Electronic correlations in oligo-acene and -thiopene organic molecular crystals.

From first-principles calculations we determine the Coulomb interaction between two holes on oligo-acene and -thiophene molecules in a crystal, as a function of the oligomer length. The electronic polarization of the molecules that surround the charged oligomer reduces the bare Coulomb repulsion between the holes by approximately a factor of 2. The effects of relaxing the molecular geometry in the presence of holes is found to be significantly smaller.

The phantom portion of the American College of Radiology (ACR) computed tomography (CT) accreditation program: practical tips, artifact examples, and pitfalls to avoid.

The ACR CT accreditation program, begun in 2002, requires the submission of approximately 20 images, several completed data sheets and printouts of three Excel worksheets. The procedure manual is very detailed, yet participants unfamiliar with the program or having minimal CT experience have needed to redo aspects of their submission, or in some cases do not receive accreditation, due to mistakes made by the physicist. This review of the phantom portion of the ACR CT accreditation program supplements the ACR provided instructions with additional photos of phantom setup, region-of-interest (ROI), and image placement on the film sheets, and examples of completed portions of actual (but anonymous) submissions.

Influence of systematically varied nanoscale topography on the morphology of epithelial cells.

With the knowledge that cells can react to lithographically manufactured nanometer-sized surface objects, our interest concerned whether cells would respond to surface structures of systematically increasing size. Our approach to answer this question was to fabricate surfaces with the same surface chemistry and similar surface roughness but increasing size of structural features. To fabricate large areas of patterned surfaces, required for cell culture studies, we used colloidal lithography utilizing colloidal particles as a template for surface nanostructuring.

Emergency radiology coverage: technical and clinical feasibility of an international teleradiology model.

The purpose of the study was to determine the feasibility of international teleradiology, utilizing day-night time differences, for online interpretation of overnight computed tomography (CT) studies. One hundred and two consecutive Emergency Room patients who underwent CT examinations between the hours of 11 pm and 7 am were enrolled. All age groups and study types were included.

Implementation of an international teleradiology staffing model.

Although teleradiology is presently being used extensively in the United States-for both overseas subspecialty consultations and overnight coverage of imaging services at domestic medical centers-there has been limited investigation of its potential to help provide staffing support to U.S. medical centers from offshore locations.

Theoretical and numerical aspects of transmit SENSE.

The ideas of parallel imaging techniques, designed to shorten the acquisition time by the simultaneous use of multiple receive coils, can be adapted for parallel transmission of a spatially selective multidimensional RF pulse. In analogy to data acquisition, a multidimensional RF pulse follows a certain trajectory in k-space. Shortening this trajectory shortens the pulse duration.

Respiratory herpes simplex virus type 1 infection/colonisation in the critically ill: marker or mediator?

Background: The clinical significance and pulmonary pathogenicity of herpes simplex virus type 1 (HSV-1) in mechanically ventilated, critically ill patients are unclear.

Objective: To determine the clinical features and course of respiratory HSV-1 infections/colonisations in the critically ill, in order to evaluate the contribution to outcome.

Design: A retrospective cohort study in the intensive care unit of an university hospital, involving 22 patients with a HSV-1 isolated from bronchoalveolar lavage (BAL) fluid, divided into survivors (n = 13) and non-survivors (n = 9).

Diagnostic CT scans: assessment of patient, physician, and radiologist awareness of radiation dose and possible risks.

Purpose: To determine the awareness level concerning radiation dose and possible risks associated with computed tomographic (CT) scans among patients, emergency department (ED) physicians, and radiologists.

Materials And Methods: Adult patients seen in the ED of a U.S.

Experimental verification of conformational variation of human fatty acid synthase as predicted by normal mode analysis.

Fatty acid synthase (FAS) is a 550 kDa homodimeric enzyme with multiple functional and structural domains. Normal mode analysis of a previously determined 19 A structure of FAS suggested that this enzyme might assume different conformational states with several distinct hinge movements. We have used a simultaneous multiple-model refinement method to search for the presence of the structural conformers from the electron images of FAS.

Detection of colorectal lesions: lower-dose multi-detector row helical CT colonography compared with conventional colonoscopy.

Purpose: To compare the performance of lower-dose multi-detector row helical computed tomographic (CT) colonography with that of conventional colonoscopy in the detection of colorectal lesions.

Materials And Methods: One hundred fifty-eight patients underwent multi-detector row helical CT colonography (beam collimation, 4 x 2.5 mm; table feed, 17.

Computerized tomographic colonography: performance evaluation in a retrospective multicenter setting.

Background & Aims: No multicenter study has been reported evaluating the performance and interobserver variability of computerized tomographic colonography. The aim of this study was to assess the accuracy of computerized tomographic colonography for detecting clinically important colorectal neoplasia (polyps >or=10 mm in diameter) in a multi-institutional study.

Methods: A retrospective study was developed from 341 patients who had computerized tomographic colonography and colonoscopy among 8 medical centers.

Contrast optimization and scan timing for single and multidetector-row computed tomography.

Various complex pharmacokinetic interrelationships affect the use of contrast media for computed tomography (CT) imaging. These include factors related to each patient's unique body habitus and their degree of health, such as their age, gender, height, weight, and cardiovascular status. Of equal importance are factors related to the contrast material injection.

Assessing socio-economic factors in relation to stigmatization, impairment status, and selection for socio-economic rehabilitation: a 1-year cohort of new leprosy cases in north Bangladesh.

The current leprosy elimination strategy focuses almost exclusively on delivery of leprosy diagnostic services and multi-drug treatment (MDT). However, the specific problems of people newly diagnosed with leprosy or cured with MDT primarily relate to impairment of nerve function and social and economic consequences of the diagnosis of leprosy. This study was carried out to investigate the relation between socio-economic factors and the development of nerve impairments and stigma.

Analysis of the frequent R1141X mutation in the ABCC6 gene in pseudoxanthoma elasticum.

Purpose: To characterize the ABCC6 R1141X nonsense mutation, which is implicated in more than 25% of a cohort of patients from The Netherlands with pseudoxanthoma elasticum (PXE).

Methods: A combination of single-strand conformational polymorphism (SSCP), PCR, sequencing, and Southern blot analysis was used to identify mutations in the ABCC6 gene in 62 patients. Haplotypes of 16 patients with the R1141X mutation were determined with eight polymorphic markers spanning the ABCC6 locus.

An information system to support the care for head and neck cancer patients.

The potential of Information and communication technology (ICT) as a method to improve care is widely acknowledged. However, before ICT can be used in a specific patient population, the needs of that population must first be made explicit. In this paper we aim to explore the feasibility and functionality of an electronic information system to support head and neck (H&N) cancer care.

Portal vein thrombosis after laparoscopy-assisted splenectomy and cholecystectomy.

A 12-year-old girl underwent laparoscopy-assisted splenectomy and cholecystectomy with removal of her spleen through a small Pfannenstiel incision. She had an unremarkable postoperative course but returned 16 days later because of increasing right-sided abdominal pain. The pain was constant, sharp, and stabbing without radiation.

ABCC6/MRP6 mutations: further insight into the molecular pathology of pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is a hereditary disease characterized by progressive dystrophic mineralization of the elastic fibres. PXE patients frequently present with skin lesions and visual acuity loss. Recently, we and others showed that PXE is caused by mutations in the ABCC6/MRP6 gene.

The challenge of pediatric cardiac services in the developing world.

Pediatric cardiac services are too expensive for most developing nations. Problems other than cardiac disease take priority when it comes to budget allocations. Poor health infrastructure and referral systems, malnutrition, and the HIV/AIDS pandemic aggravate the situation, and the increasing economic divide is threatening what services do exist.

Implications of SENSE MR in routine clinical practice.

Sensitivity encoding (SENSE) uses multiple MRI receive coil elements to encode spatial information in addition to traditional gradient encoding. Requiring less gradient encodings translates into shorter scan times, which is extremely beneficial in many clinical applications. SENSE is available to routine diagnostic imaging for the past 2 years.

Use of high concentration contrast media (HCCM): principles and rationale--body CT.

Numerous complex pharmacokinetic interrelationships affect the use of contrast media for computed tomography (CT) imaging. The volume, concentration, and rate of injection, all affect the degree of enhancement that is achieved with an injection of contrast material. In addition, the injection technique, whether the contrast is infused with a constant injection rate (uniphasic injection) or whether the rate is altered during the injection (multiphasic injection) also affect the magnitude and duration of contrast enhancement.

Transmit SENSE.

The idea of using parallel imaging to shorten the acquisition time by the simultaneous use of multiple receive coils can be adapted for the parallel transmission of a spatially-selective multidimensional RF pulse. As in data acquisition, a multidimensional RF pulse follows a certain k-space trajectory. Shortening this trajectory shortens the pulse duration.

Evaluation of peripheral blood CD4 and CD8 lymphocyte subsets, CD69 expression and histologic rejection grade as diagnostic markers for the presence of cardiac allograft rejection.

We investigated the dynamics of the CD4+ and CD8+ lymphocyte subsets, and the expression of activation markers in cardiac transplant recipients. We tested 132 peripheral blood samples from 62 cardiac transplant recipients using fluorescent staining and flow cytometry analysis. The results were correlated with histological rejection grade of concurrently taken biopsies, and 5-year survival of the recipients.

CT colonography: multiobserver diagnostic performance.

Purpose: To prospectively evaluate multiobserver diagnostic performance and reader agreement for colorectal polyp detection in a well-characterized cohort of patients with increased number of polyps, compared with an average-risk patient, with colonoscopy as the reference standard.

Materials And Methods: A cohort of 70 patients suspected of having polyps was examined with spiral computed tomographic (CT) colonography, with colonoscopy performed the same day. After air insufflation per rectum, supine and prone images were obtained with single-detector row CT (5-mm collimation, 8-mm table increment, 2-mm reconstruction interval).

Antihypertensive effects of angiotensin converting enzyme inhibition by lisinopril in post-transplant patients.

Background: It is not known whether strict control of blood pressure (BP) in mild post-transplant hypertension gives any benefit. Our primary objective was to test the antihypertensive effects of lisinopril added to standard therapy on ambulatory BP (ABP) of post-transplant patients. The secondary objective was to monitor echocardiographic and hemodynamic end points.