Multi-scale hyperspectral imaging of cervical neoplasia.

PURPOSE: This preliminary study aimed at investigating the feasibility and effective of multi-scale hyperspectral imaging in detecting cervical neoplasia at both tissue and cellular levels. METHODS: In this paper, we describe a noninvasive diagnosis method with a hyperspectral imager for detection and location of cervical intraepithelial neoplasia (CIN) at multiple scales. At the macroscopic level, the hyperspectral imager was applied to capture the reflectance images of the entire cervix in vivo at a series of wavelengths. At the microscopic level, the hyperspectral imager was coupled with a microscope to collect the transmittance images of the pathological slide. The collected image data were calibrated. A wide-gap second derivative analysis was applied to differentiate CIN from other types of tissue. RESULTS: At both macroscopic and microscopic levels, hyperspectral imaging analysis results were consistent with those of histopathological analysis, indicating the technical feasibility of multi-scale hyperspectral imaging for cervical neoplasia detection with accuracy and efficacy. CONCLUSION: We propose a multi-scale hyperspectral imaging method for noninvasive detection of cervical neoplasia. Comparison of the imaging results with those of gold standard histologic measurements demonstrates that the hyperspectral diagnostic imaging system can distinguish CIN at both tissue and cellular levels.

Thermal conductivity at finite temperature and electronic structure of the ultra-wide band gap fluorinated 2D GaN.

Passivation makes 2D hexagonal structure more stable than the planar variant. Surface fluorinated monolayer of GaN have been found to have ultra-wide band gap and have promising applications in optoelectronic conversion devices. In this work, using theoretical method, we have explored the thermal conductivity as well as the electronic structure of F-GaN. It has a low thermal conductivity of 7.67 W (mK)-1due to the low group velocity and short phonon lifetime. The calculated direct band gap value is 4.63 eV, which could be modulated by strain and biaxial strain is found to more effective. Attractively, direct band gap can be maintained under tensile strain. Breakdown of symmetry by uniaxial strain lifts the band degeneracy of the VBM, which will lead to polarized light emission. The in-depth analysis shows that Ga-F as well as N-F bonds are strongly ionic, which is responsible for its low thermal conductivity and ultra-wide band gap.

Features of the Carrier Concentration Determination during Irradiation of Wide-Gap Semiconductors: The Case Study of Silicon Carbide.

In this paper, the features of radiation compensation of wide-gap semiconductors are discussed, considering the case study of silicon carbide. Two classical methods of concentration determination are compared and analyzed: capacitance-voltage (C-V) and current-voltage (I-V) characteristics. The dependence of the base resistance in high-voltage 4H-SiC Schottky diodes on the dose of irradiation by electrons and protons is experimentally traced in the range of eight orders of magnitude. It is demonstrated that the dependence of the carrier concentration on the irradiation dose can be determined unambiguously and reliably in a very wide range of compensation levels, based on the results of measuring the I-V characteristics. It is shown that the determination of the carrier removal rate using the I-V characteristics is more correct than using the C-V characteristics, especially in the case of high radiation doses.

Hole Concentration Reduction in CuI by Zn Substitution and its Mechanism: Toward Device Applications.

Copper iodide (CuI) is a promising p-type transparent semiconductor with excellent carrier mobility. However, the high hole concentration in conventionally fabricated CuI including the single crystal hinders its applicability to the channel layer of thin-film transistors. We found that Zn substitution into Cu+ sites can effectively reduce the hole concentration. Experimental and computational examinations showed that the dominant mechanism involved the formation of a defect pair, the Zn-substituted Cu site (ZnCu) and Cu vacancy (VCu), and the simultaneous suppression of VCu arising from the stabilization of Cu+ in the Zn-substituted CuI lattice, rather than hole compensation by the electrons generated from Zn2+ substitution into Cu+ sites. Our results show that the hole concentration of Zn-substituted CuI is tunable in the range of 1014-1018 cm-3, making it suitable for thin-film transistors and hole transport layers in OLEDs.

Wide-Gap Brazing of K417G Alloy Assisted by In Situ Precipitation of M3B2 Boride Particles.

In this study, K417G Ni-based superalloy with a 20-mm gap was successfully bonded at 1200 °C using powder metallurgy with a powder mixture. The results indicated that the microstructure and mechanical properties of the as-bonded alloy were highly dependent on the brazing time (15-45 min), mainly due to the precipitation and distribution characteristics of M3B2 boride particles. Specifically, alloy brazed for 30 min exhibited desirable mechanical properties, such as a high tensile ultimate strength of 971 MPa and an elongation at fracture of 6.5% at room temperature, exceeding the balance value (935 MPa) of the base metal. The excellent strength and plasticity were mainly due to coherent strengthening and dispersion strengthening of the in situ spherical and equiaxed M3B2 boride particles in the γ + γ' matrix. In addition, the disappearance of dendrites and the homogenization of the microstructure are other factors that cannot be excluded. This powder metallurgy technique, which can avoid the eutectic transformation of traditional brazing, provides a new effective method for wide-gap repair of alloy materials.

Quantum dot vertical-cavity surface-emitting lasers covering the 'green gap'.

Semiconductor vertical-cavity surface-emitting lasers (VCSELs) with wavelengths from 491.8 to 565.7 nm, covering most of the 'green gap', are demonstrated. For these lasers, the same quantum dot (QD) active region was used, whereas the wavelength was controlled by adjusting the cavity length, which is difficult for edge-emitting lasers. Compared with reports in the literature for green VCSELs, our lasers have set a few world records for the lowest threshold, longest wavelength and continuous-wave (CW) lasing at room temperature. The nanoscale QDs contribute dominantly to the low threshold. The emitting wavelength depends on the electron-photon interaction or the coupling between the active layer and the optical field, which is modulated by the cavity length. The green VCSELs exhibit a low-thermal resistance of 915 kW-1, which benefits the CW lasing. Such VCSELs are important for small-size, low power consumption full-color displays and projectors.

Endoscopic esophageal substitution for pure esophageal atresia and wide gap esophageal atresia: A report of five cases with minimum follow-up of twelve months.

AIM: The aim of the study is to report feasibility and safety of endoscopic esophageal substitution in infants with pure esophageal atresia and wide gap tracheoesophageal fistula with a minimum one year follow-up. MATERIALS AND METHODS: This prospective study was conducted from January 2012 for twenty four consecutive months at Apollo Hospital, New Delhi. All babies either followed up or referred for esophageal substitution without any history of mediastinitis or associated major congenital anomaly and weighing greater than 6kg were to be included in the study. The indication, intraoperative details, operative approach, conversion to open, esophageal substitute, postoperative ventilation, ICU and hospital stay, time to solid foods, morbidity and mortality were recorded. Informed consent was obtained from all the parents and ethical clearance was obtained for the study from the hospital ethical committee. Postoperatively babies were followed up monthly for first six months, 3 monthly for next six months and annually thereafter. RESULTS: Between January 2012 and December 2013, in the two year period six infants were admitted for laparoscopic gastric transposition. In five patients the procedure was completed by the laparoscopic approach and one required conversion to open surgery owing to dense adhesions. The age range at the time of surgery was from 8months to 12months with a mean age of 10months. Four patients had pure esophageal atresia (type A) and two had wide gap esophageal atresia with distal tracheoesophageal atresia (type C). Five had primary esophagostomy and gastrostomy as a newborn, the sixth had postoperative anastomotic leak and required subsequent diversion. The mean operating time was 194minutes (range 170-210minutes). The mean stay in ICU was 7days with a range of 4-12days. All patients were ventilated in the postoperative period for an average of 5days with a range of 4-7days. One patient had prolonged gastric ileus which delayed the oral feeds by 14days. The mean time to start the oral feeds was 8days with a range of 6-14days. The mean hospital stay was 19.6days (range 16-23days). Early complications were pneumonia and pleural effusion in one patient. One patient developed anastomotic stricture which was amenable to dilatation. One patient had leak from esophagogastric anastomosis which healed spontaneously. All children are now orally fed, swallow without difficulty, and parents report an excellent cosmetic outcome. The follow-up ranges from 12 to 36months. CONCLUSION: The initial results of endoscopic esophageal substitution are encouraging and easily comparable to the outcome of open surgery with all the attendant benefits of minimally invasive approach.

Towards colorless transparent organic transistors: potential of benzothieno[3,2-b]benzothiophene-based wide-gap semiconductors.

Colorless, highly transparent organic thin-film transistors (TOTFTs) with high performance are realized based on benzothieno[3,2-b]benzothiophene (BTBT) derivatives that simultaneously exhibit a wide energy gap and high transport properties. Multilayer transparent source/drain electrodes maintain the transparency, and ultrathin fluoropolymer dielectric layers enable stable, low-voltage operation of the proposed TOTFTs.

Two-Dimensional Hexagonal Beryllium Sulfide Crystal.

We report a new two-dimensional hexagonal beryllium sulfide (h-BeS) sheet with exceptional properties by extensive first-principles calculations. The h-BeS sheet presents an indirect energy gap of 4.26 eV and an outstanding thermodynamic stability up to 1000 K. Armchair-edged nanoribbons of h-BeS are wide-energy-gap semiconductors with a giant Stark effect, while the zigzag-edged ones are metals with spin glass state. Especially, the ferromagnetic zigzag nanoribbons exhibit a net magnetic moment of nearly 1.15 µB. These interesting electronic and magnetic properties suggest the promise of the h-BeS crystal for potential applications and should inspire experimental enthusiasm.

Treatment of Wide Gap Non-Unions in Lower Extremities

PURPOSE: To analyze the end results of the treatment for patients with wide gap non-unions of the long bones in the lower extremities. MATERIALS AND METHODS: A total of 62 cases of wide gap unions, with a mean age of 38 years, were included for analysis. Study cohort included six children under the age of seven years. The average size of established bone defect was 7 cm (4-23 cm). Bone defects under 7 cm were treated with plating and various bone grafts, and those over 7 cm were managed with vascularized fibular graft (VFG), distraction-osteogenesis, tibial strut, plating and etc. Two boys with a defect of the whole tibia but with an intact fibula were treated with tibialization of intact fibula and with rotation-plasty of the leg. Their end results were evaluated by the time of bony union in accordance with the treatment of defect size of the long bone as well as their age. RESULTS: Bony unions were obtained for an average period of at least 27 months. Fifty-one cases showed an average leg-length discrepancy of 2.8 cm, and 11 cases showed no leg-length discrepancy. The VFG, distraction-osteogenesis, and tibial cortical-strut graft and plating were the most effective methods for non-unions of wide, long bone defections (>7 cm). The prognosis was more favorable in children, muscular femur, and in cases with tibial defect but intact fí bula. CONCLUSION: Various bone union techniques should be considered carefully, considering the ages of patients and the size of bone defects. Due to severe physical and mental disabilities of patients during the long-treatment period, specialized orthopedic doctors for trauma and mental care were necessary.

Treatment of Wide Gap Non-Unions in Lower Extremities

PURPOSE: To analyze the end results of the treatment for patients with wide gap non-unions of the long bones in the lower extremities. MATERIALS AND METHODS: A total of 62 cases of wide gap unions, with a mean age of 38 years, were included for analysis. Study cohort included six children under the age of seven years. The average size of established bone defect was 7 cm (4-23 cm). Bone defects under 7 cm were treated with plating and various bone grafts, and those over 7 cm were managed with vascularized fibular graft (VFG), distraction-osteogenesis, tibial strut, plating and etc. Two boys with a defect of the whole tibia but with an intact fibula were treated with tibialization of intact fibula and with rotation-plasty of the leg. Their end results were evaluated by the time of bony union in accordance with the treatment of defect size of the long bone as well as their age. RESULTS: Bony unions were obtained for an average period of at least 27 months. Fifty-one cases showed an average leg-length discrepancy of 2.8 cm, and 11 cases showed no leg-length discrepancy. The VFG, distraction-osteogenesis, and tibial cortical-strut graft and plating were the most effective methods for non-unions of wide, long bone defections (>7 cm). The prognosis was more favorable in children, muscular femur, and in cases with tibial defect but intact fí bula. CONCLUSION: Various bone union techniques should be considered carefully, considering the ages of patients and the size of bone defects. Due to severe physical and mental disabilities of patients during the long-treatment period, specialized orthopedic doctors for trauma and mental care were necessary.