A tunable topological insulator in the spin helical Dirac transport regime.

Helical Dirac fermions-charge carriers that behave as massless relativistic particles with an intrinsic angular momentum (spin) locked to its translational momentum-are proposed to be the key to realizing fundamentally new phenomena in condensed matter physics. Prominent examples include the anomalous quantization of magneto-electric coupling, half-fermion states that are their own antiparticle, and charge fractionalization in a Bose-Einstein condensate, all of which are not possible with conventional Dirac fermions of the graphene variety. Helical Dirac fermions have so far remained elusive owing to the lack of necessary spin-sensitive measurements and because such fermions are forbidden to exist in conventional materials harbouring relativistic electrons, such as graphene or bismuth. It has recently been proposed that helical Dirac fermions may exist at the edges of certain types of topologically ordered insulators-materials with a bulk insulating gap of spin-orbit origin and surface states protected against scattering by time-reversal symmetry-and that their peculiar properties may be accessed provided the insulator is tuned into the so-called topological transport regime. However, helical Dirac fermions have not been observed in existing topological insulators. Here we report the realization and characterization of a tunable topological insulator in a bismuth-based class of material by combining spin-imaging and momentum-resolved spectroscopies, bulk charge compensation, Hall transport measurements and surface quantum control. Our results reveal a spin-momentum locked Dirac cone carrying a non-trivial Berry's phase that is nearly 100 per cent spin-polarized, which exhibits a tunable topological fermion density in the vicinity of the Kramers point and can be driven to the long-sought topological spin transport regime. The observed topological nodal state is shown to be protected even up to 300 K. Our demonstration of room-temperature topological order and non-trivial spin-texture in stoichiometric Bi(2)Se(3).M(x) (M(x) indicates surface doping or gating control) paves the way for future graphene-like studies of topological insulators, and applications of the observed spin-polarized edge channels in spintronic and computing technologies possibly at room temperature.

Observation of time-reversal-protected single-dirac-cone topological-insulator states in Bi2Te3 and Sb2Te3.

We show that the strongly spin-orbit coupled materials Bi2Te3 and Sb2Te3 and their derivatives belong to the Z2 topological-insulator class. Using a combination of first-principles theoretical calculations and photoemission spectroscopy, we directly show that Bi2Te3 is a large spin-orbit-induced indirect bulk band gap (delta approximately 150 meV) semiconductor whose surface is characterized by a single topological spin-Dirac cone. The electronic structure of self-doped Sb2Te3 exhibits similar Z2 topological properties. We demonstrate that the dynamics of spin-Dirac fermions can be controlled through systematic Mn doping, making these materials classes potentially suitable for topological device applications.

Points to consider about prescription drug prices: an overview of federal policy and pricing studies.

Pharmaceutical prices in the United States are under evaluation as policy makers decide how to reduce health care expenditures and public subsidy of the pharmaceutical industry. Furthermore, evidence of higher drug prices in the United States, compared with those in other countries, fuels the prescription drug price debate. These issues are not new to the public forum and much can be learned from prior debates and policies. This paper begins by reviewing the pricing debate with the Kefauver hearings on monopolies held during the late 1950s and early 1960s and continues with the current price debate. Government reports and academic studies are discussed, addressing the methodological differences and their implications to policy makers. Finally, the literature review includes foreign government prescription drug programs with their respective prescription drug expenditures. Evidence provided by academics about the pricing practices of the drug manufacturers indicates product quality and price information would force firms to compete on the price level, thus reducing pharmaceutical product pricing to the "true" market price.

The grid radiograph. A simple technique for consistent high-resolution visualization of the hip.

The grid radiograph, a new technique for radiographic evaluation of total hip replacements, ensures reproducible positioning of the hip and the x-ray beam. When this method was used, the images of stable acetabular and femoral components on one radiograph could be superimposed perfectly on the images of these components on subsequent radiographs. Subtle shifts in the positions of the components, such as tilting of the femoral surface replacement, subsidence of the femoral component, or migration of the acetabular component, were detected. When used with high-contrast radiographic technique and film, the implant-bone interfaces were depicted better by this method than by others. Grid radiographs can be used for detailed prospective evaluation of total hip replacements and are of practical value in counseling patients about the probable durability of the replacement.

Marketing concepts for pharmaceutical service development.

Marketing concepts as a mechanism to help pharmacy develop, communicate, and sell future pharmaceutical services to consumers are discussed. Pharmacy as a profession must define itself broadly to take advantage of future growth opportunities. These growth opportunities will be realized from unmet health-care needs and changing consumer life style trends and values. New services must therefore be oriented toward consumers (i.e., patients, health professionals, and third-party agencies) to gain acceptance. Dispensing and drug-knowledge-distribution pharmaceutical services are reviewed by a product life cycle analysis of sales profits versus time. A marketing mix for new pharmaceutical services is developed consisting of service, price, distribution, and promotion strategies. Marketing can encompass those key elements necessary to meet the organizational goals of pharmacy and provide a systematic, disciplined approach for presenting a new service to consumers.

Improving a hospital pharmacy department's profitability.

Measures taken by a pharmacy department to increase its contribution to meeting hospital operating expenses are described. A pharmacy department in a 1000-bed university hospital used management techniques to help contain costs, maintain quality care, and meet short-term cash flow and long-range financial objectives. Overtime and differential hours, primarily caused by turnover and sick leave, were reduced by offering technicians opportunities for advancement and better scheduling. Drug costs were reduced through use of therapeutic equivalent bidding, formulary drug-class reviews, and reductions in drug inventory. Equipment and computer expenses were analyzed, and future applications that would result in substantial labor savings and more efficient billing were planned. Measures were taken to reduce lost charges, and the number of patient charge items was increased. Charge reimbursement versus cost reimbursement was studied; a pharmacy billing mix in which more dollars are billed by charge reimbursement was sought. A new satellite in the surgical intensive-care area reduced lost charges and converted cost transfers to patient charges. Implementation of these programs increased pharmacy department contributions to meeting hospital expenses by 96% in fiscal year 1981-82.

The relationship of service user closeness and belief in departmental values with perceived marketing effectiveness of hospital pharmacy directors.

This study examines the relationships between department values, service user closeness and marketing effectiveness as perceived by hospital pharmacy directors. Data from 171 hospital pharmacy directors, representing a cross-section of hospitals, revealed that departments of pharmacy characterized as having superior perceived marketing effectiveness also have shared department value profiles. However, no significant relationship was found between perceived level of marketing effectiveness and perceived service user closeness. More years of experience as a director and the larger the size of pharmacist staff each positively influence the director's perception of marketing effectiveness. The results of the study indicate that hospital pharmacy directors generally perceive the services offered by their respective departments are marketed effectively.

Marketing perspectives of hospital pharmacy directors.

The familiarity of hospital pharmacy directors (HPDs) with various marketing concepts for the development of pharmaceutical services was assessed. A questionnaire was designed to assess whether (1) HPDs seek input from relevant publics when evaluating or designing pharmaceutical services; (2) HPDs use marketing concepts in the development and implementation of pharmaceutical programs; and (3) marketing perspectives of HPDs differ depending on their institutional affiliations and personal characteristics. The questionnaire was sent to 320 HPDs in seven states. A total of 158 unable questionnaires were received. In response to the questions concerning input from relevant publics, HPDs agreed that they should seek input from all relevant publics with the exception of third-party agencies and patients. HPDs put more emphasis on obtaining information for evaluating existing programs and designing long-term plans from physicians, nurses, patients, and hospital administrators and less emphasis on understanding the needs of third-party agencies. HPDs seem to use marketing concepts in the development and implementation of pharmaceutical programs. HPDs indicated a clear perception of pharmacy goals, target segments among relevant publics, and a dynamic orientation toward changes in the health-care marketplace. Hospital size, level of pharmaceutical education, and years of administrative experience were found to influence the marketing perspectives of HPDs. HPDs were familiar with marketing concepts, and a favorable climate seems to exist for transferring marketing approaches to the hospital pharmacy setting.

Expression of a novel Müller glia specific antigen during development and after optic nerve lesion.

To generate monoclonal antibodies, immunogen fractions were purified from embryonic chick retinae by temperature-induced detergent-phase separation employing Triton X-114. Under reducing conditions, the monoclonal antibody (mAb) 2M6 identifies a protein doublet at 40 and 46 x 10(3) Mr, which appears to form disulfide-coupled multimers. The 2M6 antigen is regulated developmentally during retinal histogenesis and its expression correlates with Müller glial cell differentiation. Isolated glial endfeet and retinal glial cells in vitro were found to be 2M6-positive, identified with the aid of the general glia marker mAb R5. mAb 2M6 does not bind to any other glial cell type in the CNS as judged from immunohistochemical data. Cell-type specificity was further substantiated by employing retinal explant and single cell cultures on laminin in conjunction with two novel neuron-specific monoclonal antibodies. MAb 2M6 does not bind either to neurites or to neuronal cell bodies. Incubation of retinal cells in vitro with bromodeoxyuridine (BrdU) and subsequent immunodouble labelling with mAb 2M6 and anti-BrdU reveal that mitotic Müller cells can also express the 2M6 antigen. To investigate whether Müller cell differentiation depends on interactions with earlier differentiating ganglion cells, transections of early embryonic optic nerves in vivo were performed. This operation eliminates ganglion cells. Müller cell development and 2M6 antigen expression were not affected, suggesting a ganglion-cell-independent differentiation process. If, however, the optic nerve of juvenile chicken was crushed to induce a transient degeneration/regeneration process in the retina, a significant increase of 2M6 immunoreactivity became evident. These data are in line with the hypothesis that Müller glial cells, in contrast to other distinct glial cell types, might facilitate neural regeneration.

The effects of intermittent passive exercise on joint stiffness following periarticular fracture in rabbits.

To determine the effects of intermittent passive motion on joint stiffness following periarticular fracture, bilateral distal tibia fractures were produced in 31 rabbits. Following immobilization and fracture union at three weeks, one ankle on each rabbit underwent passive exercise daily until sacrifice at six weeks. The contralateral ankle remained immobile, except for weekly stiffness determinations. Passive exercise produced limb swelling and resulted in temporarily decreased ankle stiffness to, but not significantly below, control values. Between exercise sessions, the exercised ankles became significantly stiffer than the contralateral immobilized ankles. The cause of stiffness was not determined, but extrapolation from other work would suggest that the regimens of intermittent passive exercise tested in this study additionally traumatized the healing tissues surrounding the fracture.

Fiscal and clinical evaluation of home parenteral nutrition.

The clinical management activities performed by nonphysician members of a home parenteral nutrition (HPN) service were evaluated, and the costs of providing a home-care service with a hospital-based supply were projected. The nutrition support service team included two pharmacists, one nurse, one dietitian, one social worker, and two physicians. The clinical activities of the nonphysician members of the service were documented for a one-year period involving 13 patients. Inventory data for items dispensed were obtained from the commercial vender supplying the patients during the study. Projected charges for the hospital pharmacy to deliver supplies were based on actual contract costs to the hospital. An arbitrarily assigned markup of 40% was used to calculate break-even data. The clinical management of the HPN patients required 203 hours of the nonphysician health-care professionals' time. For the initial fiscal year, the fixed and variable costs were projected as $253,360, which amounted to $89.82 per calendar day of home therapy. The hospital would have to provide 1416 calendar days of home parenteral nutrition before revenues equaled expenses at $168,504. The projected annual savings for a patient receiving parenteral nutrition at home rather than in the hospital was $651,651. Supply alternatives for HPN should be evaluated according to specific institutional needs.

Providing 24-hour nutrient infusions to critically ill patients.

The outcome of critically ill patients receiving total parenteral nutrient (TPN) therapy was evaluated, and the percentage of wasted TPN solutions administered as one-per-day (2- or 3-L) or multiple-per-day (750-mL or 1-L) infusions was determined. Between March 31 and June 1, 1984, all patients who were treated by the nutritional support service (NSS) and who met the study criteria were included in the study. The 24-hour nutrient content of each TPN solution was determined using a published method. Patient outcome was determined using TPN therapy data that were collected from the patients' medical charts and NSS records. To determine waste, all discarded TPN solutions were recorded. A total of 20 patients (10 men and 10 women) were included, representing 23.6% of the 76 patients who received TPN therapy during the study period. Study patients received 24-hour nutrient solutions for a mean of 16.4 +/- 12.9 days and required a mean of 3.9 +/- 4.6 days to reach sufficient metabolic stability to qualify for 24-hour infusions. During the study period, 56 (2.8 +/- 2.5 per patient) orders were changed. The percentage of wasted TPN solutions was low; 4.3% (17 of 1326) multiple-per-day and 1.7% (5 of 292) one-per-day solutions were wasted. Twenty-four-hour TPN solutions can be used successfully in critically ill patient populations.