Design, optimization and production of impact absorbing porous polymer materials with 3D prototyping technology

Otomotiv sektörü, günümüzde vazgeçilemez ulaşım unsurlarının başında gelmektedir. Resmi rakamlara göre ülkemizde yirmi bir milyonu aşkın araç trafiğe kayıtlıdır. Sayının artmasıyla birlikte trafik kazalarında da genel çerçevede artış gözlemlenmiştir. Yine resmi rakamlara göre ülkemizde son yıllarda ortalama bir milyon trafik kazası meydana gelmektedir. Trafik kazaları maddi hasarla birlikte beraberinde can kaybı da yaşanabilmektedir. Yaşanan bu gelişmelerle birlikte taşıtlarda darbe emici özelliğin hayati bir öneme sahip olduğu gözler önüne serilmektedir. Taşıt imalatçılarının da darbe emici malzemeler yoğun çalışma yaptıkları bilinmektedir. Günümüzde darbe emici özelliğe sahip malzemelerin başında da gözenekli malzemeler gelmektedir. Gözenekle malzemelerin başında metalik köpükler gelmektedir. Ancak metalik köpükler çok yüksek enerjili kazalarda ön plana çıkmaktadırlar ve üretim esnasında gözenek boyutları kontrol edilemediğinden random bir üretim söz konusudur. Taşıt-yaya gibi düşük enerjili kazalarda metalik köpüklerden enerji absorbesi beklenmemektedir. Yapılan bu çalışmada polimer köpüklü malzemeler üretilerek, düşük enerjili kazalarda taşıtlarda kullanılan malzemelerin darbe emici özelliklerinin iyileştirilmesi hedeflenmiştir. Klasik yöntemlerle yapılan polimerik köpük üretiminde gözenek boyutları kontrol edilemezken bu çalışmada günümüz popüler üretim yöntemlerinden olan 3B yazıcılarla üretim sayesinde gözenek şekilleri ve boyutları kontrol altına alınarak üretilmiştir. Ayrıca üretilen olan farklı boyutlarda ve şekillerde gözenek boyutlarına sahip numunelerin çeşitli mekanik testleri yapılarak darbe emici özellikleri analiz edilmiştir. Analizler sonucu yapılan olan optimizasyon çalışması ile maksimum verim elde edilmeye çalışılmıştır. Gözenek boyutu ve hücre duvar kalınlığının malzemelerin darbe dayanımı etkileyen ana unsurlardan olduğu tespit edilmiştir. Ayrıca eklemeli imalatla, darbe emici gözenekli yapının kullanılacağı alana uygun olarak, tasarlanıp uygulanabileceği de görülmüştür.The automotive industry is one of the indispensable transportation elements today. According to official figures, more than twenty-one million vehicles in our country are registered to traffic. With the increase in the number of traffic accidents, an increase has been observed in the general framework. According to official figures, an average of 1 million traffic accidents has occurred in our country in recent years. Traffic accidents can occur along with financial damage, as well as loss of life. With these developments, it is revealed that the shock absorbing feature of vehicles is of vital importance. Vehicle manufacturers are also known to work hard on shock absorbing materials. Porous materials are one of the most shock absorbing materials today. Metallic foams are the leading materials. However, metallic foams come to the fore in very high energy accidents and there is a random production as the pore sizes cannot be controlled during production. Energy absorption from metallic foams is not expected in low energy accidents such as vehicle-pedestrian. In this study, it is aimed to improve the shock absorbing properties of the materials used in vehicles in low energy accidents by producing polymer foam materials. While the pore sizes cannot be controlled in the production of polymeric foam made by classical methods, in this study, it will be produced by controlling the pore shapes and sizes thanks to the production with 3D printers, which is one of the popular production methods of today. In addition, the impact absorbing properties of the samples with different sizes and shapes of pore sizes will be analyzed by performing various mechanical tests. Maximum efficiency will be tried to be obtained with the optimization study to be carried out as a result of the analyzes. It is determined that the pore size and cell wall thickness are the main factors affecting the impact resistance of the materials. It has also been found that with the additive manufacturing, the impact absorbing porous structure can be designed and applied in accordance with the area to be used

The effects of exercise on kidney oxidant and antioxidant systems in rats with experimental hyperthyroidism

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Evaluation of anti-body response of anti-Hbc only-positive patients to hepatitis-B vaccine

Hepatit B için yüzey antijeni ve antikorunun negatif, yalnızca anti-HBc total pozitifliği olan hastalar ile zaman zaman karşılaşılmaktadır. Kliniğimizde Kasım 2000- Haziran 2004 tarihleri arasında hepatit belirteçleri araştırılan 767 hastadan 39’unda (%5,8) izole anti-HBc pozitifliği saptanmıştır. İzole anti-HBc pozitifliği saptanan hastaların 14’ü kadın, 25’i erkek olup, ortalama yaş 49.810.33 idi. Bu hastalara 0, 1 ve 6. aylarda rekombinant hepatit B virüs aşısı uygulandı. Her aşılamadan 1 ay sonra anti-HBs titresi kontrol edildi. Hepatit belirteçleri 3. kuşak ELİSA testi ile çalışıldı. Olguların 1’inde (% 2,6) HBeAg, 10’unda (%25,6) anti-HBe ve 3’ünde (%7,7) anti-HCV pozitifliği saptandı. Birinci aşıdan sonra 20 (% 51,2) hastada, 2. aşıdan sonra 31 hastada (%86,1) ve 3. aşıdan sonra 32 hastada (% 91,4) anti-HBs düzeyi 10 IU/L saptandı. 4 kişi 2. ve 3. aşılamaya katılmadı, 1 kişi 3. aşılamaya katılmadı. İki (% 5,1) olguda 3 doz aşılama sonrası yeterli bağışıklık sağlanamadı. Sonuç olarak izole anti-HBc pozitif olan kişilerde aşılama ile yüksek oranda koruyucu antikor titresi sağlanmıştır. Bu hastalarda doğrudan nükleik asid testleri yapmak yerine yalnızca aşıya yanıt oluşturmayan hastalarda bakılması ile önemli oranda tasarruf sağlanabilir.We sometimes meet some patients with HBsAg and anti-HBs negativity, and anti-HBc total positivity only. These patients are called as isolated anti-HBc positive. Thirty nine (5.80%) of total 767 patients applied to our outpatient clinic showed isolated anti-HBc positivity between November 2000-June 2004. Thirty nine patients were taken into study (14 female and 25 male). The mean age was 49,8±10.33. Patients were vaccinated with recombinant HBV vaccine at months 0, 1 and 6. Anti-HBs titers were performed after one month for each vaccination. Hepatitis markers were detected by third generation ELISA method. Among these subjects HBeAg, anti-HBe, and anti-HCV positivity were found in 1 (2,6%), 10 (25,6%) and 3 (7,7%) cases, respectively. The patient&#8217;s numbers whose Anti-HBs titers were detected &#8805; 10 IU/L after first, second and third vaccination were 20 (51,2%) , 31 (86,1%) and 32 (91,4%) patients, respectively. Four of 39 patients were lost on second and third vaccination whereas one of them on third only. Immunity was insufficient (<10 IU/L) in 2 (5,1%) cases after 3 total doses of vaccination. As a result, high ratio of preventive antibody titers can was achieved with vaccination in isolated anti-HBc positive patients. Looking for nucleic acid tests in nonresponder patients instead of all in these patients can be cost-effective

First case of continuous ambulatory peritoneal dialysis peritonitis due to Candida sake

WOS: 000264820200014PubMed: 18627471Fungal peritonitis is a relatively uncommon complication of peritoneal dialysis that contributes significantly to morbidity, drop out from the continuous ambulatory peritoneal dialysis (CAPD) program, and mortality. Candida sake infections were rarely published in literature. We present the first case of peritonitis due to C. sake. A 41-year-old man was admitted to our hospital with abdominal pain, nausea, vomiting, fever, weakness. Abdominal ultrasonography demonstrated a fistula tract, which has an opening at inferolateral of the umbilicus extending 5 cm from the skin into the abdominal cavity with a foreign body (11 x 10 mm length) inside the fistula. The foreign body was removed by surgery being apparently a part of a previously inserted peritoneal catheter. Postoperative specimens revealed polymorph leucocytes and yeast cells in Gram stain, and culture on Sabouraud dextrose agar (SDA) yielded a growth of a fungus, subsequently identified as C. sake with Api ID 32C. Fluconazole (200 mg/day) therapy was started. He recovered after two weeks of therapy. In conclusion, C. sake, a rare type of Candida species, should be considered as a probable peritoneal pathogen in patients with multiple episodes of bacterial peritonitis, previous broad-spectrum antibiotic therapy and diabetes mellitus

Evaluation of anti-body response of anti-Hbc only-positive patients to hepatitis-B vaccine

Hepatit B için yüzey antijeni ve antikorunun negatif, yalnızca anti-HBc total pozitifliği olan hastalar ile zaman zaman karşılaşılmaktadır. Kliniğimizde Kasım 2000- Haziran 2004 tarihleri arasında hepatit belirteçleri araştırılan 767 hastadan 39’unda (%5,8) izole anti-HBc pozitifliği saptanmıştır. İzole anti-HBc pozitifliği saptanan hastaların 14’ü kadın, 25’i erkek olup, ortalama yaş 49.810.33 idi. Bu hastalara 0, 1 ve 6. aylarda rekombinant hepatit B virüs aşısı uygulandı. Her aşılamadan 1 ay sonra anti-HBs titresi kontrol edildi. Hepatit belirteçleri 3. kuşak ELİSA testi ile çalışıldı. Olguların 1’inde (% 2,6) HBeAg, 10’unda (%25,6) anti-HBe ve 3’ünde (%7,7) anti-HCV pozitifliği saptandı. Birinci aşıdan sonra 20 (% 51,2) hastada, 2. aşıdan sonra 31 hastada (%86,1) ve 3. aşıdan sonra 32 hastada (% 91,4) anti-HBs düzeyi 10 IU/L saptandı. 4 kişi 2. ve 3. aşılamaya katılmadı, 1 kişi 3. aşılamaya katılmadı. İki (% 5,1) olguda 3 doz aşılama sonrası yeterli bağışıklık sağlanamadı. Sonuç olarak izole anti-HBc pozitif olan kişilerde aşılama ile yüksek oranda koruyucu antikor titresi sağlanmıştır. Bu hastalarda doğrudan nükleik asid testleri yapmak yerine yalnızca aşıya yanıt oluşturmayan hastalarda bakılması ile önemli oranda tasarruf sağlanabilir.We sometimes meet some patients with HBsAg and anti-HBs negativity, and anti-HBc total positivity only. These patients are called as isolated anti-HBc positive. Thirty nine (5.80%) of total 767 patients applied to our outpatient clinic showed isolated anti-HBc positivity between November 2000-June 2004. Thirty nine patients were taken into study (14 female and 25 male). The mean age was 49,8±10.33. Patients were vaccinated with recombinant HBV vaccine at months 0, 1 and 6. Anti-HBs titers were performed after one month for each vaccination. Hepatitis markers were detected by third generation ELISA method. Among these subjects HBeAg, anti-HBe, and anti-HCV positivity were found in 1 (2,6%), 10 (25,6%) and 3 (7,7%) cases, respectively. The patient&#8217;s numbers whose Anti-HBs titers were detected &#8805; 10 IU/L after first, second and third vaccination were 20 (51,2%) , 31 (86,1%) and 32 (91,4%) patients, respectively. Four of 39 patients were lost on second and third vaccination whereas one of them on third only. Immunity was insufficient (<10 IU/L) in 2 (5,1%) cases after 3 total doses of vaccination. As a result, high ratio of preventive antibody titers can was achieved with vaccination in isolated anti-HBc positive patients. Looking for nucleic acid tests in nonresponder patients instead of all in these patients can be cost-effective

Üriner sistem enfeksiyonlarının erken saptanmasında hızlı tanı testlerinin değeri

Urinary tract infectious (UTI) is the most common of all bacterial infections; the purpose of the present study was to determine the validity of rapidly diagnostic tests for the early detection of UTIs in patients. 128 patients who had UTIs and control group consisted of 128 subjects who had not UTIs were included to the study. Urine specimens obtained from the patients were evaluated for possible UTI by Gram staining, microscopic pyuria, dipstick (nitrite and leukocyte esterase), and quantitative urine culture. Using the quantitative urine culture as the gold standard (reference test), the sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) of all the screening tests were determined and compared. The sensitivity, specificity, PPV, and NPV for the four screening methods were calculated against the urine culture (reference method) for the diagnosis of UTI. In conclusion, validity of Gram stain was found higher compared to other rapid diagnostic tests.üriner sistem enfeksiyonları (üSİ) tüm bakteriyel enfeksiyonların en sık nedenidir; sunulan bu çalışmanın amacı üriner sistem enfeksiyonlarının erken saptanmasında hızlı tanı testlerinin değerinin belirlenmesidir. üSİ olan 128 hasta ve kontrol grubu olarak 128 sağlıklı kişi çalışmaya dahil edildi. Hastalardan elde edilen idrar örnekleri Gram boyama, mikroskopik piyüri, dipstik (nitrit ve lökosit esteraz) ve kantitatif idrar kültürü ile olası üSİ yönünden değerlendirildi. Tüm tarama testlerinin duyarlılığı, özgüllüğü, pozitif (PPV) ve negatif kestirim değerleri (NPV) altın standart olarak idrar kültürleri kullanılarak belirlendi ve karşılaştırmalar yapıldı. Bu dört tarama metodu için duyarlılık, özgüllük, PPV ve NPV değerleri idrar kültür sonuçlarına (referans yöntem) göre hesaplandı. Sonuç olarak, Gram boyama diğer hızlı tanı yöntemleri ile karşılaştırıldığında daha değerli bulundu

Hand carriage of Candida occurs at lesser rates in hospital personnel who use antimicrobial hand disinfectant

WOS: 000340457700004PubMed: 24953067Background: The hands of hospital personnel are considered to be important for colonization and infection of patients with Candida spp. The aim of this study was to evaluate the effectiveness of different hand disinfectants in reducing the carriage of Candida species on the hands of hospital personnel. Methods: A controlled study was conducted at Duzce University School of Medicine Hospital. Eighty hospital personnel were included in the trial. Subjects were divided into 4 groups according to hand hygiene procedures: group 1, hand rubbing with alcohol-based solution; group 2, hand washing with 4% chlorhexidine gluconate; group 3, hand washing with 7.5% povidone-iodine; group 4, hand washing with plain soap and water. The hands of all participants were tested by culture with the broth wash technique. Results: Hand carriage of Candida spp. was lower in the 4% chlorhexidine gluconate group (10.5%, p = 0.006), in the 7.5% povidone-iodine group (18.7%, p = 0.043), and in the alcohol-based hand rub group (21.1%, p = 0.048) compared to the group washing hands with plain soap and water (50%). Conclusions: The use of hand disinfectant containing antimicrobial agents is more effective than hand washing with water and soap in reducing carriage of Candida on the hands of hospital personnel. It is recommended that hospital personnel use an antimicrobial hand disinfectant in units where there is a high risk of Candida infection

Multiple brain abscesses and mastoiditis due to Morganella morgonii after chronic otitis media - Case report and literature review

WOS: 000251195500008Morganella morganii is a Gram-negative facultative anaerobic rod. It frequently causes urinary-tract and wound infections. We identify 4 M. morganii brain abscess cases previously reported in adults in the literature. This is the first case of multiple brain abscesses after mastoiditis secondary to chronic otitis media. The patient presented to an emergency service with fever, nausea, vomiting, headache, otalgia, and a tendency to sleep. Computerized tomography of the brain and temporal bone tomography scan demonstrated subdural abscesses in the frontal and parietal areas, parenchymal abscess in the temporal lobe, and mastoiditis. The abscesses were evacuated immediately with surgery and M. morganii was grown from the aspirate. The patient was treated with intravenous meropenem (3 x 2 g/d) and improved without neurologic sequelae

The diagnostic value of protein carbonyl levels inAcute carbon monoxide intoxication

Amaç: Karbonmonoksit (CO) gelişmiş ülkelerde zehirlenme ile ilişkili mortalite ve morbiditenin ana nedenidir ve birçok ülkede ölümcül zehirlenmelerin yarısından fazlasından sorumlu tutulmaktadır. Bu çalışmada akut CO zehirlenmeli hastalarda meydana gelen hipoksi nedeniyle ortaya çıkan oksidatif strese bağlı olarak, iyi bir oksidatif stres markerı olan protein karbonilin (PC) tanısal değerini belirlemek amaçlanmıştır. Gereç ve Yöntem: Acil serviste CO zehirlenmesi tanısı alan 34 hasta ve sağlıklı 38 gönüllü çalışmaya alınmıştır. Hastaların başvuru anı ve tedavi sonrası PC seviyeleri, kontrol grubu ile karşılaştırılmıştır. Bulgular: Başvuru anında ortalama PC seviyeleri arasında hasta grubu ve kontrol grubu arasında istatistiksel olarak anlamlı fark tespit edilmemiştir, p 0.305 (hasta grubu 0.025 0.01, kontrol grup 0.026 0.01). Hasta grubunda tedavi sonrası PC seviyelerinde başvuru anına göre anlamlı bir düşüş tespit edilmiştir, p 0.006 (başvuru 0.025 0.01, tedavi sonrası 0.017 0.008). Hastalarda başvuru anında CO-Hb seviyeleri ile PC seviyeleri arasında istatistiksel olarak anlamlı bir korelasyon tespit edilmemiştir (Corelation coefficient -0.006, p 0.971). Sonuç: PC'nin CO zehirlenmeli hastalarda akut dönemde bir biyobelirteç olarak kullanılmasının uygun olmadığını düşünmekteyiz.Objective: Carbon monoxide (CO) is the main cause of intoxication-related mortality and morbidity in developed countries. It is responsible for more than half of fatal intoxications in many countries. The purpose of this study was to determine the diagnostic value of protein carbonyl (PC), a good marker of oxidative stress, in association with oxidative stress resulting from hypoxia emerging in patients with acute CO intoxication. Methods: Thirty-four patients diagnosed with acute CO intoxication at the Emergency Department and 38 healthy volunteers were included in the study. Patients' PC levels at time of admission and after treatment were compared with those of a control group. Results: No statistically significant difference was observed among PC levels at time of admission in the patient and control groups (p 0.305, patient group 0.025 ± 0.01, control group 0.026 ± 0.01). A significant decrease was determined in post-treatment PC levels in the patient group compared to those at time of admission (p 0.006, admission 0.025 ± 0.01, post-treatment 0.017 ± 0.008). No significant correlation was determined between patients' carboxyhemoglobin (CO-Hb) levels and PC levels at time of admission (Correlation coefficient -0.006, p 0.971). Conclusions: We think that PC is not suitable for use as a biomarker in the acute period in patients with CO intoxication