Transfer-free, scalable vertical heterostructure FET on MoS2/WS2continuous films

Taking into account the novel layered structure and unusual electronic properties of MoS₂and WS₂on the side the lack of dangling bonds between these two components and donor-acceptor linkage effects, growth of the MoS₂/WS₂vertical heterojunction film on the amorphous SiO₂/Si substrate have created high demand. In this study, we reported the continuous, scalable, and vertical MoS₂/WS₂heterostructure film by using a sputtering without a transfer step. The WS₂film was continuously grown on MoS₂and eventually led to the formation of the MoS₂/WS₂vertical heterojunction film. Dozens of FETs fabricated on MoS₂/WS₂continuous heterojunction film were created on the same substrate in a single lithographic fabrication step, allowing them to be commercialized and not only used in research applications. RAMAN spectra proved the formation of the MoS₂/WS₂heterostructure film. In XPS measurements, it was shown that a separate MoS₂and WS₂layer was grown instead of the alloy structure. The polarity behavior of the MoS₂/WS₂heterostructure FET was found to be modulated with different drain voltages as p-type to ambipolar and finally n-type conductivity because of the transition of band structure and Schottky barrier heights at different drain voltages. Electron mobility (7.2 cm²V.s^-1) and on/off ratio (10⁴-10⁵) exhibited by the MoS₂/WS₂heterostructure FETs displayed a more improved electrical performance than that of individual WS₂, MoS₂devices. It was observed that the mobility value of MoS₂/WS₂FET was approximately 514 times greater than WS₂FET and 800 times greater than MoS₂FET. Additionally, the MoS₂/WS₂FET on/off ratio was larger than 2 order MoS₂FET and 1 order WS₂FET. The film of continuous vertical heterojunctions as in the MoS₂/WS₂currents in the study would be a promising candidate for nanoelectronics fields. This work demonstrated the progress towards realizing carrier-type controlled high-performance MoS₂/WS₂heterojunction-based FETs for future logic devices.

Highly Responsive Pd-Decorated MoO3 Nanowall H2 Gas Sensors Obtained from In-Situ-Controlled Thermal Oxidation of Sputtered MoS2 Films

Among transition metal oxides, MoO₃ is a promising material due to its layered structure and different oxidation states, making it suitable for different device applications. One of the methods used to grow MoO₃ is radio frequency magnetron sputtering (RFMS), which is the most compatible method in industry. However, obtaining nanostructures by RFMS for metal oxides is challenging because of compact morphology film formation. In this study, α-MoO₃ with vertical nanowalls is obtained by a two-step process; deposition of magnetron-sputtered MoS₂ vertical nanowalls and postoxidation of these structures without changing the morphology. In situ transmittance and electrical measurements are performed to control the oxidation process, which shed light on understanding the oxidation of MoS₂ nanowalls. The transition from MoS₂ to α-MoO₃ is investigated with partially oxidized MoS₂/MoO₃ samples with different thicknesses. It is also concluded that oxidation starts from nanowalls perpendicular to the substrate and lasts with oxidation of basal planes. Four different thicknesses of α-MoO₃ nanowall samples are fabricated for H₂ gas sensors. Also, the effect of Pd deposition on the H₂-sensing properties of sensors is deeply investigated. An outstanding response of 3.3 × 10⁵ as well as the response and recovery times of 379 and 304 s, respectively, are achieved from the thinnest Pd-loaded sample. Also, the gas-sensing mechanism is explored by gasochromic measurements to investigate the sensor behaviors under the conditions of dry air and N₂ gas as the carrier gas.

Production of novel carbon nanostructures by electrochemical reduction of polychlorinated organic rings under mild conditions for supercapacitors

Here, new carbon-based nanostructures were prepared via a one-step electrochemical method using hexagonal and pentagonal polychlorinated organic rings as the carbon source.

Growth Control of WS2: From 2D Layer by Layer to 3D Vertical Standing Nanowalls

Large area 2D WS₂ has been grown successfully by radio frequency magnetron sputtering (RFMS) method. First, in order to investigate the pressure dependence on the grown WS₂ samples, WS₂ were grown at 5 different growth pressures, 5, 10, 15, 20, and 25 mTorr. It has been observed that the surface morphology changes for the samples grown at higher growth pressures, 15, 20, and 25 mTorr. Vertically standing nanowall (NW)-like structures have been formed at these relatively high growth pressures. It has also been observed that the (002) plane is highly dominant, which means layer by layer growth parallel to the substrate, for the sample grown at 20 mTorr. X-ray photoelectron spectroscopy (XPS) measurements revealed an increasing atomic percentage of the S element to W element, S/W, ratio in thin films, as the growth pressure increases. Growth dynamics of WS₂ has been investigated by time-dependent-growth WS₂ samples, 5, 10, 20, 40, and 80 s under 20 mTorr pressure. It has been shown by atomic force microscopy, scanning electron microscopy, and transmission electron microscopy that a highly smooth surface has been achieved in the samples grown for the duration of 5 and 10 s. Raman mapping measurements on the sample grown at 5 s have revealed large area homogeneous growth. As the growth time gets longer, the NWs emerge on the surface at some nucleation points. Only the peak that belongs to the (002) plane has been observed for samples grown at 5 and 10 s by the X-ray diffraction (XRD) measurements. XRD measurements have revealed the appearance of turbostratic peaks of (11l) and (10l) as the thickness increases. Photoluminescence measurements have indicated near-band-edge emission centered at 630 nm for only 5 and 10 s samples.

Synthesis of Graphene-like Films by Electrochemical Reduction of Polyhalogenated Aromatic Compounds and their Electrochemical Capacitor Applications

Graphene is a promising two-dimensional nanomaterial for many applications due to its exciting properties. In the past decade, a variety of techniques-each with its own set of advantages and disadvantages-have been developed to prepare graphene, and there are ongoing efforts to improve these techniques and to reveal new approaches. Here, we describe a simple and low-cost process for the bottom-up synthesis of graphene-like films. This new methodology involves a two-step procedure: (i) formation of polyaromatic ring structures by the repeated covalent coupling of aryl radicals generated from electrochemical reduction of polyhalogenated aromatic compounds in aprotic solvent, and (ii) production of carbon networks by heating of polyaromatic surface films. Accordingly, polymeric films were prepared on the electrodes by electrochemical reduction of polyhalogenated compounds such as hexafluorobenzene (HFB), hexachlorobenzene (HCB), and hexabromobenzene (HBB), and then polymer films were annealed at 400 °C for 30 min. The structure and surface characteristics of electrodeposited carbon films under self- and thermal-annealing conditions were studied by spectroscopic and morphological techniques. Also, the capacitance performance of the films was evaluated by means of cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. Results indicate that graphene-like carbon films can be achieved by use of the electrochemical approach under mild conditions without expensive equipment, and also that these carbon materials are very promising for low-cost energy-storage devices.

Stress evolution of Ge nanocrystals in dielectric matrices

Germanium nanocrystals (Ge NCs) embedded in single and multilayer silicon oxide and silicon nitride matrices have been synthesized using plasma enhanced chemical vapor deposition followed by conventional furnace annealing or rapid thermal processing in N₂ ambient. Compositions of the films were determined by Rutherford backscattering spectrometry and x-ray photoelectron spectroscopy. The formation of NCs under suitable process conditions was observed with high resolution transmission electron microscope micrographs and Raman spectroscopy. Stress measurements were done using Raman shifts of the Ge optical phonon line at 300.7 cm^-1. The effect of the embedding matrix and annealing methods on Ge NC formation were investigated. In addition to Ge NCs in single layer samples, the stress on Ge NCs in multilayer samples was also analyzed. Multilayers of Ge NCs in a silicon nitride matrix separated by dielectric buffer layers to control the size and density of NCs were fabricated. Multilayers consisted of SiN _y :Ge ultrathin films sandwiched between either SiO₂ or Si₃N₄ by the proper choice of buffer material. We demonstrated that it is possible to tune the stress state of Ge NCs from compressive to tensile, a desirable property for optoelectronic applications. We also observed that there is a correlation between the stress and the crystallization threshold in which the compressive stress enhances the crystallization, while the tensile stress suppresses the process.

Whole-genome sequencing and antigenic analysis of the first equine influenza virus identified in Turkey

BACKGROUND

In 2013, there was an outbreak of acute respiratory disease in racehorses in Turkey. The clinical signs were consistent with equine influenza (EI).

OBJECTIVE

The aim was to confirm the cause of the outbreak and characterise the causal virus.

METHODS

A pan-reactive influenza type A real-time RT-PCR and a rapid antigen detection kit were used for confirmatory diagnosis of equine influenza virus (EIV). Immunological susceptibility to EIV was examined using single radial haemolysis and ELISA. Antigenic characterisation was completed by haemagglutinin inhibition using a panel of specific ferret antisera. Genetic characterisation was achieved by whole-genome sequencing using segment-specific primers with M13 tags.

RESULTS

A H3N8 EIV of the Florida clade 2 sublineage (FC2) was confirmed as the causal agent. The index cases were unvaccinated and immunologically susceptible. Phylogenetic analysis of the HA1 and NA genes demonstrated that A/equine/Ankara/1/2013 clustered with the FC2 strains circulating in Europe. Antigenic characterisation confirmed the FC2 classification and demonstrated the absence of significant drift. Whole-genome sequencing indicated that A/equine/Ankara/1/2013 is most closely related to the viruses described as the 179 group based on the substitution I179V in HA1, for example A/equine/East Renfrewshire/2/2011, A/equine/Cambremer/1/2012 and A/equine/Saone et Loire/1/2015. The greatest diversity was observed in the NS1 segment and the polymerase complex.

CONCLUSIONS

The first recorded outbreak of EI in Turkey was caused by an FC2 virus closely related to viruses circulating in Europe. Antigenic and genetic characterisation gave no indication that the current OIE recommendations for EI vaccine composition require modification.

Bilateral Krukenberg tumor in a 16-week pregnant woman

The authors present the case of a G2P1001 who presented in 16-week gestation with bilateral Krukenberg tumor, abdominal pain, and iterative vomiting episodes. Although a few cases of Krukenberg tumor in pregnant women have been reported, no case reports asymptomatic and free of disease at 18 months were found in the English literature. Early detection followed by surgery and chemotherapy during pregnancy could possibly result in a favorable outcome in such patients.

Influence of Bacillus Calmette-Guèrin vaccination at birth and 2 months old age on the peripheral blood T-cell subpopulations [gamma/delta and alpha-beta T cell]

The neonatal immune system is immature and may be affected by Bacillus Calmette-Guèrin (BCG) vaccine. We investigated the influence of BCG given at two different ages on the peripheral blood (PB) T-cell subpopulations. Forty full term healthy newborns were randomly chosen. Twenty of them were vaccinated with BCG at birth (group I) and the remaining at the age of 2 months (group II). The cell analysis were carried out before (pre-BCGI and pre-BCGII), and 2 months after (post-BCGI and post-BCGII) the vaccination. The analysis of the gamma/delta and alpha/beta T-cell receptor (TCR) antigens was done by two-colour flowcytometer. The purified protein derivative (PPD) response was investigated 2 months after vaccination. The results showed that although T-cell (TCR+ cell) counts showed no difference in PB before and after vaccination in both study groups, the total lymphocyte and non-T cell (TCR- cell) populations increased significantly whereas alphabetaT-cell population significantly decreased after vaccination. On the contrary, gammadeltaT-cell counts in PB increased significantly 2 months after vaccination in group I but not in group II. Total lymphocyte and non-T cell counts in vaccinated infants at 2 months of age (post-BCGI) were significantly higher than in unvaccinated infants of the same age whereas alphabetaT-cell count in vaccinated infants was significantly low. However, total T-cell and gammadeltaT-cell counts showed no difference. PPD positivity was similar in both study groups (61% in group I, 66% in group II). Neither alphabetaT- nor gammadeltaT-cell counts were different in PPD positive and PPD negative infants. Our study shows that BCG causes marked quantitative changes in the PB T-cell subpopulations in young infants.

Outcomes of acute arthroscopic repair and conservative treatment following first traumatic dislocation of the shoulder joint in young patients

INTRODUCTION

The aim of this study was to compare patients who had arthroscopic repair done following the first traumatic dislocation with patients who were treated conservatively, in terms of stability and function.

MATERIALS AND METHODS

Acute arthroscopic Bankart repair with absorbable tack was used in 30 shoulders after the first dislocation, while 32 patients who sustained traumatic anterior dislocation were treated conservatively at Gülhane Military Medical Academy, Department of Orthopaedics and Traumatology between March 1997 and April 2001. Preoperative and postoperative range of motion of the shoulder and Constant score of all patients were recorded.

RESULTS

In the conservative group, the average pretreatment Constant score was 46.8 (range, 30 to 70) and the average post-treatment Constant score was 71.4 (range, 30 to 95). In the surgical group, the average preoperative Constant score in cases with Bankart lesion was 44.7 (range, 30 to 60) and the average postoperative Constant score was 92.3 (range, 65 to 100), (P = 0.0001).

CONCLUSION

Our results support the use of acute arthroscopic repair of traumatic anterior shoulder dislocations with absorbable tacks. Arthroscopic repair is the treatment of choice in young and active patients who are having their first traumatic dislocation.

Placental and decidual lipid peroxidation and antioxidant defenses in preeclampsia. Lipid peroxidation in preeclampsia

We evaluated lipid peroxidation in serum, placenta and decidua basalis and antioxidant defenses in preeclampsia and normal pregnancy. The study group consisted of 70 women with preeclampsia and 72 healthy pregnant women. Lipid peroxides in serum, placenta and decidua basalis, and serum vitamin E and total carotene were measured by spectrophotometric methods. Unpaired Student's t-test, chi(2)-test and Pearson correlation test were used for the statistical analyses. Levels of lipid peroxides in serum, placenta and decidua basalis were markedly higher; and serum vitamin E, total carotene, bilirubin, albumin levels were markedly lower in preeclamptic pregnants compared with healthy pregnant women. Our findings demonstrated that both placenta and decidua basalis tissues may be a source of lipid peroxides in preeclamptic pregnancies. Prophylactic antioxidant therapy may abate the disease process. Further studies are needed to clarify the pathophysiology of preeclampsia and effectiveness of prophylactic antioxidant therapy in preeclampsia.

Are ferric compounds useful in treatment of iron deficiency anemia?

The effect of ferric compounds in therapy of iron deficiency anemia is doubtful; however, the absorption of iron is not affected negatively by food or drugs. In our Well Baby Clinic, ferric polymaltose (6 mg/kg/d) was given to 59 infants (Group 1) and ferrous sulphate (same doses) was given to 64 infants (Group 2) (74 +/- 9 d, 70 +/- 7 d, respectively). These infants had iron deficiency anemia, and their therapy was continuous. Ferric polymaltose was not as effective as ferrous sulphate, although it increased hemoglobin and serum iron. Mean corpuscular volume and serum ferritin were not significantly changed after therapy. For this reason, we prefer to use only ferrous salts in therapy.

Iron status in breast-fed full-term infants

The aim of this study was to evaluate the iron status of full-term babies breast-fed exclusively for four months and the importance of iron supplementation. One hundred sixteen term infants followed up since the newborn period by a well baby clinic were included in the study. Iron deficient and/or anemic infants were excluded from the study at four months. Some of the infants (51) were later given appropriate complementary food besides breast-feeding (Group A) and some (42) were given ferrous sulfate (1 mg/kg/d) (Group B). Blood count and serum iron and ferritin measurements were done at four and six months of age. At the 4th month, iron deficiency was found in 23 (19.8%) infants, 11 of which had iron deficiency anemia. At the 6th month, 23 (45%) infants in Group A were iron deficient and 11 (21.6%) of them had iron deficiency anemia. In Group B, three (7.1%) infants were iron deficient and one (2.4%) of them also had iron deficiency anemia (p < 0.0001). Significant iron deficiency and iron deficiency anemia have been found in four-month-old exclusively breast-fed full-term infants. It is observed that complementary food alone is insufficient; there is need for iron supplementation.

Below-knee amputations as a result of land-mine injuries: comparison of primary closure versus delayed primary closure

BACKGROUND

Antipersonnel land mines are designed to maim by mutilating the lower extremities, and these injuries are at higher risk for infection than injuries from other weapon systems.

METHODS

The results of 474 unilateral traumatic below-knee amputations as a result of land-mine injuries were reviewed. If the delay in evacuation between the injury and arrival to the battle field hospital was less than 6 hours, 392 amputation stumps (group I) were closed primarily after meticulous debridement. Open amputation was performed after debridement in the remaining 82 amputation stumps (group II), because there was a suspicion of ineffective debridement, although they were evacuated in less than 6 hours or delay was more than 6 hours.

RESULTS

Eleven patients in group I (2.8%) were reoperated because of wound sepsis of the stump. Wound sepsis was not encountered in group II. A total of 87.4% of stumps in group I and 81.2% of stumps in group II had healed without a problem. No gas gangrene or tetanus was encountered in any cases.

CONCLUSION

Our results reveal that primary closure may be done in traumatic below-knee amputations caused by land-mine injuries with an acceptable infection rate, if the evacuation time is less than 6 hours, and if there is meticulous debridement.

Bilateral lower limb amputations as a result of landmine injuries

Landmine explosions cause most of the war injuries in the battlefield. Amputations resulting from severe injuries reveal serious problems despite the improvements in surgery. Bilateral lower limb amputations have more impact than unilateral on social life. Some 29 cases with lower limb amputations due to landmine injuries were treated in the Department of Orthopaedics and Traumatology, Gülhane Military Medical Academy between January 1992 and December 1996. Amputation levels were as follows: 1 case had hip disarticulation and a trans-femoral amputation, 6 had bilateral trans-femoral amputations, 6 had trans-femoral and trans-tibial amputations, 12 had bilateral trans-tibial amputations, 1 had trans-femoral and Chopart amputations and the remaining 3 cases had trans-tibial and Chopart amputations. The initial treatment was done for all cases in the first 6-8 hours after injury at the field hospitals. Aggressive debridement, excision and primary closure were performed. None of the stumps required reamputations and/or revision. No case had gas gangrene or tetanus. Postoperative, pre-prosthetic training programme which ranged between 30-120 days with an average 48 days; and prosthesis fitting and adequate post-prosthetic training programme which ranged 32-126 (average 94) days was applied. All the cases were followed-up with a mean of 38.5 months (14-72 months). Nine (9) cases (31%) returned to their previous occupation, while 20 (69%) cases had to change their jobs.

Treatment of complex calcaneal fractures with bony defects from land mine blast injuries with a circular external fixator

Four calcanei, which were massively destroyed as a result of blasting injuries from land mines, and 18 severely comminuted calcaneal fractures with bony defects (in one patient, both feet), also from land mines, were treated using a circular external fixator for reconstruction by osteogenic distraction. Because of the severe destruction of tissue to be treated, definitive orthopaedic treatment was delayed for 3 to 28 months (average, 10.1 months) after injury. Time from first use of the circular external fixator to removal of the apparatus ranged from 110 to 175 days (average, 143.7 days). Mean follow-up was 18 months. Of the 22 calcaneal injuries, 4 had excellent results, 11 good, 5 fair, and 2 had poor results. Better results were achieved in cases with lesser defects in bone and where definitive orthopaedic treatment was delayed until problems in soft tissue could be treated.

Treatment of tibial bone defects with the Ilizarov circular external fixator in high-velocity gunshot wounds

One of the applications for circular external fixators is the treatment of large-bone defects which may be difficult to manage with conventional methods. Successful results have been reported with the use of circular external fixators, particularly in the treatment of infected tibial pseudoarthroses and those with bone loss. In this study, a total of 43 cases with tibial bone defects (18 infected) as a result of high-velocity gun-shot injuries were treated with circular external fixators between January 1, 1988 and December 31, 1995. The mean follow-up period was 50 months (range: 28-98 months) after the removal of the Ilizarov device. Satisfactory union was obtained in 40 cases without any major complication or additional surgical intervention, in spite of the large and in some cases infected defects. We conclude that this is a safe method for the treatment of infected or noninfected tibial bone defects.

Erectile dysfunction following treatments of benign prostatic hyperplasia: a prospective study

The effects of open prostatectomy, transurethral resection, transurethral vaporization, doxazosin and finasteride on sexual functions of men were investigated in a total of 305 patients with benign prostatic hyperplasia. The sexual functions of the patients were assessed with a questionnaire before treatment and 3 and 6 months after the treatment. A total of 212 (70%) patients were judged to be potent before the treatment. At 3 months, open prostatectomy and transurethral resection caused erectile dysfunction in 2 of 40 (5%) and 5 of 89 (6%) potent patients, respectively. At 6 months, one of the patients from the former and 2 of the patients from the latter groups who developed erectile dysfunction at 3 months stated improvement. Transurethral vaporization caused loss of erectile functions in 4 of 14 potent patients (29%) at the 3-month follow-up and, one of these patients recovered erectile functions at 6 months. Only one of the 33 patients (3%) using doxazosin stated that he lost his erectile functions both at 3 months and 6 months. At 3 months follow-up, finasteride caused loss of erectile functions in 8 of 36 potent patients (22%). Four of these patients underwent surgery (transurethral resection) after 3 months of finasteride use. At the 6-month follow-up, 4 more patients suffered from loss of erectile functions. We suggest that finasteride and transurethral vaporization have the greatest potential of impairing the sexual functions among the treatment options investigated in this study and that they must be carefully offered to the potent patients.

Malignant gonadal stromal tumor with bulky metastasis at diagnosis

A 63-year-old man underwent inguinal orchiectomy for painless enlargement of the left testis. The diagnosis of malignant gonadal stromal tumor was made on the basis of morphology and immunohistochemical studies. At computed tomography there was bulky retroperitoneal metastasis. The patient then underwent retroperitoneal lymphadenectomy and received 6 courses of platinum-based chemotherapy at the end of which complete response was documented. However, at 18 months' follow-up, computed tomography revealed recurrent retroperitoneal metastasis. The patient was put on chemotherapy regimen again. But he developed pulmonary metastasis and died 28 months after the initial diagnosis. The clinical course of this patient suggests that malignant gonadal stromal tumor, if metastatic at diagnosis, may have a poor prognosis against most aggressive treatment approaches.