Investigation of the inverse magnetocaloric effect with the fraction method.

In this study, we examine Ni49Nb1Mn36In14(nom. at.%) magnetic shape memory alloy (MSMA) to illustrate the inverse magnetocaloric effect (MCE) using the fraction method. The magnetic entropy change,ΔSmag, was calculated with both, the fraction method and the thermomagnetic Maxwell relation. Our results demonstrate that there exists a large magnetization difference between field-cooling and field-heating histories in Ni49Nb1Mn36In14(nom. at.%) MSMA, which can be attributed to the pinning of lattice entropy and magnetic entropy, as it is well-known that the temperature and applied magnetic fields have an opposing effect on the total entropy change. In addition, we describe the inverse MCE and the contradictory roles on the total entropy change between the two stimuli via the fraction method.

On the instability of the giant direct magnetocaloric effect in CoMn0.915Fe0.085Ge at. % metamagnetic compounds.

The giant magnetocaloric effect was quantified in CoMn1-xFexGe (x = 0.085-0.12) nom. at. % polycrystals across the high temperature hexagonal (P63/mmc) to low temperature orthorhombic (Pnma) phase transition via differential scanning calorimetry (DSC) and multiple (thermo) magnetization measurements. It was found that increasing Fe content led to the decrease of both the martensitic transformation temperature and entropy change ([Formula: see text]) at the point of the phase transition. Moreover, first-time magnetocaloric measurements resulted in irreproducible entropy change versus temperature diagrams, which was attributed to the release of internal pressure in bulk samples that disintegrated into powder upon transformation. CoMn1-xFexGe demonstrated larger magnetic field-induced entropy changes and giant magnetocaloric effect (MCE) compared to other CoMnGe alloys doped with Si, Sn, Ti, and Ga. However, the observed brittleness and apparent change in volume at the magnetic transition was posited to influence the material's potential for regenerative applications.

Interplay between physical cleaning, membrane pore size and fluid rheology during the evolution of fouling in membrane bioreactors.

Fouling is one of the most pressing limitations during operation of membrane bioreactors, as it increases operating costs and is the cause of short membrane lifespans. Conducting effective physical cleanings is thus essential for keeping membrane operation above viable performance limits. The nature of organic foulants present in the sludge and the membrane properties are among the most influential factors determining fouling development and thus, efficiency of fouling mitigation approaches. The role of other factors like sludge viscosity on fouling is still unclear, given that contradictory effects have been reported in the literature. In the present study we use a new research approach by which the complex interplay between fouling type, levels of permeate flux, membrane material and feed properties is analyzed, and the influence of these factors on critical flux and membrane permeability is evaluated. A variety of systems including activated sludge and model solutions with distinct rheological behavior has been investigated for two membranes differing in pore size distribution. We present a novel method for assessing the efficiency of fouling removal by backwash and compare it with the efficiency achieved by means of relaxation. Results obtained have proven that backwash delays development of critical fouling as compared with relaxation and reduces fouling irreversibility regardless of fluid rheology. It was shown that backwash is especially effective for membranes for which internal fouling is the main cause of loss in permeability. Nonetheless, we found out that for membranes with tight pores, both relaxation and backwash are equally effective. The critical flux decreases significantly for high-viscosity fluids, such as activated sludge. This effect is mainly caused by an intensified concentration polarization at the feed side rather than by internal fouling events. However, membrane permeability has been proven to rely more on the permeate viscosity than on the feed viscosity: poor rejection of organic fractions showcasing high viscosity causes an acute decline in membrane permeability as a consequence of increased shear stress inside the membrane pores.

Protective effects of thymoquinone and alpha-tocopherol on the sciatic nerve and femoral muscle due to lower limb ischemia-reperfusion injury.

OBJECTIVE: Thymoquinone (TQ) is an antioxidant and anti-apoptotic substance found in the Nigella sativa plant. Alpha-tocopherol (α-TP) is a potent antioxidant. We aimed to determine whether or not TQ and TP have a protective effect against lower limb ischemia-reperfusion (IR) injury of muscle and the sciatic nerve. MATERIALS AND METHODS: A single dose of TQ 25 mg/kg was given intraperitoneally to the TQ group, a single dose of α-TP 200 mg/kg was given intraperitoneally to the α-TP group. IR was performed for 45 minutes after the drugs' applications. RESULTS: While serum levels of malondialdehyde (MDA) and interleukin-6 (IL-6) of the IR group were significantly higher than those of the TQ plus α-TP, TQ and α-TP groups (p<0.001, p<0.001, p=0.008, respectively) and IL-6 (all p<0.001), the reduced glutathione (GSH) level of the IR group was lower than that of the other three groups. While neuronal nitric oxide synthase activity of nerve tissues of the IR group was significantly lower than that of the TQ plus α-TP group, the muscle tissue caspase-3 activity was higher than that of the TQ plus α-TP group. CONCLUSIONS: Administration of TQ plus α-TP may strongly protect muscle and nerve tissues against IR injury via their synergistic effects.

Middle ear pressure changes with sevoflurane and propofol-remifentanil.

The present study aimed to compare the effects of sevoflurane (a commonly used inhalation anesthetic) and intravenous propofol on middle ear pressure (MEP) and determine the more appropriate option for middle ear operations. Fifty-seven American Society of Anesthesiologists risk class I-II patients aged 18-65 years who were not scheduled for ear or tympanic membrane operations were included in the study. The patients were randomly divided into two groups using the sealed envelope method. Propofol (0.2-0.5 mg/kg; Group P) and sevoflurane (1-2%; Group S) were used to maintain anesthesia. Baseline tympanometry was conducted on both ears and recorded before anesthesia was induced. Four additional measurements were performed and recorded at 5, 10, 15, and 30 minutes after induction. All post-induction MEP values were significantly higher than baseline measurements in Group S (P < 0.05 for all); there were no differences between post-induction and baseline measurements in Group P. At 10, 15, and 30 min post-induction, MEP values were significantly higher in Group S than in Group P (P < 0.05). Sevoflurane increased MEP values significantly compared with propofol anesthesia. We conclude that propofol can be used more reliably than sevoflurane in middle ear operations.

Comparison of the effect of the rotation palatoplasty and V-Y pushback palatoplasty techniques on palate elongation with magnetic resonance imaging.

Most surgical techniques used in cleft palate repair require the extension of the palate to the pharynx. However, no adequate information exists regarding the extent to which this elongation obtained during operation continues in late postoperative period. In this study, we compared and measured palate elongation in patients with a cleft palate who underwent a V-Y pushback or rotation palatoplasty, by means of magnetic resonance images obtained before and 1 year after surgery. The hard palate, soft palate, and total palate lengths were measured for all of the patients, and the velopharyngeal opening area width was calculated. In patients who underwent the V-Y pushback technique (n=13), the total palate and soft palate lengths were shortened by an average of 0.10 and 0.14cm after surgery, respectively. However, the hard palate length was elongated by an average of 0.13cm. In the rotation palatoplasty group (n=13), the total palate, hard palate, and soft palate lengths were elongated by 0.57, 0.10, and 0.49cm, respectively. The velopharyngeal opening was narrowed by 0.06cm(2) using the V-Y pushback technique and by 0.29cm(2) using the rotational palatoplasty. This study demonstrated that the palate does not elongate during the V-Y pushback technique, as expected. However, rotational palatoplasty elongates the soft palate.

Topiramate has protective effect on renal injury.

BACKGROUND: Topiramate (TPM) decreases tumor necrosis factor-alpha (TNF-α) and oxidative stress. We investigated protective effects of TPM on cell damage in kidney tissue during ischemia-reperfusion (I/R) damage. METHODS: A total of 30 male Wistar albino rats were divided into three groups: control, I/R, and I/R plus TPM (I/R+TPM). Laparotomy without I/R injury was performed in control group. After laparotomy, cross ligation of infrarenal abdominal aorta was applied for two hours in I/R groups which was followed by two hours of reperfusion. TPM (100 mg/kg/day) was orally administrated to animals in the I/R+TPM group for seven consecutive days before I/R. RESULTS: The I/R group's TNF-α and interleukin-1 beta (IL-1ß) levels were significantly higher (1184.2 ± 129.1 pg/mg protein; 413.1 ± 28.8 pg/mg protein, respectively) than those of the control (907.8 ± 113.0 pg/mg protein, p = 0.002; 374.7 ± 23.7 pg/mg protein, p = 0.010, respectively) and I/R+TPM groups (999.5 ± 115.2 pg/mg protein, p < 0.001; 377.9 ± 30.9 pg/mg protein, p = 0.007, respectively). CONCLUSION: TPM may partially prevent renal damage in rats. The opening of new horizons of this kind of knowledge will help understand the complex challenge in the prevention of renal I/R damage (Tab. 1, Fig. 3, Ref. 42).

A case report of retroperitoneal extrahepatic hepatocellular carcinoma presented with elevated level of Alpha fetoprotein.

BACKGROUND: High level of alpha-fetoprotein is usually associated with testis cancer or hepatocellular carcinoma a primary tumor of the liver. CASE: We report the case of a 72-year-old male patient with chronic renal failure who presented with a high alpha-fetoprotein (AFP) level and a retroperitoneal mass, which was subsequently diagnosed to be an extrahepatic hepatocellular carcinoma. CONCLUSION: A retroperitoneal mass with elevated AFP level and no detected liver lesions is not always caused by a testicular cancer.

Prognostic value of serum Tie-2 and vascular endothelial growth factor levels in cancer patients.

BACKGROUND: Angiogenesis is a very essential process in tumor biology. Vascular endothelial growth factor (VEGF), angiopoietin and its receptor (TIE-2) are very important mediators for angiogenesis. In this trial, we aimed to analyze the role of these mediators on chemotherapy response and survival. PATIENTS AND METHODS: Forty four cancer patients and 22 healthy controls were included in the study. Baseline serum samples were obtained from all participants and post-chemotherapy serum samples were obtained from the cancer patients. Serum vascular endothelial growth factor and TIE-2 levels were measured with quantitative enzyme-linked immunosorbent assay techniques. RESULTS: The baseline serum vascular endothelial growth factor level was 187.5 and 120.2 pg/ml in cancer patients and the control group (p = 0.006). The baseline serum TIE-2 level was 615.9 and 242.5 pg/ml in the patients and control group (p < 0.001). There was a significant difference between patients' baseline and post-chemotherapy VEGF levels (111.9 pg/ml; p < 0.001) and patients' baseline and post-chemotherapy TIE-2 levels (344.5 pg/ml; p < 0.001). The overall survival rate was better in patients who had lower baseline VEGF and TIE-2 levels and whose TIE-2 level had decreased with chemotherapy. CONCLUSIONS: Higher baseline TIE-2 and VEGF levels are related and worsen survival. Decreasing levels of TIE-2, but not VEGF, which, with chemotherapy, may be predictive for survival.

Factors influencing skin ageing in a Mediterranean population from Turkey.

BACKGROUND: Skin ageing is a continuous process, with intrinsic factors determining which extrinsic factors (chronic sun exposure and other environmental factors, particularly smoking) have the greatest effect. AIM: To investigate the effects of lifestyle and environmental factors on skin ageing in a Mediterranean population from Ankara, Turkey. METHODS: In total, 574 (337 women, 237 men; age range 18-89 years) were enrolled into the study. Data were collected on age, gender, weight, height, body mass index (BMI), skin phototype, smoking status, consumption of alcohol (> 3 units/week) and coffee (> 1 cup/day), sun exposure, use of sunscreen and sunglasses, and involvement in sports and physical activities. The Daniell skin-wrinkling grading system was used as a marker of skin ageing. RESULTS: We found that male gender, chronic sun exposure and number of pack-years of cigarette smoking significantly contributed to the formation of facial wrinkles. There was a negative correlation between facial wrinkling and the use of sunscreen and sunglasses and facial wrinkling (P < 0.001 for both). We did not find any significant association between wrinkling score and alcohol consumption, coffee consumption, sports participation or d skin phototype. Moreover, wrinkling score was significantly higher in patients with a BMI < 25 kg/m(2) than in patients with a BMI > 25 kg/m(2) (P < 0.018). Multiple logistic regression analysis was conducted after adjusting for age, gender, smoking status, alcohol consumption, skin phototype, sun exposure, and use of sunglasses and topical sun protection. We found that gender and age were significantly associated with skin ageing (P < 0.014 and < 0.001, respectively). CONCLUSION: In this study, older age, male gender, low BMI, smoking and chronic sun exposure had a negative influence on skin ageing in a Turkish population.

Suitability of Tedlar gas sampling bags for siloxane quantification in landfill gas.

Landfill or digester gas can contain man-made volatile methylsiloxanes (VMS), usually in the range of a few milligrams per normal cubic metre (Nm(3)). Until now, no standard method for siloxane quantification exists and there is controversy with respect to which sampling procedure is most suitable. This paper presents an analytical and a sampling procedure for the quantification of common VMS in biogas via GC-MS and polyvinyl fluoride (Tedlar) bags. Two commercially available Tedlar bag models are studied. One is equipped with a polypropylene valve with integrated septum, the other with a dual port fitting made from stainless steel. Siloxane recovery in landfill gas samples is investigated as a function of storage time, temperature, surface-to-volume ratio and background gas. Recovery was found to depend on the type of fitting employed. The siloxanes sampled in the bag with the polypropylene valve show high and stable recovery, even after more than 30 days. Sufficiently low detection limits below 10 microg Nm(-3) and good reproducibility can be achieved. The method is therefore well applicable to biogas, greatly facilitating sampling in comparison with other common techniques involving siloxane enrichment using sorption media.

Siloxane removal from landfill and digester gas - a technology overview.

This paper reviews technologies for the removal of volatile methyl siloxanes (VMS) from biogas. More than 20 years after identifying silicon dioxide in gas engines running on landfill and sewage gas, three technologies are commercially available to remove siloxanes today: adsorption, absorption and deep chilling. Newer concepts based on technologies other than sorption or condensation have not yet gained access to commercial biogas purification. These emerging siloxane removal concepts include biotrickling filters, catalysts, membranes, and in the case of sewage gas, sludge stripping, peroxidation and filtration at point inlet source. This work introduces the main principles of commercial siloxane removal systems and reviews scientific progress in the field over the last decade.