Hot Extrusion of Ceramics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65963/1/j.1151-2916.1992.tb07206.x.pd

Evaluation of strain and stress states in the single point incremental forming process

Single point incremental forming (SPIF) is a promising manufacturing process suitable for small batch production. Furthermore, the material formability is enhanced in comparison with the conventional sheet metal forming processes, resulting from the small plastic zone and the incremental nature. Nevertheless, the further development of the SPIF process requires the full understanding of the material deformation mechanism, which is of great importance for the effective process optimization. In this study, a comprehensive finite element model has been developed to analyse the state of strain and stress in the vicinity of the contact area, where the plastic deformation increases by means of the forming tool action. The numerical model is firstly validated with experimental results from a simple truncated cone of AA7075-O aluminium alloy, namely, the forming force evolution, the final thickness and the plastic strain distributions. In order to evaluate accurately the through-thickness gradients, the blank is modelled with solid finite elements. The small contact area between the forming tool and the sheet produces a negative mean stress under the tool, postponing the ductile fracture occurrence. On the other hand, the residual stresses in both circumferential and meridional directions are positive in the inner skin of the cone and negative in the outer skin. They arise predominantly along the circumferential direction due to the geometrical restrictions in this direction.The authors would like to gratefully acknowledge the financial support from the Portuguese Foundation for Science and Technology (FCT) under project PTDC/EMS-TEC/1805/2012. The first author is also grateful to the FCT for the postdoctoral grant SFRH/BPD/101334/2014.info:eu-repo/semantics/publishedVersio

Bialellic Mutations in Tetratricopeptide Repeat Domain 7A (TTC7A) Cause Common Variable Immunodeficiency-Like Phenotype with Enteropathy

TTC7A deficiency typically causes severe gastrointestinal manifestations such as multiple intestinal atresia or early-onset inflammatory bowel disease. In some cases, this is associated with severe combined immunodeficiency. Partial loss-of-function mutations appear to be associated with a milder phenotype resulting in common variable immunodeficiency-like condition with enteropathy

Congenital Diarrhea and Cholestatic Liver Disease: Phenotypic Spectrum Associated with MYO5B Mutations.

Myosin Vb (MYO5B) is a motor protein that facilitates protein trafficking and recycling in polarized cells by RAB11- and RAB8-dependent mechanisms. Biallelic MYO5B mutations are identified in the majority of patients with microvillus inclusion disease (MVID). MVID is an intractable diarrhea of infantile onset with characteristic histopathologic findings that requires life-long parenteral nutrition or intestinal transplantation. A large number of such patients eventually develop cholestatic liver disease. Bi-allelic MYO5B mutations are also identified in a subset of patients with predominant early-onset cholestatic liver disease. We present here the compilation of 114 patients with disease-causing MYO5B genotypes, including 44 novel patients as well as 35 novel MYO5B mutations, and an analysis of MYO5B mutations with regard to functional consequences. Our data support the concept that (1) a complete lack of MYO5B protein or early MYO5B truncation causes predominant intestinal disease (MYO5B-MVID), (2) the expression of full-length mutant MYO5B proteins with residual function causes predominant cholestatic liver disease (MYO5B-PFIC), and (3) the expression of mutant MYO5B proteins without residual function causes both intestinal and hepatic disease (MYO5B-MIXED). Genotype-phenotype data are deposited in the existing open MYO5B database in order to improve disease diagnosis, prognosis, and genetic counseling

Manufacture of superconducting wire. Progress report, February 1-October 15, 1979

This report is divided into three major sections. The first section covers aspects of the manufacturing technology with existing and potential processes, and the second deals with the analysis of flow and fracture and the derivation of criteria to prevent failure. In the first section, typical present day procedure to assemble a billet, extrude and draw it, with intermediate and final anneals, is described. Then an hypothetical production line with potential alternative processes along the entire path from heavy billet to fine wire, is laid out. Several processes at different stages of development, are offered, with the message that their potential must be explored for the development of more reliable product, at a more economical production cost. In the second section the analysis of core fracture and its prevention during the process of drawing is provided. Treatment of velocity fields for a bi-metallic rod leads to the determination of criteria for the prevention of fracture. The criteria are presented graphically. The third section of the report describes work on micro properties of superconducting wires. A modification of the bronze method for niobium-tin superconductors is proposed and a preliminary schedule of the testing procedures is outlined

Bacterial susceptibility to oral antibiotics in community acquired urinary tract infection

Background: The most common oral antibiotics used in the treatment of urinary tract infection (UTI) are sulphonamides and cephalosporins, but emerging resistance is not unusual. Aims: To assess the change in susceptibility of urinary pathogens to oral antibiotics during the past decade in children with community acquired UTI. Methods: The study sample included two groups of children with a first community acquired UTI: 142 children enrolled in 1991 and 124 enrolled in 1999. UTI was diagnosed by properly collected urine specimen (suprapubic aspiration, transurethral catheterisation, or midstream specimen in circumcised males) in symptomatic patients. Antimicrobial susceptibility of the isolates was compared between the two groups. Results: The pathogens recovered in the two groups were similar: in 1991—E coli 86%, Klebsiella 6%, others 8%; in 1999—E coli 82%, Klebsiella 13%, and others 5%. A slight but generalised decrease in bacterial susceptibility to common antibiotics in the two groups was shown: ampicillin 35% versus 30%; cephalexin 82% versus 63% (p < 0.001); nitrofurantoin 93% versus 92%. The only exception was co-trimoxazole, 60% versus 69%. Overall resistance to antibiotics in 1999 was as follows: ampicillin 70%, cephalexin 37%, co-trimoxazole 31%, amoxicillin-clavulanate 24%, nitrofurantoin 8%, cefuroxime-axetil 5%, nalidixic acid 3%. Conclusions: This study shows a slight but generalised decrease in bacterial susceptibility to common oral antibiotics in the past decade in our population. Empirical initial treatment with co-trimoxazole or cephalexin is inadequate in approximately one third of UTI cases. A larger number of pathogens may be empirically treated with amoxicillin-clavulanate (24% resistance); 95% of organisms are susceptible to cefuroxime-axetil