Unveiling the optical parameters of vanadium dioxide in the phase transition region: a hybrid modeling approach

The phase change behavior of vanadium dioxide (VO₂) has been widely explored in a variety of optical and photonic applications. Commonly, its optical parameters have been studied in two extreme regimes: hot (metallic) and cold (insulating) states. However, in the transition temperatures, VO₂ acts like an inherent metamaterial with mixed metallic-insulating character. In this range, the portions of metallic and insulating inclusions are tuned by temperature, and therefore a gradual change of optical parameters can be achieved. In this paper, a universal hybrid modeling approach is developed to model VO₂ in the intermediate region. For this aim, the measured reflectivity data, is analyzed and matched through the transfer matrix method (TMM) simulations where an effective medium theory (EMT) is employed. Based on the findings of this approach, not only the relative portions of inclusions are tailored but also their grain shapes are significantly altered in the transition range. Finally, the modeling approach is testified by experimental findings through dynamic device applications operating at short and mid infrared wavelengths. In addition, the hysteretic behaviors on electrical, optical, and structural parameters of the VO₂ film along the heating and cooling cycles are demonstrated by the experiments and scrutinized by the simulations.

A universal hybrid modeling approach is developed to model VO₂ in transition, revealing dynamic behavior of metallic inclusions and grain shapes.     

Mechanical bowel obstruction due to colonic hemangioma: report of a case.

Colon hemangiomas are rare benign vascular lesions which are usually seen in teenagers. The frequent presentation is repetitive painless rectal bleeding. Colonic hemangiomas are occasionally found in the rectosigmoid area. A 62-year-old male patient was admitted to the hospital with the complaints of mechanical bowel obstruction. The radiological imaging techniques revealed a transverse colon tumor. Consequently, the patient was operated, and transverse colectomy and end-to-end anastomosis were performed. No postoperative complications occurred. The pathologic examination revealed cavernous hemangioma of the transverse colon. This report describes a very rare case of bowel obstruction due to colonic hemangioma.     

Examination of fabrication conditions of acrylate-based hydrogel formulations for doxorubicin release and efficacy test for hepatocellular carcinoma cell

The objective of the present study was to develop 2-hydroxypropyl methacrylate-co-polyethylene methacrylate [p(HPMA-co-PEG–MEMA)] hydrogels that are able to efficiently entrap doxorubicin for the application of loco-regional control of the cancer disease. Systemic chemotherapy provides low clinical benefit while localized chemotherapy might provide a therapeutic advantage. In this study, effects of hydrogel properties such as PEG chains length, cross-linking density, biocompatibility, drug loading efficiency, and drug release kinetics were evaluated in vitro for targeted and controlled drug delivery. In addition, the characterization of the hydrogel formulations was conducted with swelling experiments, permeability tests, Fourier transform infrared, SEM, and contact angle studies. In these drug-hydrogel systems, doxorubicin contains amine group that can be expected a strong Lewis acid–base interaction between drug and polar groups of PEG chains, thus the drug was released in a timely fashion with an electrostatic interaction mechanism. It was observed that doxorubicin release from the hydrogel formulations decreased when the density of cross-linking, and drug/polymer ratio were increased while an increase in the PEG chains length of the macro-monomer (i.e. PEG–MEMA) in the hydrogel system was associated with an increase in water content and doxorubicin release. The biocompatibility of the hydrogel formulations has been investigated using two measures: cytotoxicity test (using lactate dehydrogenase assay) and major serum proteins adsorption studies. Antitumor activity of the released doxorubicin was assessed using a human SNU398 human hepatocellular carcinoma cell line. It was observed that doxorubicin released from all of our hydrogel formulations which remained biologically active and had the capability to kill the tested cancer cells.     

Idiopathic synchronous central giant cell granulomas involving both the maxilla and mandible: a case report

The central giant cell granuloma is a well-defined lesion of the jaws and reports of multiple lesions are very uncommon. The authors report the case of a patient with idiopathic synchronous multiple central giant cell granulomas involving both the maxilla and the mandible. Surgical curettage of the lesions was performed. At the end of the 24 months follow-up, no recurrence was detected.     

Recipient splenic artery utilization for arterial re-anastomosis in living donor liver transplantation: single-center experience

Thrombosis of recipient hepatic artery is a life threatening complication for liver transplantation. The etiology of hepatic arterial thrombosis is multi-factorial and can be caused by intimal dissection, poor surgical technique and coagulopathies. The patency of hepatic arterial flow is very important for both graft survival and patient survival. Intraoperative diagnosis of inadequate hepatic arterial flow found with Doppler ultrasonography is essential in order to achieve good results after liver transplantation. Urgent re-anastomosis is necessary when the arterial blood flow is insufficient. We performed 317 living donor liver transplantations from July 2004 to July 2011. We used recipient splenic artery for hepatic artery reconstruction in six patients. These six patients were included in this study. Using the recipient splenic artery is a simple, safe and practical alternative for hepatic artery re-anastomosis in living donor liver transplantations.     

Nonsense β-thalassemia mutation at codon 37 (TGG>TGA), detected for the first time in three Turkish cases

Thalassemias are genetically heterogeneous group of disorders with reduced or absent production of globin. β-Thalassemia major can be caused by homozygosity or compound heterozygosity for β-globin gene mutation. Here we report, for the first time in Turkey, three cases who carry the nonsense β-thalassemia (β-thal) mutation at codon 37 (TGG>TGA; Trp→Stop) causing premature stop codon.     

Anatomical variations of donor portal vein in right lobe living donor liver transplantation: the safe use of variant portal veins

In right lobe (RL) living donor liver transplantation (LDLT), portal vein (PV) variations are of immense clinical significance. In this study, we describe in detail our PV reconstruction techniques in RL grafts with variant PV anatomy and evaluate the impact of accompanying biliary variations on the recipient outcomes. In a total of 386 RL LDLTs performed between July 2004 and July 2012, the clinical data on 52 (13%) transplants using RL grafts with variant PV anatomy were retrospectively analyzed. Portal vein anatomy was classified as type 2 in 20 patients, type 3 in 24 patients, and type 4 in eight patients. The PV reconstruction techniques utilized included back‐wall plasty (n = 21), back‐wall plasty with saphenous vein graft interposition (n = 6), saphenous vein graft interposition (n = 5), cryopreserved iliac vein Y‐graft interposition (n = 6), and quiltplasty (n = 3). There was no donor mortality. In a median follow‐up of 29 months, none of the recipients had vascular complications. Anomalous PV anatomy was associated with a high (54%) incidence of biliary variations; however, these variations did not result in increased biliary complication rate. Overall, the 1‐ and 3‐year patient survival rates of recipients were 91% and 81%, respectively. Vascular and biliary variations in RL grafts render LDLT technically more challenging. By employing appropriate reconstruction techniques, it is possible to successfully use RL grafts with PV variations without endangering recipient and donor safety.     

The distinction between unipolar and bipolar depression: A cognitive theory perspective

Background

There is very limited data about the cognitive structure of bipolar depression when compared to unipolar depression. The aim of the study was to look into the differences between unipolar and bipolar depressed patients regarding their cognitive structure in view of Beck's cognitive theory.

Methods

In this study, 70 bipolar patients during a depressive episode, 189 unipolar depressed patients and 120 healthy subjects were recruited. The participants were interviewed by using a structured clinical diagnostic scale. To evaluate the cognitive structure differences, the Automatic Thoughts Questionnaire (ATQ) and the Dysfunctional Attitude Scale (DAS) were used.

Results

We found that on the mean ATQ total score, the unipolar depressed patients scored significantly higher (92.9 ± 22.7) than both the bipolar depressed patients (73.2 ± 24.7) and the healthy subjects (47.1 ± 19.6), even after controlling for all confounding factors, e.g. gender, marital status, depressive symptom severity (F = 157.872, p < 0.001). The bipolar depressed patients also scored significantly higher on the mean ATQ total score than the healthy controls. On the mean DAS total score, and on the mean score of its subscale of need for approval, the bipolar depressed patients scored (152.8 ± 21.2 and 48.2 ± 7.4, respectively) significantly higher than both the unipolar depressed patients (160.9 ± 29.0 and 51.9 ± 9.7, respectively) and the healthy subjects (127.9 ± 32.8 and 40.2 ± 12.2, respectively), even after controlling for any confounding factor (F = 45.803 [p < 0.001] and F = 43.206 [p < 0.001], respectively). On the mean score of the perfectionistic attitude subscale of the DAS, the depressed groups scored significantly higher than the healthy subjects, but they did not seem to separate from each other (F = 41.599, p < 0.001).

Conclusions

These results may help enhance the understanding of the potentially unique psychotherapeutic targets and the underlying cognitive theory of bipolar depression.