Investigation of the Effect of Artificial Internal Defects on the Tensile Behavior of Laser Powder Bed Fusion 17-4 Stainless Steel Samples: Simultaneous Tensile Testing and X-Ray Computed Tomography.

Insufficient data are available to fully understand the effects of metal additive manufacturing (AM) defects for widespread adoption of the emerging technology. Characterization of failure processes of complex internal geometries and defects in metal AM can significantly enhance this understanding. We aim to demonstrate a complete experimental measurement process and failure analysis method to study the effects of AM defects. We utilized simultaneous implementation of tensile tests with high-resolution X-ray computed tomography (XCT) measurements on 17-4 stainless steel dog-bone samples with an intentional octahedron-shaped internal cavity included in the gauge length and also containing much smaller lack-of-fusion (LOF) defects, all generated by a Laser Powder Bed Fusion (LPBF) additive manufacturing process. The LOF defects were introduced by intentionally changing the LPBF default processing parameters. XCT image-based linear elastic finite element (FE) simulations were used to interpret the data. The in-situ tensile tests combined with simultaneous XCT measurements revealed the details of the failure process initiated by additively manufactured rough internal surfaces and porous defect structures, which experienced high stress concentrations. Progressive collapse of ligaments leading to larger pores was clearly observed, and the resulting porosity evolution until failure was quantitatively analyzed. The high stress concentrations were also directly confirmed by the FE simulations. The experimental methods described in this paper enable the quantitative study of the complex failure mechanisms of additively manufactured metal parts, and the image-based FE simulation method is effective for identifying and/or confirming possible failure locations and features.

Clinical profile of assault burned victims: a 16-year review.

OBJECTIVE: Assaults by burning occur infrequently and are related to the social circumstances and demographics of each population. We aimed to explore the mechanisms, complications, morbidity and mortality associated with assault burn injuries admitted to the Burns Intensive Care Unit of Merheim University Hospital in Cologne. METHODS: A retrospective data analysis of a consecutive series of 1 243 burn patients between 1989 and 2004. The cohort was divided into two groups: AG (assault group) and CG (control group). Analyses were controlled for clinical data, treatment and outcome of all patients involved. RESULTS: Forty-one patients with assault burn injuries were identified during the study period. Compared with the general burn population (CG), the AG had a significantly larger size of third-degree burns (p=0.047), a higher incidence of inhalation injury (p<0.001) and a longer intubation period (p=0.047). Patients in the AG were also more likely to undergo escharotomy (p=0.013) and to receive antibiotics on admission (p=0.016). The mortality rate was higher in the AG than in the CG (26.8% v. 19.9%), but this difference was not significant. CONCLUSIONS: Burned patients who were victims of assault tend to have more severe injuries than the general burn population. These injuries are not only physical, and their management requires a multidisciplinary approach to improve outcome.

Cologne burn centre experience with assault burn injuries.

OBJECTIVE: To evaluate demographic and socioeconomic factors associated with assault burn injuries. BACKGROUND: Assault by burning demonstrates a rare but severe public health issue and accounts for unique injury characteristics in the burn intensive care unit (BICU). METHODS: We conducted a retrospective cohort study involving patients with thermal injuries admitted to the BICU of a university hospital. The patient cohort was divided into two groups (ABI group: patients with assault burns, n=41; CONTROL GROUP: population of all other burned patients admitted to the BICU, n=1202). Bivariate and multivariate analyses including demographic and socioeconomic data were used to identify factors associated with assault burns. RESULTS: Forty-one assault-related burn victims were identified in the study period. This represents 3.3% of all significant burns admitted. Comparing battery victims with the control population, assault patients were more likely to be young (mean age 36.2 years vs. 42.2 years) and immigrants (41.5% vs. 15.1%). Furthermore, marital status (65.9% vs. 40.8% singles), employment status (36.6% vs. 9.7% unemployed) and insurance status (41.5% vs. 12.3% social insurance) were significantly different in the bivariate analysis. Logistic regression evaluation identified three variables that were independently associated with assault burns: younger age (< or =25 years) (odds ratio, 2.54 [95% confidence interval, 1.29-5.02]; p=0.007), ethnic minority (odds ratio, 3.71 [95% confidence interval, 1.91-7.20]; p<0.001) and unemployment (odds ratio, 4.02 [95% confidence interval, 2.03-7.97]; p<0.001). CONCLUSIONS: The high incidence of youngsters, unemployment and the great proportion of immigrants in victims of assault might provide several opportunities for community-based psychosocial and occupational programs. A multidisciplinary approach targeting issues specific to the violent nature of the injury and the socioeconomic background of the victims may be of benefit to improve their perspectives for rehabilitation.

Acalculous cholecystitis in severely burned patients: incidence and predisposing factors.

OBJECTIVE: To investigate the incidence and predisposing factors of acalculous cholecystitis (AAC) in severely burned patients. BACKGROUND DATA: Although some studies report on AAC in critically ill patients, very little is known about AAC after severe burns. METHODS: We conducted a retrospective cohort study involving patients with burns admitted to the burn intensive care unit (BICU) of a university hospital. The patient cohort was divided into two groups (AAC group: burned patients with histological proven acalculous cholecystitis, n=15; CONTROL GROUP: population of all other burned patients admitted to the BICU, n=1225). Univariate and multivariate analyses were used to identify predisposing factors for the development of AAC. RESULTS: Fifteen patients with acalculous cholecystitis were identified in the study period. This represents 1.2% of all significant burns admitted. Comparing the AAC group with the Control population the following patients' characteristics, therapeutic measures and outcome parameters were significantly different in the univariate analysis: mean age (54.0 years vs. 42.0 years), BMI (28.9 kg/m(2) vs. 25.6 kg/m(2)), abbreviated burn severity index (8.3 vs. 6.4), total body surface area burn deep partial thickness (12.0% vs. 6.2%) and full thickness (10.2% vs. 6.8%), concomitant inhalation injury (80.0% vs. 28.9%), sepsis (46.7% vs. 14.9%), catecholamine (100% vs. 30.4%) and antibiotic requirement (100% vs. 58.2%), non-biliary tract operations (4.9 vs. 1.5), BICU length of stay (63.4 days vs. 21.0 days), ventilator days (50.3 vs. 11.9), packed red blood cells (PRBCs) administration (70.0 units vs.13.0 units) and mortality (53.3% vs. 19.7%). In the multivariate analysis however, only age, the number of administered units of PRBCs and the duration of mechanical ventilation turned out to be independent predictors for the occurrence of AAC. CONCLUSION: AAC is a rare complication of severely burned patients and may reflect the severity of the patient's general conditions. Predisposing factors for AAC are advanced age, the need of blood transfusions and prolonged mechanical ventilation. In the presence of these predisposing factors, early monitoring may help to detect AAC earlier and to initiate appropriate intervention.

Kinetic parameters of 3-[(123)I]iodo-L-alpha-methyl tyrosine ([(123)I]IMT) transport in human GOS3 glioma cells.

The radiolabelled amino acid 3-[(123)I]iodo-L-alpha-methyl tyrosine ([(123)I]IMT) is a promising tool for the diagnosis and monitoring of brain tumors using single-photon emission tomography (SPECT). However, little is known about the precise kinetics of [(123)I]IMT uptake in human glioma cells. The kinetic analysis of [(123)I]IMT transport in human GOS3 glioma cells yielded a high-affinity apparent Michaelis constant (K(m) = 20.1 +/- 1.5 microM). The maximum transport velocity (V(max)) amounted to 34.8 +/- 1.9 nmol/mg protein/10 min. Competitive inhibition experiments revealed that [(123)I]IMT transport is mediated principally by the sodium-independent system L.

Severe and complicated malaria treated with artemisinin, artesunate or artemether in Viet Nam.

One hundred and seventy five Vietnamese adults with severe and complicated malaria admitted to a rural district hospital were entered into an open randomized comparative study to compare 4 treatment regimens based on artemisinin and its derivatives. The median time of defervescence was 48 h (95% confident interval [CI] 38-58 h) in those given intramuscular (i.m.) artemether, 42 h (95% CI 36-48 h) in those given artemisinin suppositories, 36 h (95% CI 30-42 h) in those receiving artesunate (i.m.) and 30 h (95% CI 18-42 h) in those receiving intravenous artesunate (P = 0.13). The respective median parasite clearance times were 30 h (95% CI 26-34 h), 30 h (95% CI 24-36 h), 24 h (95% CI 15-33 h), and 24 h (95% CI 15-33 h) (P = 0.30); the median times for recovery of consciousness were 47 h (95% CI 31-63 h), 24 h (95% CI 18-30 h), 30 h (95% CI 18-42 h), and 24 h (95% CI 4-44 h) (P = 0.18); and the mortality rates were 11.1%, 17.6%, 10.2% and 16.6%, respectively (P = 0.64). There was no significant difference in efficacy between the 4 treatments.