Equation of State of CO_{2} Shock Compressed to 1 TPa.

Equation-of-state (pressure, density, temperature, internal energy) and reflectivity measurements on shock-compressed CO_{2} at and above the insulating-to-conducting transition reveal new insight into the chemistry of simple molecular systems in the warm-dense-matter regime. CO_{2} samples were precompressed in diamond-anvil cells to tune the initial densities from 1.35 g/cm^{3} (liquid) to 1.74 g/cm^{3} (solid) at room temperature and were then shock compressed up to 1 TPa and 93 000 K. Variation in initial density was leveraged to infer thermodynamic derivatives including specific heat and Gruneisen coefficient, exposing a complex bonded and moderately ionized state at the most extreme conditions studied.

Ultrafast dynamics of a new class of highly fluorescent boron difluoride dyes.

The first ultrafast study of the dimeric fluorescent BF2 dye BOPHY is presented. When compared to a structurally related BODIPY dye, similar photophysical dynamics are observed, including an intermediate kinetic component present in both dye types.

3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 1: Brain Stem.

BACKGROUND AND PURPOSE: The brain stem is compactly organized with life-sustaining sensorimotor and autonomic structures that can be affected by numerous pathologies but can be difficult to resolve on conventional MR imaging. MATERIALS AND METHODS: We applied an optimized TSE T2 sequence to washed postmortem brain samples to reveal exquisite and reproducible brain stem anatomic MR imaging contrast comparable with histologic atlases. This resource-efficient approach can be performed across multiple whole-brain samples with relatively short acquisition times (2 hours per imaging plane) using clinical 3T MR imaging systems. RESULTS: We identified most brain stem structures at 7 canonical axial levels. Multiplanar or oblique planes illustrate the 3D course and spatial relationships of major brain stem white matter pathways. Measurements of the relative position, course, and cross-sectional area of these pathways across multiple samples allow estimation of pathway location in other samples or clinical subjects. Possible structure-function asymmetries in these pathways will require further study-that is, the cross-sectional area of the left corticospinal tract in the midpons appeared 20% larger (n = 13 brains, P < .10). CONCLUSIONS: Compared with traditional atlases, multiplanar MR imaging contrast has advantages for learning and retaining brain stem anatomy for clinicians and trainees. Direct TSE MR imaging sequence discrimination of brain stem anatomy can help validate other MR imaging contrasts, such as diffusion tractography, or serve as a structural template for extracting quantitative MR imaging data in future postmortem investigations.

3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 2: Basal Forebrain.

BACKGROUND AND PURPOSE: The basal forebrain contains multiple structures of great interest to emerging functional neurosurgery applications, yet many neuroradiologists are unfamiliar with this neuroanatomy because it is not resolved with current clinical MR imaging. MATERIALS AND METHODS: We applied an optimized TSE T2 sequence to washed whole postmortem brain samples (n = 13) to demonstrate and characterize the detailed anatomy of the basal forebrain using a clinical 3T MR imaging scanner. We measured the size of selected internal myelinated pathways and measured subthalamic nucleus size, oblique orientation, and position relative to the intercommissural point. RESULTS: We identified most basal ganglia and diencephalon structures using serial axial, coronal, and sagittal planes relative to the intercommissural plane. Specific oblique image orientations demonstrated the positions and anatomic relationships for selected structures of interest to functional neurosurgery. We observed only 0.2- to 0.3-mm right-left differences in the anteroposterior and superoinferior length of the subthalamic nucleus (P = .084 and .047, respectively). Individual variability for the subthalamic nucleus was greatest for angulation within the sagittal plane (range, 15°-37°), transverse dimension (range, 2-6.7 mm), and most inferior border (range, 4-7 mm below the intercommissural plane). CONCLUSIONS: Direct identification of basal forebrain structures in multiple planes using the TSE T2 sequence makes this challenging neuroanatomy more accessible to practicing neuroradiologists. This protocol can be used to better define individual variations relevant to functional neurosurgical targeting and validate/complement advanced MR imaging methods being developed for direct visualization of these structures in living patients.

Hydrazine-mediated strongly coupled Re(CO)3 dimers.

Dimeric metal complexes can often exhibit coupling interactions via bridging ligands. In this report, we present two Re(CO)3 dimers, where the metals are linked via a bis(pyca) hydrazine (pyca = pyridine-2-carbaldehyde imine) Schiff base ligand. For the dimeric compounds 4 and 5, we observe strong coupling across the dimer as measured by cyclic voltammetry: ∼480 mV separations between the first and the second reduction waves that correspond to comproportionation constants close to 1.5 × 10(8). Evidence for a mixed valence state upon one electron reduction was also observed by spectroelectrochemistry in which a clear inter-valence charge-transfer (IVCT) band was observed in [4]- and [5]-complexes. The electronic structures of all target compounds were probed by DFT and TDDFT computational methods. DFT calculations indicate that reduction takes place at the diimine units, and that the observed coupling is a ligand-based phenomenon, rather than one that involves metal-based orbitals.

Characteristics of family practitioners with large geriatric practices.

Little has been reported on the characteristics of physicians presently serving the health needs of the elderly. In this report, generated from a survey of Florida family practitioners, physicians and with large geriatric practices are compared to physicians with practices composed primarily of younger patients. Family physicians with large geriatric practices are older, and treat more chronic disease than do their peers. However, they consult the same professional journals and texts in caring for their patients, refer patients to specialists at the same rate, and have the same office facilities as do their colleagues who treat chiefly younger patients. The family physician with a large geriatric case load is less likely to have a predominantly outpatient practice and more likely to be involved with hospitalized patients. Data from the census and health manpower studies suggest that family physicians will care for substantial number of elderly patients in the future. Continuing education which addresses issues in geriatrics may help to attain optimal health care for the elderly.

Effect of nicotine on in vitro human sperm penetrability through cervical mucus and motility parameters.

Nicotine at concentrations found in the cervical mucus of female smokers appeared to enhance in vitro human sperm penetrability through ovulatory bovine cervical mucus. Sperm motility parameters were not affected by the addition of nicotine to semen samples incubated with BWW medium. Overall, these results suggest that a direct inhibitory effect of nicotine on sperm penetrability through cervical mucus is not responsible for the apparent increase in cervical factor infertility present in smoking women.

Impact of a required family medicine clerkship on medical students' attitudes about primary care.

A study of 314 medical students before and after a required third-year clerkship in family medicine explored relationships among exposure to the clerkship and changes in attitudes toward primary care. The survey instrument contained 29 statements distinguishing the philosophy of primary care from that of subspecialty-oriented medicine and asked students' to state their future residency plans. The responses of the primary care and subspecialty-oriented groups were the most disparate, whereas the students who were uncertain about residency plans shifted on several items from an alignment with the specialty group toward an alignment with the primary care group. This study shows that experience in a family medicine clerkship may be associated with changes in attitudes that represent development of a more informed image of primary care.

Ethnicity and Food Stamp program participation: effect upon dietary intakes of low-income mothers served by a north Florida family practice center.

Ethnic differences in self-reported dietary intake between blacks and whites (participants and non-participants in the Food Stamp program) were studied in a group of 102 low-income mothers presenting themselves for treatment at an urban family practice center. The study population included 51 whites, of whom 21 were participants in the Food Stamp program, and 51 blacks, of whom 29 were Food Stamp program participants. The mean age of white and black mothers was approximately 29 years. Mean numbers of children per family were 2.1 for whites and 2.82 for blacks. Food and nutrient intake data were collected using a 24-hour recall and a food frequency questionnaire. Mean intakes of calcium, iron, riboflavin, and thiamin were found to be less than the RDAs for both groups. Whites additionally had mean intakes of vitamin A and niacin that fell below the RDAs. Blacks had significantly higher mean intakes of niacin and protein and a significantly higher 24-hour mean intake of soft drinks than whites. Being a member of the black race was positively associated with consumption of chicken, hot dogs, collard/mustard greens, and white rice. Being a member of the white race was positively associated with consumption of broccoli, potatoes, and whole wheat bread. Among participants in the Food Stamp program, mean intakes of protein, niacin, and soft drinks were significantly higher for blacks than for whites. This study suggests that ethnic differences in food preferences do exist but that those preferences do not translate into major differences in daily reported nutrient intakes.

Attitudinal and behavioral characteristics of older Floridians with tooth loss.

In this cross-sectional study of Floridians aged 65 yr or older, 600 persons were interviewed to identify the characteristics of individuals who survived into old age with an intact or nearly intact dentition. Persons with total or partial tooth loss reported less frequent dental care, less ability to pay dental care fees, less frequent dental hygiene, and were more likely to have been smokers or diabetic. Persons with tooth loss also had less positive attitudes toward dentists and dental care. These cross-sectional findings are consistent with tooth loss being the result of disease-, behavior-, and attitude-related causes, and/or their interactions. Tobacco use, diabetes, and infrequent oral hygiene and dental care may increase risk for dental disease; decreased ability to pay for dental treatment may impair utilization of non-extraction treatment options, and negative attitudes toward dental treatment may influence the desire for non-extraction treatment options. Research targeted toward modifying attitudes toward dental treatment may be useful in preventing or delaying tooth loss, and measurement of attitudes may be a useful way to identify individuals at the greatest risk for tooth loss for intervention studies.

Impact of new information technologies on training and continuing education for rural health professionals.

Recently developed and emerging information and communications technologies offer the potential to move the clinical training of physicians and other health professionals away from the resource intensive urban academic health center, with its emphasis on tertiary care, and into rural settings that may be better able to place emphasis on the production of badly needed primary care providers. These same technologies also offer myriad opportunities to enhance the continuing education of health professionals in rural settings. This article explores the effect of new technologies for rural tele-education by briefly reviewing the effect of technology on health professionals' education, describing ongoing applications of tele-education, and discussing the likely effect of new technological developments on the future of tele-education. Tele-education has tremendous potential for improving the health care of rural Americans, and policy-makers must direct resources to its priority development in rural communities.

Recruitment and retention of rural physicians: issues for the 1990s.

This paper briefly describes a number of structural and economic changes in the profession of medicine and in the rural medical care delivery system that have occurred since about 1970. Changes in the national physician supply; in the training, work, and practice characteristics of physicians; in the demographic characteristics of physicians; in the medical resources available in rural communities; and in federal and state support for the provision of medical services are noted. Four conceptual models that underlie physician recruitment and retention programs for small towns and rural communities are described. These include affinity models, which attempt to recruit rural persons into training or foster interest in rural practice among trainees; economic incentive models, which address reimbursement or payment mechanisms to increase economic rewards for rural practice; practice characteristics models, which address technical, collegial, referral, and other structural barriers to rural practice; and indenture models, which recruit temporary providers in exchange for scholarship support, loan forgiveness, or licensure. Examples of applications of each model are provided and the effects of changes in the medical care system on the effectiveness of each model are assessed. Finally, it is argued that elements of an optimal model for the recruitment of physicians to rural practice include the promotion of medical careers among rural high school students, the provision of financial and cultural support for their training, the development of technical and collegial support systems, and the limited use of indenture mechanisms to meet the needs of the most impoverished or isolated rural settings.

Faculty time allocation in rural primary care training sites.

This investigation examined the allocation of time by medical school faculty who served as attending physicians on a rotating basis in rural primary care centers where medical students and house staff were trained. Two quite different methods of studying faculty time allocation produced relatively consistent results. Travel and direct care of patients (with no medical students present) accounted for the largest share of faculty time. Much of the teaching time was spent in direct student contact with no patient present. Simultaneous care of patients by an attending faculty member and a medical student accounted for less than ten percent of faculty effort. It appears that in a busy rural primary care center, faculty whose mission is intended to emphasize teaching may often be thrust into the role of care providers. Despite this problem, faculty-student contact appears to be greater than that which typically occurs in the tertiary care teaching hospital environment.

Older Floridians' attitudes toward and use of dental care.

Older Floridians (mean age 78 years) were interviewed regarding their use of dental care, attitudes toward dental care, and other characteristics hypothesized as being explanatory of dental care use. Fifty-two percent of respondents reported having been to a dentist within the past year, and 31% had not been within the previous 5 years. Five constructs measured attitudes toward dental care and dental health: (a) the importance placed on regular dental care and oral hygiene, (b) the importance of avoiding tobacco to prevent oral cancer, (c) the value of dental care, (d) negative aspects of dental care, and (e) satisfaction with the last dental visit. In a multivariate model, the value of dental care and importance of regular care and oral hygiene wer significantly correlated with dental care use. These findings are consistent with the conclusion that attitudes contribute to understanding dental care use in later life, a contribution that is independent of the direct effects of socioeconomic status and dentate status.

Sickle cell screening policies as portent: how will the human genome project affect public sector genetic services?

The Human Genome Project holds much promise for providing dramatic improvements in our understanding of and means to diagnose and treat many diseases. As this enormously important endeavor proceeds, research on ethical, legal, and social implications of this new science is being conducted to forecast problems and recommend policy option solutions to avoid what might otherwise become adverse consequences. Sickle cell screening is an example of a technology that was introduced in a manner that raised poignant issues. On the basis of sickle cell issues, we examined policy issues likely to occur as new genetic technologies are incorporated into medical practice. Discussion and development of a national consensus on the appropriate content and just delivery of public sector genetic services is vital; otherwise, the impact of Human Genome Project-derived technology may result in misadventures that amplify problems currently evident in newborn screening programs. New DNA-based diagnostic technologies and therapies will soon enter the stream of commerce. The recommendations offered here, while based on examination of sickle cell disease policies, are intended to address both current inequities as well as potential future issues related to stigmatization and distributive justice.

Psychiatric inpatient treatment of childhood schizoaffective disorder.

Psychiatric inpatient treatment of a child with multiple life-threatening symptoms, including suicidal behavior and food refusal, is described. Changes in symptomatology were monitored by applying research scales and research interview methods during the course of intervention. The process that led to the diagnosis of childhood schizoaffective disorder is discussed.

The referral process: a study of one method for improving communication between rural practitioners and consultants.

Communication between referring physicians and consultants, essential for successful completion of the consultative-referral process, was inadequate in a rural clinic. This finding prompted the authors to conduct a randomized prospective trial of a referral form and return mailer in three rural primary care clinics associated with a university medical center. The use of a return mailer increased the percentage of consultant feedback from 39 percent to 60 percent, a highly significant increase. An added benefit was a decrease in the median time interval between a patient's contact with a consultant and receipt of that consultant's report by the rural clinics. The positive effect of the return mailer was consistent among various consultant categories, with the greatest improvement coming from a teaching hospital Emergency Room. The type of referring provider or the emergency status of the patient did not affect the percentage of communications returned. The use of a referral form accompanied by a request for feedback and a return mailer is an inexpensive method of increasing communication between primary care providers and consultants, thereby enhancing the value of the consultative-referral process.