Shrinking nanowires by kinetically controlled electrooxidation.

Nanowires composed of antimony, gold, and bismuth telluride (Bi2Te3) were reduced in diameter by electrooxidation in aqueous solutions. When electrooxidation was carried out using low current densities (Jox < 150 microA cm(-2)), the mean wire diameter decreased in direct proportion to the oxidation time, as expected for a kinetically controlled process. Under these conditions, the diameter uniformity of nanowires remained constant as wires were shrunk from initial diameters of more than 120 nm to less than 40 nm, for Sb and Bi2Te3, and less than 60 nm for Au. Oxidized nanowires remained continuous for more than 100 microm. Electrooxidation at higher current densities rapidly introduced breaks into these nanowires. Electrochemical wire growth and shrinking by electrooxidation were integrated into a single electrochemical experiment that allowed the final mean diameter of nanowires to be specified with a precision of 5-10 nm.

A rechargeable aluminum-ion battery utilizing a copper hexacyanoferrate cathode in an organic electrolyte.

Reversible aluminum intercalation/deintercalation from an organic electrolyte into copper hexacyanoferrate is presented. Evidence suggest that an aluminum-solute complex is the intercalating species. The system shows initial discharge capacities as high as 60 mA h g(-1) and reversible capacities between 5 and 14 mA h g(-1), with capacity typically fading after 10 to 15 cycles.

A volume-activated cell sorter.

A sorter that is activated by the resistance pulses of a Coulter orifice (volume detector) has been developed. The problem arising from the distortion of the volume signals produced by the electric droplet forming and charging voltages are avoided by special shielding and grounding of the volume detector. Experiments with beads and leukocytes are described. The maximal processing rate at this time is 2000 cells/sec, the purity of sorted fractions is better than 97%, and the viability of sorted cells is better than 80%.

The effectiveness of prophylactic etodolac on postendodontic pain.

To determine if prophylactic etodolac would significantly reduce postendodontic pain, when compared with ibuprofen or placebo, 36 patients consented to single blind oral administration of either 400 mg of etodolac, 600 mg of ibuprofen, or a placebo, before conventional one-appointment root canal therapy. Patient-reported visual analog scale ratings of pain intensity were conducted upon initial clinical presentation, immediately postoperative, 4, 8, 12, 24, 48, and 72 h after initiation of root canal therapy. Results showed that prophylactic ibuprofen administration significantly reduced postendodontic pain at 4 and 8 h after initiation of root canal therapy, when compared with etodolac and a placebo. Patients with a periapical diagnosis of acute apical periodontitis or with a Phoenix abscess showed a significant increased need for additional medication after completion of root canal therapy, compared with all other periapical diagnoses.

The health of rural homeless women with young children.

More than 30 percent of the homeless are families with children; however, little is known about these families, particularly rural homeless mothers with children. The purpose of this study was to describe the characteristics of rural homeless mothers, their physical and mental health, and their health care practices. A descriptive cross-sectional design was used to study a sample of 76 rural mothers with children younger than age 13. An interview schedule and the SCL-90-R were used to collect data about these families. The majority of the families had been homeless for more than four months, 46 percent were woman-headed, 17 percent of the mothers reported having a physical health problem, and only 3 percent had scores on the SCL-90-R that were indicative of needing additional evaluation for possible mental health problems. The use of drugs was higher than expected, which puts both the mothers and their children at risk for health problems.

Relationship of hope and stress after myocardial infarction.

This study examines the relationship of perceived stress associated with an acute myocardial infarction and the patient's perception of hope in the coronary care unit. The subjects, 40 to 70 years of age, had experienced a first myocardial infarction. The research design was a nonexperimental, retrospective study using a convenience sample. The highest percentages of perceived stress were associated with the factors of unfamiliar surroundings and missing one's spouse. The sample population had high hopefulness scores for the factors of feelings about the future and personal motivation but ambivalent scores associated with future expectancies. Correlation of scale scores revealed no statistical relationship between perceived hope and stress for this sample population. Clinical applications are multiple. Nursing interventions to reduce stress should include an in-depth orientation to the environment and should allow for frequent contact with one's spouse. Denial must be considered as a basis for a high degree of hope perception during the first 7 days after infarction.

The depression of homeless children: a focus for nursing intervention.

Homelessness continues to be a social problem that many children experience. The loss of a home and all that is familiar to the child may have devastating short- and long-term effects on the child's psychological well-being. Some of these ill effects can potentially be mitigated by prompt nursing intervention. In this article the findings from a descriptive study that investigated 76 homeless school-age children's level of depression as measured with the Children's Depression Inventory are reported. The relevance of these findings for pediatric nurses and nursing interventions specific to this population are discussed.

A comparative study of homeless, previously homeless, and never homeless school-aged children's health.

The purpose of this cross-sectional study was to compare the mental health, physical health, and healthcare practices of homeless, previously homeless, and never homeless poor school-aged children. The sample was comprised of 134 children who ranged in age from 8 to 12 years. The children participated in health assessments and completed two psychometric tests: the Children's Depression Inventory (CDI) (Kovacs, 1985) and the Revised Children's Manifest Anxiety Scale (RCMAS) (Reynolds & Richmond, 1985). Their mothers completed the Child Behavior Problem Checklist (CBCL) (Achenbach, 1991) and participated in an interview. The homeless (n = 67), previously homeless (n = 30), and never homeless children (n = 37) were similar in regard to their health assessment findings, reported health problems, healthcare practices, and CBCL scores. The proportions of homeless and previously homeless children with CDI scores in the clinical range were significantly greater than the never homeless poor children. The homeless children had significantly higher anxiety scores than the previously homeless and never homeless children. All three groups of children were at risk for physical and mental health problems; however, the findings suggest that school-aged children who experience homelessness may be at greater risk for depression and anxiety than never homeless poor children.

Evaluating a support group for perinatal loss.

PURPOSE: This study attempted to determine if a support group intervention makes a difference in grief reactions of parents who have experienced a perinatal loss, and describes what parents perceived as being helpful and not helpful in handling the loss. DESIGN: A cross-sectional, retrospective, two-group research design was used. The independent variable was having attended or not having attended a perinatal loss support group. METHODS: A convenience sample of 121 participants (n = 67 in support groups; n = 51 not in support groups) was obtained from a mail survey to families who were on a perinatal loss support newsletter mailing list. The participants completed the Hogan Grief Reactions Checklist and a demographic questionnaire. RESULTS: There were no statistically significant differences in parents' grief reaction scores between the two groups, but there were some differences in grief scores by gender and ethnicity. In both groups, the parents perceived their spouse, their extended families, and their friends as "most helpful." Physicians were perceived as "least helpful." CLINICAL IMPLICATIONS: Grief is very individual, and not all individuals may benefit from a support group. When suggesting a support group or any intervention, timing and a caring approach are essential.

The mental health of homeless school-age children.

PROBLEM: The mental health of homeless school-age children. METHODS: A convenience sample of 46 homeless children between the ages of 8 and 12 years completed the Children's Depression Inventory (CDI) and each child's mother completed the Child Behavior Checklist (CBCL). FINDINGS: Fifty-seven percent of the children had depressive symptoms and 26% needed additional evaluation for mental health problems. Overall, the CDI and CBCL scores indicated that gender or ethnicity are not related to the children's mental health. CONCLUSIONS: The mental health of homeless schoolage children should be assessed, as they may be at risk for mental health problems.

The mental health of African-American and Caucasian-American women who are homeless.

1. Nurses can use research findings to educate other health professionals about homeless subcultures with attention to specific cultural and socioeconomic needs, as well as to develop interventions for homeless women. 2. Minority women are more susceptible to homelessness as they experience increased poverty levels and are often single mothers. Of all minority women, African-American women are the most vulnerable to physical and psychological illness. 3. In this study, 75% of the subjects had scores on a psychological assessment test that indicated they needed additional psychological testing.

Case management of homeless families.

Homeless families are the fastest growing subgroup of the homeless population. They have multiple health care needs that can be best met by the community clinical nurse specialist. Nursing actions must be planned based on an assessment of this group's unique service needs. Interventions require the use of individualized delivery strategies such as case management, which necessitates that the clinical nurse specialist develop specialized skills in both service stimulation and system advocacy.

Lithographically patterned nanowire electrodeposition.

Nanowire fabrication methods can be classified either as 'top down', involving photo- or electron-beam lithography, or 'bottom up', involving the synthesis of nanowires from molecular precursors. Lithographically patterned nanowire electrodeposition (LPNE) combines attributes of photolithography with the versatility of bottom-up electrochemical synthesis. Photolithography defines the position of a sacrificial nickel nanoband electrode, which is recessed into a horizontal trench. This trench acts as a 'nanoform' to define the thickness of an incipient nanowire during its electrodeposition. The electrodeposition duration determines the width of the nanowire. Removal of the photoresist and nickel exposes a polycrystalline nanowire--composed of gold, platinum or palladium--characterized by thickness and width that can be independently controlled down to 18 and 40 nm, respectively. Metal nanowires prepared by LPNE may have applications in chemical sensing and optical signal processing, and as interconnects in nanoelectronic devices.

Bismuth telluride (Bi2Te3) nanowires: synthesis by cyclic electrodeposition/stripping, thinning by electrooxidation, and electrical power generation.

Nanowires composed of the thermoelectric material Bi2Te3 were synthesized on highly oriented pyrolytic graphite (HOPG) electrodes using the electrochemical step edge decoration (ESED) method. Nanowire synthesis was initiated by applying a voltage pulse of -0.75 V versus SCE for 5 ms to an HOPG electrode in an aqueous solution containing both Bi3+ and TeO22-, thereby producing nuclei at the step edges. Bi2Te3 was electrodeposited onto these nuclei using a cyclic electrodeposition-stripping scheme that involved the electrodeposition of bismuth-rich Bi2Te3 on a negative-going voltammetric scan (to -0.05 V) and the subsequent anodic stripping of excess bismuth from these nanowires during a positive-going scan (to +0.35 V). When this cycle was repeated 10-50 times, Bi2Te3 nanowires in the 100-300-nm-diameter range were obtained. These nanowires were narrowly dispersed in diameter (RSDdia = 10-20%), were more than 100 microm in length, and were organized into parallel arrays containing hundreds of wires. Smaller nanowires, with diameters down to 30 nm, were obtained by electrooxidizing 150-nm-diameter Bi2Te3 nanowires at +0.37 V under conditions of kinetic control. This oxidation process unexpectedly improved the uniformity of Bi2Te3 nanowires, and X-ray photoelectron spectroscopy (XPS) shows that these nanowires retain a Bi2Te3 core but also have a thin surface layer composed of Bi and Te oxides. The ability of Bi2Te3 nanowires to generate electrical power was assessed by transferring ensembles of these nanowires onto cyanoacrylate-coated glass surfaces and evaporating 4-point nickel contacts. A dimensionless figure of merit, ZT, ranging from 0 to 0.85 was measured for fresh samples that were less than 1 day old. XPS reveals that Bi2Te3 nanowires are oxidized within a week to Bi2O3 and TeO2. These oxides may interfere with the application by evaporation of electrical contacts to these nanowires.

Shape- and size-selective electrochemical synthesis of dispersed silver(I) oxide colloids.

Silver(I) oxide (Ag2O) micro- and nanoparticles were electrochemically synthesized by anodizing a sacrificial silver wire in a basic aqueous sulfate solution. Ag2O particles were released from the silver electrode surface during synthesis producing a visible sol "stream". The composition of these particles was established using selected area electron diffraction, X-ray diffraction, and X-ray photoelectron spectroscopy. The shape of Ag2O crystallites could be adjusted using the potential of the silver wire generator electrode. The generation of a dispersed Ag2O sol and the observed shape selectivity are both explained by a two-step mechanism involving the anodic dissolution of silver metal, Ag0 --> Ag+(aq) + 1e-, followed by the precipitation of Ag2O particles, 2Ag+ + 2OH- --> Ag2O(s) + H2O. Within 100 mV of the voltage threshold for particle growth, cubic particles with a depression in each face ("hopper crystals") were produced. The application of more positive voltages resulted in the generation of 8-fold symmetric "flower"-shaped particles formed as a consequence of fast growth in the <111> crystallographic direction. The diameter of flower particles was adjustable from 250 nm to 1.8 microm using the growth duration at constant potential.

Comparison of the stressors and coping behaviors of homeless, previously homeless, and never homeless poor children.

The purpose of this study was to compare the stressors and coping behaviors of homeless, previously homeless, and never homeless poor school-aged children. Content analyses of interview data from 132 children were used. Forty-four (68%) of the homeless children identified at least one stressor related to being homeless. The three groups of children were similar in regard to stressors related to the family, self, peers, health, school, and environment. In regard to the violent behavior category, significantly more of the previously homeless and never homeless children expressed stressors compared to the homeless children. Significantly more previously homeless and never homeless children identified more social support coping behaviors compared to the homeless children. The three groups of children did not differ in regard to the use of behavioral and cognitive coping strategies.

School-aged children's perception of stress in the hospital.

This article is based on a research study of hospitalized school-aged children's perception of stress. Forty-two different stimuli were identified through the use of a projective-type game developed by the investigator. The findings of the study did not support the hypotheses that there is a relationship between the stimuli that children perceive as stressful and their preparation for hospitalization nor their length of time in the hospital.

Identification of stressors and use of coping methods in chronic hemodialysis patients.

To explore relationships among treatment-related stressors, coping methods, and length of time on hemodialysis the Baldree, Murphy, and Powers (1982) study was replicated. Sixty-eight subjects completed the Hemodialysis Stressor Scale and the Jalowiec Coping Scale. Although Baldree et al. reported no significant difference in ratings of physiological and psychosocial stressors, results of this study showed that physiological stressors were more troublesome than psychosocial stressors, t = 10.85, p less than .0001. Subjects used problem-oriented coping more often than affective methods to handle stress, t = 10.93, p less than .0001, supporting the Baldree et al. findings. The results did not duplicate previous study findings of no significant relationships between stressor and coping scores. Total hemodialysis stressor scores were related to total coping scores, r = .43, and physiological stressors to affective coping, r = .38. However, psychosocial stressors were associated with affective-oriented, r = .43, and problem-oriented coping, r = .33. Length of time of hemodialysis was associated with problem-oriented coping, r = .26.

School-aged homeless sheltered children's stressors and coping behaviors.

The purpose of this study was to examine the stressors and coping behaviors of school-aged homeless children staying in shelters. A secondary analysis of interview data from 30 children, between the ages of 8 to 12 years, was used to delineate the stressors and coping behaviors. Homeless, family, self, peer, school, and violent behavior were the stressor categories derived from content analysis. The children expressed more stresses in the homeless, family, and self categories than in the other 3 categories. The coping behaviors from the content analysis were categorized by using Ryan-Wenger's (1992) coping taxonomy. The majority of the children's coping responses were in the social support, cognitive avoidance, and behavioral distraction categories. Nurses should assess each child's stressors and coping behaviors when providing care to homeless children, and assist the child in alleviating some stressors by strengthening one's coping behaviors.