Wear mechanisms description in nanoscale by SEM/TEM of multilayer Zr/ZrN coatings in dependence on phases ratio.

As a result of loading with an external force during the wear process, coating deforms uniformly. After a certain limit load is exceeded, coating deformation is localised through the formation of the so-called shear bands. It has been showed experimentally the process of shear bands formation. The microstructural characterisation before and after the mechanical tests was performed using scanning and transmission electron microscopy (SEM and TEM) on cross-sections of the samples. The analysis indicated that in the case of multilayer coatings where the ratio of the metallic to the ceramic phase is 1:1, the shear bands are formed at an angle of 45°. With a greater proportion of the ceramic phase to metallic (ratio 1:2), the shear band changed the shear angle from ∼45° to ∼90°. Mechanical in situ tests were carried out in the chambers of SEM and TEM. The scratch tests in the SEM were done with the simultaneous observation of the phenomena occurring on the surface of the tested materials showed that at a scratch force of 0.04 N, the additional outer a-C:H layer was damaged, which was shown in the form of a fault in the force-displacement diagram, and in the form of splits visible in the SEM image. However, the application of this additional layer had a positive effect on the wear mechanism of the entire coating structure. The test also indicated that in the case of coatings with phases ratio 1:2 and 1:4 (metallic to ceramic), the characteristics of the brittle material were demonstrated, unlike the coating with a 1:1 phase ratio, where plastic properties predominated. However, for the 1:2 phase ratio coating, the chip was more ductile than for the chip formed when testing a 1:4 phase ratio coating. For in situ mechanical testing in the TEM, a straining holder was used. The test showed that the shear band angle for a 1:1 ratio coating has changed from 45° to 90° due to the different direction of force interaction.

Wear mechanisms of the biotribological nanocomposite a-C : H coatings implanted by metallic nanoparticles.

Recently, to reduce the residual stress and increase the mechanical properties of a-C:H coatings, metallic nanoparticles have been implanted into their structure. In the present work, to improve the properties of the coating, metallic nanoparticles, including Cu, Nb, Ta, Zr, AgPt and Ag, were inserted into the a-C:H structure. The applied biological and mechanical analysis allowed the optimal biotribological parameters to be indicated for the potential application as protective coatings for metallic medical tools. Wear mechanisms operating at the small length of the designed biotribological coating, such as a-C:H implanted by Zr nanoparticles, were studied by means of transmission electron microscopy (TEM). The TEM analysis confirmed very good coating adhesion to the metallic substrate.

Predictors of mortality in patients with femoral neck fracture.

PURPOSE: To identify patient and procedural factors associated with in-hospital mortality following a femoral neck fracture. METHODS: Records of 598 female and 259 male consecutive patients aged 29 to 108 (median, 82) years admitted between 2010 and 2014 with femoral neck fracture were retrospectively reviewed to determine patient and procedural factors associated with inhospital mortality. RESULTS: 73% of patients were operated on within 48 hours of admission. The in-hospital mortality was 7.5%, with 2.1% occurring preoperatively and 5.4% postoperatively. Factors associated with increased preoperative mortality included being nonambulant prior to admission (p=0.015), residence in interim care (p=0.001) or low-level care (p=0.049), having synchronous fractures (p=0.001), and having a concurrent acute medical condition (p<0.001). Patient factors associated with increased in-hospital mortality included male gender (p=0.041), age >80 years (p=0.001), non-ambulatory status (p=0.015), residence in high-level care (p=0.031) or low-level care (p=0.018), American Society of Anesthesiologists grade 4 or 5 (p<0.001), weekend admission (p<0.001), and having an acute medical condition on admission (p<0.001). Procedural factors associated with increased in-hospital mortality included >96-hour delay to surgery from admission (p<0.001), surgery over the weekend (p=0.005), and surgical interventions other than total hip arthroplasty (p<0.05). CONCLUSION: Identification of patient and procedural factors can guide changes in best practice to decrease mortality following a femoral neck fracture.

Microstructure characterization of advanced protective Cr/CrN+a-C:H/a-C:H:Cr multilayer coatings on carbon fibre composite (CFC).

Studies of advanced protective chromium-based coatings on the carbon fibre composite (CFC) were performed. Multidisciplinary examinations were carried out comprising: microstructure transmission electron microscopy (TEM, HREM) studies, micromechanical analysis and wear resistance. Coatings were prepared using a magnetron sputtering technique with application of high-purity chromium and carbon (graphite) targets deposited on the CFC substrate. Selection of the CFC for surface modification in respect to irregularities on the surface making the CFC surface more smooth was performed. Deposited coatings consisted of two parts. The inner part was responsible for the residual stress compensation and cracking initiation as well as resistance at elevated temperatures occurring namely during surgical tools sterilization process. The outer part was responsible for wear resistance properties and biocompatibility. Experimental studies revealed that irregularities on the substrate surface had a negative influence on the crystallites growth direction. Chromium implanted into the a-C:H structure reacted with carbon forming the cubic nanocrystal chromium carbides of the Cr23 C6 type. The cracking was initiated at the coating/substrate interface and the energy of brittle cracking was reduced because of the plastic deformation at each Cr interlayer interface. The wear mechanism and cracking process was described in micro- and nanoscale by means of transmission electron microscope studies. Examined materials of coated CFC type would find applications in advanced surgical tools.

Microstructure and mechanical properties of the NiNbZrTiAl amorphous alloys with 10 and 25 at.% Nb content.

The results of investigation of two different Ni-based glasses with compositions Ni(58)Nb(10)Zr(13)Ti(12)Al(7) and Ni(58)Nb(25)Zr(8)Ti(6)Al(3) are presented. The structure of the melt spun ribbons was amorphous. The supercooled liquid range decreased and primary crystallization temperature increased with increasing Nb content while the parameter T(g)/T(m) slightly increased. The crystallization process proceeded in a different way. The ribbon containing 10 at.% Nb showed typical primary crystallization of the 50 nm grains of the NiTi(Nb) cubic phase; the ribbon containing 25 at.% of Nb revealed high thermal stability of the amorphous phase, which crystallized only in a small amount in the range of primary crystallization, preserving large fraction of the amorphous phase even high above the end of the crystallization. The tensile load-displacement curves were also different. In both cases, the ribbons revealed quite a large range of the plastic elongation. The ribbon containing 10% Nb showed stress relaxation and was maximally elongated up to 0.6. The ribbon with 25 at.% Nb revealed a hardening effect and the slightly smaller maximal elongation following it. The microstructure of the deformed specimens showed deformation bands parallel to the tensile axis, microcracks formation along shear bands and river-like pattern at the fracture surfaces. In both cases, high resolution electron microscope did not reveal any crystallization after deformation.

Computerized bioterrorism education and training for nurses on bioterrorism attack agents.

BACKGROUND: Biological agents have the ability to cause large-scale mass casualties. For this reason, their likely use in future terrorist attacks is a concern for national security. Recent studies show that nurses are ill prepared to deal with agents used in biological warfare. Achieving a goal for bioterrorism preparedness is directly linked to comprehensive education and training that enables first-line responders such as nurses to diagnose infectious agents rapidly. METHODS: The study evaluated participants' responses to biological agents using a computerized bioterrorism education and training program versus a standard bioterrorism education and training program. RESULTS: Both programs improved participants' ability to complete and solve case studies involving the identification of specific biological agents. CONCLUSION: Participants in the computerized bioterrorism education and training program were more likely to solve the cases critically without reliance on expert consultants. However, participants in the standard bioterrorism education and training program reduced the use of unnecessary diagnostic tests.

Current practice in airway management: A descriptive evaluation.

BACKGROUND: Ventilator-associated pneumonia, a common complication of mechanical ventilation, could be reduced if health care workers implemented evidence-based practices that decrease the risk for this complication. OBJECTIVES: To determine current practice and differences in practices between registered nurses and respiratory therapists in managing patients receiving mechanical ventilation. METHODS: A descriptive comparative design was used. A convenience sample of 41 registered nurses and 25 respiratory therapists who manage critical care patients treated with mechanical ventilation at Sharp Grossmont Hospital, La Mesa, California, completed a survey on suctioning techniques and airway management practices. Descriptive and inferential statistics were used to analyze the data. RESULTS: Significant differences existed between nurses and respiratory therapists for hyperoxygenation before suctioning (P =.03). In the 2 groups, nurses used the ventilator for hyper-oxygenation more often, and respiratory therapists used a bag-valve device more often (P =.03). Respiratory therapists instilled saline (P <.001) and rinsed the closed system with saline after suctioning (P =.003) more often than nurses did. Nurses suctioned oral secretions (P <.001) and the nose of orally intubated patients (P =.01), brushed patients' teeth with a toothbrush (P<.001), and used oral swabs to clean the mouth (P <.001) more frequently than respiratory therapists did. CONCLUSION: Nurses and respiratory therapists differed significantly in the management of patients receiving mechanical ventilation. To reduce the risk of ventilator-associated pneumonia, both nurses and respiratory therapists must be consistent in using best practices when managing patients treated with mechanical ventilation.

Conflict management training and nurse-physician collaborative behaviors.

Collaboration between nurses and physicians continues to be elusive although it is a desirable goal for most in health care. This study used a quasi-experimental design to evaluate the outcomes of a conflict resolution (management) training program on nurses' perception of their collaboration with the physicians with whom they work. Results showed no differences between the experimental and control groups following the intervention. Individual readiness and evaluation of the antecedents of collaboration should be determined before implementing such an intervention.

Nurse-physician collaboration on medical-surgical units.

Interdisciplinary collaboration is viewed as a critical factor in delivering quality patient care. The purpose of this study was to describe nurse-physician perceptions of collaboration relationship on general medical-surgical units.

Fatigue and sleep quality in nurses.

Fatigue is a critical issue for nurses that may lead to medical errors, degradation in performance, decreased mental acuity, and social problems. Poor sleep quality is also a contributing factor in fatigue that nurses experience. Therefore, the purpose of this study was to examine the differences in perceptions of fatigue between night-shift and day-shift nurses, as measured by scores on the Brief Fatigue Inventory (BFI) and to examine differences in sleep quality between the two groups, as measured by responses on the Pittsburgh Sleep Quality Index (PSQI). Univariate analysis of variance showed significant differences between the two groups on the BFI, with the night-shift cohort reporting higher mean scores on the BFI. Significant differences were also found between the two groups on PSQI mean scores, with the night-shift cohort reporting higher mean scores. Findings from this study suggest that night-shift nurses, compared with day-shift nurses, perceived a much higher level of fatigue and had poorer sleep quality. Further research is needed to evaluate interventions that might decrease fatigue in nurses and improve their sleep quality.

Advances and problems with TEM characterization of Cr/CrN multilayer coatings.

Multilayer Cr/CrN/Cr/Cr(N,C) and Cr/CrN with 8 and 32 layer coatings were deposited on austenite substrates using pulsed laser deposition (PLD) technique. The microstructure observations were performed using Philips CM20trade mark, TECNAI G(2) F20 - TWINtrade mark and JEOL EX4000trade mark transmission microscopes. The performed experiments indicated that lowering the argon flow from 60 to 30 cm(3)/s during chromium ablation changes buffer layers microstructure from nearly amorphous to nano-crystalline. The nitride or carbo-nitride layers turned out to be less sensitive to changes in nitrogen flow during deposition. The columnar microstructure of Cr layers is coarser than those in CrN ones under the same deposition condition. This observation proved also that relying on PLD technique as thin as 30 nm layers might be formed within multilayer Cr/CrN coatings.

Cryotherapy for treatment of ECT-induced headache.

Because headache is a common side effect of electroconvulsive therapy (ECT), this study sought to determine the effectiveness of cryotherapy (i.e., a frozen gel band) in relieving pain in patients with post-ECT headaches, and whether headache intensity and physiological measurements could predict use of an alternative analgesic (rescue medication). We used a quasi-experimental, crossover design to collect data from 31 patients ages 24 to 85 who had been referred for ECT at two medical facilities in San Diego, California. Measurements of patients' pain intensity were made at three intervals: upon perceiving headache, and at 30 and 60 minutes following the cryotherapy or acetaminophen interventions, based on the order of the crossover design. Data were analyzed using Hotelling's T2 and logistic regression. No significant difference was found between cryotherapy and acetaminophen in relieving ECT-induced headaches (p = .420). There was no influence due to the crossover design (p = .313), nor where there significant changes in physiological measures from treatment (p = .420). Logistic regression showed that 50% of patients required rescue medication after 60 minutes for both treatments (R2 = .498, p = .001), and 66% required rescue medication based on pain level and physiological measures (R2 = .662, p < .008). Based on these results, cryotherapy is an alternative treatment that may be helpful to some patients with ECT-induced headaches.

Nurse internship pathway to clinical comfort, confidence, and competency.

The purpose of this article is to report the outcomes of a nurse internship program initiated at a U.S. Navy hospital designed to increase new graduate nurses' clinical competence, confidence, and comfort. Using a quasi-experimental design, the experimental group scored significantly higher on organizational core competencies than the control group. These nurses were more comfortable with their leadership and management roles following the intervention. Organizations may wish to consider a nursing internship program as a means of improving the work environment.

A structural perspective on the enzymes that convert dTDP-d-glucose into dTDP-l-rhamnose.

Bacteria have a rich collection of biochemical pathways for the synthesis of complex metabolites. These conversions often involve chemical reactions that are hard to reproduce in the laboratory. An area of considerable interest is in the manipulation and synthesis of carbohydrates. In contrast with amino acids, carbohydrates are densely functionalized (each carbon atom is attached to at least one heteroatom) and this holds out the prospect of discovering novel enzyme mechanisms. The results from the study of the biosynthetic dTDP-L-rhamnose pathway are discussed. dTDP-L-rhamnose is a key intermediate in many pathogenic bacteria, as it is the donor for L-rhamnose, which is found in the cell wall of important human pathogens, such as Mycobacteria tuberculosis and Salmonella typhimurium. All four enzymes have been structurally characterized; in particular, the acquisition of structural data on substrate complexes was extremely useful. The structural data have guided site-directed-mutagenesis studies that have been used to test mechanistic hypotheses. The results shed light on three classes of enzyme mechanism: nucleotide condensation, short-chain dehydrogenase activity and epimerization.

[Complications after angioplasty and stenting of coronary arteries in ischemic heart disease patients]. / Oslozhneniia angioplastiki i stentirovaniia koronarnykh arterii u bol'nykh s ishemicheskoi bolezn'iu serdtsa.

The authors have made an analysis of most frequent complications of angioplasty and stenting of coronary arteries in 1900 patients with various forms of ischemic heart disease. The mechanisms, pathomorphology, angiographic and clinical manifestations of such complications as dissection of the coronary artery intima, acute occlusion of the coronary artery, "no-reflow" syndrome, perforation and rupture of the coronary artery, acute thrombosis in the stent area and other complications are considered in detail. Special medical strategy, both therapeutic and surgical, is proposed for each case. The authors propose a number of prophylactic measures allowing to avoid the complications described or to minimize them. Intraoperative lethality in this group of patients was 0.5% (10 patients), during the first week after endovascular intervention 26 patients died (1.4%).

Decade-long experience with surgical therapy of myasthenia gravis: early complications of 324 transsternal thymectomies.

BACKGROUND: We studied the incidences and evaluated the management of early postoperative complications after thymectomy for myasthenia gravis. METHODS: During the period between 1987 and 1996, 324 thymectomies were performed through median sternotomy access under general anesthesia. Postoperative management was administered according to a standardized protocol of anticholinesterase medication, which was withdrawn for the 48 hours of obligatory postoperative mechanical ventilation. The mean age of patients was 34 years (range, 8 to 71 years). RESULTS: One hundred forty-nine patients made an uneventful recovery; 104 patients had only minor complications, whereas 71 patients had major complications. The mortality rate was 0.6% (2 patients). The major surgical complications were recorded as sternal bleeding (1 patient) and sternal disruption (1 patient). The major general complications were recorded as tracheal stenosis (1 patient), pneumonia (3 patients), heart failure (1 patient), gastric hemorrhage (1 patient), and respiratory insufficiency (71 patients). Forty-six reintubations were performed on 40 patients and 19 tracheostomies (6%) were performed postoperatively. CONCLUSIONS: The excessive incidence of respiratory insufficiency and airway-associated morbidity was potentially related, at least partially, to prolonged mechanical ventilation and withdrawal of anticholinesterase medication. Earlier weaning of patients with revision of 48-hour withdrawal of anticholinesterase medication is necessary.

[Analgesics-induced chronic renal failure in patients on dialysis therapy in Hungary]. / Analgetikum-nephropathia elófordulása krónikus veseelégtelenség miatt dializált betegekben Magyarországon.

In recent years elaboration of the diagnosis of analgesic-nephropathy (ANP) with the help of imaging techniques significantly increased the possibility of diagnosing the disease. Therefore, evaluating the prevalence of ANP has become more accurate in our country as well. The prevalence of ANP has been investigated in patients who have newly been taken into the dialysis program due to renal disease of unknown aetiology in 22 dialysis centers between December 1994-December 1997. The diagnosis of ANP has been based on revealing chronic drug abuse in the history and positive results of renal imaging (decrease in length of both kidneys combined with either bumpy contours and/or papillary calcification). Among 284 patients dialysed with unknown diagnosis 42 (14.8% of all cases) proved to have ANP. All patients except 2 took analgesic mixtures containing phenacetin/paracetamol, phenason derivatives, acetilsalysilic acid, caffeine and/or codeine. According to their investigations, ANP is a common disease resulting in end-stage renal failure in Hungary as well.

[Paraesophageal hiatal hernia complicated with stomach cancer]. / Paraoesophagealis hiatus hernia és gyomorrák együttes elófordulása.

The authors present the history of a 79 years old female patient who had to be operated on with paraesophageal hiatal hernia causing cahexia, hematemesis, dysphagia and pain. They found an upside down stomach with cancer inside. They emphasize that endoscopy is very important in the diagnostic process and that cancer can develop even if the stomach is located in the chest.

Codon bias at the 3'-side of the initiation codon is correlated with translation initiation efficiency in Escherichia coli.

The codon that follows the AUG initiation triplet (+2 codon) affects gene expression in Escherichia coli. We have extended this analysis using two model genes lacking any apparent Shine-Dalgarno sequence. Depending on the identity of the +2 codon a difference in gene expression up to 20-fold could be obtained. The effects did not correlate with the levels of intracellular pools of cognate tRNA for the +2 codon, with putative secondary mRNA structures, or with mRNA stability. However, most +2 iso-codons that were decoded by the same species of tRNA gave pairwise similar effects, suggesting that the effect on gene expression was associated with the decoding tRNA. High adenine content of the +2 codon was associated with high gene expression. Of the fourteen +2 codons that mediated the highest efficiency, all except two had an adenine as the first base of the codon. Analysis of the 3540 E. coli genes from the TransTerm database revealed that codons associated with high gene expression in the two expression systems are over-represented at the +2 position in natural genes. Codons that are associated with low gene expression are under-represented. The data suggest that evolution has favored codons at the +2 position that give high translation initiation.