The impact of carbon coating on the synthesis and properties of α''-Fe16N2 powders.

This paper presents the preparation of carbon composite Fe16N2 powders, and the influence of a protective carbon coating on the yield and magnetic properties of Fe16N2. Nanoparticle precursors with and without carbon were reacted under ammonia gas flow to produce Fe16N2. Neutron and X-ray powder diffraction indicate that the powders contain typically 40-60% Fe16N2, with the remaining phases being unreacted iron, Fe4N or Fe3N. Transmission electron microscopy demonstrates that the carbon coating is effective at reducing the level of sintering of Fe nanoparticles during the reduction stage prior to ammonolysis. XPS results support the retention of a carbon coating on the surface after ammonolysis, and that there is Fe-C bonding present at the particle surface. In situ TEM was used to observe loss of ordering in the nitrogen sublattice of carbon composite Fe16N2 powders in the range of 168 °C to 200 °C. Magnetic susceptibility measurements show maximum values for saturation magnetization in the range of 232 emu g(-1), and for coercivity near 930 Oe, for different samples measured up to 2 T applied field at 300 K.

Supplementing fresh bovine colostrum with gut-active carbohydrates reduces passive transfer of immunoglobulin G in Holstein dairy calves.

High concentrations of coliform bacteria in maternal colostrum (MC) have been associated with reduced IgG absorption in calves. Mannan-oligosaccharide, a gut-active carbohydrate (GAC) derived from yeast cell wall, has been shown to adsorb pathogens expressing type-1-fimbriae, reducing their ability to colonize the gastrointestinal tract. The objective of this study was to investigate if addition of a GAC to colostrum would result in increased IgG absorption in newborn calves. Newborn Holstein heifer and bull calves were enrolled in summer 2012 at a commercial transition cow facility in western Wisconsin. Each day, 7.6-L pools of fresh, first milking MC were created, split into 3.8-L aliquots, and refrigerated until feeding. Eligible newborn calves were removed from the dam 30 to 60min after birth, weighed, and randomly assigned to be fed either 3.8 L of the MC pool (control) or 3.8 L of the MC pool with 30 g of GAC mixed in immediately before feeding. Duplicate 10-mL samples of colostrum were collected and frozen at -20°C before feeding (and before addition of GAC) for bacterial culture and IgG determination. A 10-mL venous blood sample was collected from calves before feeding colostrum and 24 h after colostrum feeding, for laboratory determination of serum IgG using radial immunodiffusion analysis. Colostrum and calf characteristics, including colostrum IgG concentration (g/L), colostrum bacteria counts (log10, cfu/mL), calf dystocia scores (1 to 4), birth weights (kg), and age at first feeding (min) were not different between the group fed GAC (n=47) and the control group (n=48). Mixed linear regression analysis showed that calves fed colostrum supplemented with 30 g of GAC had lower mean (standard error) apparent efficiency of absorption of IgG and lower serum IgG concentrations at 24 h [23.9% (1.0); IgG=24.0 (1.1) g/L] than did control calves [30.4% (1.0); IgG=30.8 (1.0) g/L]. Given the negative effect observed in this study, it is not recommended that fresh colostrum be supplemented with 30 g of GAC.

Creep-resistant, Al2O3-forming austenitic stainless steels.

A family of inexpensive, Al2O3-forming, high-creep strength austenitic stainless steels has been developed. The alloys are based on Fe-20Ni-14Cr-2.5Al weight percent, with strengthening achieved through nanodispersions of NbC. These alloys offer the potential to substantially increase the operating temperatures of structural components and can be used under the aggressive oxidizing conditions encountered in energy-conversion systems. Protective Al2O3 scale formation was achieved with smaller amounts of aluminum in austenitic alloys than previously used, provided that the titanium and vanadium alloying additions frequently used for strengthening were eliminated. The smaller amounts of aluminum permitted stabilization of the austenitic matrix structure and made it possible to obtain excellent creep resistance. Creep-rupture lifetime exceeding 2000 hours at 750 degrees C and 100 megapascals in air, and resistance to oxidation in air with 10% water vapor at 650 degrees and 800 degrees C, were demonstrated.

Prevention of postsplenectomy sepsis: how much do patients know?

INTRODUCTION: Asplenia causes a deficiency in immunity with a long-term risk of fulminant infection, associated with significant mortality. Patient compliance requires an understanding of risks of infection and its prevention. The impact of patient education has been little studied. MATERIALS AND METHODS: To ascertain the degree of knowledge held by patients who have undergone splenectomy, a comprehensive survey was designed. This also aimed to determine which group of health professionals was most successful in conveying information to patients. Patients who had undergone total splenectomy were interviewed by telephone, using a standardised list of questions to assess their understanding of the post-operation risks. RESULTS: Of 40 consecutive patients, 32.5% had a good knowledge of the risks of asplenia and their prevention, 52.5% had a fair knowledge and 15% a poor knowledge. Haematologists were most successful in initially conveying information to patients, and general practitioners also played a critical role in patient education. In this survey, it appears that surgeons were not effective at educating patients. CONCLUSION: Patient education postsplenectomy is poor. Measures to prevent infection in the asplenic patient are not being adequately implemented.

A quantitative study of articular repair in the guinea pig.

This study examined the healing of articular defects, with and without carbon fiber implants, and the response of repair tissue to its interim removal in guinea pigs of different ages. These were investigated after the induction of full thickness articular cartilage defects in the patellar groove of skeletally mature and immature guinea pigs. To indicate its capacity for replacement after attrition, repair tissue occurring in untreated (control) and carbon fiber treated (experimental) defects was ablated after 8 weeks, and the animals were sacrificed after an additional 8 weeks. The repair tissue was studied quantitatively at gross and microscopic levels and qualitatively using scanning and transmission electron microscopic study. The principal findings were as follows. The initial formation of repair tissue was variable, but it occurred in most cases. Secondary repair tissue formation consistently occurred after excision. Age did not influence the degree of repair. Carbon fiber implants of the type used impaired healing of small full thickness articular cartilage defects, compared with no treatment. Microscopically, repair tissue contains five main cell types, each with a characteristic surrounding matrix. Intermediate forms also are found. These, together with four of the five main types comprise a morphologic continuum and fit readily into a proposed developmental sequence that may stem from the fibroblast.

Selective endoscopy in management of ingested foreign bodies of the upper gastrointestinal tract: is it safe?

During a four-year period, 308 patients presented following ingestion of foreign bodies. Ingestion was accidental in 272 cases (88.3%) and deliberate in the remainder. Symptoms at presentation included dysphagia, odynophagia, nausea and vomiting, chest pain and pharyngeal discomfort. Sixty-eight patients were asymptomatic. A policy of expectant management and selective endoscopy was employed. Following initial assessment 202 patients (65.6%) were discharged without treatment, 30 (9.7%) of whom were later reviewed as outpatients and did not require admission. Forty-nine patients (16%) were admitted for treatment; 27 had oesophagoscopy, five bronchoscopy and two had foreign body extraction with direct laryngoscopy. In nine patients who were endoscoped, no foreign body was identified. Twenty-seven others were referred to the otorhinolaryngology service in another hospital. There were no deaths in the group and morbidity was 1.2%. We conclude that a policy of selective endoscopy is safe and effective in the management of patients following ingestion of foreign bodies.

Deliberate ingestion of foreign bodies by institutionalised psychiatric hospital patients and prison inmates.

Deliberate and recurrent foreign body ingestion is a common problem among institutionalised patients. We review our experience with 36 cases of deliberate foreign body ingestion by prisoners or psychiatric patients, thirty of whom were institutionalised at the time of ingestion. Symptoms were frequently severe in the prison inmate group but, in contrast, psychiatric patients presented with few, if any, symptoms. A majority of objects pass spontaneously or remain in situ without complication. Twenty-four patients were discharged following initial evaluation and without specific treatment. Eight of these were reviewed electively and discharged within one week. Twelve patients were admitted for observation, seven of whom were discharged within 48 hrs. Upper gastrointestinal endoscopy was performed in four patients and an intragastric foreign body identified in two cases. Laparotomy was performed in two cases for unresolving mechanical intestinal obstruction. Management should be conservative when possible, with surgery indicated only for complications.

Infantile hypertrophic pyloric stenosis: long-term audit from a general surgical unit.

This article describes a 22 year experience of a general surgical unit in the treatment of infantile hypertrophic pyloric stenosis (IHPS). The hospital course of 229 IHPS patients is reviewed. The male:female ratio was 3.6:1, median age 6 weeks (range 2-26 weeks) with a positive family history in 8.3%. The diagnosis of IHPS was established clinically by palpation of a "pyloric tumour" during a pre operative test meal/clinical examination in 92.6%; in the remainder, the diagnosis was made radiologically. Ramstedt's pyloromyotomy was performed within 5 days of admission in 74% of patients and within 10 days of admission in 89%. The median post-operative hospital stay was 10 days (range 3-60 days). Wound morbidity occurred in 10.0% wound infection (7.3%) and wound dehiscence (2.6%). However, wound morbidity was reduced in the second half of the series, partly by greater utililisation of non-absorbable suture in place of chromic catgut for wound closure. Mucosal penetration was suspected in 14.8% of cases. Repeat pyloromyotomy was necessary in 1.3%. One baby died (0.4%)- this was in the early part of the series and was directly attributable to fluid and electrolyte disorder. We conclude that Ramstedt's pyloromyotomy for infantile hypertrophic pyloric stenosis can be performed with acceptable morbidity and minimal mortality in a general surgical unit.

Influence of teaching on the triage of multiple injury patients.

Attempts to improve the standard of early trauma management through the training and instruction of medical personnel have had variable results. Knowledge of trauma care is inadequate among all grades of medical and paramedical staff, and not much improvement has been made by the availability of instruction courses in trauma management. Staff most likely to attend such courses are seemingly already more proficient than staff who choose not to. To achieve maximum benefit from future courses, therefore, we believe attendance should be compulsory for all personnel involved in acute trauma care.

An exploratory study of the pattern of consent for autopsy in a regional hospital setting.

A prospective study of the pattern of responses to requests for autopsy in a general surgical unit was performed. Information on the characteristics of the deceased, of the requestee and of the requester was documented in the case of 66 patients who died while in hospital. Permission to perform autopsy was not requested in 39 out of 66 cases and this was the most frequent contributory factor to the low rate of autopsy. Once a decision to grant or refuse autopsy is made by relatives of the deceased, the decision is unlikely to be reversed. Permission to perform autopsy was more likely to be sought when the deceased was male than when deceased was female. The relatives of patients who had recently undergone surgery were more likely to refuse permission for autopsy than were those of patients who had not had recent surgery.

Limitations of thyroid scanning in solitary thyroid nodules.

During an 8-year period, 104 patients (19 males, 85 females) underwent surgery for a solitary thyroid nodule. There were 19 (18.3%) malignant nodules and 85 (81.7%) benign nodules. Malignancy occurred in 3 (15.8%) males and 16 (18.8%) females. Pre-operative scanning was performed prior to referral in 59 patients (52 had ultrasound, 41 had isotope scanning; the majority had both). Of the scanned patients, 12 (20%) had a malignant nodule while 7 (15.5%) of the 45 patients who did not have scanning had a malignant nodule. In patients who had an ultrasound scan, malignancy was found in 5 (23.8%) of the 21 solid nodules and 7 (22.7%) of the 31 cystic (or solid/cystic) nodules. In patients who had thyroid isotope scanning, malignancy was found in 6 (17.5%) of the 34 cold (non-functioning) nodules and 3 (43%) of the 7 warm or hot (functioning) nodules. Ultrasound and isotope scanning may be misleading and neither help to differentiate benign from malignant thyroid nodules which require surgical excision.

Paget's disease of the breast in a man without underlying breast carcinoma.

A case of histologically confirmed Paget's disease of the breast in a 72 year old man, without underlying breast carcinoma, is reported. This report raises questions about the pathogenesis of this condition and suggests that Paget's disease is an independent, intraepidermal carcinoma rather than a direct extension of intraductal carcinoma of the breast to the nipple and areola.

"How safe is splenectomy?".

The increased risk of sepsis in patients following splenectomy has been well documented. Fear of overwhelming post-splenectomy sepsis (OPSI) has resulted in a generalized trend towards splenic salvage among surgeons. However, splenorrhaphy and attempts at splenic salvage may of themselves predispose to significant morbidity, sometimes more serious than increased susceptibility to infection associated with splenectomy. This study aims to assess the risk of splenectomy and subsequent asplenia. We reviewed 246 patients who underwent splenectomy over a 16 year period. Indications for splenectomy were considered under the following headings: haematological (N = 116), trauma (N = 69), visceral carcinoma (N = 28), incidental (N = 13) and miscellaneous (N = 20). There were 28 deaths in the series, primarily among those in the intra-abdominal carcinoma (13) and multiple trauma (13) groups. Two deaths were recorded among patients undergoing elective splenectomy for benign disease. Thrombo-embolic complications were recorded in nine patients; respiratory tract infection in 36 patients and intra-abdominal abscess in two patients. Two cases of post-splenectomy pneumococcal septicaemia were documented, neither of which was fatal. While not an entirely benign procedure, splenectomy can be performed relatively safely, especially when performed for benign disease in an adult population.

Splenectomy in patients with undiagnosed splenomegaly.

Of splenectomies performed in the Cork Regional Hospital over an 11 year period, ten were undertaken primarily for diagnostic purposes. A definitive histological diagnosis was established in nine patients, seven of whom had lymphoma, two with Hodgkin's disease and five with non-Hodgkin's lymphoma. The weight of the excised spleen in all patients with lymphoma exceeded 1 kg; in all those with a diagnosis other than lymphoma, the spleen weighed less than 1 kg. A majority of patients also had symptomatic improvement from reversal of hypersplenism and from relief of the mechanical pressure effects of an enlarged spleen. Operative mortality was zero. Diagnostic splenectomy is a worthwhile procedure. Most patients will have lymphoma.

Effects of high-probability requests on the social interactions of young children with severe disabilities.

High-probability requests were used to increase social interactions in 3 young boys with severe disabilities who had been identified as severely socially withdrawn. A multiple baseline design across participants was used to evaluate the effects of high-probability request intervention on (a) social initiations, (b) social responses, (c) continued interactions, and (d) performance of high- and low-probability requests. The students were observed in a second setting to examine generalization effects across peers who did not participate in the training sequence and settings. The results demonstrated that the high-probability requests increased the students' responsiveness to low-probability requests to initiate social behavior. Increases were also found in (a) unprompted initiations and extended interactions to the training peers, (b) unprompted initiations and extended interactions to peers who were not involved in the training procedure, and (c) generalized unprompted initiations and interactions in a second nontraining setting. The students maintained increased levels of initiations and interactions after all prompts were removed from both the training and nontraining settings.

c-myc oncogene expression: a marker for females at risk of breast carcinoma.

In an attempt to identify patients at risk of breast cancer, 9E 10 c-myc monoclonal antibody was used to detect the oncogene products in 64 breast tissue biopsies. There were 44 specimens of benign breast disorders: 21 from patients who developed subsequent breast cancer, and 23 from patients who did not. The remainder were malignant tumor biopsies from those who developed breast cancer. C-myc over-expression was identified in 12 (60%) of the breast carcinomas; it was also noted in 13 (62%) of the benign biopsies from patients who developed subsequent breast carcinoma. Expression was observed in only 3 (13%) controls--patients who did not develop cancer. A prospective study is now warranted to determine the clinical usefulness of our findings.