The effect of defocus on the contrast and phase of the retinal image of a sinusoidal grating

The variation with defocus in the contrast and phase of the retinal image of a grating stimulus is computed from a knowledge of the measured wavefront aberration of individual eyes. Contrast or modulation transfer is generally lower than in the aberration-free, diffraction-limited case, even at a pupil size of 3 mm, and marked spatial phase shifts, which can be seen as sideways shifts in the retinal image, frequently occur. A simple demonstration of these effects is given. The possible significance of the focus-dependent spatial phase shifts for the phase discrimination of the visual system and accommodation is discussed.     

Cultural Competence in the Undergraduate Nursing Curriculum

Although health care providers and health care systems have increasingly acknowledged the need for culture-specific care in a global society, its implementation has remained daunting. Thus, integrating cultural competence into nursing education is no longer a choice but a requirement that builds on the values of the racially and culturally diverse population of the United States for optimal health care. The need has never been greater for nurses who understand the health implications of the demographic shifts that are shaping an American society whose African American, Hispanic, Asian, and Native American constituents compose a significantly growing portion of the population and whose health care needs will need to be served in health care settings that range from their homes to health care institutions. This article provides a blueprint on how our undergraduate program integrated cultural competence education throughout the curriculum.     

Solution structure and dynamics of a de novo designed three-helix bundle protein

Although de novo protein design is an important endeavor with implications for understanding protein folding, until now, structures have been determined for only a few 25- to 30-residue designed miniproteins. Here, the NMR solution structure of a complex 73-residue three-helix bundle protein, alpha3D, is reported. The structure of alpha3D was not based on any natural protein, and yet it shows thermodynamic and spectroscopic properties typical of native proteins. A variety of features contribute to its unique structure, including electrostatics, the packing of a diverse set of hydrophobic side chains, and a loop that incorporates common capping motifs. Thus, it is now possible to design a complex protein with a well defined and predictable three-dimensional structure.     

Development of Auditory Brainstem Responses (ABRs) in Tshr Mutant Mice Derived from Euthyroid and Hypothyroid Dams

Developmental changes in auditory brainstem responses (ABRs) to clicks and tone bursts were studied in genetically hypothyroid Tshr mutant mice that were homozygous for the hypothyroid trait (hyt/hyt), as well as in euthyroid individuals that were heterozygous for the trait (+/hyt). The developmental role of maternal thyroid hormones was determined by comparing homozygotes that were offspring of euthyroid (hyt/hyt(e)) or hypothyroid (hyt/hyt(h)) dams; all heterozygotes were born to euthyroid dams (+/hyt(e)). Clear responses to high-level stimuli were recorded from heterozygotes on postnatal day 12 (P12) for most stimulus conditions, and thresholds, response amplitudes, interpeak intervals, and latencies developed normally, achieving nearly adult properties by P21. Most hyt/hyt(h) animals were unresponsive to acoustic stimulation throughout the period of study. Grossly immature responses to high-level stimuli were observed in many hyt/hyt(e) pups on P15; however, clear, low-amplitude responses were not routinely observed until P21. Thresholds improved with age in +/hyt(e) and hyt/hyt(e) individuals, and latency-level curves were relatively steep in young animals and developed normally in +/hyt(e) mice with the most significant changes occurring between P15 and P21. In general, hyt/hyt(e) mice exhibited prolonged latencies, interpeak intervals, and central conduction times throughout the age range studied, and slopes of latency-level curves remained abnormally steep through P28. Response amplitudes were generally larger in heterozygotes than in hyt/hyt(e) mice, regardless of level. Replacement of thyroxin during the first 10 postnatal days in hyt/hyt(h) pups had little to no effect on the development of auditory function, although more animals from this group were responsive at very high stimulation levels. We conclude that auditory function is impaired in hypothyroid Tshr animals throughout development and that impairment is profound when individuals are not exposed to maternal thyroid hormone, i.e., a clear thyroxin-dependent critical prenatal period exists in the Tshr mutant mouse.     

Effectiveness of transcutaneous electrical nerve stimulation for treatment of hyperalgesia and pain

Transcutaneous electrical nerve stimulation (TENS) is a nonpharmacologic treatment for pain relief. TENS has been used to treat a variety of painful conditions. This review updates the basic and clinical science regarding the use of TENS that has been published in the past 3 years (ie, 2005–2008). Basic science studies using animal models of inflammation show changes in the peripheral nervous system, as well as in the spinal cord and descending inhibitory pathways, in response to TENS. Translational studies show mechanisms to prevent analgesic tolerance to repeated application of TENS. This review also highlights data from recent randomized, placebo-controlled trials and current systematic reviews. Clinical trials suggest that adequate dosing, particularly intensity, is critical to obtaining pain relief with TENS. Thus, evidence continues to emerge from both basic science and clinical trials supporting the use of TENS for the treatment of a variety of painful conditions while identifying strategies to increase TENS effectiveness.     

Cultural Competence in the Master's Curriculum—A Course Exemplar

Multiple teaching–learning strategies such as the online cultural self-assessment, clinical case scenario, critiques of multicultural skill vignettes, and the cultural assessment of the clinical agency helped move nurse practitioner students along the continuum to becoming culturally competent practitioners. Ongoing integration of cultural content in course curricula is necessary to prepare health care providers to meet the challenge of caring for a more diverse society. These students acknowledged this challenge and worked at conquering the cultural divide, making gains and adjustments in the areas of cultural knowledge, skills, and attitudes. There is a gap that exists between those who have been trained recently as it relates to providing culturally sensitive care and those who have not had integrated cultural content in their educational preparation. This will continue to be a challenge for educators, clinical institutions, and governmental agencies. The goal is to ensure that the implementation and integration of cultural competence concepts are not academic exercises but should serve as opportunities to reduce the gap that presently exists.