Search

Development of high power laser beams with increasing beam quality and decreasing purchase cost lead to a strong development of laser welding techniques. Narrow weld beads, high welding speed, and low heat input are the main advantages of this reliable and repeatable joining process. The aim of this study is to investigate properties of weld seam obtained by Gaussian and annular power distribution, on butt joints of 0.9 mm annealed Ti6Al4V sheet by mean of an experimental design varying power level, spot size and shape, welding speed, and face gaseous protection flow. Examined characteristics of the weld seams are geometrical (Fusion Zone FZ and Heat Affected Zone HAZ shapes and dimensions, defects like porosities, undercut and underfill, distorsions of welded plates), microstructural (FZ and HAZ nature and morphology) and mechanical (tensile test, hardness filiations). Major features concerning the use an annular power distribution concern the flawless weld seam geometry and fair mechanical properties, with relatively low levels of distortions due to residual stresses.

A 7‐year‐old mixed breed dog was presented with a 2‐week history of vomiting, diarrhoea, weakness and loss of appetite. Initial laboratory tests revealed hyponatraemia and hyperkalaemia consistent with hypoadrenocorticism. Basal plasma cortisol and adrenocorticotropic hormone concentrations were not suggestive of primary hypoadrenocorticism but the aldosterone concentration was undetectable. Abdominal ultrasound scan showed a mass within the left kidney and a nodular enlargement of the left adrenal gland. Cytological analysis revealed a large granular lymphoma. The dog died 17 days later. Post mortem histological and immunohistochemical examinations revealed a diffuse large granular T‐cell lymphoma involving the mediastinal lymph node, kidneys, pancreas, adrenal and pituitary glands. [ABSTRACT FROM AUTHOR]

The purpose of this study is to apply a local heat treatment (LHT), in-situ, on the weld bead, using a defocused Yb: YAG laser beam on a continuous regime, in order to reduce residual stresses and decompose the brittle a’ martensite, into a lamellae and fine β phase. Laser scan experiments were firstly performed on a commercially pure titanium grade 2, with a wide range of parameters, in order to provide a “heat treatment window” without titanium melting. After optimization of the processing parameters, to obtain a sufficient width and depth for the scanning zone, experiments have been performed on a β-treated, fully martensitic Ti-6Al-4V sheet. For each processing experiments, the decomposition of a’, was studied based on metallographic cross sections. A local heating with a minimum energy density at 700 J.cm-2, has a sufficient effect to destabilize a’, while for an energy density at 1000 J.cm-2 , a diffusional transformation take place, with the formation of Widmanstätten microstructure. Finally, these optimized conditions were applied on a full penetration Ti-6Al-4V welds. The results of the LHT will be described in terms of the microstructural changes observed in the welded zone and hardness evolution.

The requirements for welded aircraft parts have become increasingly severe, especially in terms of the reproducibility of the geometry and metallurgical grade of the weld bead. Laser welding is a viable method of assembly to meet these new demands, because of automation, to replace the manual TIG welding process. The purpose of this study is to determine the weldability of Hastelloy X and Haynes 188 alloys by the butt welding process with a Nd:YAG laser. To identify the influential parameters of the welding process (laser power, feed rate, focal diameter and flow of gas) while streamlining testing, an experimental design was established with the CORICO software using the graphic correlation method. The position of the focal point was fixed at 1/3 of the thickness of the sheet. The gas flow rate and the power of the beam have a major effect on the mechanical properties and geometry of the weld. The strength of the weld is comparable to that of the base metal. However, there is a significant decrease in the elongation at break of approximately 30%. The first observations of the cross section of the weld by scanning electron microscopy coupled with EBSD analysis show a molten zone presenting dendritic large grains compared to the equiaxed grains of the base metals without a heat affected zone.

Le procédé de soudage laser YAG est envisagé pour remplacer le procédé de soudage TIG manuel pour la réalisation de pièces de turboréacteur en alliage nickel-chrome-molybdène Hastelloy X. Cette étude expérimentale a permis de définir un domaine de soudabilité de cet alliage répondant aux critères spécifiques du secteur aéronautique. The YAG laser welding process is contemplated to replace the manual TIG welding process for the production of parts of turbojet in Hastelloy X. This experimental study has identified the field of weldability of this alloy to meet the specific requirements of the aerospace industry.

Background: Carboplatin is a human chemotherapeutic agent which is frequently used in dogs for the management of solid tumors. In human patient, its dosage is adjusted carefully, based on the creatinine clearance computation. In dogs however, the pharmacokinetics of carboplatin is poorly known and the dose 300 mg/m2 is based mostly on empirical data. Here, we aimed at characterizing the pharmacokinetics of carboplatin and determined the influence of several covariates, including creatinine plasma concentration and neutering status, in dogs, and used this model to predict myelotoxicity., Results: Sixteen client owned dogs were included after carboplatin administration (300 mg/m 2 ). For each animals, three to four plasma samples were collected and free plasma concentration of carboplatin was determined by HPLC/MS and analysed using Monolix® software with Non-linear mixed effect modelling. A mono-compartmental model best described the plasma concentration of carboplatin with log plasma creatinine concentration and sterilization status as covariates. After adjustment with the covariates, median population clearance was 3.62 [3.15 - 4.12] L/h/kg and volume of distribution was 3.93 [3.84 - 4.14] L/kg. The application of this model in 14 additional dogs demonstrates that individual drug exposure (model-predicted Area Under the Curve) predicted thrombocyte blood reduction (Pearson coefficient r 2  = 0.73, p = 0.002) better than dose after 14 days following administration of carboplatin., Conclusion: Based on our results, plasma creatinine concentration and the sterilization status are relevant explanatory covariates for the pharmacokinetics variability of carboplatin in client owned dogs. Dose adjustment based on these parameters could represent a promising strategy for minimizing thrombocyte toxicity., Competing Interests: Declarations. Ethics approval and consent to participate: The protocol and the design of the study were approved by our local clinical research ethics committee (protocol #2019–03-03). All owners of the included dogs signed an informed consent before enrollment and received a detailed written description of the study. Consent for publication: All participants consents to publications of the data. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Specific data regarding outcome of cats with high-grade and large granular lymphocyte alimentary lymphoma (HGAL and LGL, respectively) treated with multi-agent chemotherapy are scarce. The aims of this multi-centric, retrospective study were to describe the outcome of cats with HGAL and LGL treated with COP- or CHOP-based chemotherapy and to identify potential prognostic factors. Cats with a cytological or histological diagnosis of HGAL or LGL lymphoma treated with COP- or CHOP-based protocol as first-line chemotherapy were included. Data regarding diagnosis, staging, treatment and follow-up were collected. Fifty-seven cats treated with CHOP (n = 37) or COP (n = 20) protocols were included. Complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) were observed in 20%, 22%, 36% and 22% of cats, respectively, for an overall response rate of 42%. Median progression-free interval (PFI) was 148 days and overall median survival time (OST) was 131 days. Cats achieving CR, PR or SD showed significantly longer PFI (p < .01) and OST (p < .015) compared with cats with PD. Other positive prognostic factors in multi-variate analysis were rescue treatment (p < .001) and absence of lymph node involvement (p < .03). Negative prognostic factors were diffuse infiltration of the gastrointestinal tract (p = .035) and infiltration of a non-haematopoietic organ (p < .01)., (© 2024 The Authors. Veterinary and Comparative Oncology published by John Wiley & Sons Ltd.)

Background: Myeloma-related disorders (MRDs) are rare and poorly documented neoplasms of cats., Hypothesis/objectives: To describe clinical, clinicopathologic, and imaging findings, response to treatment, and survival time and to identify factors associated with shorter outcomes in cats with MRD., Animals: Fifty cats with a diagnosis of MRD., Methods: Cats with paraproteinemia confirmed by serum protein electrophoresis (SPE) and either intramedullary plasmacytosis >10%, marked cytonuclear atypia with intramedullary plasmacytosis that ranged between 5% and 10%, or cytologically or histologically confirmed visceral infiltration were retrospectively included from several veterinary referral centers., Results: Bone marrow plasmacytosis and splenic or hepatic involvement were present in 17/27 cats (63%), 36/42 cats (86%), and 27/38 cats (71%), respectively. Anemia was reported in 33/49 cats (67%) and thrombocytopenia in 16/47 cats (34%). Some of the treatments that the cats received included melphalan and prednisolone (n = 19), cyclophosphamide and prednisolone (n = 10), chlorambucil and prednisolone (n = 4), prednisolone (n = 4), or other (n = 4). The overall response rates to melphalan, cyclophosphamide, and chlorambucil in combination with prednisolone were 87%, 90%, and 100%, respectively. Adverse events to melphalan or cyclophosphamide occurred in 65% and 23% of cats, respectively. Median survival time was 122 days (range, 0-1403) and was not significantly associated with chemotherapy protocol. Anemia (hazard ratio [HR], 3.1; 95% confidence interval [CI], 1.0-9.8) and thrombocytopenia (HR, 2.7; 95% CI, 1.2-6.0) were risk factors for shorter survival., Conclusions and Clinical Importance: Our study confirmed the guarded prognosis of MRD in cats and identified risk factors for shorter survival times., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Cutaneous mast cell tumors are rarely reported in cattle. Although mutations in the c-KIT gene have been shown to play a central role in the oncogenesis of canine mast cell tumors, few data are available in cattle. This report describes the clinical, histologic, immunohistochemical, and genetic features of a multicentric cutaneous mast cell tumor in an adult cow. An 11-year-old Prim'Holstein cow was presented for a 5-month history of multiple skin nodules. Cytologic and histologic analyses of the nodules led to a diagnosis of mast cell tumors. Immunohistochemical analysis for KIT expression showed a moderate to strong signal in neoplastic mast cells with a cytoplasmic and membranous pattern. Sequencing of the c-KIT gene coding sequence revealed no mutation. Despite partial response after corticosteroid treatment, euthanasia was elected. No metastases to the lymph nodes, spleen, and liver were identified at post-mortem and histologic examinations., (© 2024 The Authors. Veterinary Clinical Pathology published by Wiley Periodicals LLC on behalf of American Society for Veterinary Clinical Pathology.)