Добірка наукової літератури з теми "Sharp skin effect"

The shape of the needle tip that is currently used in the medical field is a “lancet point,” which is a diagonally cut cylindrical pipe, further cut on both sides. The shape of the needle shank is typically cylindrical. In this paper, tip and shank shapes that differ from the standard shape are experimentally investigated for the purpose of reducing puncture resistance. Microneedles of various cross-sectional shapes, such as polygonal and star-like, were fabricated using stereo laser lithography. Before the needle penetrates the skin, sharp edges at the needle tip may be effective to generate a stress concentration on the skin, inducing a skin fracture. After the needle penetrates the skin, corners in the cross section of the needle shank may effectively reduce the frictional resistance because the contact area between the skin and needle is limited at the corners. A needle insertion experiment was conducted against an artificial skin made of polydimethylsiloxane. The puncture resistance decreased respectively for the circular needle, polygonal needle, and star-shaped needle. For the star-shaped needles, the maximum resistance decreased as the number of corners (N) decreased. For the polygonal needle, the maximum resistance increased as N increased from 3 to 5; however, there was no observable difference for N from 6 to 8. The experimental results show that a triangular star-shaped microneedle is the most effective in reducing the puncture resistance.

In the present study, a preparation of frog skin was presented, which can be used to demonstrate the basic concepts of blood flow regulation in a very clear and attractive way to high school and university students. In a freshly euthanized Xenopus, a patch of abdominal skin was exposed from the internal side and viewed with a USB microscope while it remained connected to a functioning circulatory system. In this way, it was possible to obtain sharp images of arteries and veins and to visualize blood flow. This allows students to learn about the functional differences between arteries and veins and about the complexity of hemodynamics as well as the particularities of the amphibian pulmocutaneous circulation. Students can then quantitatively estimate the effect of norepinephrine and epinephrine on the diameter of blood vessels by simply superfusing the skin patch with a series of solutions of the two substances. They can also test the effect of α-adrenergic receptor blockers, used to treat high blood pressure, on the norepinephrine-induced muscle tonus of blood vessels.

Abstract We investigate novel features of three-dimensional non-Hermitian Weyl semimetals, paying special attention to the unconventional bulk–boundary correspondence. We use the non-Bloch Chern numbers as the tool to obtain the topological phase diagram, which is also confirmed by the energy spectra from our numerical results. It is shown that, in sharp contrast to Hermitian systems, the conventional (Bloch) bulk–boundary correspondence breaks down in non-Hermitian topological semimetals, which is caused by the non-Hermitian skin effect. We establish the non-Bloch bulk–boundary correspondence for non-Hermitian Weyl semimetals: the topological edge modes are determined by the non-Bloch Chern number of the bulk bands. Moreover, these topological edge modes can manifest as the unidirectional edge motion, and their signatures are consistent with the non-Bloch bulk–boundary correspondence. Our work establishes the non-Bloch bulk–boundary correspondence for non-Hermitian topological semimetals.

Collagen from a marine resource is believed to have more potential activity in bone tissue engineering and their bioactivity depends on biochemical and structural properties. Considering the above concept, pepsin soluble collagen (PSC) and acid soluble collagen (ASC) from blue shark (Prionace glauca) skin were extracted and its biochemical and osteogenic properties were investigated. The hydroxyproline content was higher in PSC than ASC and the purified collagens contained three distinct bands α1, α2, and β dimer. The purity of collagen was confirmed by the RP-HPLC profile and the thermogravimetric data showed a two-step thermal degradation pattern. ASC had a sharp decline in viscosity at 20–30 °C. Scanning electron microscope (SEM) images revealed the fibrillar network structure of collagens. Proliferation rates of the differentiated mouse bone marrow-mesenchymal stem (dMBMS) and differentiated osteoblastic (dMC3T3E1) cells were increased in collagen treated groups rather than the controls and the effect was dose-dependent, which was further supported by higher osteogenic protein and mRNA expression in collagen treated bone cells. Among two collagens, PSC had significantly increased dMBMS cell proliferation and this was materialized through increasing RUNX2 and collagen-I expression in bone cells. Accordingly, the collagens from blue shark skin with excellent biochemical and osteogenic properties could be a suitable biomaterial for therapeutic application.

Spatial square waves with positive cycle are used as steady forcing technique to study drag reduction effects on a turbulent boundary layer flow. Pseudospectral method is used for performing direct numerical simulations on very high resolution grids. A smooth step function is employed to prevent Gibbs phenomenon at the sharp discontinuities of a square wave. The idea behind keeping only the positive cycle of the spatial forcing is to reduce the power consumption to boost net power savings. For some spatial frequency of the oscillations with half waves, it is possible to prevent recovery of skin friction back to the reference case values. A set of wall oscillation parameters is numerically simulated to study its effect on the power budget.

With the application of “ λ” type composite skin becoming more and more extensive and diversified, its precise forming technology is also widely concerned. This article mainly solves the quality problems of “ λ” type corner area, such as delamination dispersion and surface wrinkle, which exist in reality commonly in the manufacturing process. The prepreg is heated along the corner area of the tooling to solve the problem that prepreg is difficult to be compacted due to the large modulus of carbon fiber in “ λ” type corner area. Furthermore, two precompaction tests are creatively increased at 16 layers (middle layer) and 32 layers (last layer) for the thick structure, respectively, to ensure the compaction effect of the blank. In addition, combined with the characteristics of highly elastic rubber and carbon fiber-reinforced materials, a new type of soft mold structure with proper flexibility and good stiffness is proposed innovatively through the reasonable placement of carbon fiber-reinforced materials and the setting of exhaust holes according to the structure characteristics of “ λ” type root skin. Through further process verification, it is shown that the improved process has effectively solved the problems of wrinkles and internal delamination at the sharp corners of parts and realized zero-defect manufacturing of “ λ” type root skin for the first time.

Background:Several biologic DMARDs (bDMARDs) exist for PsA, TNFi and UST being the earliest on European markets. When bDMARDs are insufficiently effective, later-line bDMARDs typically have shorter persistence. Treatment persistence reflects a mix of effectiveness and adverse events (AEs), and persistence data are limited in PsA.Objectives:Comparative analysis of 1-year persistence of UST and TNFi within the prospective PsABio cohort.Methods:PsABio is an observational, multinational study of PsA patients (pts) treated with 1st to 3rd line UST or TNFi at their rheumatologist’s discretion.1Treatment persistence (up to 15 months of follow-up) was defined as time between start of first bDMARD treatment in PsABio, and either stop or switch to another bDMARD, or withdrawal.Persistence of UST and TNFi is shown by Kaplan-Meier curves and compared using Cox regression analysis, with propensity score (PS) to adjust for baseline imbalanced demographic and disease-related covariates (age, sex, bDMARD line, BMI, Clinical Disease Activity index for PSoriatic Arthritis [cDAPSA], 12-item PsA Impact of Disease [PsAID-12], Fibromyalgia Rapid Screening Tool [FiRST] score, co-treatments with MTX, NSAIDs, glucocorticoids, cardiovascular/metabolic comorbidities, dactylitis, enthesitis and body surface area [BSA]). Factors including concomitant MTX use and skin involvement: <3%, 3–10% and >10%, were added to the Cox model to investigate their impact on the PS-adjusted treatment effect.Results:Of 438 and 455 pts who started UST and TNF, respectively, 121 (28%) and 134 (29%) stopped or switched treatment before Month 15, with differences (as expected) according to treatment line (Fig. 1a, b). Reasons for stop/switch were related to safety/AEs in 12% (UST) and 28% (TNFi), and effectiveness (joints, nails or skin) in 77% (UST) and 69% (TNFi) of pts.The observed mean time on drug was 397 days for UST and 385 days for TNFi pts (1st line 410/397 days, 2nd 390/382 days, 3rd 381/338 days). Fig. 1b shows similar persistence for all drugs and treatment lines, except for lower persistence in TNFi 3rd line vs 1st/2nd. In PS-adjusted Cox analysis, no statistically significant difference between UST and TNFi persistence was seen; hazard ratio (HR; 95% CI) for stop/switch bDMARD (UST vs TNFi) was 0.82 (0.60, 1.13). In the model, bDMARD monotherapy (without MTX) and extensive skin involvement (BSA >10%), showed significantly better persistence for UST (HR 0.61 [0.42, 0.90] and 0.41 [0.19, 0.89] respectively; unadjusted Kaplan-Meier graphs shown in Fig. 1c, d). MTX co-therapy and low BSA did not affect the PS-adjusted treatment effect. Other factors added to the PS-adjusted Cox model did not show significant effects.Conclusion:In this real-world PsA cohort undergoing bDMARD treatment, persistence was generally comparable for UST and TNFi, but some clinical situations led to better drug persistence with UST compared to TNFi – particularly monotherapy, more extensive skin involvement, and in 3rd-line treatment. Our data emphasise the importance of skin involvement for pts with PsA.References:[1]Gossec L, et al.Ann Rheum Dis. 2018;77(suppl 2):Abstract AB0928Acknowledgments:This study was funded by Janssen.Disclosure of Interests:Laure Gossec Grant/research support from: Lilly, Mylan, Pfizer, Sandoz, Consultant of: AbbVie, Amgen, Biogen, Celgene, Janssen, Lilly, Novartis, Pfizer, Sandoz, Sanofi-Aventis, UCB, Stefan Siebert Grant/research support from: BMS, Boehringer Ingelheim, Celgene, GlaxoSmithKline, Janssen, Novartis, Pfizer, UCB, Consultant of: AbbVie, Boehringer Ingelheim, Janssen, Novartis, Pfizer, UCB, Speakers bureau: AbbVie, Celgene, Janssen, Novartis, Paul Bergmans Shareholder of: Johnson & Johnson, Employee of: Janssen, Kurt de Vlam Consultant of: Celgene Corporation, Eli Lilly, Novartis, Pfizer, UCB – consultant, Speakers bureau: Celgene Corporation, Eli Lilly, Novartis, Pfizer, UCB – speakers bureau and honoraria, Elisa Gremese Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Sanofi, UCB, Roche, Pfizer, Speakers bureau: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Sanofi, UCB, Roche, Pfizer, Beatriz Joven-Ibáñez Speakers bureau: Abbvie, Celgene, Janssen, Merck Sharp & Dohme, Novartis, Pfizer, Tatiana Korotaeva Grant/research support from: Pfizer, Consultant of: Abbvie, BIOCAD, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Novartis-Sandoz, Pfizer, UCB, Speakers bureau: Abbvie, BIOCAD, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Novartis-Sandoz, Pfizer, UCB, Wim Noel Employee of: Janssen Pharmaceuticals NV, Michael T Nurmohamed Grant/research support from: Abbvie, Bristol-Myers Squibb, Celltrion, GlaxoSmithKline, Jansen, Eli Lilly, Menarini, Merck Sharp & Dohme, Mundipharma, Pfizer, Roche, Sanofi, USB, Consultant of: Abbvie, Bristol-Myers Squibb, Celltrion, GlaxoSmithKline, Jansen, Eli Lilly, Menarini, Merck Sharp & Dohme, Mundipharma, Pfizer, Roche, Sanofi, USB, Speakers bureau: Abbvie, Bristol-Myers Squibb, Celltrion, GlaxoSmithKline, Jansen, Eli Lilly, Menarini, Merck Sharp & Dohme, Mundipharma, Pfizer, Roche, Sanofi, USB, Petros Sfikakis Grant/research support from: Grant/research support from Abvie, Novartis, MSD, Actelion, Amgen, Pfizer, Janssen Pharmaceutical, UCB, Elke Theander Employee of: Janssen-Cilag Sweden AB, Josef S. Smolen Grant/research support from: AbbVie, AstraZeneca, Celgene, Celltrion, Chugai, Eli Lilly, Gilead, ILTOO, Janssen, Novartis-Sandoz, Pfizer Inc, Samsung, Sanofi, Consultant of: AbbVie, AstraZeneca, Celgene, Celltrion, Chugai, Eli Lilly, Gilead, ILTOO, Janssen, Novartis-Sandoz, Pfizer Inc, Samsung, Sanofi

Appropriate control interventions are necessary to show the treatment effect of dry needling. Different control procedures, such as dry needling of the contralateral side, and sham treatments, such as random and superficial needle insertion, have been utilized in trials. However, those methods might elicit a physiological response and are subsequently not ideal for use as a control. This descriptive study illustrates the construction of low-cost sham dry needles and evaluates their validity. Forty-two healthy asymptomatic subjects received either sham or real dry needling intervention to their right gluteal muscles and reported if they felt that the needle pierced the skin. They also graded the severity and qualified (sharp or dull) the pain associated with the intervention. The results showed that most of the subjects in both groups believed the needle penetrated the skin. The quantity of pain associated with the treatment was similar in both groups, but the quality assigned was different. The authors conclude that sham dry needling can be accomplished and used as a valid control treatment in dry needling research using these low-cost sham needles.

BACKGROUND: Hydroxyurea (HU) is an antimetabolite agent that interferes with the S-phase of cellular replication and inhibits DNA synthesis, with little or no effect on RNA or protein synthesis. It is used in the treatment of many myeloproliferative disorders (MD) and is particularly a first line treatment drug for intermediate to high-risk essential thrombocythemia. Although safe and very well tolerated by the patients suffering from MD, there have been numerous reports of a broad palette of cutaneous side effects associated with prolonged intake of the medication. These may include classical symptoms such as xerosis, diffuse hyperpigmentation, brown-nail discolouration, stomatitis and scaling of the face, hands, and feet or more serious side effects such as actinic keratosis lesions, leg ulcers and multiple skin carcinomas.CASE REPORT: We report a case of a 52-year-old man, on long-term therapy with HU for essential thrombocytosis, with several concurrent skin lesions. Despite the perennial use of HU, the cutaneous changes were neglected. The local dermatological examination revealed oval perimalleolar ulcer on the right leg, with dimensions 6 x 4 cm, clearly demarcated from the surroundings with regular margins, periulcerous erythema, with very deep and highly fibrinous bed of the ulcer, positive for bacterial infection. The ulcer was treated with topical wound therapy with alginate and parenteral antibiotics. The extended dermatological screening also showed two nummular lesions in the right brachial region, presenting as erythematous papules with sharp margins from the surrounding skin, gritty desquamation and dotted hyperpigmentations inside the lesion. Further dermoscopy and biopsy investigations confirmed a diagnosis of basal cell carcinoma. Nasal actinic keratosis was also noted. The patient was advised for discontinuing or substituting the HU therapy.CONCLUSION: We present this case to draw attention to the various cutaneous side effects that occur with perennial HU use and suggest an obligatory reference to a dermatological consult.

Дисертація на здобуття наукового ступеня доктора філософії за спеціальністю 141 – Електроенергетика, електротехніка та електромеханіка (14 – Електрична інженерія). – Національний технічний університет "Харківський політехнічний інститут" Міністерства освіти і науки України, Харків, 2020. Об’єктом дослідження є імпульсне магнітне поле, що утворюється масивними одновитковими соленоїдами при магнітно-імпульсній обробці металевих заготовок. Предметом дослідження є профілі масивних одновиткових соленоїдів, що забезпечують заданий розподіл імпульсного магнітного поля на поверхні оброблюваної металевої заготовки. В дисертаційній роботі вирішена науково-практична задача визначення профілів масивних одновиткових соленоїдів за допомогою аналітичних розв’язків задач аналізу імпульсного магнітного поля, що утворюється джерелами елементарної форми. Дослідження виконано за допомогою фундаментальних положень теоретичної електротехніки, математичної фізики, чисельних методів аналізу та сучасних інформаційних технологій. У вступі обґрунтовано актуальність теми дисертації, визначені задачі дослідження, показано зв’язок роботи з науковими програмами, планами, темами, наведено дані про наукову новизну, практичне значення, апробацію результатів та публікації. У першому розділі проведено огляд конструкцій полеутворюючих систем для магнітно-імпульсної обробки металів та аналіз відомих методів визначення їх форми. Детально розглядаються два підходи до вирішення цієї задачі. Перший базується на ітеративному або аналітичному підборі параметрів полеутворюючої системи, другий – на вирішенні задачі продовження поля з граничної поверхні. Обґрунтовано необхідність розвитку методів, заснованих на використанні аналітичних розв’язків задач аналізу для джерел елементарної форми, обрано напрями досліджень, поставлені основні задачі дисертаційної роботи. У другому розділі запропоновано метод визначення форми масивних одновиткових соленоїдів для створення заданого розподілу азимутальної складової індукції магнітного поля на поверхні циліндричної та плоскої заготовки, що засновується на використанні систем елементарних джерел зі струмами, котрі розташовані поблизу цих поверхонь. При цьому середовище поза провідниками вважається непровідним і немагнітним, а заготовка замінюється ідеальним надпровідником: нескінченно довгим циліндром або півпростором. Розглядаються три випадки. У першому елементарні джерела – це кільця зі струмами нескінченно малого перетину, що розташовуються співвісно внутрішньому циліндру, у другому – такі ж співвісні кільця, але розташовані паралельно плоскій границі нижнього півпростору, у третьому – осі зі струмами, розташовані паралельно нижньому півпростору. Наведено формули для розрахунку індукції магнітного поля та магнітного потоку, що створюються такими джерелами. Варіацією геометричними параметрами елементарних джерел та струмами, що в них протікають досягнуто відповідності утвореного поверхневого розподілу індукції та заданого. Для підбору оптимальних параметрів системи застосовано метод градієнтного спуску. Для визначення шуканого контуру профілю масивного соленоїда побудовано силові лінії магнітного поля систем елементарних джерел, що забезпечують найменшу похибку відтворення заданого розподілу. Правильність визначення точного контуру профіля соленоїда підтверджується за допомогою методу інтегральних рівнянь. У третьому розділі запропоновано апроксимацію точного контуру профілю масивного одновиткового соленоїда багатокутником, що дозволило значно спростити його проєктування і виготовлення. Досліджено розподіли індукції магнітного поля та їх розбіжності із заданим для соленоїдів точного та апроксимованих профілів. Розраховано та порівняно індуктивність системи соленоїд – циліндр. Детально розглянуто розподіли поверхневої густини струму на крайках апроксимованих соленоїдів і визначено вплив радіуса скруглення та величини кута, що скруглюється, на її максимальні значення. Розрахунки третього розділу виконано за допомогою чисельного розв’язання інтегрального рівняння відносно поверхневої густини струму. У четвертому розділі експериментально досліджено розподіли індукції плоскомеридіанного магнітного поля, що створюється масивним одновитковим соленоїдом поблизу циліндричної поверхні заготовки. Для цього із латуні було виготовлено соленоїд, контур профілю котрого отримали за допомогою методу, який запропоновано в дисертації. Точний контур профіля масивного соленоїда, котрий отримали за допомогою системи дев’яти елементарних кільцевих джерел, було апроксимовано шестикутником. Соленоїд розміщувався на спеціальному стенді співвісно з мідною оболонкою, яка імітувала заготовку. У проміжку між соленоїдом та оболонкою розташовувався індукційний перетворювач, за допомогою якого вимірювали відносну індукцію в контрольних точках поблизу поверхні оболонки. Через соленоїд пропускали імпульси струму від низьковольтного генератора, котрі мали форму експоненційно згасаючою синусоїди. Частота імпульсів змінювалась в діапазоні (40÷225) кГц зміною ємності батареї конденсаторів в генераторі. Наведено відносні розбіжності між виміряними та заданими розподілами, які при всіх варіантах імпульсу не перевищують 6 відсотків по всій довжині оброблюваної поверхні. Результати досліджень дозволили отримати низку наукових результатів: - уперше для визначення форми одновиткового масивного соленоїда, що забезпечує заданий розподіл імпульсного магнітного поля на циліндричній поверхні металевої заготовки при магнітно-імпульсній обробці, застосовано функцію Гріна; - уперше запропоновано апроксимацію складного криволінійного контуру профілю масивного соленоїда контуром багатокутника, що дозволило суттєво спростити його проєктування та виготовлення; - отримало подальший розвиток застосування функцій Гріна для визначення профілів масивних соленоїдів, що забезпечують заданий розподіл плоскомеридіанного та плоскопаралельного магнітного поля на плоскій поверхні металевої заготовки; - достовірність теоретичних результатів, отриманих у дисертації, підтверджено вимірюваннями відносних розподілів індукції магнітного поля, що створюється масивним соленоїдом, поблизу поверхні циліндричної заготовки на стенді для фізичного моделювання; - Результати досліджень використано в НТУ "ХПІ" при виконанні науково-дослідних робіт на кафедрі інженерної електрофізики.
The thesis is submitted to obtain a scientific degree of Doctor of Philosophy, specialty 141 – Electricity, electronics and electrical engineering (14 – Electrical engineering). – National Technical University “Kharkiv Polytechnic Institute” of the Ministry of Education and Science of Ukraine, Kharkiv, 2020. The object of research is the pulsed electromagnetic field, which is created using massive single-turn solenoid in the process of electromagnetic forming of metal workpieces. The subject of research are profiles of massive single-turn solenoids which generate a given distribution of magnetic field at the surface of a metal workpiece. The scientific and practical task of determining the massive single-turn solenoid profiles is solved using analytical solutions of analysis problems for pulsed magnetic field which is created by elementary sources. The problems of scientific research were solved using fundamental concepts of theoretical electrical engineering, mathematical physics, numerical methods of analysis and modern informational technologies. The introduction substantiates the relevance of research tasks showing connection between the work and scientific programs, plans, themes. The information on the scientific novelty and practical value the obtained results are stated. The first chapter provides an overview of known systems for generating electromagnetic pulsed field and methods which are used to determine its shape. Two different approaches are emphasized. The former is based on iterative or analytical adjustment of field-generating system parameters. The latter is the use of the solution of the problem of field continuation from boundary surface. The further development of the methods which are based on analytical solutions of analysis problems for elementary field sources is justified, the direction of research is chosen and objectives are formulated. The second chapter presents the method aimed to determine the shape of massive single-turn solenoids which generates a given distribution of tangent component of magnetic induction at the surfaces of cylindrical or sheet metal workpieces in the process of electromagnetic forming. The method is based on using the solutions of analysis problems for systems which consist of current carrying conductors of elementary shape that are placed near the boundary surfaces, whereas environment outside the conductors is supposed to be nonconducting and nonmagnetic. The ideal skin-effect approximation is used, according to which we suppose that currents flow within the infinitely thin surface layers. With accordance to the approximation the cylindrical workpiece is replaced by ideal superconductive cylinder of infinite length, the flat workpiece is replaced by superconductive half-space. There are three cases described. In the first case elementary sources is represented by annular current carrying conductors which are places axially with the inner cylinder. The cross section of the annular conductors is infinitely small. In the second case there are the same annular axisymmetric conductors but placed above the flat boundary of superconducting half-space and are parallel to it. In the third case elementary sources are straight current carrying axes which are parallel to each other and to the lower superconducting half-space. The formulas for magnetic induction and magnetic flux for that systems are stated. Compliance with given boundary distribution of magnetic induction is achieved by varying of system parameters using gradient descent optimization method. Field lines for the system of elementary sources, that provides the smallest differences between given and obtained induction distributions, were built and used to determine the exact profile of massive single-turn solenoid that generate given magnetic induction distribution. The correctness of exact profile was verified using the method of integral equations. In the third chapter approximation of exact massive single-turn solenoid profile, which significantly simplify its design and manufacturing, is proposed. Magnetic induction distributions, which are generated by the solenoids, are calculated and errors due to the approximation are investigated. Inductance of the solenoid-cylinder system is compared for different accuracy of approximation and different outer radius of the solenoid. Surface current density distributions at the solenoid contour are shown. An influence of radius of rounding of sharp edges is considered and relation between the angle of rounded edge corner and maximum surface current density is described. Calculations of the third chapter were performed using a numerical solution of the integral equation with respect to surface current density. In the fourth chapter an experimental research on relative induction distributions of axisymmetric magnetic field that is created using brass massive single-turn solenoid at the surface of cylindrical workpiece is stated, whereas the shape of the solenoid was determined according to the method which is described in the thesis. The exact profile contour was chosen by one of the field lines which cover the system of nine annular conductors. With accordance to the approximation method the exact profile contour was replaced by six-sided polygon. The solenoid is placed at the special installation axially with a cylindrical copper shell. Induction sensor is placed into the gap between the solenoid and the shell to measure relative induction at reference points near the shell boundary. The solenoid is connected to low voltage pulse generator which creates the pulses of exponentially damped sine wave. The frequency of the pulses is changed in the range of (40÷225) kHz varying the capacitance of the generator battery. Relative differences between measured and given induction distributions are shown and do not exceed 6 percent at all reference points within working area for every variant of pulse frequency. The research results have allowed obtaining a number of scientific results: - for the first time, an approach which is based on the use of Green’s function to determine a shape of massive single-turn solenoid for generating a given magnetic induction distribution at cylindrical workpiece surface is proposed for electromagnetic forming; - for the first time, approximation of curvilinear contour of massive single-turn solenoid profile by a polygon, which allow to significantly simplify its design and manufacturing, is researched; - the use of Green’s functions is developed for determining of massive singleturn solenoids which generates given distribution of axisymmetric or plane-parallel magnetic field at the flat surface of sheet metal workpiece; - theoretical results obtained in the dissertation are confirmed by measurements of relative distributions of magnetic induction which is created by massive single-turn solenoid at the cylindrical boundary of metal workpiece using the installation for physical modeling; - the results of the research were used for research work at Engineering electrophysics department of National Technical University “Kharkiv Polytechnic Institute”.

Boards can delegate some of the task of monitoring management to financial analysts, who reduce the asymmetry of information between a firm’s insiders and outside investors, which makes the various tools for reducing manager-shareholder conflict more effective. This chapter uses events at SPX, a mid-western manufacturing firm undergoing explosive growth, to explain the role that financial analysts play in monitoring management. It shows how career concerns can give financial analysts—who typically have little direct exposure to a firm’s share price—a strong incentive to monitor management. It also shows how analysts’ effectiveness as delegated monitors is limited by their own conflicts of interest and how the market’s response to analysts’ recommendations can have unwelcome effects on managers’ behavior.

Affirmative action is a term used in the USA to depict a set of laws, policies, guidelines, and government-mandated and government-sanctioned administrative practices, including those of private institutions, intended to end and correct the effects of a specific form of discrimination. It seeks to end the effects of discriminatory practices that violate the inherent equality of persons who, because they share certain attributes such as sex or skin colour, have been denied opportunities on the grounds that they are inferior or different. Affirmative action aims to reduce present discrimination against members of targeted groups such as African, Native or Hispanic Americans, women, and the handicapped, and to increase their numbers within certain occupations and professions and at universities and colleges.

Hantaviruses (genus Hantavirus, family Bunyaviridae) are rodent- and insectivore-borne zoonotic viruses. Several hantaviruses are human pathogens, some with 10-35% mortality, and cause two diseases: hemorrhagic fever with renal syndrome (HFRS) in Eurasia, and hantavirus cardiopulmonary syndrome (HCPS) in the Americas. Hantaviruses are enveloped and have a three-segmented, single-stranded, negative-sense RNA genome. The L gene encodes an RNA-dependent RNA polymerase, the M gene encodes two glycoproteins (Gn and Gc), and the S gene encodes a nucleocapsid protein. In addition, the S genes of some hantaviruses have an NSs open reading frame that can act as an interferon antagonist. Similarities between phylogenies have suggested ancient codivergence of the viruses and their hosts to many authors, but increasing evidence for frequent, recent host switching and local adaptation has led to questioning of this model. Infected rodents establish persistent infections with little or no effect on the host. Humans are infected from aerosols of rodent excreta, direct contact of broken skin or mucous membranes with infectious virus, or rodent bite. One hantavirus, Andes virus, is unique in that it is known to be transmitted from person-to-person. HFRS and HCPS, although primarily affecting kidneys and lungs, respectively, share a number of clinical features, such as capillary leakage, TNF-, and thrombocytopenia; notably, hemorrhages and alterations in renal function also occur in HCPS and cardiac and pulmonary involvement are not rare in HFRS. Of the four structural proteins, both in humoral and cellular immunity, the nucleocapsid protein appears to be the principal immunogen. Cytotoxic T-lymphocyte responses are seen in both HFRS and HCPS and may be important for both protective immunity and pathogenesis. Diagnosis is mainly based on detection of IgM antibodies although viral RNA (vRNA) may be readily, although not invariably, detected in blood, urine and saliva. For sero/genotyping neutralization tests/RNA sequencing are required. Formalin-inactivated vaccines have been widely used in China and Korea but not outside Asia. Hantaviruses are prime examples of emerging and re-emerging infections and, given the limited number of rodents and insectivores thus far studied, it is likely that many new hantaviruses will be detected in the near future.

The Invisible Man and Jekyll and Hyde movies share many features. One of the more interesting chemical threads is that the Hyde formula and the invisibility drug accumulate more realistic drug-like properties with every adaptation. For instance, in the earliest Jekyll and Hyde films, the effects of the transformative formula are permanent until the antidote is taken or is psychologically triggered. Jump forward to the 1960 version starring Paul Massie, and the injected drug doesn’t cause an immediate transformation and its effect wears off after four days. We can infer that Jekyll spontaneously reverts to Hyde because the compound is metabolized in the bloodstream just like any other drug by a process called pharmacokinetics. Once a drug is in the bloodstream, it must travel to its “site of action,” or receptor, before it can exert its effect. This process is called pharmacodynamics. In the 1960 version of Jekyll and Hyde, for example, the receptors must be skin and hair follicles since the transformation causes the facial hair to disappear, the skin to gain color, and the facial skin to tighten so much that Hyde now smiles. The injected compound is dispersed throughout the circulatory system by the pumping of the heart such that the average concentration of the compound rises to a certain value. When the concentration rises above the pharmacological threshold concentration, enough of it is bound to its targeted receptor that it elicits a physiological response. The invisibility effect wears off after a few hours in The Invisible Woman (1940) and The Invisible Agent (1942). Prior to those versions and in the 2000 version, invisibility was portrayed as being permanent. The two films from the 1940s were produced by Universal Studios, which produced many of the classic horror films of the 1930s, including The Invisible Man (1933). Soon thereafter, when Universal revived their monsters for a B movie titled House of Dracula (1945), the benign physician Dr. Edelman is able to explain each monster’s affliction as the result of a disease that can be cured.

Electroporation has been traditionally used to enhance molecular transport into cells (e.g. gene therapy) and through tissues (e.g. skin) by creating reversible pores with short electrical pulses [1]. Increasing the parameters (electrical field, pulse duration and number) can induce irreversible damage to the cells and tissue. Recently, irreversible electroporation (IRE) has been investigated as a new tumor ablation method [2]. The advantages of the IRE include the simple and fast procedure (train of μs pulses), sharp demarcation between treated and untreated regions, destruction of tumor cells while preserving the connective tissue, and minimal effect of immune response on treatment efficacy [3]. The unique interaction of electrical field with heterogeneous structures prevents damage to nerves, blood vessels and ducts [4]. IRE has been claimed to produce negligible thermal injury and protein denaturation typical to thermal ablation [5]. However, how each electroporation parameter in IRE affects tumor destruction and the possibility of heating remains to be studied in tumors vivo.

Abstract In this paper, we use a CFD analysis of a simplified, 2D geometry to study the ability of mako shark denticles to mitigate flow separation. We represent the viscous sublayer below a turbulent boundary layer streak as a Couette flow. Incipient separation is simulated by balancing upper wall velocity and adverse pressure gradient to achieve zero net mass flow, and we add various denticle geometries to study their effects. Each modeled denticle protrudes at an angle from 15° to 85° and sublayer blockage ratio from 0.05 to 0.85. Through variation of fluid properties and boundary conditions, we show that the anti-flow-reversal abilities of a single, bristled shark denticle are independent of Reynolds number, and we investigate the effect of the denticle at cases other than zero net mass flux. Based on these results, we create a new relationship to predict separation inhibition. These conclusions are highly generalizable and represent previously undiscovered universal behavior.

Sharks, dolphins and butterflies swim and fly in different flow regimes, yet the structure of their surfaces interacting with the surrounding fluid all appear to contain very important microscopic features that lead to reduced drag and increased flying or swimming efficiency. Sharks have moveable scales (approximately 200 microns in size) that act as a passive, flow-actuated dynamic roughness for separation control. Water tunnel experiments with real shortfin mako shark skin samples mounted to models have shown significant control of flow separation in both laminar and turbulent boundary layer scenarios. Dolphins have sinusoidal-shaped millimeter-sized transverse grooves covering a large percentage of their body. Experiments show that similar geometries embedded in a turbulent boundary layer can lead to separation control at the slight expense of increased friction drag. Alternatively, butterfly scales (100 microns in size covering the wings in a roof shingle pattern) appear to fundamentally alter the local skin friction drag depending on flow orientation for what is dominantly a laminar boundary layer interacting with the wings. However, in this case the surface may also slow the growth and formation of the leading-edge vortex and these effects shown in experiments may help explain a mean decrease in climbing efficiency (joules per flap) of 37.8% for live butterflies once their scales were removed. An overview of these results is discussed for these three cases, bringing out the importance of finding solutions in nature for essential engineering problems.

Experiments are conducted on a flat recovery wall downstream of sustained concave curvature in the presence of high free-stream turbulence (TI∼8%). This flow simulates some of the features of the flow on the latter parts of the pressure surface of a gas turbine airfoil. The combined effects of concave curvature and TI, both present in the flow over a turbine airfoil, have so far little been studied. Computation of such flows with standard turbulence closure models has not been particularly successful. This experiment attempts to characterize the turbulence characteristics of this flow. In the present study, a turbulent boundary layer grows from the leading edge of a concave wall then passes onto a downstream flat wall. Results show that turbulence intensities increase profoundly in the outer region of the boundary layer over the recovery wall. Near-wall turbulent eddies appear to lift off the recovery wall and a “stabilized” region forms near the wall. In contrast to a low-free-stream turbulence intensity flow, turbulent eddies penetrate the outer parts of the “stabilized” region where sharp velocity and temperature gradients exist. These eddies can more readily transfer momentum and heat. As a result, skin friction coefficients and Stanton numbers on the recovery wall are 20% and 10%, respectively, above their values in the low-free-stream turbulence intensity case. Stanton numbers do not undershoot flat-wall expectations at the same ReΔ2 values as seen in the low-TI case. Remarkably, the velocity distribution in the core of the flow over the recovery wall exhibits a negative gradient normal to the wall under high free-stream turbulence intensity conditions. This velocity distribution appears to be the result of two effects: 1) cross transport of kinetic energy by boundary work in the upstream curved flow and 2) readjustment of static pressure profiles in response to the removal of concave curvature.

This paper deals with the study of different structuring methods for high temperature nickel alloys, which are used for compressor and turbine blades in aeroengines. The ideal structured surface combines high oxidation resistance with low drag in a hot gas flow. The effect of drag reduction due to riblet structured surfaces was originally inspired by the shark scales, which have a drag reducing riblet structure. Riblets were successfully produced on a NiCoCrAlY coating by picosecond laser treatment. This method is suitable for larger structures within the range of some tens of micrometers. Furthermore, experiments were performed by depositing different materials through polymer and metal masks via electrodeposition and physical vapor deposition. All fabricated structures were oxidized at 900–1100°C for up to 100 h to simulate the temperature conditions in an aeroengine. The resulting shape of the riblets was characterized using scanning electron microscopy. The most accurate structures were obtained by using photolithography with a subsequent electrodeposition of nickel. This method is suited for single digit micrometer structures. The reduction of the wall shear stress was measured in an oil channel. The riblet structures prior to oxidation showed a reduction of the wall shear stress of up to 4.9%.

Safety of cargo transfer operations between side-by-side vessels depends on accurate modelling of hydrodynamic behavior, especially in terms of predicting the gap free surface elevations between the two vessels. The common industry practice of using linear potential flow models to study these interactions over-predicts the free surface elevations, due to the fact that potential flow does not include viscous dissipation effects such as flow separation at hull corners and skin friction. This may result in inaccurate projections of the time-window when these operations can safely take place. This is an important aspect for developments such as Floating Liquefied Natural Gas (FLNG) platforms, where side-by-side cargo offloading is an essential operation. In a recent research [1], an approach of splitting the amount of energy lost through viscous dissipation (calculated from three-dimensional viscous CFD simulations) into components representative of the flow phenomena has been proposed. Using the approach, referred to as component energy dissipation, the amount of energy lost due to vortex shedding and skin friction can be estimated. Modifications to linear potential flow were also proposed in the referenced research, such that the energy loss components can be converted into dissipative coefficients that are used in terms added to the free surface and body boundary conditions. By combining use of the component energy dissipation approach and the modified dissipative potential flow model, better predictions of gap hydrodynamic interaction can be obtained, compared to using conventional potential flow. In this paper, results from viscous simulations of two identical fixed-floating side-by-side barges of 280m (length) × 46m (breadth) × 16.5m (draught) under excitation from regular incident waves are presented, and compared with corresponding results from the modified dissipative potential flow model. Two types of side-by-side hull configurations were investigated, the first using rectangular barges with sharp bilge corners at varying gap distances and the second using barges with rounded bilge corners of varying radii at a fixed gap distance. Estimation of the dissipative coefficients used in the modified potential flow model, calculated from the viscous results, will also be discussed. The comparison of results serves both as a validation of the modified potential flow model, and to highlight the importance of including viscous dissipation when analyzing hydrodynamic interactions.

The main goal of this study is the optimization of vibration reduction on helicopter blade by using macro fiber composite (MFC) actuator under pressure loading. Due to unsteady aerodynamic conditions, vibration occurs mainly on the rotor blade during forward flight and hover. High level of vibration effects fatigue life of components, flight envelope, pleasant for passengers and crew. In this study, the vibration reduction phenomenon on helicopter blade is investigated. 3D helicopter blade model is used to perform the aeroelastic behavior of a helicopter blade. Blade design is created by Spaceclaim and finite element analysis is conducted by ANSYS 19.0. Generated model are solved via Fluent by using two-way fluid-solid coupling analysis, then the analyzed results (all aerodynamic loads) are directly transferred to the structural model. Mechanical results (displacement etc.) are also handed over to the Fluent analysis by helping fluid-structure interaction interface. Modal and harmonic analysis are performed after FSI analysis. Shark 120 unmanned helicopter blade model is used with NACA 23012 airfoil. The baseline of the blade structure consists of D spar made of unidirectional Glass Fiber Reinforced Polymer +45°/−45° GFRP skin. MFC, which was developed by NASA’s Langley Research Center for the shaping of aerospace structures, is applied on both upper and lower surfaces of the blade to reduce the amplitude in the twist mode resonant frequency. D33 effect is important for elongation and to observe twist motion. To foresee the behavior of the MFC, thermo-elasticity analogy approach is applied to the model. Therefore, piezoelectric voltage actuation is applied as a temperature change on ANSYS. The thermal analogy is validated by using static behavior of cantilever beam with distributed induced strain actuators. Results for cantilever beam are compared to experimental results and ADINA code results existing in the literature. The effects of fiber orientation of MFC actuator and applied voltage on vibration reduction on helicopter blade are represented. The study shows that torsion mode determines the optimum placement of actuators. Fiber orientation of the MFC has few and limited influences on results. Additionally, the voltage applied on MFC has strong effects on the results and they must be selected according to applied model.

Potato (Solanum tuberosum L.) skin is composed of suberized phellem cells, the outer component of the tuber periderm. The focus of the proposed research was to apply genomic approaches to identify genes that control tuber skin appearance - smooth and shiny skin is highly preferred by the customers while russeted/netted skin potatoes are rejected. The breeding program (at Cornell University) seeks to develop smooth-skin varieties but has encountered frequent difficulties as inheritance of russeting involves complementary action by independently segregating genes, where a dominant allele at each locus is required for any degree of skin russeting. On the other hand, smooth-skin varieties frequently develop unsightly russeting in response to stress conditions, mainly high soil temperatures. Breeding programs in Israel aimed towards the improvement of heat tolerant varieties include skin quality as one of the desired characteristics. At the initiation of the present project it was unclear whether heat induced russeting and genetically inherited russeting share the same genes and biosynthesis pathways. Nevertheless, it has been suggested that russeting might result from increased periderm thickness, from strong cohesion between peridermal cells that prevents the outer layers from sloughing off, or from altered suberization processes in the skin. Hence, the original objectives were to conduct anatomical study of russet skin development, to isolate skin and russeting specific genes, to map the loci that determine the russet trait, and to compare with map locations the candidate russet specific genes, as well as to identify marker alleles that associated with russet loci. Anatomical studies suggested that russet may evolve from cracking at the outer layers of the skin, probably when skin development doesn’t meet the tuber expansion rate. Twodimensional gel electrophoresis and transcript profiling (cDNA chip, potato functional genomic project) indicated that in comparison to the parenchyma tissue, the skin is enriched with proteins/genes that are involved in the plant's responses to biotic and abiotic stresses and further expand the concept of the skin as a protective tissue containing an array of plantdefense components. The proteomes of skin from heat stressed tubers and native skin didn’t differ significantly, while transcript profiling indicated heat-related increase in three major functional groups: transcription factors, stress response and protein degradation. Exceptional was ACC synthase isogene with 4.6 fold increased level in the heat stressed skin. Russeting was mapped to two loci: rusB on chromosome 4 and rusC on chromosome 11; both required for russeting. No evidence was found for a third locus rusA that was previously proposed to be required for russeting. In an effort to find a link between the russeting character and the heat-induced russeting an attempt was made to map five genes that were found in the microarray experiment to be highly induced in the skin under heat stress in the segregating russet population. Only one gene was polymorphic; however it was localized to chromosome 2, so cannot correspond to rusB or rusC. Evaluation of AFLP markers tightly linked to rusB and rusC showed that these specific alleles are not associated with russeting in unrelated germplasm, and thus are not useful for MAS per se. To develop markers useful in applied breeding, it will be necessary to screen alleles of additional tightly linked loci, as well as to identify additional russet (heat-induced and/or native) related genes.