Diffraction and trapping in circular lattices

When a single two-level atom interacts with a pair of Laguerre-Gaussian beams with opposite helicity, this leads to an efficient exchange of angular momentum between the light field and the atom. When the radial motion is trapped by an additional potential, the wave function of a single localized atom can be split into components that rotate in opposite direction. This suggests a novel scheme for atom interferometry without mirror pulses. Also atoms in this configuration can be bound into a circular lattice

High-pressure structural, elastic and electronic properties of the scintillator host material, KMgF_3

The high-pressure structural behaviour of the fluoroperovskite KMgF_3 is investigated by theory and experiment. Density functional calculations were performed within the local density approximation and the generalized gradient approximation for exchange and correlation effects, as implemented within the full-potential linear muffin-tin orbital method. In situ high-pressure powder x-ray diffraction experiments were performed up to a maximum pressure of 40 GPa using synchrotron radiation. We find that the cubic Pm\bar{3}m crystal symmetry persists throughout the pressure range studied. The calculated ground state properties -- the equilibrium lattice constant, bulk modulus and elastic constants -- are in good agreement with experimental results. By analyzing the ratio between the bulk and shear modulii, we conclude that KMgF_3 is brittle in nature. Under ambient conditions, KMgF_3 is found to be an indirect gap insulator with the gap increasing under pressure.Comment: 4 figure

Opto-Mechanical Pattern Formation in Cold Atoms

Transverse pattern formation in an optical cavity containing a cloud of cold two-level atoms is discussed. We show that density modulation becomes the dominant mechanism as the atomic temperature is reduced. Indeed, for low but achievable temperatures the internal degrees of freedom of the atoms can be neglected, and the system is well described by treating them as mobile dielectric particles. A linear stability analysis predicts the instability threshold and the spatial scale of the emergent pattern. Numerical simulations in one and two transverse dimensions confirm the instability and predict honeycomb and hexagonal density structures, respectively, for the blue and red detuned cases.Comment: submitted to Physical Review Letter

Coherent Control of Atomic Beam Diffraction by Standing Light

Quantum interference is shown to deliver a means of regulating the diffraction pattern of a thermal atomic beam interacting with two standing wave electric fields. Parameters have been identified to enhance the diffraction probability of one momentum component over the others, with specific application to Rb atoms.Comment: 5 figure

Application of the fluorescence spectroscopy for the analysis of the state of abdominal cavity organs tissues in mini-invasive surgery

At present, minimally invasive interventions become more widespread for treating hepatopancreatoduodenal area pathologies. However, new methods and approaches are necessary for obtaining more diagnostic information in real time. Several methods within the framework of "optical biopsy" concept are considered. The features and areas of application of each method are reviewed to find out which of them can be used in further studies to assess the possibility of intraoperative use in minimally invasive abdominal surgery. Preliminary measurements with fluorescence spectroscopy method have been performed at excitation wavelengths 365 nm and 450 nm. Areas of interest were common bile duct, gallbladder and liver abscess. In our opinion, the obtained results can be a basis for further research and provide a deeper understanding of pathological processes of abdominal cavity organs tissues

Влияние полиморфизмов генов CYP2D6 и CYP2C9 на клиническую эффективность трамадола и кеторолака при использовании протокола ускоренного восстановления у пациентов с неосложненным острым калькулезным холециститом, перенесших холецистэктомию

Relevance. One of the key components of the accelerated recovery protocols (ARP), in addition to minimizing the surgical approach, is an adequate postoperative analgesia. Despite this, applied postoperative analgesia combinations are not devoid of drawbacks, such as lack of effective postoperative analgesia and the presence of side effect. The use of a pharmacogenetic approach to analgesic therapy for the purpose of its personalization may increase the effectiveness and safety of the use of analgesics. In particular, the presence of an inactive CYP2D6*4 allele , in which the conversion of tramadol to its active metabolite is reduced, contributes to the insufficient efficacy of the drug. As for non-steroidal anti-inflammatory drugs, the presence of CYP2C9*2/*3 polymorphisms leads to a decrease in drug metabolism and a longer half-life, resulting in the increase of the clinical effect and the risk of adverse reactions. Thus, genotyping of patients with the determination of the presence of specific genetic factors can rationalize the postoperative analgesia.Aim of study. Evaluation of the possible association of polymorphisms of the CYP2D6 and CYP2C9 genes with the clinical efficacy of tramadol and ketorolac in relation to postoperative pain.Material and methods. This observational clinical study involved 107 patients with uncomplicated acute calculous cholecystitis who underwent videolaparoscopic cholecystectomy and perioperative treatment according to ARP. All patients underwent whole blood sampling followed by real-time polymerase chain reaction genotyping. Analgesic efficacy was assessed using a visual analog scale (VAS) and McGill Pain Questionnaire.Results. In CYP2D64* carriers pain was higher than that of wild-type carriers, according to VAS and McGill Pain Questionnaire in all investigated periods. In carriers of CYP2C9*2, the pain syndrome was lower than in carriers of the wild type at all intervals studied. In carriers of CYP2C9*3 pain was lower only after 2 and 6 hours, also according to McGill Pain Questionnaire.Conclusion. 1. The presence of the polymorphic marker CYP2D6*4 may reduce the efficacy of postoperative tramadol analgesia compared with wild type. 2. The presence of the polymorphic marker CYP2C9*2 and CYP2C9*3 may increase the efficacy of ketorolac pain relief compared to wild type.Актуальность. Одним из ключевых компонентов всех протоколов ускоренного восстановления (ПУВ), помимо минимизации операционного доступа, является адекватная послеоперационная аналгезия. Несмотря на это применяемые комбинации послеоперационного обезболивания не лишены недостатков, таких как недостаточно эффективная послеоперационная аналгезия и наличие побочных эффектов от используемых препаратов. Применение фармакогенетического подхода к обезболивающей терапии с целью ее персонализации может повысить эффективность и безопасность применения анальгетиков. В частности, наличие неактивного аллеля CYP2D6*4, при котором снижено преобразование трамадола в его активный метаболит, способствует недостаточной эффективности препарата. Что касается нестероидных противовоспалительных препаратов, наличие полиморфизмов CYP2C9*2/*3 приводит к снижению метаболизма лекарств и более длительному периоду полувыведения, вследствие чего может усилиться клинический эффект и повыситься риск нежелательных реакций. Таким образом генотипирование пациентов с определением наличия конкретных генетических полиморфизмов может рационализировать послеоперационную аналгезию.Цель. Оценка возможной ассоциации полиморфизмов генов CYP2D6 и CYP2C9 с клинической эффективностью трамадола и кеторолака в отношении послеоперационной боли.Материал и методы. В этом обсервационном клиническом исследовании принимали участие 107 пациентов с неосложненным острым калькулезным холециститом, которым выполняли видеолапароскопическую холецистэктомию и проводили периоперационное лечение согласно оптимизированному ПУВ. Всем пациентам осуществлялся забор цельной крови с последующим генотипированием методом полимеразной цепной реакции в режиме реального времени. Обезболивающая эффективность оценивалась при помощи визуальной аналоговой шкалы (ВАШ) и опросника боли Мак-Гилла.Результаты. У носителей CYP2D6*4 болевой синдром был выше, чем у носителей дикого типа, по данным ВАШ и болевого опросника Мак-Гилла во все исследуемые промежутки. У носителей CYP2C9*2 болевой синдром был ниже, чем у носителей дикого типа во все исследуемые промежутки. У носителей CYP2C9*3 болевой синдром был ниже только через 2 и 6 часов, а также по данным оценочной шкалы боли Мак-Гилла.Выводы. 1. Наличие полиморфного маркера CYP2D6*4 может снизить эффективность послеоперационного обезболивания трамадолом по сравнению с диким типом. 2. Наличие полиморфного маркера CYP2C9*2 и CYP2C9*3 может повысить эффективность обезболивания кеторолаком по сравнению с диким типом

Optical diagnostics of bile duct tissues state with tumor compression

The paper presents the results of in vivo experimental measurements of the endogenous fluorescence and blood perfusion in common bile duct tissues in obstructive jaundice patients during minimally invasive surgical operations. Nowadays the type of interventions become more widespread for treating hepatopancreatobiliary pathologies. An effective feedback which can be established by one or more optical diagnostic channels integrated into the standard instruments for minimally invasive manipulations would be of particular value to practical surgeons. To collect reference data, an experimental study has been conducted using a fiber optical probe with fluorescence spectroscopy and laser Doppler flowmetry channels. For every measurement, the areas of interest were different areas of common bile duct obstructed by a malignant tumor. Obtained results demonstrated significant variety registered intensities of fluorescence spectra and values of blood perfusion. Tested fiber optical endoscopic system showed sensitivity to the tissue state in the investigated area, so the two modal approach seems to be promising for further research and implementation in clinical practice