Hydrogen passivation of the n-GaN nanowire/p-Si heterointerface.

The influence of hydrogen plasma treatment on the electrical and optical properties of vertical GaN nanowire (NW)/Si heterostructures synthesized via plasma assisted molecular beam epitaxy is studied. The effect of the treatment is thoroughly studied via variation of the passivation duration. Photoluminescence investigation demonstrates that the passivation affects the doping of the GaN NWs. The samples were processed as photodiodes with a top transparent electrode to obtain detailed information about the n-GaN NWs/p-Si heterointerface under illumination. The electron beam induced current measurements demonstrated the absence of potential barriers between the active parts of the diode and the contacts, indicating ohmic behavior of the latter. I-V characteristics obtained in the dark and under illumination show that hydrogen can effectively passivate the recombination centers at the GaN NWs/Si heterointerface. The optimum passivation duration, providing improved electrical properties, is found to be 10 min within the studied passivation regimes. It is demonstrated that longer treatment causes degradation of the electrical properties. The discovered phenomenon is discussed in detail.

Effects of the surface preparation and buffer layer on the morphology, electronic and optical properties of the GaN nanowires on Si.

The role of Si (111) substrate surface preparation and buffer layer composition in the growth, electronic and optical properties of the GaN nanowires (NWs) synthesized via plasma-assisted molecular beam epitaxy is studied. A comparison study of GaN NWs growth on the bare Si (111) substrate, silicon nitride interlayer, predeposited AlN and GaO x buffer layers, monolayer thick Ga wetting layer and GaN seeding layer prepared by the droplet epitaxy is performed. It is demonstrated that the homogeneity and the morphology of the NW arrays drastically depend on the chosen buffer layer and surface preparation technique. An effect of the buffer and seeding layers on the nucleation and desorption is also discussed. The lowest NWs surface density of 14 µm-2 is obtained on AlN buffer layer and the highest density exceeding the latter value by more than an order of magnitude corresponds to the growth on the 0.3 ML thick Ga wetting layer. It is shown, that the highest NWs mean elongation rate is obtained with AlN buffer layer, while the lowest elongation rate corresponds to the bare Si (111) surface and it is twice as lower as the first case. It is found, that use of AlN buffer layer corresponds to the most homogeneous NWs array with the smallest length dispersion while the least homogeneous array corresponds to the bare Si substrate. Vertically aligned GaN NWs array on the wide bandgap GaO x semiconductor buffer layer grown by plasma-enhanced chemical vapor deposition demonstrates its potential for electronic applications. Photoluminescence (PL) study of the synthesized samples is characterized by an intense optical response related to the excitons bound to neutral donors. The highest PL intensity is obtained in the sample with AlN buffer layer.

Accessible and reliable neurometric testing in humans using a smartphone platform.

Tests of human brain circuit function typically require fixed equipment in lab environments. We have developed a smartphone-based platform for neurometric testing. This platform, which uses AI models like computer vision, is optimized for at-home use and produces reproducible, robust results on a battery of tests, including eyeblink conditioning, prepulse inhibition of acoustic startle response, and startle habituation. This approach provides a scalable, universal resource for quantitative assays of central nervous system function.

[The dynamics of contamination of Kozhanovskoe lake with 137Cs in the post-Chernobyl period].

The paper presents the dynamics and the current state of radioactive contamination with 137Cs of low--running Kozhanovskoe lake situated in Bryansk region. Semi-empiric assessment of the current radiation state based on the analysis of dynamics of contamination of Kozhanovskoe lake with 137Cs corresponds satisfactory to experimental data. Integral 137Cs inventories were estimated for the main components of the lake, including water, bottom sediments and aquatic vegetation for the period of 2005-2007.

Applications of islet musculocutaneous flap from the trapezius muscle for primary plastic operations of oral cavity defects.

13 patients after major resection of oral cavity malignancies had primary plastic operation performed using trapezius muscle musculocutaneous flaps to cover the defect. The flaps were mobilized on a vascular pedicle supplied by the superficial cervical artery and drained by the concomitant vein. Partial flap necrosis was seen in two patients--mainly due to thrombosis of the vein of the pedicle. The vein should have an inside diameter of at least 0.4 cm. In the remaining cases, satisfactory functional and aesthetic results were obtained. In the flap mobilization region there is, as a rule, no growth of hair, which is important as the skin layer of the flap provides the inner lining of the oral cavity.

[Possibilities of correcting adverse effects of anti-arrhythmia agents]. / Vozmozhnosti korrektsiii neblagopriiatnykh éffektov antiaritmicheskikh preparatov.

A hundred and twenty two patients with premature ventricular contractions and paroxysmal tachycardias were comprehensively studied prior to and following treatment regimen with ethacizin, befol, sodium succinate and their combinations. Besides its significant antiarrhythmic activity, ethacizin displayed a number of adverse cardiac effects, such as excessive negative inotropic and dromotropic ones. Befol and sodium succinate in combination with ethacizin can reduce or even eliminate these side effects in rest and during simulated mental stress and graded exercise. The antiarrhythmic effect of the combined therapy preserved or even became stronger. This therapy may be long performed for arrhythmias even in patients with circulatory insufficiency and cardiac conduction disturbances caused or redoubled by ethacizin.

[Reconstructive surgery and organ-sparing methods in the treatment of patients with laryngeal and oral cavity tumors]. / Rekonstruktivnye operatsii i organosokhraniaiushchie metody lecheniia u bol'nykh opukholiami gortani i polosti rta.

Some advances have been recently made to improve survival rates among patients with common advanced larynx and oropharyngeal cancer. In this connection, it is essential to improve the quality of such patients' life. A total 382 patients with Degrees III-IV laryngeal and oral cancers were followed up. New approaches to treating these patients by combining various radiation, chemoradiation and surgical treatments, as well wide application of various primary plastic surgeries have yielded good functional and cosmetic results in most patients.

[Differential diagnosis of B-cell lymphoma rich in T cells and peripheral T-cell lymphomas]. / O differentsial'noi diagnostike B-kletochnoi limfomy, bogatoi T-kletkami, i perifericheskikh T-kletochnykh limfom.

Clinicomorphological analysis of T-cell-rich B-cell lymphoma in a 50-year-old female and literature data revealed objective difficulties in morphological diagnosis using cytological and histological methods. Large number of epithelioid histiocytes and tumor cells polymorphism resembled Lennert's lymphoma (peripheral T-cell lymphoma). Immunohistochemical study confirmed B-cell origin of tumor cells and large number of reactive T-cells. It is suggested that it would be more correctly to use the term "Lennert-like areas" in such cases with subsequent immunohistochemical study.

[Surgical treatment of residual or recurrent cancer of the oral cavity organs after radiotherapy]. / Khirurgicheskoe lechenie ostatochnogo ili retsidivnogo raka organov polosti rta posle luchevoi terapii.

The experience of surgical treatment of residual tumor or recurrent carcinoma of the oral cavity at different stages after high-dose (more than 50 Gy) radiotherapy makes a case for wider application of surgery in cases that would be otherwise thought hopeless. Although the overall frequency of local postoperative complications is still high, the use of arterialized myocutaneous or adipose-cutaneous flaps during one-stage reconstructive surgery and effective postoperative management can provide a means to cut down the incidence of such grave complications as acute necrosis of tissues leading to hazardous bleeding and development of extensive defects of mandibular tissues and orostomas. More effort should be made to evolve procedures of surgical treatment to be given after high-dose radiotherapy.

[The need for using single-stage reconstructive operations following the removal of malignant head and neck tumors]. / O neobkhodimosti primeneniia odnomomentnykh vosstanovitel'nykh operatsii posle udaleniia zlokachestvennykh opukholei golovy i shei.

The paper discusses the results of treatment of 102 cases of locally-advanced malignant tumors of the head and neck. Myocutaneous flaps including m.m. platysma, sternocleidomastoideus, trapezius and pectoralis major were used to rectify primary postexcisional defects. Preoperative radiation treatment (30-100 Gy) was given to 92 patients. Primary reconstruction for defects of the head and neck failed to stimulate recurrence development or affect survival as compared to controls. Frequency of complications involved in the said method proved lower while stay at the hospital shorter as compared to other reconstructive procedures. The above method assured a shorter period of rehabilitation and thus saved funds.

[The clinico-diagnostic significance of qualitative cough indices in nonspecific lung diseases]. / Kliniko-diagnosticheskoe znachenie kachestvennykh pokazatelei kashlia pri nespetsificheskikh zabolevaniiakh legkikh.

It is proposed to make a qualitative analysis of one of the most frequent bronchopulmonary symptoms--cough. This involves dynamic tussographic evaluation of the cough and expectoration in the original inulin test. The analysis covered such cough characteristics as resistance, efficacy, intensity, volleys assessed in patients with lung cancer, chronic bronchitis, tracheobronchial dyskinesia. Typical changes in the above indices observed in each of the patient groups have been defined which are essential for diagnosis and differential diagnosis.

[Results of organ-preserving and reconstructive surgery of the mandible in patients with cancer of the oral cavity]. / Rezul'taty organosokhraniaiushchikh i rekonstruktivnykh operatsii na nizhnei cheliusti u bol'nykh rakom polosti rta.

Surgery is the basic procedure of combined therapy for locally-advanced carcinoma of the oral mucosa. It is intended to excise involved mucosa and soft tissues of the oral cavity and to resect the mandible. Rim resection (55) produces good functional and cosmetic results and was followed by 5-year survival in 76.4%. Due to median mandibulotomy (24), optimal access was provided to tumor involving the whole tongue and sitting at the back of the oral cavity (5-year survival--58.3%). Postoperative complication incidence was significantly lowered when titanium miniplates were used for mandibular arch reconstruction. When these miniplates and osteomyocutaneous flaps were used for mandibular reconstruction, following segmental resection, good cosmetic and functional results were recorded in 5 out of 8 cases (5-year survival--75%).

[The use of clindamycin and netilmicin for preventing postoperative wound infection in patients with cancer of the upper respiratory and digestive tracts]. / Primenenie klindamitsina i netilmitsina dlia profilaktiki posleoperatsionnoi ranevoi infektsii u bol'nykh rakom verkhnikh dykhatel'nykh i pishchevaritel'nykh putei.

Clindamycin (2.7 g/day) and netilmicin (5.6 mg/kg) were used for 6-10 days in 27 patients with laryngeal and oral cancer versus beta-lactam antibiotics and aminoglycosides received by 56 matched patients to prevent infection of the operative wound. Suppuration was observed in 11.1 and 41.4% of the patients, respectively (p < 0.05), the temperature rose over 38 degrees C in 22.2% and 42.9% of the patients, respectively (p < 0.05). The regimens showed similar toxicity. The findings proved high efficacy of clindamycin combination with netilmicin in infection prophylaxis in patients operated on for upper respiratory and digestive tract cancer.

[Choice of the optimal variant of plastic surgery in head and neck tumors]. / Vybor optimal'nogo varianta plastiki pri opukholiakh golovy i shei.

Indications for planning primary and delayed operations for head and neck tumors have been evolved on the basis of our 15-year experience with 667 reconstructive surgeries (550 patients) 425 of which (77%) were conducted in one stage.

[Tussograph, a device for monitoring tussive impulses]. / Tussograf--ustroistvo dlia monitorirovaniia kashlevykh tolchkov.

The paper describes the basic circuit of a tussograph, a device that monitors cough in patients with bronchopulmonary diseases. An NKT-I makes it possible to calculate the number of tussive expulsions, total and peak expulsions, as well as to record their time distribution. The device may be useful in the study into the efficacy of new antitussive drugs and the assessment of cough clearance. It can provide an insight into mucociliary clearance.

[Primary plastic repair in the surgical treatment of cancer of the anterior portions of the mouth]. / Pervichnaia plastika pri khirurgicheskom lechenii raka perednykh otdelov polosti rta.

An experience with using the method of primary plasty of 54 patients with carcinoma of frontal portions of the oral cavity with muscular-cutaneous flaps is described. Preoperative irradiation (from 30 to 80 Gr) was given to 51 patients. Radical operations on the neck were performed on all the patients (in 15 patients the operations were bilateral). Necroses of the flaps were noted in 27.8% of the patients, mainly after doses of X-ray therapy of 50-80 Gr, suppuration of the wound in 64.8%. Good cosmetic and functional results were obtained in 44 patients (81.3%). The average time of staying at the hospital was 33.7 days.

[Correction of soft tissue defects of the head and neck with a cutaneo-muscular flap from the greater pectoral muscle]. / Zameshchenie defektov miagkikh tkanei golovy i shei kozhno-myshechnym loskutom s bol'shoi grudnoi myshtsei.

Plasty of defects of head and neck by a flap with musculus pectoralis major is described. In 20 patients the substitution of the defects was fulfilled simultaneously with the main operation. In 12 patients it was performed within 2-12 months. The method described gives a valuable substitution of lack of the soft tissues resulting from oncological operations, gives good cosmetic results and shortens the period of staying at the hospital.