the largest contributor to overall cost (38%). Although per patient surgical costs themselves were high (ranging from approximately $2,800 to $9,200), when averaged over the 4 years the mean annual cost was approximately $2,400, less than the cost of medications. Treatment of macroadenomas cost more than treatment of microadenomas ($11,425 versus $4,442 annually). The treatment of acromegaly costs $14.7 million annually in Canada (95% confidence interval, $10.6 to $18.8 million) and, if patterns of care are similar, about $139 million annually in the United States. CONCLUSION: Treatment of acromegaly is no more costly than therapy for other chronic diseases, especially those with a surgical component. Early diagnosis (at the stage of microadenoma) resulted in better outcomes and lower costs. Thus, from the standpoint of economics and well-being, a continued aggressive attitude toward screening programs and treatment of persistently active acromegaly seems warranted.

Building the Hospital Without Walls--a CSIRO home telecare initiative.

Aging populations and rising health costs have created the need to care for more patients in their own homes. Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) is developing a project, Hospital Without Walls, which aims to provide continuous monitoring of patients in certain diagnostic categories. The key technology is a miniature, wearable, low-power radio that can transmit vital sign and activity information to a home computer, from which data may be sent by telephone line and the Internet to appropriate medical professionals. The initial clinical scenario for this work is monitoring of elderly patients who have presented to hospitals following repeated falls. Accelerometers built into the radio sets will monitor activity and detect and characterise falls. Simultaneous measurement of heart rate will provide information about abnormalities of cardiovascular physiology at the time of a fall. The system has been tested in laboratory conditions and is being adapted for initial clinical trials.

Elastography--the movement begins.

The advent of real-time ultrasound in the 1970s, together with a growing interest in tissue characterization, led to a number of investigators using the nature of tissue motion to distinguish healthy from diseased tissue. Our group at the (then) Ultrasonics Institute demonstrated the use of phase methods for detecting very small tissue motions, using natural stimuli. The method could also be applied in the lag (autocorrelation) domain to directly measure the amount of deformation to high accuracy. This method was also applied to measuring the amount of dilatation of blood vessels using both conventional and intravascular ultrasound. A basic limitation of these techniques was the poor spatial resolution, and quasistatic methods soon replaced this method of measuring tissue deformation. However, a new way of assessing the health of tissues had been established.

Pancreatic cancer: total costs and utilization of health services.

BACKGROUND AND OBJECTIVES: Pancreatic cancer ranks 11th in incidence, and fifth in cancer deaths, with 29,000 affected annually. Accurate estimates of the cost of pancreatic cancer are unavailable; existing estimates are variable or not generalizable. This paper presents detailed cost estimates for pancreatic cancer by service, age, and gender. METHODS: Direct and indirect societal costs are determined using a prevalence-based, human capital approach. RESULTS: Total annual costs are $4.9 billion, (men: $3.0 billion, women: $1.9 billion). Total direct costs are $881 million, with 71% ($627.1 M/$881.3 M) for those over 65 years. Total hospital costs are 77% ($679.5 M/$881.3 M) of total direct costs. Total indirect costs are $4.0 billion, with 63% ($2,518.43 M/$4,018 M) for those 45 to 64 years. Mortality costs are $3.7 billion, 93% ($3,739 M/$4,018 M) of indirect costs. CONCLUSIONS: This paper presents cost estimates that are precise and generalizable to the general population. The surgical cost burden may be less than indicated previously, with most hospitalizations not including a major procedure, and average operating room costs accounting for only 9% ($1,045/$11,055) of hospital costs. Women have significantly less cancer-directed surgery than men.

Knowledge-based method for segmentation and analysis of lung boundaries in chest X-ray images.

We present a knowledge-based approach to segmentation and analysis of the lung boundaries in chest X-rays. Image edges are matched to an anatomical model of the lung boundary using parametric features. A modular system architecture was developed which incorporates the model, image processing routines, an inference engine and a blackboard. Edges associated with the lung boundary are automatically identified and abnormal features are reported. In preliminary testing on 14 images for a set of 18 detectable abnormalities, the system showed a sensitivity of 88% and a specificity of 95% when compared with assessment by an experienced radiologist.

Method for segmenting chest CT image data using an anatomical model: preliminary results.

We present an automated, knowledge-based method for segmenting chest computed tomography (CT) datasets. Anatomical knowledge including expected volume, shape, relative position, and X-ray attenuation of organs provides feature constraints that guide the segmentation process. Knowledge is represented at a high level using an explicit anatomical model. The model is stored in a frame-based semantic network and anatomical variability is incorporated using fuzzy sets. A blackboard architecture permits the data representation and processing algorithms in the model domain to be independent of those in the image domain. Knowledge-constrained segmentation routines extract contiguous three-dimensional (3-D) sets of voxels, and their feature-space representations are posted on the blackboard. An inference engine uses fuzzy logic to match image to model objects based on the feature constraints. Strict separation of model and image domains allows for systematic extension of the knowledge base. In preliminary experiments, the method has been applied to a small number of thoracic CT datasets. Based on subjective visual assessment by experienced thoracic radiologists, basic anatomic structures such as the lungs, central tracheobronchial tree, chest wall, and mediastinum were successfully segmented. To demonstrate the extensibility of the system, knowledge was added to represent the more complex anatomy of lung lesions in contact with vessels or the chest wall. Visual inspection of these segmented lesions was also favorable. These preliminary results suggest that use of expert knowledge provides an increased level of automation compared with low-level segmentation techniques. Moreover, the knowledge-based approach may better discriminate between structures of similar attenuation and anatomic contiguity. Further validation is required.

The effect of variations in transducer position and sound speed in intravascular ultrasound: a theoretical study.

The intravascular insonation of a blood vessel in the presence of an impedance interface between blood and the inner vessel wall is studied theoretically. The model, which uses a ray approximation, is three dimensional and allows consideration of arbitrary noncircular lumen shapes. Model results are presented for the image geometry, and the insonating intensity over the vessel wall. It is shown that the inner lumen can be imaged accurately with the transducer at any position within the lumen, and at any forward viewing angle, provided the point of origin of the beam is stationary. If it is not stationary but rotating with the same angular velocity as the beam itself, the inner vessel wall is not mapped accurately. A particular geometric distortion which has been observed in practice is predicted if the transducer is near vessel wall. Acoustic impedance interfaces will be encountered in vascular disease because the speed of sound in fatty plaque is less than in blood, whereas the speed of sound in fibrous and calcified plaque is greater than in blood. A simplified model representation of an atherosclerotic lumen in developed using a cardioid-like curve and a single impedance interface. Model results show that refraction at this interface leads to an intensity distribution which is not uniform around the lumen, and which depends on lumen shape and transducer position. The exception is the special case of a circular lumen with a centrally positioned transducer. Noncircular impedance interfaces encountered in vivo in vascular disease may cause considerable intensity distortion, particularly if the transducer is close to the wall in an irregularly shaped lumen.

Preliminary results from attenuation-slope mapping of plaque using intravascular ultrasound.

Excised femoral and iliac artery segments have been examined with 20 MHz intravascular ultrasound followed by histological assessment. During the ultrasound examinations, radio-frequency (RF) data were recorded digitally, and used for calculating local values of attenuation slope throughout the tissue, using a frequency-domain technique. The RF data were also reconstructed as conventional ultrasound images, and the attenuation-slope information presented as a threshold colour overlay. Areas identified as degenerative plaque in the histological assessments were usually found to correspond to areas of high attenuation slope, and were clearly identified from the pattern of colours on the combined image. Some examples are presented, illustrating the appearance of various pathologies imaged by this technique.

Spectral tissue strain: a new technique for imaging tissue strain using intravascular ultrasound.

Spectral tissue strain (STS) is a new technique for measuring and imaging tissue strain from a set of images using intravascular ultrasound. The technique is based on the Fourier scaling property and uses the chirp z-transform (CZT) to estimate strain within the vessel walls. Some preliminary results, both in vitro and in vivo, are described. A novel display technique has also been developed for encoding radial strain and displaying the resulting colour map as an overlay on the original image.

Measurement of two-dimensional blood velocity vectors by the ultrasonic speckle projection technique.

A technique has been developed for measuring the two in-plane components of blood velocity using ultrasound. The principle is based on analyzing a time sequence of successive images of the speckle pattern, and forming spatial projections of the resulting three-dimensional data set. The mathematics may be understood in terms of sections through a three-dimensional Fourier transform of the original data. The technique has been tested with data from a computer-controlled scanner using a tissue-mimicking phantom, and with data from a commercial ultrasound scanner using images of flowing blood in a jugular vein. In both cases, velocity vectors with many different orientations were measured, demonstrating the feasibility of the method. A less restrictive real-time implementation is suggested.