Utilizing Polyethylene Terephthalate PET in Concrete: A Review.

In general, plastic waste has been growing remarkably. Numerous waste plastic products are generated by manufacturing processes, service industries, and municipal solid waste (MSW). The increase in plastic waste increases concern about the environment and how to dispose of the generated waste. Thus, recycling plastic waste becomes an alternative technique to the disposal of plastic waste in a limited landfill. One of the solutions is to use plastic waste as recycled material in concrete construction to produce what is called green concrete. This research illustrates a summary of studies that utilized polyethylene terephthalate (PET) in concrete as a volume ratio or concrete aggregate replacement. It presents data with regard to mixing design and concrete behavior when PET is used. Moreover, using PET in concrete industries may reduce environmental pollution such as the emission of carbon dioxide and plastic waste disposal problems.

Effects of chopped CFRP fiber on mechanical properties of concrete.

Enhancing concrete's mechanical properties has become a prominent field in recent years. Numerous studies investigated the possibility of enhancing the mechanical properties of concrete by adding additive materials. Few studies investigated the effects of copped CFRP on the tensile strength of normal-strength concrete (NSC) and low-strength concrete (LSC). In this study, the effects of Chopped Carbon Fiber Reinforced Polymer (CCFRP) on the mechanical properties of LSC and NSC were investigated. The method of the study was experimentally investigating the effects of CCFRP on the mechanical properties of LSC and NSC. Different volume fractions (0%, 0.25%, 0.5%, and 0.75%) of chopped carbon fibers were added to the concrete mix for the 13 MPa and 28 MPa concrete grades, and five mix trials were conducted to achieve concrete with 13 MPa and 28 MPa. The ratios (1:1.5:2.5) for the normal strength mix and (1:2.6:4.1) for the low strength mix were chosen. Three tests were conducted to evaluate the effects of chopped CFRP on the mechanical properties of concrete: compressive strength, tensile strength, and flexural strength. A total of 120 pieces were cast, including 24 beams, 48 cubes, and 48 cylinders. The casted cubes were 15 × 15 × 15 cm and the cylinders were 15 cm in diameter and 30 cm in length. Prism beams with a 15 × 15 cm cross-section and a 56 cm length were tested under a single point load. The samples were tested at 7 and 28 days of age, and the sample density was recorded. The results revealed that adding 0.25% CCFRP increased the compressive strength of LSC from 9.5 MPa to 11.2 MPa which is about 10% enhancement and slightly affected the compressive strength of NSC by about 5%. On the other hand, adding 0.25% CCFRP to both LSC and NSC increased split tensile strength from 2.5 MPa to 3.6 MPa which is about 44% enhancement for NSC and 16.6% for LSC. Similar improvements were made in flexural strength of normal strength increased from 4.5 MPa to 5.4 MPa. Whereas the effects on LSC were unremarkable. As such, this study recommends 0.25% CCFRP fiber as the ideal dosage.

Therapeutic potential of cristobalite in the treatment of calf diarrhea.

Calf diarrhea continues to be the major problem of calves in the neonatal period. The effect of zeolites has been increasingly studied in ruminant health in recent years. In the present study, the efficacy of cristobalite, a zeolite, in neonatal calf diarrhea was studied first time. For this purpose, twenty-five neonatal calves with diarrheas were divided into two groups, and Group 1 (n=12) received conventional treatment and Group 2 (n=13) received cristobalite (Zoosorb 10 mg/kg) orally 3 times a day in addition to conventional treatment. Escherichia coli k99 and CS31a, bovine rotavirus and bovine coronavirus were isolated from fecal samples at the beginning of the treatment, on the third day and before discharge. It was determined that the recovery period in Group 2 was 0.95 (20.6%) days shorter than in Group 1 (p⟨0.05) while no viral agents were found on the fifth day in Group 2, viral shedding continued in 4 of 5 calves in Group 1. In conclusion, the study revealed that cristobalite speeds the recovery time and possibly decreases viral shedding in neonatal calf diarrhea, demonstrating a remarkable efficiency in the treatment.

Investigation of the effectiveness of CFRP strengthening of concrete made with recycled waste PET fine plastic aggregate.

In recent decades, several studies have considered the use of plastic waste as a partial substitute for aggregate in green concrete. Such concrete has been limited to non-structural applications due to its low strength. This raises whether such concrete can be enhanced for use in some structural applications. This paper reports an attempt to develop a structural-grade concrete containing plastic waste aggregate with high proportions of substitution and confined with carbon fiber reinforced polymer (CFRP) fabrics. Experimental research was conducted involving the casting and testing 54 plain and confined concrete cylinders. A concrete mixture was designed in which the fine aggregate was partially replaced by polyethylene terephthalate (PET) waste plastic at ratios of 0%, 25%, and 50%, and with different w/c ratios of 0.40, 0.45, and 0.55. The results show that confinement has a substantial positive effect on the compressive behavior of PET concrete. The enhancement efficiency increases by 8-190%, with higher enhancement levels for higher substitution ratios. Adding one layer of CFRP fabric raises the ultimate strength of samples that have lost compressive strength to a level close to that of unconfined samples not containing PET. This confinement is accompanied by an increase in the slope of the stress-strain curve and greater axial and lateral strain values at failure. For the specimens confined by CFRP fabric, PET aggregate can be used as a partial substitute for sand at a replacement ratio of up to 50% by volume for structural applications. This paper also considers the ability of existing models to predict the strength of confined-PET concrete circular cross-sections by comparing model predictions with experimental results. The strength of confined PET concrete elements can't be accurately predicted by any of the models that are already out there. It's important to come up with a new model for these elements.

Efficiency of intravenous iron carboxymaltose in patients with iron-deficiency anemia due to heavy menstrual bleeding: a single-center experience.

OBJECTIVE: Heavy menstrual bleeding (HMB) is the most common cause of iron deficiency anemia (IDA) in premenopausal women. Clinical studies have shown that iron carboxymaltose (ICM) is an appropriate, effective, and well-tolerated treatment option for clinical situations associated with iron deficiency (ID). PATIENTS AND METHODS: This study took 78 out of 400 consecutive patients diagnosed with IDA due to HMB and intolerant or insufficient response of oral iron. All patients were administered the total calculated dose of ICM separately, based on the body weight and current hemoglobin (Hb) level. All the anemia parameters of the patients were compared before and after treatment. RESULTS: All anemia parameters, including median Hb, ferritin, and transferrin saturation, significantly increased four weeks after treatment. Pre- and post-treatment mean Hb levels were 8.9 (± 1.7) g/dL and 12.3 (± 1.2) g/dL, respectively. The mean ferritin level of the patients before treatment was 3.93 (± 2.7) ng/mL. After treatment, the mean ferritin level was 244 (± 185) ng/mL. The mean transferrin saturation levels before and after treatment were 5.7% (± 5.0) and 43.1% (± 20.9), respectively. Although no serious side effects were observed in all patients, headache was detected in 2 patients (2.6%), urticaria in 3 patients (3.8%), and flushing in 2 patients (2.6%). CONCLUSIONS: ICM is an effective and safe treatment option for patients with IDA due to HMB, in which oral iron therapy is insufficient or intolerant. In fact, without waiting for the failure or intolerance of oral iron therapy, moving ICM to the frontline could be cost-effective and more convenient to patients with HMB and health care providers.

Risk factors for post-ERCP pancreatitis: it depends on the ERCP indication.

BACKGROUND AND AIMS: Endoscopic retrograde cholangiopancreatography (ERCP) is an invasive modality, and has a high risk of causing post-ERCP pancreatitis (PEP). Risk factors of PEP have been investigated and conflicting results are present for most risk factors. The aim of this study was to evaluate the risk factors for PEP and to determine whether the risk factors differ due to the ERCP indication. PATIENTS AND METHODS: A retrospective study was conducted which included 666 patients with 968 ERCP procedures. Some risk factors were evaluated for PEP, and they were also evaluated separately for patients with bile duct stones and patients who underwent ERCP for other reasons than bile duct stones. RESULTS: In patients with bile duct stones detected on ERCP ; female gender, lower diameter of the common bile duct, placing a biliary plastic stent and not having a cholecystectomy history were risk factors for PEP, whereas in patients without bile duct stones the only risk factor for PEP was not having a prior endoscopic sphincterotomy. CONCLUSIONS: Our study revealed that PEP risk factors depend on the indication of ERCP. To the best of our knowledge our study is the first study defining cholecystectomy as a protective factor for PEP in patients with bile duct stones and endoscopic sphincterotomy history as a protective factor for PEP in patients without bile duct stones. Our study also showed that female gender, lower diameter of the common bile duct and placing a plastic biliary stent were risk factors for PEP in patients with bile duct stones.

N-acetylcysteine protects testicular tissue against ischemia/reperfusion injury via inhibiting endoplasmic reticulum stress and apoptosis.

BACKGROUND: In animal models, endoplasmic reticulum (ER) stress has been reported to play a vital role in mediating ischemia/reperfusion (I/R) injury in certain organs, such as brain, liver, and intestine. However, there are a limited number of studies examining the relationship between ER stress and torsion and detorsion (T/D)-induced testicular injury. OBJECTIVE: To investigate the effects of N-acetylcysteine (NAC) on ER-stress and apoptosis in an experimental testicular I/R injury model. DESIGN: A non-blinded experimental study with three arms. Rats were divided into three groups: control group, T/D group, and NAC group. In the pretreatment of the NAC group, 20 mg/kg NAC was given intraperitoneally 30 min before detorsion. Tissue 4-hydroxynonenal (4-HNE), 78-kDa glucose-regulated protein (GRP78), and activating transcription factor 6 (ATF6) levels were determined using enzyme-linked immunosorbent assay. The apoptosis levels were evaluated using terminal deoxynucleotide transferase-mediated dUTP nick-end label assay. RESULTS: In T/D group, tissue 4-HNE, GRP78, ATF6, and apoptotic index levels were significantly higher than control group. These increases were significantly reversed with NAC pretreatment. DISCUSSION: There are some potential drugs that have been shown to reduce ER stress in the experimental ischemia model, and it is questioned that these drug candidates can be used as a therapeutic agent in the treatment of ischemic diseases in the near future. This study was not without limitations. First, the authors applied NAC only 20 mg/kg. In a future study, a dose-dependent assay should be performed to assess the likelihood of an additional testicular protective effect. One limitation of this research is also that in vivo studies cannot be extrapolated to possible effect in clinics. More experiments therefore need to be conducted to extrapolate the study findings to humans. CONCLUSION: The study results showed that, after testicular torsion (TT), the ER stress-related apoptotic pathway plays a pivotal role in testicular injury. Further studies of other experimental models of TT may prove that NAC is a useful agent as an adjunctive treatment in surgical repair in human cases.

Biochemical and morphological evaluation of the effects of propolis on cisplatin induced kidney damage in rats.

Cisplatin (CP) is a chemotherapeutic agent used to treat various types of cancer; nephrotoxicity is the most common adverse effect of the drug. We investigated the protective effects of propolis against CP induced kidney injury. Thirty-six male rats were divided into six equal groups: untreated control group, 50 mg/kg/day propolis group, 100 mg/kg/day propolis group, single-dose 7 mg/kg CP group, 7 mg/kg CP + 50 mg/kg/day propolis and 7 mg/kg CP + 100 mg/kg propolis. Rats were sacrificed after 14 days and kidneys were removed for histopathological and biochemical analyses. We used hematoxylin & eosin and periodic acid-Schiff staining to evaluate kidney histopathology and we used the TUNEL technique to assess apoptosis. We also measured total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), ischemia-modified albumin (IMA) and malondialdehyde (MDA) levels in tissue and blood specimens. Normal morphology was observed in the control, 50 mg/kg/day propolis and 100 mg/kg/day propolis groups by light microscopy. Degeneration of tubule cells, edema and tubule dilation were increased in the CP group compared to the control group. Degeneration of tubule cells and dilation of Bowman's spaces were decreased in the CP + 50 mg/kg/day propolis and CP + 100 mg/kg/day propolis groups compared to the CP group. Tubule dilation decreased significantly in the CP + 100 mg/kg propolis group compared to the CP group. Also, the 7 mg/kg CP group exhibited altered proximal tubule epithelial cells, loss of brush border and thickening of the parietal layer of Bowman's capsule in glomeruli and basal laminae of tubules. A normal brush border was observed in the CP + 50 mg/kg/day propolis and CP + 100 mg/kg/day groups. Serum OSI and MDA levels were increased in the CP group compared to the control group. Serum MDA levels decreased significantly in the CP + 50 mg/kg/day propolis and 100 mg/kg CP + propolis groups compared to the CP group. CP caused significant damage to kidney tissue; propolis exhibited dose-dependent prevention of tissue damage.

Effect of iloprost on contractile impairment and mitochondrial degeneration in ischemia-reperfusion of skeletal muscle.

Purpose Acute lower extremity ischemia is still a main cause of mortality and morbidity in orthopedic traumatology and reconstructive surgery. In acute lower extremity ischemia, the skeletal muscles are the tissues that are the most vulnerable to ischemia. The aim of this study was to evaluate the effects of iloprost (IL) therapy on skeletal muscle contractile impairment and mitochondrial degeneration in an acute lower extremity ischemia-reperfusion rat model. Main Methods Forty Wistar albino rats were randomly divided into a control group and four experimental groups. Experimental groups were either subjected to 2 h of lower extremity ischemia followed by a 4-h reperfusion period or to 4 h of ischemia followed by an 8-h reperfusion period. Except for the animals in the control group, all animals received IL (1 ng/kg/min) or saline (1 ml/kg) by intraperitoneal infusion for 10 min immediately before reperfusion. At the end of the recording of skeletal muscle electrical activity and contractility, all rats were sacrificed by decapitation and muscle samples of lower extremity were immediately harvested for histopathologic analyses. Results After ischemia-reperfusion, a breakdown in the force-frequency curves of extensor digitorum longus muscle was observed, showing the diminished muscle contractility. However, IL significantly improved muscle contractility following injury induced by 2 h of ischemia followed by a 4-h reperfusion period. In addition, IL partially ameliorated mitochondrial degeneration in the muscle cells of ischemia groups. Conclusion This study indicates that immediate IL therapy repairs muscle damage especially after 2 h of ischemia and 4 h of reperfusion and therefore that IL improves contractile function.

Is torrefaction of polysaccharides-rich biomass equivalent to carbonization of lignin-rich biomass?

Waste biomass species such as lignin-rich hazelnut shell (HS) and polysaccharides-rich sunflower seed shell (SSS) were subjected to torrefaction at 300°C and carbonization at 600°C under nitrogen. The structural variations in torrefied and carbonized biomasses were compared. Also, the burning characteristics under dry air and pure oxygen (oxy-combustion) conditions were investigated. It was concluded that the effects of carbonization on HS are almost comparable with the effects of torrefaction on SSS in terms of devolatilization and deoxygenation potentials and the increases in carbon content and the heating value. Consequently, it can be proposed that torrefaction does not provide efficient devolatilization from the lignin-rich biomass while it is relatively more efficient for polysaccharides-rich biomass. Heat-induced variations in biomass led to significant changes in the burning characteristics under both burning conditions. That is, low temperature reactivity of biomass reduced considerably and the burning shifted to higher temperatures with very high burning rates.

Endocrine therapy alone vs. chemotherapy plus endocrine therapies for the treatment of elderly patients with endocrine-responsive and node positive breast cancer: a retrospective analysis of a multicenter study (Anatolian Society of Medical Oncology).

PURPOSE: The extra benefit of adding chemotherapy to effective endocrine therapy (ET) has not been clearly or consistently identified in patients older than 70 years with estrogen receptor (ER) positive and node positive breast cancer. The aim of this study was to evaluate the efficacy of adjuvant ET vs. chemotherapy plus endocrine therapies (Chemo/ET) in such patients. METHODS: In this retrospective multicenter study 191 patients ≥ 70 years with operated hormone receptor breast cancer, who were administered adjuvant ET or Chemo/ET were assessed. RESULTS: The median patient follow-up time was 29.0 months (range 1-252). Therefore disease free survival (DFS) and overall survival (OS) analysis was limited, due to the rather short median follow-up, and only 30-month cumulative percentages are reported herein. The 30-month DFS rates were 50.0% in the ET arm and 49.0% in the Chemo/ET arm (p=0.79). The 30-month OS rates were 86% in the ET arm and 96.0% in the Chemo/ET arm (p=0.08). Cox proportional hazard model showed that only surgery was independent prognostic factor for survival (p=0.047), while tumor size showed a strong trend for statistical significance (p=0.051). CONCLUSION: The addition of chemotherapy to endocrine therapy in older patients has no significant impact on DFS and OS.

Administration of contrast media just before cisplatin-based chemotherapy increases cisplatin-induced nephrotoxicity.

PURPOSE: There is a clinical need to predict the probability of cisplatin-induced nephrotoxicity (CIN) in order to make decisions about patient management and relevant preventive measures. The purpose of this study was to develop a risk prediction methodology of CIN. METHODS: 197 consecutive cancer patients, whose serum creatinine was measured at least 48 h before every cycle of cisplatin-based chemotherapy, were included in the study. Demographic and clinical data were collected from the patient medical records. Renal function was evaluated at least 48 h before treatment (day 0) of each cycle, based on the Modification of Diet in Renal Disease (MDRD) formula. CIN was defined as a decrease of ≥ 25% in glomerular filtration rate (GFR) compared to baseline GFR values. RESULTS: The mean age of the study population was 54.5±9.6 years. Fifty-eight patients (29.4%) whose GFR had decreased by at least 25% compared to baseline values formed the CIN group, and the remaining 139 patients formed the non-CIN group. No significant differences were noted between the CIN and non-CIN groups in terms of age, gender, body mass index and smoking history. Metastatic disease was similar in both groups (p=0.86). History of hypertension (p=0.81), diabetes mellitus (p=0.72), and cardiovascular disease (p=0.58) were similar in the two groups. Chemotherapeutic agents used concurrently with cisplatin were similar in both groups. Significantly more radiologic examinations using contrast media were performed in the CIN group compared with the non-CIN group (p=0.01). In patients exposed to contrast media within a week before cisplatin administration, the risk of CIN was 2.56-fold higher (957 percent; CI 1.28-5.11) than in patients without such exposure (p=0.009). CONCLUSION: In patients with exposure to contrast media within a week before cisplatin administration, the risk of CIN was significantly higher than in patients without such an exposure. No additional risk factors for CIN were found in this retrospective observational study.

Evaluation of the renal function using cystatin C level in the patients receiving cisplatin-based chemotherapy.

OBJECTIVE: There are some data regarding the role of cystatin C, a cysteine proteinase inhibitor, in determining the glomerular filtration rate (GFR) more accurately. We aimed to evaluate the correlation of serum cystatin C levels with the serum creatinine levels and GFR calculated by Cockcroft-Gault and modification of diet in renal disease (MDRD) formulations in the patients who received cisplatin-based chemotherapy. We also intended to demonstrate its potential use in the early prediction of the renal function changes in these patients. MATERIALS AND METHODS: In the study, 34 patients receiving cisplatin-based chemotherapy with various malignancies were included. The levels of cisplatin were determined prior to the chemotherapy and at the end of cisplatin infusion during the therapy. GFR was calculated by Cockcroft-Gault and MDRD formulations prior to the therapy and at the end of the third course. RESULTS: A statistically significant linear correlation was found between the serum levels of cystatin C and creatinine prior to the chemotherapy (r = 0.42, p = 0.013). However, there was no correlation among the level of cystatin C subsequent to the cisplatin infusion and serum creatinine level following the third course and MDRD and creatinine clearance-Cockcroft-Gault formulations. CONCLUSION: Even though the serum cystatin C levels were correlated with the serum creatinine levels in our study, it was concluded that it was not an appropriate parameter to predict the potential impairments in the renal function during the chemotherapy.

ERCC1 expression in triple negative breast cancer.

PURPOSE: Excision repair cross-complementation group 1 (ERCC1), which is a component of nucleotide excision repair (NER) pathway, removes platinum-induced DNA adducts. Overexpression of ERCC1 has been associated with resistance to platinum-based chemotherapy in ovarian and lung cancers. Detecting ERCC1 overexpression is important in considering treatment options for triple negative breast cancer (TNBC), and in conducting and interpreting trials that search to find specific chemotherapy regimens for TNBC. In this study we aimed to study ERCC1 overexpression in patients with TNBC. METHODS: A monoclonal antibody against ERCC1 was used for immunohistochemical (IHC) analysis of tumor samples. Tumor samples from 45 patients were evaluated by two experienced pathologists who were blinded to clinical data. A semi-quantitative H score (intensity staining scale ranging from no staining/0 to very intense staining/3+) was calculated by multiplying staining intensity with extent score. Tumors with H score ≥ 1 were classified as ERCC1-positive. RESULTS: ERCC1 expression was positive in 73.3% of the tumor samples with an H score ≥ 1 and 26.7% of the tumor samples stained negative with an H score lt; 1. Of the tumor samples 15.5% stained diffusely and intensively. CONCLUSION: Our study demonstrated that about two thirds of the TNBC showed positive expression of ERCC1, which may be predictive of a poor response to platinum-based chemotherapy.

Thermal reactivity of rapeseed (Brassica napus L.) under different gas atmospheres.

Non-isothermal thermogravimetric method was applied to rapeseed to investigate its thermal reactivity under both individual dynamic atmospheres of nitrogen, steam, carbon dioxide and dry air, and under several mixtures of these gases (nitrogen+steam), (steam+dry air), and (nitrogen+carbon dioxide+steam). In this method, the sample was heated from ambient to 1273 K with a constant heating rate of 20 K/min. The trend of the TGA curves and the derived DTG profiles were interpreted regarding the conversion yields and the reactivity of the samples. Conversion yields of biomass to gaseous products changed in the range of 75-94% on original basis, with respect to the atmosphere under which the experiment was carried out. The maximum rates of the mass losses from the sample were found between 2.6 and 4.3 mg/min. The activation energies were calculated using the method of Coats-Redfern, and varied between 21.3 and 96.0 kJ/mol.

Effect of co-combustion on the burnout of lignite/biomass blends: a Turkish case study.

Co-combustion of Turkish Elbistan lignite and woody shells of hazelnut was performed in a TGA up to 1173 K with a heating rate of 20 K/min. SEM images of each fuel revealed the differences in their physical appearances. Hazelnut shell was blended with lignite in the range of 2-20 wt% to observe the co-combustion properties. Maximum burning rates (Rmax), temperatures of the maximum burning rates (T(R-max)), and the final burnout values of the parent samples and the blends were compared. The results were interpreted considering lignite properties and the major biomass ingredients such as cellulosics, hemicellulosics, and lignin. Deviations between the theoretical and experimental burnout values were evaluated at various temperatures. Burnout characteristics of the blends up to 10 wt% were concluded to have a synergistic effect so the addition of hazelnut shell up to 8 wt% provided higher burnouts than the expected theoretical ones, whereas addition of as much as 10 wt% led to a decrease in the burnout. However, the additive effects were more favorable for the blend having a biomass content of 20 wt%. Apparent activation energy, Rmax, and T(R-max), were found to follow the additive behavior for the blend samples.

Effects of ovulation induction on ovarian morphology: an animal study.

OBJECTIVE: The aim of this study was to investigate whether the ovulation induction has relation with postneoplastic lesions. MATERIALS AND METHODS: Seventy-eight female, 90-day-old rats were enrolled for the trial. They were divided into three groups. In the first group, 13 rats received one cycle of ovulation induction with Follitropin Beta and human chorionic gonadotropin. The second group of 13 rats received three cycles of ovulation induction, and the third study group consisted of 13 rats which received six cycles of ovulation induction. Each group had a control group consisting of same number of rats that had not received ovulation induction. At the 12th month after the ovulation induction protocols ended, rat ovaries were extirpated for histopathological examination. In histopathological examination, malignant lesions, ovarian cyst and cyst diameter, epithelial stratification, epithelial tufting, mitotic index, polymorphism of epithelial cells and nucleus, epithelial cell nuclear diameter, chromatin density nuclear atypia, and mitotic activity in ovarian cyst epithelium were evaluated. RESULTS: No malignant ovarian lesion was found in the three groups. Ovarian cyst development was most frequent in the rats that underwent six cycles of ovulation induction. Epithelial stratification and tufting were most frequent in the rats which underwent ovulation induction six times. Significant difference was found between induction and control groups in second and third groups for cellular and nuclear polymorphism, presence of nucleolus, and nuclear chromatin density. CONCLUSIONS: Although development of malignant lesion were not found in any of the rat ovaries after ovulation induction, increase in the prevalence of epithelial dysplasia especially with increase in the number of induction cycles shows that some ovarian pathologies can occur subsequent to ovulation induction.

Results of the pregnancies with HELLP syndrome.

In this study, clinical features, developing complications, and results of thirty-six patients, which were followed up in our Obstetrics and Gynecology and Nephrology departments between 1997 and 2001, with the diagnosis of HELLP syndrome were searched retrospectively. The mean age of the cases followed up with diagnosis of HELLP syndrome were 30.2 +/- 5.9 (17-46) years. HELLP syndrome was diagnosed on average in the 32.6 +/- 4.8th (23-41) week of gestations. Seventy percent of the cases were with severe preeclampsia and 30% of the cases were with mild preeclampsia. Eleven cases (30%) were nullipara and twenty-five cases (70%) multipara. The average of arterial systolic blood pressure of the cases were 161.6 +/- 26 mmHg, and that of diastolic blood pressure was 98.5 +/- 16.8 mmHg. In thirteen cases (36%) acute renal failure (ARF), six cases (17%) placenta detachment, two cases disseminate intravascular coagulation (DIC), one case Adult Respiratory Distress Syndrome (ARDS) were developed. In seven cases (19%) intrauterine dead fetuses were detected. In twenty-three cases by cesarian section (64%), in thirteen cases by induction (36%) the pregnancies were terminated in 72 h after diagnosing HELLP syndrome. Birth weights of eleven babies (30%) were below 1500 g. Five of the eleven babies were dead in the neonatal period. Six of the thirteen patients who had ARF were given hemodialysis. Two patients died because of the development of ARF + DIC and ARDS. No predicting factors for the development of HELLP syndrome could be detected, but severe preeclampsia. Therefore we think that preeclamptic pregnancies must be followed up very closely and if HELLP syndrome develops, termination of the pregnancy would be proper as soon as possible.

Finite element analysis of strength characteristics of various resin based restorative materials in Class V cavities.

This study investigated the strength characteristics of various composites (Tetric Ceram, Tetric Flow, Prisma AP.H, Synergy Duo Shade, Synergy Compact, and Z 100) and compomers (Compoglass, Compoglass F, Dyract AP, F 2000) that were applied in a Class V cavity of a maxillary central incisor. The study was conducted by using a 3-dimensional finite element approach and in the study ansys package program was used. The tooth model had 294 elements and 420 nodes. The teeth considered were assumed to be subjected to an incisal load of 200 N acting at an angle of 26 degrees with the longitudinal axis of the tooth but the effects of different loading angles and different loads were also analysed. Hence, the loads of 100 and 400 N and the loading angles of 0 degrees representing bruxism and 90 degrees representing a traumatic load were also taken into consideration. The effects of the cavity preparation size were also studied. It was determined that any increase in the loading angle and/or the amount of the load resulted in a proportional increase in the stresses developed in the tooth. Furthermore it was also verified that, as a cavity weakens the tooth structure by creating a discontinuity in an intact tooth, the larger sized cavity preparations inevitably cause larger stresses to be developed in the tooth. Strictly from the mechanical point of view, the stresses developed in the restored teeth were determined to be inversely proportional with the modulus of elasticity of the restorative materials. Therefore within the scope of the study Z 100 was found to be superior to the other materials concerned.

Fracture resistance of Class II approximal slot restorations.

STATEMENT OF PROBLEM: Determination of the fracture resistance of various restorative materials in Class II approximal slot restorations has not been studied. PURPOSE: This study evaluated the effects of retention grooves and different restorative materials in Class II approximal slot restorations. To explore the possibilities for further research, the probable effects of preparation size and loading angle were investigated in a limited manner. MATERIAL AND METHODS: Ninety sound, caries-free human maxillary premolars were divided into 9 groups. The cavities were prepared either by hand or in a computer-controlled CNC machine with or without retention grooves. Four were restored with adhesive amalgam, another 4 with composite, and a single group with Compomer resin. The gingival floor depth was 1.5 mm. The specimens were loaded at an angle of 13. 5 degrees to their longitudinal axes by using a computer-controlled material testing machine until failure occurred. For one specific preparation of adhesive amalgam, loading was applied at 0 and 30 degrees to determine the probable effects of the loading angle. For a specific composite, resin application, the effects of the change in gingival floor depth were analyzed by assigning the depth to 2.0 mm. RESULTS: Composite and Compomer resin and composite exhibited better performance than amalgam. The existence of the retention grooves proved to be effective for adhesive amalgam restorations but did not have any advantageous effect in composite and Compomer restoration. CONCLUSION: For improved fracture resistance in small approximal restorations, the use of composite was the appropriate choice. Compomer also gave satisfactory results. Use of amalgam restoration should be accompanied with retention grooves and an adhesive system to improve its performance.