Interface-Driven Strain in Heavy Ion-Irradiated Zr/Nb Nanoscale Metallic Multilayers: Validation of Distortion Modeling via Local Strain Mapping.

Nanolayered metallic alloys are promising materials for nuclear applications thanks to their resistance to radiation damage. Here, we investigate the effect of ion (C, Si, and Cu) irradiation at room temperature with different fluences into sputtered Zr/Nb metallic multilayer films with periods 27 nm (thin) and 96 nm (thick). After irradiation, while a high strain in the entire thin nanoscale metallic multilayer (NMM) is observed, a quite small strain in the entire thick NMM is established. This difference is further analyzed by a semianalytical model, and the reasons behind it are revealed, which are also validated by local strain mapping. Both methods show that within a thick layer, two opposite distortions occur, making the overall strain small, whereas in a thin layer, all the atomic planes are affected by the interface and are subjected to only a single type of distortion (Nb─tension and Zr─compression). In both thin and thick NMMs, with increasing damage, the strain around the interface increases, resulting in a release of the elastic energy at the interface (decrease in the lattice mismatch), and the radiation-induced transition of the Zr/Nb interfaces from incoherent to partially coherent occurs. Density functional theory simulations decipher that the inequality of point defect diffusion flux from the inner to the interface-affected region is responsible for the presence of opposite distortions within a layer. Technologically, based on this work, we estimated that Zr/Nb55 with thicknesses around Zr = 24 nm and Nb = 31 nm is the most promising multilayer system with the high radiation damage resistance and minimum swelling for nuclear applications.

Deformation-Controlled Design of Metallic Nanocomposites.

Achieving the theoretical strength of a metallic alloy material is a demanding task that usually requires utilizing one or more of the well-established routes: (1) Decreasing the grain size to stop or slow down the dislocation mobility, (2) adding external barriers to dislocation pathways, (3) altering the crystal structure, or (4) combining two of the previous discrete strategies, that is, implementing crystal seeds into an amorphous matrix. Each of the outlined methods has clear limitations; hence, further improvements are required. We present a unique approach that envelops all the different strength-building strategies together with a new phenomenon-phase transition. We simulated the plastic deformation of a Zr-Nb nanolayered alloy using molecular dynamics and ab initio methods and observed the transition of Zr from hexagonal close-packed to face-centered cubic and then to body-cenetered cubic during compression. The alloy, which was prepared by magnetron sputtering, exhibited near-theoretical hardness (10.8 GPa) and the predicted transition of the Zr structure was confirmed. Therefore, we have identified a new route for improving the hardness of metallic alloys.

Viewpoint: Atomic-Scale Design Protocols toward Energy, Electronic, Catalysis, and Sensing Applications.

Nanostructured materials are essential building blocks for the fabrication of new devices for energy harvesting/storage, sensing, catalysis, magnetic, and optoelectronic applications. However, because of the increase of technological needs, it is essential to identify new functional materials and improve the properties of existing ones. The objective of this Viewpoint is to examine the state of the art of atomic-scale simulative and experimental protocols aimed to the design of novel functional nanostructured materials, and to present new perspectives in the relative fields. This is the result of the debates of Symposium I "Atomic-scale design protocols towards energy, electronic, catalysis, and sensing applications", which took place within the 2018 European Materials Research Society fall meeting.

Comparison of hemodynamic responses to endotracheal intubation with the GlideScope video laryngoscope and Macintosh laryngoscope in patients undergoing cardiovascular surgery.

BACKGROUND: This study aimed to compare hemodynamic response to endotracheal intubation using GlideScope and Macintosh laryngoscopes in patients who underwent cardiovascular surgery. METHODS: A total of 74 patients were enrolled in the study. Patients were randomly assigned into two groups either a GlideScope (n=37) or a Macintosh laryngoscope (n=37). Laryngoscopy time, heart rate, invasive arterial pressure and rate pressure product were compared during induction and until five minutes after laryngoscopy at 11 time points. RESULTS: Seventy patients completed the study. The intubation time was similar in both groups (14.1±4.0 sec vs. 13.2±4.2 sec; p=0.22). Hemodynamic values including heart rate, systolic, diastolic and mean arterial pressure and rate pressure product were similar at all-time points. The laryngoscopy time was also similar between groups. CONCLUSION: The GlideScope video laryngoscope did not show any advantage on hemodynamic response in patients undergoing cardiovascular surgery when compared to Macintosh laryngoscope.

Comparison of two different doses of lidocaine on the pain sensation during transrectal ultrasound-guided prostate biopsy.

OBJECTIVE: To compare two different doses of lidocaine used for periprostatic nerve block on pain perception during transrectal ultrasound (TRUS) guided prostate biopsy. MATERIAL AND METHODS: A total of 288 patients with elevated prostate specific antigen (PSA) levels and/or abnormal digital rectal examination who underwent TRUS-guided prostate biopsy were included in the study. The patients were divided into 3 groups: Group 1 (n=103) prostate biopsy were performed after administering perianal intrarectal application of 10 mL 2% lidocaine gel, Group 2 (n=98) 2 mL of 2% lidocaine injection on each side following rectal installation of lidocaine gel and Group 3 (n=87) 4 mL of 2% lidocaine injection on each side after rectal instillation of lidocaine gel. Patients' pain scores during biopsy procedure were reported using visual analogue score (VAS). Independent sample t test, ANOVA test and Tukey test were used for statistical evaluation. RESULTS: The mean age, prostate volume and PSA level were 65.6±8.4 years, 58.2±34.8 mL, and 11.8±3.4 ng/mL respectively. There were no statistically significant differences in baseline characteristics between the groups. The mean VAS scores were 2.4±1.8 in Group 1, 2.5±1.9 in Group 2 and 1.6±1.6 in Group 3. Patients in Group 3, reported significant pain reduction compared with patients in Groups 1 and 2 (p=0.002, and 0.001, respectively). However, there was no statistically significant difference in VAS scores between Groups 1 and 2 (p=0.815). CONCLUSION: According to our results we recommend the use of perianal intrarectal lidocain gel application, and periprostatic nerve block with injection of 4 ml 2% lidocaine per side combination in TRUS-guided prostate biopsies. Further large-scale randomized control studies are needed to validate these finding.

How important is the butyrylcholinesterase level for cesarean section?

OBJECTIVES: Butyrylcholinesterase (BChE), commonly known as pseudocholinesterase or non-neural cholinesterase, hydrolyzes neuromuscular blocker agents containing choline esters such as succinylcholine that is widely used in rapid sequence induction (RSI) for general anesthesia. The aim of this study is to compare plasma BChE levels and investigate the affects and relationship of succinylcholine on BChE levels in preeclamptic, gestational diabetic and healthy pregnants. STUDY DESIGN: We designed a prospective, controlled, pilot single-center study. Thirty (n=30) pregnant women who were scheduled for cesarean section under general anesthesia (refusal of regional anesthesia) with RSI involved. Group 1 included ten (n=10) preeclamptic pregnancies, Group 2 included ten (n=10) gestational diabetic (GD) pregnancies and Group 3 included ten (n=10) healthy pregnancies. MAIN OUTCOME MEASURES: BChE levels of all patients were measured prior to the initiation of cesarean section. Train-of-four recovery of 90% (TOF T1) was used to monitor the degree of neuromuscular block beginning from the administration of succinylcholine. RESULTS: No statistically significant difference was found between the groups comparing BChE levels and the duration between tracheal intubation and formation of TOF T1 (p>0.05). CONCLUSIONS: As similar results were gathered from normal and high-risk pregnancies (preeclamptic pregnancy or gestational diabetic pregnancy) who underwent cesarean section under general anesthesia, we believe that succinylcholine is still neuromuscular agent of choice in cesarean section.

Molecular entrapment of volatile organic compounds (VOCs) by electrospun cyclodextrin nanofibers.

In this paper, we reported the molecular entrapment performance of hydroxypropyl-beta-cyclodextrin (HPßCD) and hydroxypropyl-gamma-cyclodextrin (HPγCD) electrospun nanofibers (NF) for two common volatile organic compounds (VOCs); aniline and benzene. The encapsulation efficiency of CD samples were investigated depending on the various factors such as; CD form (NF and powder), electrospinning solvent (DMF and water), CD (HPßCD and HPγCD) and VOCs (aniline and benzene) types. BET analysis indicated that, electrospun CD NF have higher surface area compared to their powder form. In addition DMA measurement provided information about the mechanical properties of CD NF. The encapsulation capability of CD NF and CD powder was investigated by (1)H-NMR and HPLC techniques. The observed results suggested that, CD NF can entrap higher amount of VOCs from surroundings compared to their powder forms. Besides, molecular entrapment efficiency of CD NF also depends on CD, solvent and VOCs types. The inclusion complexation between CD and VOCs was determined by using TGA technique, from the higher decomposition temperature of VOCs. Finally, our results were fortified by the modeling studies which indicated the complexation efficiency variations between CD and VOC types. Here, the inclusion complexation ability of CD molecules was combined with very high surface area and versatile features of CD NF. So these findings revealed that, electrospun CD NF can serve as useful filtering material for air filtration purposes due to their molecular entrapment capability of VOCs.

The effect of serum, intestinal and peritoneal visfatin levels on early diagnosis of acute mesenteric ischemia.

BACKGROUND: Acute mesenteric ischemia (AMI) is a rapidly progressive disease where early diagnosis is life-saving. As a new cytokine, levels of thevisfatin might be affected during the ischema and reperfusion. In our study, we obtained changes of visfatin levels in the serum, peritoneal and intestinal lavage samples in rats, to investigate the effectiveness of these changes in the early diagnosis of AMI. METHODS: In group 1 (Sham group) the intestine was exteriorated after the laparotomy was performed and allowed to stand for 3 hours without ischemia. In group 2 (acute mesenteric ischemia-reperfusion group) the mesenteric artery was ligated and, mesenteric blood flow was restored after 60-minute ischemia. To compare with intestinal injury, in group 3 (acute pancreatitis group) the ductus pancreaticus was ligated, and the abdomen was closed for 3 days in expectation of the formation of pancreatitis. In all of the groups, the intestinal lavage, peritoneal lavage and blood samples were analyzed to evaluate the levels of visfatin, TNF-alpha, IL-6 and IL-8. Samples were taken before the procedure in all groups; additionally 60 minutes after ischemia and 120 minutes after reperfusion in group 2; and after the development of the pancreatitis in group 3. RESULTS: Serum, intestinal and peritoneal lavage visfatin levels were found to be increased in group 2 and group 3 (P<0.05). In group 2, while serum TNF-alpha levels were increased in both ischemia and reperfusion; in intestinal lavage sample the increase was only in the ischemic phase (P<0.05). In group 2, IL-8 levels were significantly increased after ischemia in serum (P=0.03) and after reperfusion in intestinal lavage (P=0.004) samples. CONCLUSIONS: Serum, intestinal and peritoneal visfatin levels were increased not only in the case of mesenteric ischemia, but also in acute pancreatitis. In these two clinical pathologies, the visfatin levels of the intestinal and peritoneal cavitiesmay increase parallel to the serum visfatin levels.

Sulfisoxazole/cyclodextrin inclusion complex incorporated in electrospun hydroxypropyl cellulose nanofibers as drug delivery system.

Herein, hydroxypropyl-beta-cyclodextrin (HPßCD) inclusion complex (IC) of a hydrophobic drug, sulfisoxazole (SFS) was incorporated in hydroxypropyl cellulose (HPC) nanofibers (HPC/SFS/HPßCD-IC-NF) via electrospinning. SFS/HPßCD-IC was characterized by DSC to investigate the formation of inclusion complex and the stoichiometry of the complex was determined by Job's plot. Modeling studies were also performed on SFS/HPßCD-IC using ab initio technique. SEM images depicted the defect free uniform fibers and confirmed the incorporation of SFS/HPßCD-IC in nanofibers did not alter the fiber morphology. XRD analyses showed amorphous distribution of SFS/HPßCD-IC in the fiber mat. Release studies were performed in phosphate buffered saline (PBS). The results suggest higher amount of SFS released from HPC/SFS/HPßCD-IC-NF when compared to free SFS containing HPC nanofibers (HPC/SFS-NF). This was attributed to the increased solubility of SFS by inclusion complexation. Sandwich configurations were prepared by placing HPC/SFS/HPßCD-IC-NF between electrospun PCL nanofibrous mat (PCL-HPC/SFS/HPßCD-IC-NF). Consequently, PCL-HPC/SFS/HPßCD-IC-NF exhibited slower release of SFS as compared with HPC/SFS/HPßCD-IC-NF. This study may provide more efficient future strategies for developing delivery systems of hydrophobic drugs.

Takotsubo Cardiomyopathy Occurring in the Postoperative Period.

Takotsubo cardiomyopathy simulates acute myocardial infarction, and it is characterised by reversible left ventricular failure. A case of Takotsubo cardiomyopathy diagnosed after emergency angiography performed in a patient with evidence of acute myocardial infarction in the postoperative period will be described in this report. Transurethral resection of a bladder tumour (TUR-BT) was performed in a 92-year-old male patient by the urology clinic. The patient was transferred to the post-anaesthesia care unit after the operation. An echocardiography was performed because of the sudden onset of dyspnoea, tachycardia (140-150 beats per minute, rhythm-atrial fibrillation) and ST-segment elevation on electrocardiography (ECG) at the first postoperative hour, and midapical dyskinesia was detected at the patient. An immediate angiography was performed due to suspicion of acute coronary syndrome. Patent coronary arteries and temporary aneurysmatic dilatation of the apex of the heart were revealed by angiography. As a result of these findings, the patient was diagnosed with Takotsubo cardiomyopathy by the cardiology service. The patient was discharged uneventfully following 10 days in the intensive care unit. Aneurysm of the apex of the left ventricle and normal anatomy of the coronary arteries in the angiography have diagnostic value for Takotsubo cardiomyopathy. Diuretics (furosemide) and beta-blockers (metoprolol) are commonly used for the treatment of Takotsubo cardiomyopathy. Even though Takotsubo cardiomyopathy is a rare and benign disease, it should be kept in mind in patients suspected for acute myocardial infarction in the postoperative period.

Effects of dexpanthenol and N-acetylcysteine pretreatment in rats before renal ischemia/reperfusion injury.

BACKGROUND: We investigated the anti-inflammatory and protective effects of concomitant use of dexpanthenol (DXP) and N-acetylcysteine (NAC) induced ischemia/reperfusion (I/R) injury of kidney. METHODS: Forty rats were randomly divided into 5 groups. In all groups except for Group 1(Sham), renal arteries bilaterally occluded with vascular clamp for IR injury. Group 1(Sham), received a single dose of 10 mL/kg isotonic saline daily by intraperitoneal (IP) injection for three days. Group 2(IR), received a single dose of 10 mL/kg isotonic saline daily by IP injection for three days. Group 3(IR + NAC), received 300 mg/kg NAC daily by IP injection for three days. Group 4(IR + DXP), received 500 mg/kg DXP daily by IP injection for three days. Group 5(IR + NAC + DXP), received 500 mg/kg DXP and 300 mg/kg NAC daily by IP injection for three days. Serum urea (BUN), creatinine (Cr) and neutrophil gelatinase-associated lipocalin (NGAL, lipocalin 2, siderocalin) levels were measured as kidney function tests. TNF-α levels were measured as inflammatory marker. Tissue sections were evaluated histopathologically under light microscopy. RESULTS: IR + NAC + DXP group received both NAC and DXP before induction of renal I/R and as the biochemical and histopathological data revealed the results of the IR + NAC + DXP group and sham group were similar. Biochemically and histopathologically, combined use of NAC and DXP has better results when each of them used alone. CONCLUSION: We concluded that concomitant use of DXP and NAC plays a major role against I/R injury and may be useful in acute treatment of I/R induced renal failure.

Spontaneous high piezoelectricity in poly(vinylidene fluoride) nanoribbons produced by iterative thermal size reduction technique.

We produced kilometer-long, endlessly parallel, spontaneously piezoelectric and thermally stable poly(vinylidene fluoride) (PVDF) micro- and nanoribbons using iterative size reduction technique based on thermal fiber drawing. Because of high stress and temperature used in thermal drawing process, we obtained spontaneously polar γ phase PVDF micro- and nanoribbons without electrical poling process. On the basis of X-ray diffraction (XRD) analysis, we observed that PVDF micro- and nanoribbons are thermally stable and conserve the polar γ phase even after being exposed to heat treatment above the melting point of PVDF. Phase transition mechanism is investigated and explained using ab initio calculations. We measured an average effective piezoelectric constant as -58.5 pm/V from a single PVDF nanoribbon using a piezo evaluation system along with an atomic force microscope. PVDF nanoribbons are promising structures for constructing devices such as highly efficient energy generators, large area pressure sensors, artificial muscle and skin, due to the unique geometry and extended lengths, high polar phase content, high thermal stability and high piezoelectric coefficient. We demonstrated two proof of principle devices for energy harvesting and sensing applications with a 60 V open circuit peak voltage and 10 µA peak short-circuit current output.

The effects of clipping on thoracic sympathetic nerve in rabbits: early and late histopathological findings.

BACKGROUND: The clipping of the thoracic sympathetic nerve, which has been a technique used for approximately the past 10 years, has rapidly become popular because of its "bring-back" claim. However, the information regarding the mechanism behind this claim is based on investigator's comments and has not been proven by objective research, such as the histopathological examination of the clipped nerve and/or ganglion. We aimed to evaluate sympathetic regeneration and degeneration after clip removal. METHODS: The rabbits were divided into two groups with six rabbits per group. For the first group (group A), the sympathetic chain was clipped using two titanium clips, and a right thoracotomy was made at the T4 and T5 levels. For the second group (group B), the animals were also operated on, which was similar to the rabbits in group A. At the end of a 48-hour follow-up period, the clips were removed after a second operation. The rabbits in group B were followed for 45 days and sympathetic nerves were also examined histopathologically. RESULTS: In group A, hemorrhage, fibrinous material, polymorphonuclear leukocyte infiltration, and acute inflammation with fat necrosis were observed in and around the sympathetic ganglia and trunk. Loss of nuclei and vacuolization in some sympathetic ganglia cells were also observed. These findings demonstrated severe degeneration of the sympathetic ganglia and trunk. For group B, microscopic examination revealed a loss of sympathetic ganglion cells as well as fibrosis within and around the ganglia. No signs of regeneration were detected and the progression of nerve degeneration was observed. CONCLUSIONS: The clips used in our study were shown to cause the degeneration of neural structures within 2 days. At the end of the 45 days following the removal of the clips, progressive, degenerative changes radiating along the axons of the sympathetic cells were seen.

Therapeutical potential of autologous peripheral blood mononuclear cell transplantation in patients with type 2 diabetic critical limb ischemia.

AIM: The aim was to evaluate the therapeutic effectiveness of granulocyte colony-stimulating factor (G-CSF) mobilized peripheral blood mononuclear cells (PBMNCs) in critical limb ischemia (CLI) of type 2 diabetic patients. METHOD: Forty diabetic patients with CLI were enrolled and randomized to treatment and control groups. In the treatment group, the patients received subcutaneous injections of recombinant human G-CSF (30 MU/day) for 5 days to mobilize stem cells. PBMNCs were collected and transplanted by multiple intramuscular injections of 1 ml in 1-1.5-cm depth into ischemic limbs. RESULTS: At the end of 12 weeks of follow-up, the baseline and end point results in transplant group were as follows: Fontaine score improved from 3.8±03 to 3±0.5 (P=.0001), ankle brachial pressure index increased from 0.68±0.24 to 0.87±024 (P=.001), transcutaneous oxygen increased from 33±14 mmHg to 44±10 mmHg (P=.0001), and 6-min walking distance improved from 280±82 m to 338±98 m (P=.0001). Pain score decreased from 8.2±1.3 to 5.63±1.6 (P=.001), and the number of patients with limb ulcers was reduced from 9/20 (45%) to 3/20 (15%) (P=.031). In the control group, Fontaine score, 6-min walking distance, and pain score were improved; ankle brachial pressure index and transcutaneous oxygen pressure were not improved. The number of patients with limb ulcers did not change in the control group. There are improvement in amputation rates, collateral vessel development, and number of limb ulcers healed. CONCLUSIONS: These results indicate that the autologous transplantation of G-CSF that mobilized PBMNCs in CLI diabetic patients is safe and effective in patient compliant reduction and improved perfusion.

The influence of specific factors on postoperative morbidity in young adults with bronchiectasis.

BACKGROUND: Surgical treatment of bronchiectasis is associated with acceptable mortality and morbidity rates. To date, few reports on the prediction of postoperative morbidity using some preoperative measures have been presented. We present our results regarding the influence of some specific factors on postoperative morbidity on young adult patients who were treated surgically for bronchiectasis. METHODS: Between January 2000 and July 2007, 122 patients were operated upon. Female gender, increased number of resected segments, presence of haemoptysis and bilateral disease, compromised pulmonary function test (FEV1/VC<60%) and absence of preoperative fiberoptic bronchoscopy (FOB) were examined as the potential risk factors for postoperative complications such as persistent air leak (PAL), atelectasis, residual air space (RAS), bronchopleural fistula (BPF) and empyaema. RESULTS: There was no operative mortality. Morbidity was observed in a total of 16 patients with an overall morbidity rate of 13.1%. Complete resection was achieved in 88 patients (72.1%). The number of resected segments was not found to be significantly associated with increased morbidity. Presence of preoperative haemoptysis did not correlate with postoperative complications significantly. Absence of preoperative FOB was not found to be associated with post-operative complications (p<0.05). Compromised PFT was significantly associated with RAS (p=0.028), however it was not associated with increased risk of PAL, atelectasis or empyaema significantly. CONCLUSION: Multi-segmental resectable bronchiectasis should not be considered an occult risk factor for morbidity after resection. Associated non-severe haemoptysis and absence of preoperative bronchoscopy are not associated with significant increased risk of postoperative morbidity.