Investigation of the Effect of Tempering and Cryogenic Treatment on Mechanical Properties of Boron Steels

Boron steels are a group of steels that stand out with their high wear resistance and hardenability. In this study, 33MnCrB5-2 boron steel was shaped by applying hot forging process. After the hot forging process, the microstructure examinations and mechanical tests of the materials were carried out. A group of materials was cryogenically treated at -80 °C for 2 hours. Then, a different group of materials was austenitized at 890 °C and quenched, and then tempered at 400 °C for 90 minutes. In the last group of materials, after tempering heat treatment, cryogenic treatment was applied at -80 °C for 2 hours. Hardness and abrasion tests were carried out on the samples that were subjected to cryogenic treatment and tempering heat treatment. Microstructure analyzes were examined with the help of scanning electron microscope (SEM) and optical microscope. Element distributions from different regions in the microstructure were analyzed with energy-dispersive X-ray spectrometry (EDS). The crystallite size of the materials were calculated by X-ray diffraction. The results showed that the hardness value and wear resistance of the samples that were cryogenically treated after tempering gave higher values compared to the other samples

EFFECT OF CRYOGENIC AND NATURAL AGING PROCESS APPLIED TO Al-Zn-Mg-Cu ALLOYS ON LIFE TIME CALCULATION: Received: 19th June 2023; Revised: 29th June 2023, 12th October 2023, 25th October 2023; Accepted: 31st October 2023

In this study, life time calculation of aluminum 7075 alloy with cryogenic and natural aging processes was performed by thermal analysis. The aluminum alloy was quenched after solid solution treatment at 480°C and naturally aged for 10-100 days at room temperature (25°C). Other samples were cryogenically treated at -40°C and -80°C for 2 hours after solid solution treatment at 480°C. After the cryogenic treatment, natural aging was done at room temperature for 10-100 days. At the end of each period determined for the samples, the hardness values were measured. It was observed that there was no significant change in hardness values at the end of 10 and 100 days at -80 °C. Thus, it was determined that the natural aging process does not start after cryogenic treatment at -80 °C. It was observed that the hardness value of naturally aged samples after cryogenic treatment at -40 °C increased more than the natural aged samples only. This showed that -40 °C improved the mechanism by creating a driving force in the material. Life time calculations between 30 °C and 320 °C also showed that -40 °C cryogenic treatment + natural aging increased life time by approximately 20% compared to natural aging alone

The effects of fresh frozen plasma on cholinesterase levels and outcomes in patients with organophosphate poisoning

Objective: The aim of this study is to determine the effects of fresh frozen plasma, as a source of cholinesterase, on butyrylcholinesterase (BuChE; plasma or pseudo cholinesterase) levels and outcomes in patients with organophosphate poisoning. Materials and Methods: This prospective study was performed at the Department of Intensive Care of Erciyes University Medical School. Over 2 yrs, patients admitted to the ICU for OP poisoning were entered into the study. OP poisoning was diagnosed on the basis of history and BuChE levels. All patients received atropine. Fresh frozen plasma was given to 12 patients. The study was approved by the Ethical Committee, and verbal informed consent was obtained. Results: Thirty-three patients were included in the study. BuChE levels measured at admission and the pralidoxime and atropine doses administered were not different between groups (p>0.05). Although intermediate syndrome developed in 28.6% of patients receiving pralidoxime, there were no intermediate syndrome cases in patients receiving plasma prior to developing intermediate syndrome. The mortality rates were 14.3% in the pralidoxime group and 0% in the plasma+ atropine+ pralidoxime group. Two patients received plasma after developing the intermediate syndrome, and one patient who received only atropine died. BuChE levels of fresh frozen plasma were 4069.5 +/- 565.1 IU/L. Every two bags of plasma provided an increase in BuChE levels of approximately 461.7 +/- 142.1 IU/L. Conclusion: Fresh frozen plasma therapy increases BuChE levels in patients with organophosphate poisonings. The administration of plasma may also prevent the development of intermediate syndrome and related mortality. Plasma (fresh frozen or freshly prepared) therapy may be used as an alternative or adjunctive treatment method in patients with organophosphate pesticide poisoning, especially in cases not given pralidoxime. Further randomized controlled and animal studies are required to infer a definitive result

Severe thrombotic microangiopathy associated with brucellosis: Successful treatment with plasmapheresis

Brucellosis is a disease that may lead to changes in hematologic parameters such as anemia, neutropenia, and thrombocytopenia; however, thrombotic microangiopathy (TMA) is a rare finding. Severe TMA may be associated with life-threatening hematologic, renal, and neurologic disorders. To prevent this mortality caused by brucellosis, prompt recognition of this complication and prompt therapy are essential. A patient with TMA associated with Brucella melitensis is presented who initially presented with fever, skin purpura, epistaxis, confusion, microangiopathic hemolytic anemia, and thrombocytopenia. TMA was treated with plasmapheresis with cryosupernatant plasma replacement, energetically. A rapid improvement in platelet count, lactate dehydrogenase level, hemolytic anemia, and neurologic symptoms was observed with this treatment. For cases with infection-induced thrombotic microangiopathy, short-term plasmapheresis may be applied as an urgent therapy in addition to antimicrobial therapy

Isolated microorganisms from febrile neutropenic patients and their antimicrobial susceptibility: A data of 2005 Febril nötropenik hastalardan i̇zole edilen mikroorganizmalar ve antimikrobiyal duyarliliklari: 2005 Yili verileri

Purpose:There is a close correlation between favour of initial antimicrobial therapy and mortality of infection in febrile neutropenic patients. Material and Methods:Isolated microorganizms from febrile neutropenic patients with hematologic malignancy and their antimicrobial susceptibility was evaluated by retrospective. We evaluated the results of blood, sputum, urine, wound and catheter tip cultures of these patients. Results:Among 206 isolates, in 134 episodes, from blood and other cultures of 86 of 176 febrile neutropenic patients, gram-negative bacteria was prevalent (74.2%). Among the gram-positives coagulase-negative staphylococci (CNS) were the predominant bacteria (39.6%). Bacteremia in 77(37.7%) patients and polymicrobial isolation in 13 (15.1%) patients was obtained. Escherichia coli and Klebsiella spp. were the most common species among gram-negative bacteria. E. coli has been the highest rate of antibacteriel resistance against ciprofloxacin (68%), followed by piperaciilin-tazobactam (44,7%) and cefepime (38.1%).Furthermore, increasing incidence of carbapenem resistant strains and that strains are nosocomial multidrug resistant gram negative bacteries are remarkable. Although the rate of gram positive microorganisms is less than gram negatives, the rate of antimicrobial resistance is increasing. Conclusion:It is most suitable and rationalist approach that ampiric treatment of febrile neutropenic patients is manage according to results of local epidemiolgic data, frequency and susceptibility pattern of isolated microorganisms

Acil Servise Başvuran Pulmoner Tromboemboli Olgularının Retrospektif Olarak Değerlendirilmesi

Amaç: Pulmoner tromboemboli (PTE) tanısı ile acil servisimize başvuran hastaların klinik, radyolojik ve laboratuar bulgularını incelemek ve klinik skorlamaların tanıdaki etkinliğini değerlendirmektir. Gereç ve Yöntemler: Bu çalışmada üniversitemiz acil servisine başvuran 33 pulmoner tromboemboli olgusu geriye dönük olarak incelendi. Bulgular: Olguların yaş ortalaması 56,218,2 yıl idi. Kadın/erkek oranı ise 1,5 idi. Başvuru yakınmaları arasında en sık neden nefes darlığı (%51,5) idi. Risk faktörleri arasında ise çoğunluğu (%39,3) operasyona bağlı immobilizasyon hikayesi oluşturmaktaydı. Well's klinik skorlamasına göre olguların 29'u (%87,8) yüksek olasılıklı iken modifiye geneva skoruna göre ise olguların 18'i (%55,5) yüksek olasılıklı grupta idi. Well's skorunun yüksek olasılıklı PTE tahmin oranı Modifiye Geneva skoruna göre anlamlı oranda fazla idi (p0,017). En sık görülen klinik bulgular taşipne (%69,6) ve taşikardi (%27,3) idi. 15 (%45,4) olguda patolojik akci- ğer grafisi vardı. Bilgisayarlı Tomografik (BT) Anjiografide PTE en sık bilateral pulmoner ana dallara yerleşim göstermekte idi. Yirmi yedi (%81,8) olguya standart düşük molekül ağırlıklı heparinwarfarin tedavisi uygulanırken 6 (%18,2) olguya ise doku plazminojen aktivatörü (tPA) tedavisi uygulanmıştı. Sonuç: PTE tanısında; klinik, laboratuar ve radyolojik bulguların birlikte değerlendirilmesi önemlidir. PTE kuşkusu olan hastaların klinik olasılık tahmininde Well's skorunun kullanımı tercih edilmelidir.Aim: To examine the clinical, radiological, and laboratory findings of pulmonary thromboembolism (PTE) patients who were admitted to our emergency department and to evaluate the effectiveness of clinical diagnosis scores.Materials and Methods: We retrospectively evaluated 33 PTE patients who were referred to our emergency department. Results: The mean age of the patients was 56.2±18.2 years. The female:male ratio was 1.5. The most common cause of complaints was dyspnoea (51.5%). Risk factors in the majority (39.3%) included immobilisation due to surgery. According to the Wells clinical scoring system, 29 patients (87.8%) had a high probability of PTE; however, 18 of the patients (55.5%) had high probability of PTE according to the modified Geneva score. The estimated rate ratio of high probability of PTE with the Wells score was statistically significant compared with the estimate rate ration with the modified Geneva score (p0.017). The most common clinical findings included tachypnoea (69.6%) and tachycardia (27.3%). Fifteen (45.4%) patients had pathologic chest X-ray findings. Computed tomographic (CT) angiography most often showed PTE placement of the bilateral pulmonary main branches. While standard low-molecular-weight heparin and warfarin treatment was administered to 27 (81.8%) patients, tissue plasminogen activator (tPA) treatment was administered to 6 (18.2%) patients. Conclusion: The evaluation of clinical, laboratory and radiological findings together in PTE diagnosis is important. It is preferable to use the Wells score for the estimation of clinical probability in patients with suspected PT