Mechanical characterization of athletic helmet shells

Our purpose was to compare the mechanical properties of the protective outer shells of various athletic helmets in their final, fully manufactured form. Sections were taken from 3 different helmet shells (Bauer RE-AKT hockey helmet, Cascade R lacrosse helmet, and Riddell Speedflex football helmet) at 4 different locations (front, side, top, and rear) for a total of 12 test specimens. The 4 specimens from each helmet shell were potted together in epoxy resin moulds and mechanically polished. The hardness, elastic modulus and phase angle were measured using dynamic nanoindentation performed at 100 Hz with an oscillation amplitude of 1 nm (rms). Repeated ANOVA analysis was used to compare each of the dependent variables for each of the 3 helmets across the 4 different locations. The interaction between helmet type and location was significant for hardness (F6,63 = 2.84, P = 0.032, Pη2 = 0.21), elastic modulus (F6,63 = 6.412, P < 0.001, Pη2 = 0.38), and phase angle (F6,63 = 7.65, P < 0.001, Pη2 = 0.42). Polycarbonate has a higher ability to dissipate mechanical energy making it the recommended superior choice for helmet shells. In addition, the results lead us to speculate that manufacturing causes changes in the molecular weight or the distribution of fillers across locations for polyethylene but not for polycarbonate since mechanical properties are fairly uniform over the surface of football helmets, at least within a given helmet.

Gamma ray measurements with photoconductive detectors using a dense plasma focus

Photons in the MeV range emitted from the dense plasma focus (DPF) at the NSTec North Las Vegas Facility have been measured with both neutron-damaged GaAs and natural diamond photoconductive detectors (PCDs). The DPF creates or "pinches" plasmas of various gases (e.g., H2, D2, Ne, Ar., etc.) that have enough energy to create MeV photons from either bremsstrahlung and/or (n,n(')) reactions if D2 gas is used. The high bandwidth of the PCDs enabled the first ever measurement of the fast micro-pinches present in DPF plasmas. Comparisons between a slower more conventional scintillator/photomultiplier tube based nuclear physics detectors were made to validate the response of the PCDs to fast intense MeV photon signals. Significant discrepancies in the diamond PCD responses were evident.

ToxML, a data exchange standard with content controlled vocabulary used to build better (Q)SAR models

Development of accurate quantitative structure-activity relationship (QSAR) models requires the availability of high quality validated data. International regulations such as REACH in Europe will now accept (Q)SAR-based evaluations for risk assessment. The number of toxicity datasets available for those wishing to share knowledge, or to use for data mining and modelling, is continually expanding. The challenge is the current use of a multitude of different data formats. The issues of comparing or combining disparate data apply both to public and proprietary sources. The ToxML project addresses the need for a common data exchange standard that allows the representation and communication of these data in a well-structured electronic format. It is an open standard based on Extensible Markup Language (XML). Supporting information for overall toxicity endpoint data can be included within ToxML files. This makes it possible to assess the quality and detail of the data used in a model. The data file model allows the aggregation of experimental data to the compound level in the detail needed to support (Q)SAR work. The standard is published on a website together with tools to view, edit and download it.

The neutron imaging diagnostic at NIF (invited)

A neutron imaging diagnostic has recently been commissioned at the National Ignition Facility (NIF). This new system is an important diagnostic tool for inertial fusion studies at the NIF for measuring the size and shape of the burning DT plasma during the ignition stage of Inertial Confinement Fusion (ICF) implosions. The imaging technique utilizes a pinhole neutron aperture, placed between the neutron source and a neutron detector. The detection system measures the two dimensional distribution of neutrons passing through the pinhole. This diagnostic has been designed to collect two images at two times. The long flight path for this diagnostic, 28 m, results in a chromatic separation of the neutrons, allowing the independently timed images to measure the source distribution for two neutron energies. Typically the first image measures the distribution of the 14 MeV neutrons and the second image of the 6-12 MeV neutrons. The combination of these two images has provided data on the size and shape of the burning plasma within the compressed capsule, as well as a measure of the quantity and spatial distribution of the cold fuel surrounding this core.

Progress toward the development and testing of source reconstruction methods for NIF neutron imaging

Development of analysis techniques for neutron imaging at the National Ignition Facility is an important and difficult task for the detailed understanding of high-neutron yield inertial confinement fusion implosions. Once developed, these methods must provide accurate images of the hot and cold fuels so that information about the implosion, such as symmetry and areal density, can be extracted. One method under development involves the numerical inversion of the pinhole image using knowledge of neutron transport through the pinhole aperture from Monte Carlo simulations. In this article we present results of source reconstructions based on simulated images that test the methods effectiveness with regard to pinhole misalignment.

Defining the intelligent public sector construction client

Recent efforts and aspirations to transform the delivery of major capital programmes and projects in UK public sector construction by focusing on achievement of value for money, whole-life asset management and sustainable procurement have led to the adoption of integrated procurement routes characterised by multiplicity of stakeholders with a diversity of differing and often competing requirements. A study of the challenges faced by the public sector to deliver present and future major capital programmes and projects gravitates to the role of the intelligent client, and concomitant skills and capabilities. The results of the multiple case studies research show that the challenges of this role are especially evident at the interface between the internal organisation and the external suppliers and advisors from the private sector. The research concludes that the intelligent client role requires an individual champion with a unique set of skills working in an environment of a supporting team and capable organisation.

An actualistic perspective into Archean worlds - (cyano-)bacterially induced sedimentary structures in the siliciclastic Nhlazatse Section, 2.9 Ga Pongola Supergroup, South Africa

Extensive microbial mats colonize sandy tidal flats that form along the coasts of today's Earth. The microbenthos (mainly cyanobacteria) respond to the prevailing physical sediment dynamics by biostabilization, baffling and trapping, as well as binding. This biotic-physical interaction gives rise to characteristic microbially induced sedimentary structures (MISS) that differ greatly from both purely physical structures and from stromatolites. Actualistic studies of the MISS on modern tidal flats have been shown to be the key for understanding equivalent fossil structures that occur in tidal and shelf sandstones of all Earth ages. However, until now the fossil record of Archean MISS has been poor, and relatively few specimens have been found. This paper describes a study location that displays a unique assemblage with a multitude of exceptionally preserved MISS in the 2.9-Ga-old Pongola Supergroup, South Africa. The 'Nhlazatse Section' includes structures such as 'erosional remnants and pockets', 'multidirected ripple marks', 'polygonal oscillation cracks', and 'gas domes'. Optical and geochemical analyses support the biogenicity of microscopic textures such as filamentous laminae or 'orientated grains'. Textures resembling filaments are lined by iron oxide and hydroxides, as well as clay minerals. They contain organic matter, whose isotope composition is consistent with carbon of biological origin. The ancient tidal flats of the Nhlazatse Section record four microbial mat facies that occur in modern tidal settings as well. We distinguish endobenthic and epibenthic microbial mats, including planar, tufted, and spongy subtypes. Each microbial mat facies is characterized by a distinct set of MISS, and relates to a typical tidal zone. The microbial mat structures are preserved in situ, and are consistent with similar features constructed today by benthic cyanobacteria. However, other mat-constructing microorganisms also could have formed the structures in the Archean tidal flats.

Learning Activities and Third-Year Medical Student Ratings of High Quality Teaching Across Different Clerkships

OBJECTIVE

To identify and compare learning activities that students associate with high quality teaching across clerkships.

METHODS

For six months, 110 third year medical students recorded data on learning activities and teaching quality using personal digital assistants (PDAs) during five different required clinical clerkships. Univariate and multivariate analyses were performed to assess the association between learning activities and student ratings of high teaching quality.

RESULTS

11,450 teaching interactions were recorded. Univariate analysis revealed that feedback was associated with perceptions of high quality teaching in all clerkships. Proposing a plan, formulating an assessment and giving an oral case presentation were associated with high quality teaching in 80% of the clerkships (p < 0.01). Multivariate analysis demonstrated that receiving high quality feedback was an independent predictor of student ratings of high quality teaching for all clerkships.

CONCLUSION

Receiving high quality feedback is the learning activity most strongly associated with students' ratings of high quality teaching across four different clerkships.

Understanding the careers of physician educators in family medicine

PURPOSE

Little is known about what contributes to the career decisions of physician educators in family medicine. This study sought to understand the variables that influence these decisions and to identify key sources of vitality for physician educators in family medicine.

METHOD

A national sample of randomly selected physician educators in family medicine responded to a postcard survey regarding their contribution(s) to education and career satisfaction. A series of exclusion criteria were applied to 399 useable responses, yielding 24 physician educators who participated in a semi-structured telephone interview focusing on their careers. Using qualitative research methods, themes were identified and categorized from the transcribed interviews and investigators' field notes.

RESULTS

The career decisions and actions of physician educators in family medicine emanated from an underlying set of values and beliefs associated with "making the world better." Participants sought challenging, diverse, and stimulating positions from which they could have an impact in ways that were consistent with their values. Three major sources of vitality (learners, colleagues, and patients) complemented the desire for challenging positions. Physician educators in family medicine, however, continually struggled to balance their personal and professional lives.

CONCLUSION

The study results highlight the key variables that draw faculty into education and sustain their vitality, and the professional and personal challenges that can derail or support their careers. This information can be used to recruit, develop, and retain successful and productive physician educators in family medicine.

Coping with dementia: evaluation of four nonpharmacologic interventions

To evaluate nonpharmacologic interventions, caregivers (65 women, 38 men) and their dementia-diagnosed spouses (patients) were randomized to one of four treatment programs (cognitive stimulation, dyadic counseling, dual supportive seminar, and early-stage day care) or to a wait-list control group. Assessments occurred initially and at postintervention (3 months). Patients were evaluated on memory, verbal fluency, and problem-solving ability, and caregivers were assessed on marital interaction, emotional status, and physical health, along with stress, coping, and social support. Caregivers also completed a program evaluation. Repeated measures procedures showed that patients in the cognitive stimulation group demonstrated more improvement over time in cognitive outcomes, and caregivers decreased in depressive symptoms. Early-stage day-care and dual supportive seminar group caregivers reported a decrease in hostility and a decrease in use of negative coping strategies, respectively. Although qualitatively derived benefits differed across groups, similarities in program content reduced the potential for quantitative differentiation among the groups.

Residents find clinical practice guidelines valuable as educational and clinical tools

BACKGROUND AND OBJECTIVES

Information regarding clinical practice guideline (CPG) use in residency education is limited. We surveyed a regional population of family practice residents to determine use, attitudes, and curricular needs for practice guidelines.

METHODS

A written survey was developed that measured residents' exposure to, frequency of use, attitudes, access, and knowledge about use of CPGs. The survey was mailed to 114 family practice residents.

RESULTS

The response rate was 75%. The most frequently seen guidelines were immunization schedules, cancer screening, hyperlipidemia, and hypertension management. The residents reported positive attitudes toward CPGs; 75% thought CPGs were easy to use, 80% thought they improved their efficiency, 78% thought they improved their residency education, and 75% thought they improved patient care. Barriers to effective use of practice guidelines were also identified; 20% knew where to find guidelines in their clinic, 35% had faculty modeling, and 22% knew how to evaluate the validity of a guideline. Eighty-nine percent of respondents desired instruction on CPG use and interpretation.

CONCLUSIONS

The surveyed family practice residents have similar usage rates for CPGs as the literature reports for practicing physicians, but residents report more positive attitudes. Barriers that prevent effective use of CPGs in training environments include lack of critical appraisal abilities and faculty role modeling.

Supportive seminar groups: an intervention for early stage dementia patients

A supportive seminar group was developed and conducted for individuals with early stage dementia and their caregivers. The eight sessions focused on pertinent topics, namely, coping with memory problems, daily living, self-esteem, relationships, health, legal, and financial concerns. Content analysis of the evaluative statements from nine men and six women patients revealed positive themes of feelings of purposefulness, gratification, belongingness, and survival, while other themes reflected the turmoil of the disease, namely, feelings of helplessness, devaluation, and unpredictability. These preliminary findings lend support to the feasibility of a group approach for early stage dementia patients.

Research-Related Learning Needs of Ohio Nurses

Barriers to research utilization continue to obstruct nursing's goal of research-based practice. A survey was conducted to explore the diverse research-related learning needs of Ohio nurses. The survey results suggest at least two distinct nursing practice groups. One nursing group cited an educational need for basic, general research information that included how to utilize research in practice and teaching; the second group was most concerned with the actual performance of research. In order to maximize nursing research utilization in the 1990s, nurse educators must address the profession's diverse research-focused learning needs.

Level of cancer pain knowledge among baccalaureate student nurses

Inadequate nursing education is a major impediment to effective pain relief for cancer patients throughout the world. This study was conducted to identify the level of cancer pain knowledge among baccalaureate student nurses and to determine whether specific activities affect this level of knowledge. Two questionnaires were administered to 82 baccalaureate student nurses in the final course of their program. Although the students displayed a realistic perspective about the severity and prevalence of cancer pain and psychological dependence, specific knowledge deficits and negative attitudes suggest the possibility of inadequate pain management. Specifically, the students believed that (a) maximal analgesic therapy should be delayed until the patient's prognosis was less than 12 months; (b) the proportion of patients whose pain can be controlled by appropriate therapy is less than is possible; (c) increasing pain is related to tolerance rather than to progression of the disease; (d) the preferred route of administration is intravenous rather than oral; and (e) the degree of respiratory depression, rather than constipation, does not decrease with repeated administration. Significant positive correlations (P < or = 0.05) were found between age and cancer pain knowledge and between attendance at seminars/workshops and time spent reading professional journal articles. Of the 30% of the participants who perceived a particular person to be a source for obtaining information about cancer pain management, 52% specified a practicing registered nurse. Seminars and workshops were chosen by 59% of the students as the most effective way for nurses to increase their knowledge.(ABSTRACT TRUNCATED AT 250 WORDS)

The safety and lack of efficacy of vinpocetine in Alzheimer's disease

Fifteen Alzheimer patients were treated with increasing doses of vinpocetine (30, 45, and 60 mg per day) in an open-label pilot trial during a one-year period. Patients were assessed seven times both on and off drug with: the Buschke Selective Reminding Task, a letter fluency test, a category fluency test, the Boston Naming Test, a cognitive capacity screening examination, and a clinical global impression. Vinpocetine failed to improve cognition on psychometric testing or overall functioning, as measured by the clinical global impression, at any dose tested. Patients showed significant decline in most measures during the course of the study, at the same rate as a matched control group, consistent with progressive dementia. There were no significant side effects from drug therapy. We conclude that vinpocetine is ineffective in improving cognitive deficits and does not slow the rate of decline in individuals with Alzheimer's disease.

Use of performance-intensity functions for diagnosis

Performance-intensity (PI) functions for phonetically balanced (PB) word lists were obtained for a group of normal listeners (27 ears), and for two groups of patients with cochlear (89 ears) and retrocochlear disorders (eight ears). Listeners with normal hearing or cochlear disorders exhibited mild to moderate reductions in discrimination score as the speech level was raised above the PB maximum. In contrast, patients with retrocochlear disorders showed a pronounced rollover phenomenon, characterized by a rapid decline in performance as the speech level was raised above the maximum discrimination score.

Observations on inshore and pelagic Dolphins on the South-Eastern Cape coast of South Africa

The occurrence, size and seaward distribution of schools of inshore and pelagic dolphins is described for three study areas on the south-eastern Cape coast (Algoa Bay; the Tsitsikama Coastal National Park and Plettenberg Bay). Inshore dolphins {Tursiops and Sousa sp.) frequented the coastline in relatively small schools whereas pelagic dolphins {Delphinus delphis and Stenella caeruleoalba) occurred in very large schools far out to sea. Different ecological zones were used by Sousa for feeding and for social behaviour and maintenance activities. The frequency of occurrence of Sousa at Plettenberg Bay was not affected by seasonal fluctuations in sea surface temperatures. The role of dolphins as predators and their implication in the regulation of the ecosystem of the Tsitsikama Coastal National Park is discussed.

Demonstration of Paneth cell granules using Naphthalene Black

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Demonstration of Paneth cell granules using Naphthalene Black

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Simultaneous demonstration of mast cells and plasma cells

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