Cigarette smoking and thinning of the brain's cortex.

Cigarette smoking is associated with cognitive decline and dementia, but the extent of the association between smoking and structural brain changes remains unclear. Importantly, it is unknown whether smoking-related brain changes are reversible after smoking cessation. We analyzed data on 504 subjects with recall of lifetime smoking data and a structural brain magnetic resonance imaging at age 73 years from which measures of cortical thickness were extracted. Multiple regression analyses were performed controlling for gender and exact age at scanning. To determine dose-response relationships, the association between smoking pack-years and cortical thickness was tested and then repeated, while controlling for a comprehensive list of covariates including, among others, cognitive ability before starting smoking. Further, we tested associations between cortical thickness and number of years since last cigarette, while controlling for lifetime smoking. There was a diffuse dose-dependent negative association between smoking and cortical thickness. Some negative dose-dependent cortical associations persisted after controlling for all covariates. Accounting for total amount of lifetime smoking, the cortex of subjects who stopped smoking seems to have partially recovered for each year without smoking. However, it took ~25 years for complete cortical recovery in affected areas for those at the mean pack-years value in this sample. As the cortex thins with normal aging, our data suggest that smoking is associated with diffuse accelerated cortical thinning, a biomarker of cognitive decline in adults. Although partial recovery appears possible, it can be a long process.

A pilot study of a telehealth intervention for persons with spinal cord dysfunction.

STUDY DESIGN: Single-blind randomized controlled trial of 6 months' duration. OBJECTIVES: To evaluate the efficacy of a novel telehealth intervention, 'CareCall', on reducing pressure ulcers and depression and enhancing the use of appropriate health care. SETTING: General community, Massachusetts and Connecticut, United States METHODS: 'CareCall' is an automated, interactive voice response system that combines patient education, cognitive behavioral interventions, screening and referrals, with alerts to a nurse telerehabilitation coordinator for direct non-emergent phone follow up. Participants consisted of a convenience sample of 142 persons with multiple sclerosis or spinal cord injury using a wheelchair >6 h per day. The intervention group received CareCall (n=71) The control group received usual care (n=71). The main outcome measures were: The pressure ulcer scale for healing tool, Patient Health Questionnaire-9 depression scale, Cornell Services Index and Craig Hospital Inventory of Environmental Factors-Short Form Question 5. RESULTS: CareCall achieved a reduction in presence of pressure ulcers at 6 months in women (P<0.0001). Among those with baseline depression, CareCall reduced 6-month severity of depression, adjusting for age and gender (P<0.047). CareCall did not have a significant impact on health-care utilization (OR=1.8, P=0.07), but did significantly improve participants' report of health-care availability (OR=2.03, P<0.04). CONCLUSION: This is the first study to demonstrate the efficacy of a largely automated telehealth intervention for adults with spinal cord dysfunction. Future research needs to replicate this study in a larger, multisite trial.

www.elearnSCI.org: a global educational initiative of ISCoS.

OBJECTIVE: To develop a web-based educational resource for health professionals responsible for the management of spinal cord injury (SCI). The resource:www.elearnSCI.org is comprised of seven learning modules, each subdivided into various submodules. Six of the seven modules address the educational needs of all disciplines involved in comprehensive SCI management. The seventh module addresses prevention of SCI. Each submodule includes an overview, activities, self-assessment questions and references. DEVELOPMENT OF THE RESOURCE: Three hundred and thirty-two experts from The International Spinal Cord Society (ISCoS) and various affiliated societies from 36 countries were involved in developing the resource through 28 subcommittees. The content of each submodule was reviewed and approved by the Education and Scientific Committees of ISCoS and finally by an Editorial Committee of 23 experts. KEY FEATURES: The content of the learning modules is relevant to students and to new as well as experienced SCI healthcare professionals. The content is applicable globally, has received consumer input and is available at no cost. The material is presented on a website underpinned by a sophisticated content-management system, which allows easy maintenance and ready update of all the content. The resource conforms to key principles of e-learning, including appropriateness of curriculum, engagement of learners, innovative approaches, effective learning, ease of use, inclusion, assessment, coherence, consistency, transparency, cost effectiveness and feedback. CONCLUSION: www.elearnSCI.org provides a cost effective way of training healthcare professionals that goes beyond the textbook and traditional face-to-face teaching.

Homogeneous switching in ultrathin ferroelectric films.

It is well known that there are two possible switching mechanisms in ferroelectric crystals and films (see, e.g., Tagantsev et al 2010 Domains in Ferroic Crystals and Thin Films (Berlin: Springer)). The first mechanism, which follows from the mean-field theory of Landau-Ginzburg, is a homogeneous one and does not connect domains. This mechanism was never observed before 1998. The second mechanism, connected with nucleation and domain movement, is common for the ferroelectrics and is well known from the time of domain discovery (1956). In the present paper the existence of a homogeneous mechanism of switching in ultrathin copolymer films is confirmed by piezoresponse force microscopy. The results of the present paper permit us to suppose that homogeneous switching exists in other ultrathin ferroelectric films.

Nanoscale domain patterns in ultrathin polymer ferroelectric films.

High-resolution studies of domain configurations in Langmuir-Blodgett films of ferroelectric polymer poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE), have been carried out by means of piezoresponse force microscopy (PFM). Changes in film thickness and morphology cause significant variations in polarization patterns. In continuous films and nanomesas with relatively low thickness/grain aspect ratio (<1/10), the relationship between the average domain size and thickness follows the Kittel law. Nanomesas with high aspect ratio (>1/5) exhibit significant deviations from this law, suggesting additional surface-energy-related mechanisms affecting the domain patterns. Polarization reversal within a single crystallite has been demonstrated and local switching parameters (coercive voltage and remnant piezoresponse) have been measured by monitoring the local hysteresis loops. Reliable control of polarization at the sub-grain level demonstrates a possibility of studying the mechanism of the intrinsic switching behavior down to the molecular scale.

Intrinsic ferroelectric coercive field

The Landau-Ginzburg theory of ferroelectricity predicts the intrinsic coercive field for polarization reversal, but the observed extrinsic coercive field is always much smaller as a result of nucleation, dynamic processes not covered by the static theory. We have realized the intrinsic coercive field for the first time, in two-dimensional Langmuir-Blodgett polymer films as thin as 1 nm. The measured coercive field is in good agreement with the theoretical intrinsic value, exhibits the expected dependence on temperature, and does not depend on thickness below 15 nm.

Employment after spinal cord injury: an analysis of cases from the Model Spinal Cord Injury Systems.

OBJECTIVE: To describe the relationship of multiple biographic, injury-related, and educational factors with employment outcomes after spinal cord injury (SCI). DESIGN: Cross-sectional. SETTING: Data were collected through 18 model SCI systems, a nationwide network of hospitals that treat approximately 14% of all SCIs in the United States. PARTICIPANTS: A total of 3,756 persons with traumatic SCI who completed the Form II data collection during their annual follow-up at years 1, 2, 5, 10, 15, 20, or 25 years (the most recent Form II was accepted). MAIN OUTCOME MEASURES: The Model Systems Forms I and II were used to identify biographic, injury-related status, employment at injury, and productivity status upon follow-up (Form I is used to elicit basic demographic and discharge information, whereas Form II is used to track multiple outcomes during annual follow-ups). The Craig Handicap Assessment Reporting Technique (CHART) was used to assess hours spent in gainful employment and other productive activities. RESULTS: CHART data revealed only a modestly higher Employment rate (24.8%) than that of the traditional single Form II item (22%). Being Caucasian, younger at injury, having lived more years with SCI, having a less severe injury, and having more years of education were all predictive of being employed. Violence at injury was associated with lower employment rates (only 12.9% employed), especially among Caucasians (only 24% employed). Being employed at injury was associated with a greater probability of postinjury employment, but only in the first few years after injury. Among employed participants, women and those who had been injured fewer years averaged fewer hours spent at work. CONCLUSIONS: Findings were consistent with those in previous studies. Interventions to improve employability should focus on education and the needs of individuals from minority backgrounds.

Unilateral iliac vein occlusion, caused by bladder enlargement, simulating deep venous thrombosis.

A variety of conditions cause unilateral leg swelling and thus mimic deep venous thrombosis (DVT). A heretofore-underappreciated condition that may lead to unilateral iliac vein compression, simulating DVT, is massive enlargement of the bladder caused by urinary retention. A case that demonstrates this condition is described. Although this disorder has been reported only three times before, its occurrence should be recognized by clinicians in light of the overall aging of our society. In addition, this case highlights the need for careful and thorough evaluation of patients who have unilateral lower-extremity edema.

Absorption, distribution and excretion of GT31-104, a novel bile acid sequestrant, in rats and dogs after acute and subchronic administration.

The absorption, distribution, and excretion of GT31-104, a novel bile acid sequestrant, was studied in rats and dogs after both acute and subchronic oral administration. The polyallylamine backbone of GT31-104 was labeled with tritium and one of the alkyl side chains was labeled with 14C. The mean blood and plasma concentration of [3H, 14C]GT31-104 in rats, in both treatment regimens, was negligible at all time points, with the highest amount observed being 0.69 microgram eq/g blood; in dogs the mean blood and plasma concentration of [3H, 14C]GT31-104 was below the limit of quantitation (< 0.001% total dose) at all time points. In both rats and dogs, the mean total urinary excretion of [3H, 14C]GT31-104 was approximately 0.06% of the total dose. The fecal excretion data indicates that both 3H- and 14C-derived radioactivity was excreted entirely in the feces. Mean total radioactivity excreted in the feces ranged from approximately 95 to 105% in the rats and 92 to 102% in the dogs. Across the different treatment regimens, in both species, tissue concentrations were negligible (< 0.01% total dose) and no differences in tissue profile were noted, indicating that there was no effect of pretreatment on [3H, 14C]GT31-104 absorption. GT31-104 was extracted with water, and the water-soluble portion contained radioactivity that would correlate to approximately 0.19% of the 3H dose and 0.41% of the 14C dose; this portion probably accounted for the negligible radioactivity observed systemically. Analysis of gastrointestinal (GI) tract tissues with contents indicated that GT31-104 is rapidly cleared from the GI tract. These data indicate that GT31-104 is not absorbed from the GI tract in rats and dogs.

Tissue distribution of the cytofectin component of a plasmid-DNA/cationic lipid complex following intravenous administration in mice.

Allovectin-7 is a gene therapy agent that consists of plasmid DNA (pDNA) encoding the human HLA-B7 class I and beta2-microglobulin genes (VCL-1005), complexed with the cationic lipid DMRIE Br and DOPE. A tritiated version of the cytofectin component, DMRIE Br, was synthesized by regiospecific isotope incorporation to a very high specific activity. The 3H-labeled DMRIE/DOPE mixture was complexed with VCL-1005 to produce a radiolabeled version of Allovectin-7. The VCL-1005/3H-DMRIE/DOPE complex was administered intravenously to mice, and the tissue distribution of radioactivity was analyzed 24 hr later. Excretion of radioisotope was monitored for 96 hr post dosing. At 24 hr post administration, a tissue distribution for the radioisotope of liver >> spleen > lung >> heart > brain approximately muscle approximately blood was observed. During the 96-hr period post dose, very little administered radioactivity (<17%) was excreted and the majority of the isotope (83%) remained in the animal. This is the first report on the biodistribution of the cytofectin component of a pDNA-cationic lipid complex for which the distribution of the plasmid component has also been reported.

High-performance photorefractive polymers.

Photorefractive materials can form "instant" holograms without time-consuming development steps. Their potential applications include image processing, optical data storage, and correction of image distortion, but the cost of crystal growth and preparation has been a primary impediment to commercial application. Polymers, on the other hand, are low in cost and readily fabricated in a variety of forms. Photorefractive polymers were constructed with performance that matched or exceeded the performance of available photorefractive crystals. The largest observed two-beam energy coupling gain coefficient for the polymers was 56 per centimeter.

Electric-field stabilization and competition of gratings in a photorefractive polymer.

We report observations of electric-field stabilization of gratings and grating competition in a new photorefractive polymer mixture composed of 40 wt. % diethylamino-benzaldehyde-diphenyl hydrazone dissolved in Bisphenol A 4,4'-nitroaminotolane. Gratings formed with a 650-nm optical wavelength in 145-microm-thick films at 138-kV/cm bias field have a diffraction efficiency as high as 0.11%, require an energy density of ~1 J/cm(2) for formation, and show cancellation, revelation, and electric-field-stabilized persistence. We propose a model in which fast recording is associated with one set of photosensitive traps, whereas a slower cancellation and subsequent revelation are associated with a competing grating formed in a set of insensitive shallow traps. The model also accounts for observed fatigue of the photoconductivity.

Pyro-electro-optic phase gratings.

A new physical mechanism is proposed for generating transient phase gratings in transparent pyroelectric materials. The mechanism combines the pyroelectric and electro-optic effects to convert spatial intensity variations into transient phase gratings. The grating diffraction efficiency increases with a figure of merit that is proportional to the pyroelectric, electro-optic, and absorption coefficients and is inversely proportional to the specific heat. The grating response time is proportional to the specific heat and inversely proportional to the thermal conductivity. Diffraction efficiencies that approach unity are predicted in several readily available electro-optic materials with modest pulse energies from Q-switched Nd:YAG lasers. Observation with cw laser sources is also proposed. The pyro-electro-optic mechanism is compared with other known mechanisms.