A facile strategy for the growth of high-quality tungsten disulfide crystals mediated by oxygen-deficient oxide precursors

Chemical vapor deposition (CVD) has been established as a versatile route for the large-scale synthesis of transition metal dichalcogenides, such as tungsten disulfide (WS₂). Yet, the precursor composition's role on the CVD process remains largely unknown and remains to be explored. Here, we employ Pulsed Laser Deposition (PLD) in a two-stage approach to tune the oxygen content in the tungsten oxide (WO_3-x) precursors and demonstrate the presence of oxygen vacancies in the oxide films leads to a more facile conversion from WO_3-x to WS₂. Using a joint study based on ab initio density functional theory (DFT) calculations and experimental observations, we unravel that the oxygen vacancies in WO_3-x can serve as niches through which sulfur atoms enter the lattice and facilitate an efficient conversion into WS₂ crystals. By solely modulating the precursor stoichiometry, the photoluminescence emission of WS₂ crystals can be significantly enhanced. Atomic resolution scanning transmission electron microscopy imaging (STEM) reveals that tungsten vacancies are the dominant intrinsic defects in mono- and bilayers WS₂. Moreover, bi- and multilayer WS₂ crystals derived from oxides with a high V₀ content exhibit dominant AA'/AB or AA(A…) stacking orientations. The atomic resolution images reveal local strain buildup in bilayer WS₂ due to competing effects of complex grain boundaries. Our study provides means to tune the precursor composition to control the lateral growth of TMDs while revealing insights into the different pathways for forming grain boundaries in bilayer WS₂.

Gettering in PolySi/SiOx Passivating Contacts Enables Si-Based Tandem Solar Cells with High Thermal and Contamination Resilience

Multijunction solar cells in a tandem configuration could further lower the costs of electricity if crystalline Si (c-Si) is used as the bottom cell. However, for direct monolithic integration on c-Si, only a restricted number of top and bottom cell architectures are compatible, due to either epitaxy or high-temperature constraints, where the interface between subcells is subject to a trade-off between transmittance, electrical interconnection, and bottom cell degradation. Using polySi/SiO_x passivating contacts for Si, this degradation can be largely circumvented by tuning the polySi/SiO_x stacks to promote gettering of contaminants admitted into the Si bottom cell during the top cell synthesis. Applying this concept to the low-cost top cell chalcogenides Cu₂ZnSnS₄ (CZTS), CuGaSe₂ (CGSe), and AgInGaSe₂ (AIGSe), fabricated under harsh S or Se atmospheres above 550 °C, we show that increasing the heavily doped polySi layer thickness from 40 to up to 400 nm prevents a reduction in Si carrier lifetime by 1 order of magnitude, with final lifetimes above 500 μs uniformly across areas up to 20 cm². In all cases, the increased resilience was correlated with a 99.9% reduction in contaminant concentration in the c-Si bulk, provided by the thick polySi layer, which acts as a buried gettering layer in the tandem structure without compromising the Si passivation quality. The Si resilience decreased as AIGSe > CGSe > CZTS, in accordance with the measured Cu contamination profiles and higher annealing temperatures. An efficiency of up to 7% was achieved for a CZTS/Si tandem, where the Si bottom cell is no longer the limiting factor.

Spin-coated [Formula: see text] solar cells: A study on the transformation from ink to film

In this paper, we study the DMSO/thiourea/chloride salt system for synthesis of pure-sulfide [Formula: see text] (CZTS) thin-film solar cells under ambient conditions. We map out the ink constituents and determine the effect of mixing time and filtering. The thermal behavior of the ink is analyzed, and we find that more than 90% of the solvent has evaporated at [Formula: see text]. However, chloride and sulfoxide species are released continually until [Formula: see text], suggesting the advantage of a higher pre-annealing temperature, which is also commonly observed in the spin-coating routines in literature. Another advantage of a higher pre-annealing temperature is that the worm-like pattern in the spin-coated film can be avoided. We hypothesize that this pattern forms as a result of hydrodynamics within the film as it dries, and it causes micro-inhomogeneities in film morphology. Devices were completed in order to finally evaluate the effect of varying thermal exposure during pre-annealing. Contrary to the previous observations, a lower pre-annealing temperature of [Formula: see text] results in the best device efficiency of 4.65%, which to the best of our knowledge is the highest efficiency obtained for a pure-sulfide kesterite made with DMSO. Lower thermal exposure during pre-annealing results in larger grains and a thicker [Formula: see text] layer at the CZTS/Mo interface. Devices completed at higher pre-annealing temperatures display the existence of either a Cu-S secondary phase or an incomplete sulfurization with smaller grains and a fine-grain layer at the back interface.

Energy band alignment at the heterointerface between CdS and Ag-alloyed CZTS

Energy band alignment at the heterointerface between CdS and kesterite Cu₂ZnSnS₄ (CZTS) and its alloys plays a crucial role in determining the efficiency of the solar cells. Whereas Ag alloying of CZTS has been shown to reduce anti-site defects in the bulk and thus rise the efficiency, the electronic properties at the interface with the CdS buffer layer have not been extensively investigated. In this work, we present a detailed study on the band alignment between n-CdS and p-CZTS upon Ag alloying by depth-profiling ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). Our findings indicate that core-level peaks and the valence band edge of CdS exhibit a significant shift to a lower energy (larger than 0.4 eV) upon the etching of the CdS layer, which can be assigned due to band bending and chemical shift induced by a change in the chemical composition across the interface. Using a simplified model based on charge depletion layer conservation, a significantly larger total charge region depletion width was determined in Ag-alloyed CZTS as compared to its undoped counterpart. Our findings reveal a cliff-like band alignment at both CdS/CZTS and CdS/Ag-CZTS heterointerfaces. However, the conduction-band offset decreases by more than 0.1 eV upon Ag alloying of CZTS. The approach demonstrated here enables nanometer-scale depth profiling of the electronic structure of the p–n junction and can be universally applied to study entirely new platforms of oxide/chalcogenide heterostructures for next-generation optoelectronic devices.

Persistent Double-Layer Formation in Kesterite Solar Cells: A Critical Review

In kesterite Cu₂ZnSn(S,Se)₄ (CZTSSe) solar cell research, an asymmetric crystallization profile is often obtained after annealing, resulting in a bilayered - or double-layered - CZTSSe absorber. So far, only segregated pieces of research exist to characterize the appearance of this double layer, its formation dynamics, and its effect on the performances of devices. In this work, we review the existing research on double-layered kesterites and evaluate the different mechanisms proposed. Using a cosputtering-based approach, we show that the two layers can differ significantly in morphology, composition, and optoelectronic properties and complement the results with a large statistical data set of over 850 individual CZTS solar cells. By reducing the absorber thickness from above 1000 to 300 nm, we show that the double-layer segregation is alleviated. In turn, we see a progressive improvement in the device performance for lower thickness, which alone would be inconsistent with the well-known case of ultrathin CIGS solar cells. We therefore attribute the improvements to the reduced double-layer occurrence and find that the double layer limits the efficiency of our devices to below 7%. By comparing the results with CZTS grown on monocrystalline Si substrates, without a native Na supply, we show that the alkali metal supply does not determine the double-layer formation but merely reduces the threshold for its occurrence. Instead, we propose that the main formation mechanism is the early migration of Cu to the surface during annealing and formation of Cu_2-xS phases in a self-regulating process akin to the Kirkendall effect. Finally, we comment on the generality of the mechanism proposed by comparing our results to other synthesis routes, including our own in-house results from solution processing and pulsed laser deposition of sulfide- and oxide-based targets. We find that although the double-layer occurrence largely depends on the kesterite synthesis route, the common factors determining the double-layer occurrence appear to be the presence of metallic Cu and/or a chalcogen deficiency in the precursor matrix. We suggest that understanding the limitations imposed by the double-layer dynamics could prove useful to pave the way for breaking the 13% efficiency barrier for this technology.

Characterization of Cu2ZnSnS4 Particles Obtained by the Hot-Injection Method

In the last decade, Cu2ZnSnS4 (CZTS) has been a promising earth-abundant, nontoxic candidate material for absorption layers within thin-film solar cells. One major issue preventing this type of solar cells from achieving competitive efficiency is impurity phases and structural defects in the bulk of the absorber; as a four-element compound, the formation of CZTS is highly sensitive to synthesis conditions. The impurity phases and defects differ by the fabrication method, and thus experimental characterization is vital for the successful development of CZTS photovoltaics. In this work, we characterize CZTS nanoparticles obtained by the hot-injection method and a standard N2/S annealing procedure. Phase-pure kesterite CZTS samples in the desired compositional range were characterized by standard means, i.e., Raman spectroscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. However, using synchrotron X-ray diffraction with Rietveld refinement, we show that the as-synthesized nanoparticles consist of a mixture of the tetragonal and the fully disordered cubic sphalerite phase and transform into the tetragonal structure after heat treatment. Sn vacancies are seen in the annealed samples. X-ray total scattering with pair distribution function analysis furthermore suggests the presence of a nanostructured CZTS phase along with a bulk material. Finally, this study compares the benefits of applying synchrotron radiation instead of a standard laboratory X-ray diffraction when characterizing highly complex materials.

Incidence and predictors of recurrent and other new diabetic foot ulcers: a retrospective cohort study

AIMS

To estimate progression rates, evaluate risk factors for progression, and study rate ratios for progression among people with a healed diabetic foot ulcer according to whether the healed ulcer was neuropathic, neuro-ischaemic or critically ischaemic.

METHODS

We conducted a retrospective cohort study in all individuals with a healed diabetic foot ulcer treated at the Steno Diabetes Centre Copenhagen foot clinic in the period 2010 to 2016. The outcome of interest was recurrent/other new diabetic foot ulcers.

RESULTS

A total of 780 people had a healed diabetic foot ulcer in the study period (2010-2016). The participants were followed for 1249 person-years [median (Q1-Q3) 1.04 (0.38-2.46) person-years] in total. One-third (33.1%) developed a recurrent/other new diabetic foot ulcer per year. Male gender, people with Type 2 diabetes and smokers had a statistically significantly higher risk of progression to a recurrent/other new diabetic foot ulcer compared to participants without these risk factors. Participants with neuro-ischaemic or critically ischaemic diabetic foot ulcers had statistically significantly higher progression rates than participants with neuropathic diabetic foot ulcers.

CONCLUSIONS

Focus should be on preventing future recurrent/other new diabetic foot ulcers especially in people with ischaemia.

Liquid phase assisted grain growth in Cu2ZnSnS4 nanoparticle thin films by alkali element incorporation

We present a route where organic ligand-free, KCl-functionalized Cu₂ZnSnS₄ nanoparticles grow into large, dense grains during annealing in nitrogen/sulfur atmosphere.

Synthesis of ligand-free CZTS nanoparticles via a facile hot injection route

Single-phase, ligand-free Cu2ZnSnS4 (CZTS) nanoparticles that can be dispersed in polar solvents are desirable for thin film solar cell fabrication, since water can be used as the solvent for the nanoparticle ink. In this work, ligand-free nanoparticles were synthesized using a simple hot injection method and the precursor concentration in the reaction medium was tuned to control the final product. The as-synthesized nanoparticles were characterized using various techniques, and were found to have a near-stoichiometric composition and a phase-pure kesterite crystal structure. No secondary phases were detected with Raman spectroscopy or scanning transmission electron microscopy energy dispersive x-ray spectroscopy. Furthermore, high resolution transmission electron microscopy showed large-sized nanoparticles with an average diameter of 23 nm ± 11 nm. This approach avoids all organic materials and toxic solvents that otherwise could hinder grain growth and limit the deposition techniques. In addition the synthesis route presented here results in nanoparticles of a large size compared to other ligand-free CZTS nanoparticles, due to the high boiling point of the solvents selected. Large particle size in CZTS nanoparticle solar cells may lead to a promising device performance. The results obtained demonstrate the suitability of the synthesized nanoparticles for application in low cost thin film solar cells.

Synthesis of large CZTSe nanoparticles through a two-step hot-injection method

We present an alternative synthesis route to achieve larger Cu₂ZnSnSe₄ nanoparticles with targeted S/Se-ratios, by introducing selenium in the liquid phase – as liquid selenization!

Contextual factors associated with pain response of preterm infants to heel-stick procedures

BACKGROUND

Evidence indicates that medical and demographic contextual factors (cFs) impact pain responses in preterm neonates, but the existing evidence is very heterogeneous.

AIM

To explore the effect of cFs on pain responses to heel-stick procedures of preterm infants.

METHODS

This study was a secondary analysis of data collected during a randomized controlled trial examining pain response to non-pharmacological interventions across repeated heel sticks. Five heel sticks across the first 14 days of life were videotaped. Pain response was rated with the Bernese Pain Scale for Neonates (BPSN) by four raters blinded to the heel-stick phases (baseline, heel stick, recovery). Demographic and medical cFs were extracted from medical charts. Mixed single and multiple regression analyses were performed controlling for the intervention group, site and heel-stick phase.

RESULTS

Apgar scores at 1 min were negatively associated with behavioural (p = 0.002) BPSN scores, while Apgar scores at 5 min after birth were positively associated with behavioural (p = 0.006) scores. Accumulated number of painful procedures (p = 0.002) and gender (p = 0.02) were positively associated with physiological scores while continuous positive airway pressure CPAP (p = 0.009) and mechanical ventilation (p = 0.005) were negatively associated.

CONCLUSION

Higher exposure to painful procedures, male infants and having CPAP or mechanical ventilation were cFs associated with physiological response. The only variables significantly associated with behavioural BPSN scores were Apgar scores but these relationships were inconsistent.

Nurse-reported patient safety climate in Swiss hospitals: a descriptive-explorative substudy of the Swiss RN4CAST study

QUESTIONS UNDER STUDY

Measuring the patient safety climate in the organisation of healthcare can help to identify problematic issues with a view to improving patient safety. We aimed (1) to describe the nurse-reported engagement in safety behaviours, (2) to describe the prevailing nurse-reported patient safety climate of general medical, surgical and mixed medical-surgical units in Swiss acute-care hospitals and (3) to explore differences between hospital type, unit type and language regions.

METHODS

This substudy utilised data from the nurse survey (N = 1,633) of the multicentre-cross sectional RN4CAST study. Patient safety climate was measured with the 9-item Safety Organizing Scale (SOS) which captured registered nurses' engagement in safety behaviours and practices at the unit level.

RESULTS

A total of 35 Swiss hospitals participated in the study. Of the 120 eligible units included in the analysis, only on 33 units (27.5%) did at least 60% of the nurses report a positive patient safety climate. A majority of nurses (51.2-63.4%, n = 1,564) reported that they were "consistently engaged" in only three of the nine measured patient safety behaviours. Our multilevel regression analyses revealed both significant between-unit and between-hospital variability. From our three variables of interest (hospital type, unit type and language regions) only language regions was consistently related to nurse-reported patient safety climate. Nurses in the German-speaking region reported a more positive patient safety climate than nurses in the French- and Italian-speaking language regions.

CONCLUSIONS

The findings of this study suggest a need to improve the patient safety climate on many units in Swiss hospitals. Leaders in hospitals should strengthen the patient safety climate at unit level by implementing methods, such as root cause analysis or patient safety leadership walk rounds, to improve individual and team skills and redesign work processes. The impact of these efforts should be measured by periodically assessing the patient safety climate with the SOS.

The unspoken disease: symptom experience in women with vulval neoplasia and surgical treatment: a qualitative study

Women with vulval neoplasia often experience severe post-surgical complications. This study focuses on symptom experience of women during the first 6 months following surgical treatment for vulval neoplasia considering their socio-cultural context. In this qualitative study using a critical hermeneutic approach, narrative interviews were conducted. A purposeful sample of 20 patients was recruited from one Swiss and two German university hospitals. Content analysis was employed to analyse the transcribed interviews considering women's experiences and social perceptions. Narratives showed eight interrelated themes: delayed diagnosis, disclosed disease, disturbed self-image, changed vulva care, experienced wound-related symptoms, evoked emotions, affected interpersonal interactions and feared illness progression. The women experienced a general lack of information pertaining to above themes and all described strategies used to handle their situation, which affected their distress. The communication, assessment and treatment of symptoms were hampered by the society's and the health system's tendency to overlook these symptoms and leave them in the realm of the unspeakable. Health professionals need new strategies to support these women to recognise, assess and evaluate the seriousness of symptoms, and to communicate their symptom experience so that timely medical treatment is sought. This support may minimise potentially preventable complications and symptom-related distress.

Facilitated tucking as a non-pharmacological intervention for neonatal pain relief: is it clinically feasible?

There is an impressive body of knowledge on pain management in infants hospitalized in neonatal intensive care units. However, deficits in the clinical management of pain in these infants remain. One reason is the gap between research evidence and translation of this knowledge into the clinical setting. This is particularly true for non-pharmacological pain-relieving methods. Effective performance of some of these methods requires additional staffing and time. This viewpoint articles describes the clinical challenges associated with implementing 'facilitated tucking'. Although 'facilitated tucking' is described as an efficient method for acute pain relief, the clinical facilitators required to successfully implement such a resource consuming-intervention remain unclear.

CONCLUSION

  Translational research on the feasibility of using 'facilitated tucking' in the management of neonatal pain is warranted, including the economic impact of this intervention. Increased manpower costs need to be weighed against the possible long-term economical consequences of pain exposure in infants.

Differential relationship between physical activity and progression to diabetes by glucose tolerance status: the Inter99 Study

AIMS/HYPOTHESIS

The aim of the study was to analyse how strongly commuting and leisure-time physical activity affect progression to diabetes and to study whether this relationship is different in individuals with isolated impaired fasting glucose (i-IFG) and isolated impaired glucose tolerance (i-IGT).

METHODS

We studied the incidence of diabetes in 4,031 individuals without diabetes at baseline who participated in the baseline and 5 year follow-up examinations of a population-based primary prevention study, the Inter99 Study. Glucose tolerance status at baseline and at follow-up were based on OGTTs. Commuting and leisure-time physical activity at baseline were assessed by questionnaire. We present rate ratios from Poisson regression analyses adjusted for relevant confounders.

RESULTS

The progression rate to diabetes was lower among physically active individuals in the total study population and particularly among those with i-IGT. The associations were attenuated and lost statistical significance after further adjustment for BMI. We observed no impact of physical activity on the progression to diabetes in individuals with i-IFG.

CONCLUSIONS/INTERPRETATION

Physical activity was associated with a lower progression to diabetes in the total study population and in individuals with i-IGT, a condition primarily characterised by muscle insulin resistance. Physical activity did not predict progression to diabetes in individuals with i-IFG, a condition primarily characterised by hepatic insulin resistance. Our results suggest that there is a differential relationship between physical activity and progression to diabetes among those with i-IFG and i-IGT. Therefore, clinical trials testing the effect of physical activity on progression from i-IFG to diabetes are needed.

TRIAL REGISTRATION

ClinicalTrials.gov ID No.: NCT00289237

FUNDING

The Danish Medical Research Council, the Danish Center for Evaluation and Health Technology Assessment, Novo Nordisk, Copenhagen County, the Danish Heart Foundation, the Danish Diabetes Association, the Danish Pharmaceutical Association, the Augustinus Foundation, the Ib Henriksen Foundation and the Becket Foundation.

Variability in pain response to a non-pharmacological intervention across repeated routine pain exposure in preterm infants: a feasibility study

AIM

To explore the variability in pain response in preterm infants across time who received sucrose during routine heel stick.

METHOD

Single group, exploratory repeated measures design.

SETTING

Two tertiary level neonatal intensive care units (NICU) in Switzerland.

SUBJECTS

Nine preterm infants born between 28 2/7 and 31 4/7 weeks of gestation during their first 14 days of life.

MEASUREMENTS

Pain was assessed by the Bernese Pain Scale for Neonates (BPSN), the Premature Infant Pain Profile (PIPP) and the Visual Analogue Scale (VAS). Salivary cortisol was analysed.

RESULTS

72-94% of the variability was within-subject variability, indicating inconsistency of pain responses across the 5 heel sticks. Interrater agreement was highest during heel sticks 1-3 and decreased during heel stick 4 and 5, indicating a possible alteration of pain patterns. No significant differences in the amount of cortisol could be detected before and after the heel sticks (p = 0.55), indicating no stress-induced peak after the painful intervention. However, a general gradual decrease of cortisol levels across time could be detected.

CONCLUSION

A high variability in pain response among preterm neonates across time could be described. Consistency of cortisol levels before and after the heel sticks could indicate the effectiveness of sucrose across time.

Alternative exon usage selectively determines both tissue distribution and subcellular localization of the acyl-CoA thioesterase 7 gene products

Acyl-CoA thioesterases (ACOTs) catalyze the hydrolysis of acyl-CoAs to free fatty acids and coenzyme A. Recent studies have demonstrated that one gene named Acot7, reported to be mainly expressed in brain and testis, is transcribed in several different isoforms by alternative usage of first exons. Strongly decreased levels of ACOT7 activity and protein in both mitochondria and cytosol was reported in patients diagnosed with fatty acid oxidation defects, linking ACOT7 function to regulation of fatty acid oxidation in other tissues. In this study, we have identified five possible first exons in mouse Acot7 (Acot7a-e) and show that all five first exons are transcribed in a tissue-specific manner. Taken together, these data show that the Acot7 gene is expressed as multiple isoforms in a tissue-specific manner, and that expression in tissues other than brain and testis is likely to play important roles in fatty acid metabolism.

Prevalence and recognition of depressive symptoms among homebound older adults with urinary incontinence

Within a group of homebound elders with urinary incontinence, the objectives of this study were to (1) examine the prevalence of depressive symptoms, (2) examine the extent to which depression had previously been recognized by health care providers, (3) describe the type and intensity of antidepressant treatment prescribed for subjects, and (4) identify the demographic and functional characteristics associated with depressive symptomatology. A descriptive correlational design was used. The 15-item Geriatric Depression Scale (GDS-15) was administered to 345 homebound adults age 60 years and over referred to a study examining the effectiveness of behavioral therapy for urinary incontinence. Individuals were referred to the study by home care nurses from two large Medicare-approved home health agencies in a large metropolitan county in Pennsylvania. Data were collected during in-home assessments and by chart review. Measures included the GDS-15, structured medical history, in-home review of medications, Older Americans Research and Service Center Physical and Instrumental Activities of Daily Living scales, Mini-Mental State Examination (MMSE), Clock Drawing Test, Performance-Based Toileting Assessment, and bladder diaries. One half of the participants (n = 173; 50.1%) had significant depressive symptomatology, with 35.7% having scores suggesting mild depression and 14.5% severe depression. Only 26.4% and 34.7% of those with mild and severe depressive symptoms, respectively, had a previous diagnosis of depression and only 21.7% and 34.0%, respectively, had been prescribed an antidepressant. The most commonly prescribed class of antidepressants was tricyclic antidepressants, being taken by 9.0% (n = 31) of the total sample, 14 (11.4%) of those with mild symptoms and 4 (8.0%) of those with severe depressive symptomatology. A little over half (60.0%) of subjects being treated with antidepressants continued to exhibit significant depressive symptomatology. Greater dependence in physical activities of daily living, the need for assistance during ambulation, higher MMSE scores, and higher levels of comorbidity were associated (P < .05) with a GDS-15 score of 5 or higher. Depression symptoms are common in homebound older adults with urinary incontinence, but clinical recognition and treatment are limited.

Effectiveness of behavioral therapy to treat incontinence in homebound older adults

OBJECTIVES

To examine the (1) short-term effectiveness of behavioral therapies in homebound older adults and (2) characteristics of responders and nonresponders to the therapies.

DESIGN

Prospective, controlled clinical trial with cross-over design.

SETTING

Adults aged 60 and older with urinary incontinence and who met Health Care Financing Administration criteria for being homebound were referred to the study by homecare nurses from two large Medicare-approved home health agencies in a large metropolitan county in southwestern Pennsylvania.

MEASURES

Structured continence and medical history, OARS Physical and Instrumental Activities of Daily Living scales, Folstein Mini-Mental State Examination Score, Clock Drawing Test, Geriatric Depression Scale, Performance-Based Toileting Assessment, bladder diaries, and physical examination.

RESULTS

One hundred five subjects were randomized to biofeedback-assisted pelvic floor muscle training (53 to the treatment group and 52 to the control groups). Control subjects with complete pre- and post-control data (n = 45) experienced a median 6.4% reduction in urinary accidents in contrast to a median 75.0% reduction in subjects with complete pre- and post-treatment data (n = 48, P < .001). Following the control phase, subjects crossed over to the treatment protocol. Eighty-five subjects completed treatment, achieving a median 73.9% reduction in UI. Exercise adherence was the most consistent predictor of responsiveness to the behavioral therapy.

CONCLUSIONS

Clinically significant reductions in urinary incontinence are achievable with behavioral therapies in many cognitively intact homebound older adults despite high levels of co-morbidity and functional impairment.

Survival and 2-year outcome with expectant management of second-trimester rupture of membranes

OBJECTIVE

To evaluate the perinatal and 2-year outcomes in pregnancies complicated by preterm premature rupture of membranes (PROM) during the second trimester.

METHODS

Fifty-three consecutive singleton pregnancies with PROM at 14 to 28 weeks of gestation were studied retrospectively. Management goals were to prolong the pregnancies to 32 weeks through expectant management and to avoid fetal compromise through closer monitoring and active intervention, when necessary, after 23 weeks. Outcome of the surviving infants was based on neurologic, audiometric, and ophthalmologic examinations at 2 years of corrected age.

RESULTS

Rupture of membranes occurred at 14-19 weeks (mean 17.4 weeks) in 10 women, at 20-25 weeks (mean 24.0 weeks) in 24, and at 26-28 weeks (mean 27.6 weeks) in 19. The median latency periods to delivery were 72 days, 12 days, and 10 days when rupture of membranes occurred at 14-19 weeks, 20-25 weeks, and 26-28 weeks, respectively. The overall incidence of chorioamnionitis was 28%. There were no fetal deaths and nine neonatal deaths. When rupture of membranes occurred at 14-19 weeks, 20-25 weeks, and 26-28 weeks, the perinatal survival rates were 40%, 92%, and, 100%, respectively. Pulmonary hypoplasia accounted for seven deaths. Of the live-born infants, 81% were alive at 2 years of corrected age. Survival without major impairment was observed in 75%, 80%, and 100% of the survivors when rupture of membranes occurred at 14-19 weeks, 20-25 weeks, and 26-28 weeks, respectively.

CONCLUSION

Expectant management of second-trimester PROM offers better perinatal and long-term survival than previously thought.

In vitro digestion of proteins in human milk fortifiers and in preterm formula

BACKGROUND

Knowledge about the digestibility of the proteins in new products designed for feeding preterm infants is limited. The purpose of this study was to observe in vitro the hydrolysis of the bovine and human whey proteins in such products.

METHODS

Proteins in human milk, in human milk fortifiers (Presemp [Semper AB, Stockholm, Sweden] and Enfamil [Mead Johnson, Evansville, IN, U.S.A.] human milk fortifiers), in preterm formulas (Similac Special Care [Ross, Columbus, OH, U.S.A.] and Enfalac [Mead Johnson]), and whey protein concentrates with varying degrees of denaturation were digested by duodenal juice from healthy preterm infants, from a 3-year-old child, and from adults. Digestion was studied in vitro using polyacrylamide gradient gel electrophoresis, electroimmunoassay, and nonprotein nitrogen analysis.

RESULTS

Casein was the protein most rapidly degraded in all products. Human and bovine whey proteins were more slowly digested; as much as 68% of human lactoferrin was still immunoreactive after 40 minutes of digestion. The corresponding figure for bovine serum albumin was 24-69%; for B-lactoglobulin, 20-40%; for bovine alpha-lactalbumin, 20-51%; and for human alpha-lactalbumin, 41%. Contrary to common belief, digestibility of bovine whey proteins decreased with a high degree of denaturation of the proteins.

CONCLUSIONS

Bovine whey proteins in human milk fortifiers and in preterm formulas are relatively slowly digested in vitro by normal duodenal juice. The results may have implications for the design of products for feeding preterm infants.

Assessment and management of urinary incontinence among homebound older adults: a clinical trial protocol

Urinary incontinence is a common and costly problem among homebound older adults. This article describes the assessment and management protocols utilized in a clinical trial examining the effectiveness of behavioral interventions in treating urinary incontinence in homebound older adults. Individuals with urinary incontinence were identified and referred to the study by home care nurses from two large home health agencies. Following in-home assessment, eligible subjects were randomized to an immediate treatment group or a delayed treatment group (control group). Subjects who were cognitively intact were treated with biofeedback-assisted pelvic floor muscle training, while subjects with cognitive impairments were treated with a program of prompted voiding. Two nurse practitioners assessed and treated subjects participating in the study.

Health-related quality of life in chronic disorders: a comparison across studies using the MOS SF-36

The purpose of this report is to examine health-related quality of life (HRQoL) as measured by the Medical Outcomes Study Short Form-36, across patient populations with chronic disorders and to compare quality of life (QoL) in these subjects with normative data on healthy persons. Six studies, within the Center for Research in Chronic Disorders at the University of Pittsburgh School of Nursing, in patients with urinary incontinence, prostate cancer, chronic obstructive pulmonary disease (COPD), acquired immune deficiency syndrome (AIDS), fibromyalgia and hyperlipidaemia provided the data for analysis. The results demonstrated that not only did the prostate cancer and hyperlipidaemia patients have the highest QoL across the chronic disorders, but their QoL was comparable to normative data on healthy persons. Homebound, elderly, incontinent patients had the lowest QoL for physical functioning, whereas patients hospitalized with AIDS had the lowest QoL in general health and social functioning. Patients with COPD had the lowest QoL in role-physical, role-emotional and mental health. Patients with fibromyalgia had the lowest QoL in bodily pain and vitality. Compared to normative data, patients with urinary incontinence, COPD, AIDS and fibromyalgia generally had lower QoL. Prostate cancer and hyperlipidaemia patients had QoL comparable to normative data. Compared to normative data, patients with urinary incontinence, COPD, AIDS and fibromyalgia had more variability for role-emotional. AIDS patients had more variability on physical functioning, bodily pain and social functioning compared to the normative data. These data suggest that patients with various chronic disorders may have QoL that is lower in most domains compared to a healthy population. However, there may be differences in the domains affected as well as the extent of variation across specific chronic disorders.

Geropsychiatric restraint use

OBJECTIVES

To investigate predictors and reasons for restraint use with geropsychiatric patients.

DESIGN

A prospective, correlational study.

SETTING

The geriatric unit of an acute-care psychiatric hospital.

PARTICIPANTS

Twenty-one staff nurses and 131 patients admitted consecutively over a period of 6 months.

MEASUREMENTS

Disruptive behaviors were measured with the Nursing Home Behavior Problem Scale (NHBPS), cognitive function was measured with the Mini-Mental State Examination (MMSE), mobility was measured with a Functional Mobility Screen (FMS), and reasons for restraint use were obtained with a questionnaire completed by nurses.

RESULTS

Patients with a diagnosis of dementia, impaired mobility, or behavioral problems were more likely to be restrained. The most frequent reasons given by staff for restraint use were an unsteady gait and a risk of falling. The incidence of restraint use was 27.1%.

CONCLUSIONS

The use of restraint with geropsychiatric patients may be more common than previously reported and requires further investigation.

Treatment of urinary incontinence in homebound older adults: interface between research and practice

Urinary incontinence is one of the most common problems afflicting older adults and a major contributor to healthcare costs for homebound older individuals. The authors conducted a randomized controlled clinical study examining the effectiveness of biofeedback-assisted pelvic floor muscle training and prompted voiding in treating urinary incontinence in homebound older adults. This article briefly describes the assessment and treatment protocols utilized during this study and describes their subsequent application to clinical practice within a large urban home health agency.

Digestion of proteins in human milk, human milk fortifier, and preterm formula in infant rhesus monkeys

BACKGROUND

There is limited information in the literature on the capacity of the preterm infant to digest human and bovine milk proteins. We therefore studied in vivo the luminal phase of the hydrolysis of proteins in human milk, human milk fortifier, and preterm formula in preterm rhesus monkeys and in infant rhesus monkeys at 6 weeks and 7 months of age.

METHODS

Protein hydrolysis was followed by polyacrylamide gradient gel electrophoresis and electroimmunoassay. The serum level of absorbed unhydrolyzed human alpha-lactalbumin was measured by a radioimmunoassay method. Trypsin and elastase activities in duodenal contents were measured before and after the meal.

RESULTS

In 6-week-old monkeys, the enzyme activities decreased by 50% postprandially, whereas they increased in 7-month-old monkeys. In preterm and in 6-week-old monkeys, hydrolysis of human and bovine whey proteins was slow, and in 6-week-old monkeys, 30-50% of the proteins could still be detected immunochemically in duodenal contents after 60 min. At these ages, serum level of absorbed alpha-lactalbumin were high. At 7 months of age, no or small (lactoferrin and bovine serum albumin) amounts of the proteins could be detected in duodenal contents after 15 min. At this age alpha-lactalbumin was not measurable in serum.

CONCLUSIONS

The low capacity to digest whey proteins in suckling monkeys may depend upon an immaturity of the exocrine pancreas to respond to secretogogues.

Spread of Klebsiella in a neonatal ward

The colonization of infants with Klebsiella pneumoniae was prospectively studied. Samples were taken from nose, throat, umbilicus and rectum on the day of arrival and thereafter once a week. Phage typing was performed the first time K. pneumoniae was found at any of these sites. Settle plates were exposed in the incubators and in the patient rooms 5 h/day. The study lasted for 32 weeks. The first 15 weeks was a control period with no information to the staff, the following 4 weeks was a period of intervention and education and the last 13 weeks was a second control period. In all, 603 infants were investigated. The number of infants nursed per week and severity of their disease was comparable in the 3 periods. The colonization rates were 65, 34 and 58%, respectively. The acquisition of new strains was 1.4 per infant in the first and last periods, but only 0.4 in the period of intervention. Thus, colonization rates decreased only during the period of continuous education in hygiene.

Surface ultrastructure of the small intestine mucosa in children with celiac disease. I. Untreated disease and effects of long-term gluten elimination and challenge

Forty-eight gut mucosa specimens from 27 children with celiac disease, diagnosed by means of conventional serial biopsies taken at different dietary conditions, were studied by means of scanning electron microscopy (SEM). The observations were correlated with those made by concomitant dissection microscope (DM), light microscope (LM), and transmission electron microscope (TEM) examinations. Five children with constitutional short stature served as controls. The results of the SEM analyses were in good conformity with the observations made by DM, LM, and TEM. In addition, SEM was found to offer further structural variables to be analyzed. In active celiac disease and after challenge with dietary gluten, which is necessary to establish the diagnosis of children, the lesions specifically observed by SEM were (1) a strikingly uniform destruction of the villi and a distortion of the enterocytes but with preserved extrusion zones, and (2) a decrease and disruption of the glycocalyx of the enterocytes with marked irregularity of the microvilli. After successful dietary treatment and despite a normalization of the gut mucosa by routine LM, SEM often disclosed persisting lesions of the enterocytes. It was concluded that by inclusion of SEM in the routine assessments of gut biopsy specimens in children with celiac disease, the diagnostic precision becomes increased.

Influence of type of feeding on lymphocyte function and development of infantile allergy

Symptom scores indicating infantile allergy were recorded longitudinally in a group of infants during the first year of life. The symptom scores were related to duration of breast-feeding. Lymphocyte function, measured as the proliferative responsiveness to PHA-stimulation, was related to feeding with breast-milk or cow's milk. Babies with a short duration of breast-feeding; i.e. 1 month or less had significantly higher symptom scores at the ages of 1 month (P less than 0.05), 3 months (P less than 0.05), 6 months (P less than 0.001) and 12 months (P less than 0.05), than babies who were breast-fed for more than 1 month. The lymphocyte responsiveness to PHA was significantly higher at 3 and 6 months in babies who were fed cow's milk compared with those who were solely or partially breast-fed (P less than 0.05 and P less than 0.01 respectively). There was no correlation between symptom scores and lymphocyte responsiveness. It is concluded that infantile allergy is more common in babies with a short duration of breast-feeding and that feeding with cow's milk, compared to breast-feeding, causes a changed lymphocyte reactivity to PHA, which latter finding indicates an altered T-cell function between the two feeding groups.

Treatment of infantile atopic dermatitis with a strict elimination diet

Of twenty-one infants with atopic dermatitis, twenty were treated with a strict elimination diet for a period of up to 6 weeks. Seven infants healed and twelve improved. The infants who healed were less than 6 months old and had had a short duration of dermatitis. For one infant the skin condition was unchanged. Another infant was breast-fed throughout the period with dermatitis. Blood eosinophilia and/or elevated serum IgE commonly found on admission decreased significantly (P less than 0.01) during the diet period. On challenge with cows' milk, twelve infants were considered as intolerant. At the age of 2 years the dermatitis had cleared in all but four children. Of these four children, two were still cows' milk intolerant. Another two infants were also cows' milk intolerant, but without dermatitis.