Perturbation theory for the one-dimensional optical polaron

The one-dimensional optical polaron is treated on the basis of the perturbation theory in the weak coupling limit. A special matrix diagrammatic technique is developed. It is shown how to evaluate all terms of the perturbation theory for the ground-state energy of a polaron to any order by means of this technique. The ground-state energy is calculated up to the eighth order of the perturbation theory. The effective mass of an electron is obtained up to the sixth order of the perturbation theory. The radius of convergence of the obtained series is estimated. The obtained results are compared with the results from the Feynman polaron theory.Comment: 9 pages, 2 figures, RevTeX, to be published in Phys. Rev. B (2001) Ap

Standardizing training for Pressurized Intraperitoneal Aerosol Chemotherapy.

PIPAC is a novel mode of intraperitoneal drug delivery for patients with peritoneal cancer (PC). PIPAC is a safe treatment with promising oncological results. Therefore, a structured training program is needed to maintain high standards and to guarantee safe implementation. An international panel of PIPAC experts created by means of a consensus meeting a structured 2-day training course including essential theoretical content and practical exercises. For every module, learning objectives were defined and structured presentations were elaborated. This structured PIPAC training program was then tested in five courses. The panel consisted of 12 experts from 11 different centres totalling a cumulative experience of 23 PIPAC courses and 1880 PIPAC procedures. The final program was approved by all members of the panel and includes 12 theoretical units (45 min each) and 6 practical units including dry-lab and live surgeries. The panel finalized and approved 21 structured presentations including the latest evidence on PIPAC and covering all mandatory topics. These were organized in 8 modules with clear learning objectives to be tested by 12 multiple-choice questions. Lastly, a structured quantifiable (Likert scale 1-5) course evaluation was created. The new course was successfully tested in five courses with 85 participants. Mean overall satisfaction with the content was rated at 4.79 (±0.5) with at 4.71 (±0.5) and at 4.61 (±0.7), respectively for course length and the balance between theory and practice. The proposed PIPAC training program contains essential theoretical background and practical training enabling the participants to safely implement PIPAC

How close can one approach the Dirac point in graphene experimentally?

The above question is frequently asked by theorists who are interested in graphene as a model system, especially in context of relativistic quantum physics. We offer an experimental answer by describing electron transport in suspended devices with carrier mobilities of several 10^6 cm^2V^-1s^-1 and with the onset of Landau quantization occurring in fields below 5 mT. The observed charge inhomogeneity is as low as \approx10^8 cm^-2, allowing a neutral state with a few charge carriers per entire micron-scale device. Above liquid helium temperatures, the electronic properties of such devices are intrinsic, being governed by thermal excitations only. This yields that the Dirac point can be approached within 1 meV, a limit currently set by the remaining charge inhomogeneity. No sign of an insulating state is observed down to 1 K, which establishes the upper limit on a possible bandgap

ИНТРАОПЕРАЦИОННАЯ ФОТОДИНАМИЧЕСКАЯ ТЕРАПИЯ БОЛЬНЫХ РАКОМ ЖЕЛУДКА

Results of intraoperative photodynamic therapy (IOPDT) in patients with gastric cancer are represented in the article. The study included 240 patients with gastric cancer stage II-IV (Т3-4N0-3M0-1) with  evident or suspected peritoneal dissemination who underwent  examination and treatment in P.Herzen Moscow Oncology Research  Institute. The group 1, the study group, included 140 patients who  underwent nominally curative or palliative surgery for locally  advanced and disseminated gastric cancer with IOPDT as additional  intraoperative intervention for antiblastics and cancer treatment. The group 2, the control group, included 100 patients who also  underwent nominally curative or palliative surgery (equal to extent  of surgery in patients from the study group) for locally advanced and disseminated gastric cancer and no intraoperative implication of physical or chemical treatment methods. IOPDT did not worsen a course of early post-operative period, did not impact on severity of  post-operative complications and was not associated with increase of post-operative mortality. IOPDT allowed for improvement of 1-year  and 3-year disease-specifi c survival rates: by 16.1% and 16.7%,  respectively. For nominally curative resections, median survival, 1- year and 3-year disease-specifi c survival rates were improved by 14 months, 17.8% and 31.3%, respectively. For R1, R2 resections,  IOPDT improved 1-year disease-specifi c survival rates by 16.4%. Additionally, for nominally curative resections IOPDT did not increase the recurrence rate and improved median recurrence-free survival,  1-year and 3-year recurrence-free survival rates by 16 months,  27.2% and 25.4%, respectively. В статье представлены результаты применения интраоперационной фотодинамической терапии (ИОФДТ) у больных раком желудка. В исследование включены 240 пациентов  раком желудка II-IV стадии (Т3-4N0-3M0-1) с наличием или подозрением на  перитонеальную диссеминацию, которым в МНИОИ им. П.А. Герцена были проведены  обследование и лечение. В первую, основную группу включено 140 больных, которым  выполнены условно-радикальные или паллиативные операции по поводу местно- распространенного и диссеминированного рака желудка с применением в качестве метода  дополнительного интраоперационного воздействия с целью интраоперационной  антибластики и противоопухолевого воздействия – ИОФДТ. Вторую, контрольную группу  составили 100 больных, которым были выполнены также условно-радикальные и  паллиативные операции (по объему соответствующие хирургическим вмешательствам у  больных основной группы) по поводу местно-распространенного и диссеминированного рака желудка без интраоперационного применения физических или химических методов  воздействия. ИОФДТ не ухудшила течение раннего послеоперационного периода, не влияла на тяжесть послеоперационных осложнений и не ассоциирована с увеличением  послеоперационной летальности. Проведение ИОФДТ позволило улучшить показатели 1- летней и 3-летней общей специфической выживаемости: на 16,1% и 16,7%, соответственно. При условно-радикальных операциях – медиану выживаемости на 14 мес, показатели 1- летней и 3-летней общей специфической выживаемости – на 17,8% и 31,3%, соответственно. При операциях в объеме R1, R2 проведение ИОФДТ улучшило 1- летнюю общую специфическую выживаемость на 16,4%. Кроме того, при условно- радикальных операциях проведение ИОФДТ не увеличило частоту рецидивов и улучшило медиану безрецидивной выживаемости на 16 мес, показатели 1-летней и 3-летней безрецидивной выживаемости – на 27,2% и 25,4%, соответственно

On-chip picosecond pulse detection and generation using graphene photoconductive switches

We report on the use of graphene for room temperature on-chip detection and generation of pulsed terahertz (THz) frequency radiation, exploiting the fast carrier dynamics of light-generated hot carriers, and compare our results with conventional low-temperature-grown gallium arsenide (LT-GaAs) photoconductive (PC) switches. Coupling of picosecond-duration pulses from a biased graphene PC switch into Goubau line waveguides is also demonstrated. A Drude transport model based on the transient photoconductance of graphene is used to describe the mechanism for both detection and generation of THz radiation

ИНТРАОПЕРАЦИОННАЯ ФОТОДИНАМИЧЕСКАЯ ТЕРАПИЯ ПРИ МЕЗОТЕЛИОМЕ БРЮШИНЫ

Abstract Results of application of a new technology of intraoperative photodynamic therapy (IOFDT) in patients with peritoneal mesothelioma developed at P. Herzen Moscow Oncology Research Institute are presented. The study included 8 patients. 3 patients underwent surgery in various amount: 1 – limited peritonectomy in the volume of tumor foci resection and resection of a large omentum, 1 – limited peritonectomy in the volume of tumor foci resection and atypical resection of the right lobe of the liver, 1 – only resection of the large omentum due to the fact that the tumor was located only in a large omentum and no signs of lesions of the parietal peritoneum was revealed by intraoperative revision. Surgical intervention in these patients was concluded by IOPDT. The remaining 5 patients underwent only IOPDT. After the treatment, two patients underwent additional courses of laparoscopic IOPDT. Of the 8 patients enrolled in the study, 4 died from the underlying disease, 1 from cardiovascular disease with recurrence of the disease, 1 from cardiovascular disease without signs of recurrence, 2 were monitored for 6 months and 146 months (12 years). Thus, in the group of patients with peritoneal mesothelioma, the maximum observation period was 146.44 months, the median survival was 48.4 months, the total specific 1-year survival was 85.7±13.2%, the three-year survival was 68.5±18.6%, the 5-year survival was 45.7 ± 22.4 %. The average life expectancy after treatment of patients with repeated courses of laparoscopic IOPDT was 87 months, without repeated courses – 35.8 months. Thus, life expectancy was higher in patients with repeated courses of laparoscopic IOPDT. Small sample size caused to the rarity of this pathology does not allow for statistically significant conclusions. However, the results of the study indicate the prospects of multi-course intraoperative photodynamic therapy in patients with peritoneal mesothelioma.Приведены результаты применения разработанной в МНИОИ им. П.А. Герцена новой технологии интраоперационной фотодинамической терапии (ИОФДТ) у больных с мезотелиомой брюшины. В исследование включено 8 пациентов. 3 пациентам выполнено оперативное вмешательство в различном объеме: 1 – ограниченная перитонэктомия в объеме резекции опухолевых очагов и резекция большого сальника, 1 – ограниченная перитонэктомия в объеме резекции опухолевых очагов и атипичная резекция правой доли печени, 1 – только резекция большого сальника в связи с тем, что опухолевые очаги располагались только в большом сальнике и признаков поражения париетальной брюшины при интраоперационной ревизии выявлено не было. Хирургическое вмешательство у этих пациентов завершали проведением ИОФДТ. У остальных 5 пациентов была выполнена только ИОФДТ. После проведенного лечения у 2 больных дополнительно были проведены повторные курсы лапароскопической ИОФДТ. Из 8 пациентов, включенных в исследование, 4 умерли от основного заболевания, 1 – от сердечно-сосудистой патологии с рецидивом заболевания, 1 – от сердечно-сосудистой патологии без признаков рецидива заболевания, 2 – находятся под наблюдением в течение 6 мес и 146 мес (12 лет). Таким образом, в группе больных мезотелиомой брюшины максимальный срок наблюдения составил 146 мес, медиана выживаемости равнялась 48,4 мес, общая специфическая 1-летняя выживаемость составила 85,7±13,2%, 3-летняя – 68,5±18,6%, 5-летняя – 45,7±22,4%. Средняя продолжительность жизни после лечения у больных с повторными курсами лапароскопической ИОФДТ составила 87 мес, без повторных курсов – 35,8 мес. Таким образом, продолжительность жизни была выше у больных с повторными курсами лапароскопической ИОФДТ. Малое число наблюдений, связанное с редкостью данной патологии, не позволяет делать статистически значимых выводов. Однако результаты исследования свидетельствуют о перспективности применения многокурсовой интраоперационной фотодинамической терапии у пациентов с мезотелиомой брюшины.

Preliminary results from the Russian-American Gallium Experiment Cr-neutrino source measurement

The Russian-American Gallium Experiment has been collecting solar neutrino data since early 1990. The flux measurement of solar neutrinos is well below that expected from solar models. We discuss the initial results of a measurement of experimental efficiencies by exposing the gallium target to neutrinos from an artificial source. The capture rate of neutrinos from this source is very close to that which is expected. The result can be expressed as a ratio of the measured capture rate to the anticipated rate from the source activity. This ratio is 0.93 + 0.15, - 0.17 where the systematic and statistical errors have been combined. To first order the experimental efficiencies are in agreement with those determined during solar neutrino measurements and in previous auxiliary measurements. One must conclude that the discrepancy between the measured solar neutrino flux and that predicted by the solar models can not arise from an experimental artifact

ВНУТРИБРЮШНАЯ АЭРОЗОЛЬНАЯ ХИМИОТЕРАПИЯ ПОД ДАВЛЕНИЕМ В СОЧЕТАНИИ С СИСТЕМНОЙ ХИМИОТЕРАПИЕЙ – НОВЫЙ ПОДХОД В ЛЕЧЕНИИ БОЛЬНЫХ РАКОМ ЖЕЛУДКА С ПЕРИТОНЕАЛЬНЫМ КАРЦИНОМАТОЗОМ

The aim of the study was to analyze the immediate and long-term outcomes of pressurized intraperitoneal aerosol chemotherapy (PIPAC) in gastric cancer patients with peritoneal carcinomatosis (PC). Material and methods. The treatment protocol included diagnostic laparoscopy with PCI score assessment and peritoneal biopsy and 4 courses of systemic chemotherapy with XELOX or FOLFOX followed by PIPAC with cisplatin and doxorubicin at 6–8 week intervals. Between the PIPAC cycles patients received systemic chemotherapy according to previous regimen. Each PIPAC procedure included laparoscopy, evaluation of Peritoneal Carcinomatosis Index (PCI) and peritoneal biopsies. Results. 102 (80.3 %) patients had primary gastric cancer with PC and 25 (19.7 %) had peritoneal recurrence of gastric cancer. PCI<10 points was found in 60 (47.2%) patients, PCI 10–18 in 33 (26 %) patients and PCI>18 in 34 (26.7 %) patients. Diffuse type of cancer was diagnosed in 114 patients (89.7 %), intestinal type in 6 (4.7 %) patients and the mixed type in 7 (5.5 %) patients. 127 patients underwent 310 PIPAC procedures. No severe complications and were observed. Pathological response (PRGC score) was evaluated in 72 patients. Partial pathological response (PRGS 2) was achieved in 40 (55.6 %) cases and complete pathological response (PRGS 1) – in 10 (13.9 %). Survival was evaluated in 63 % (n=80) patients who received more than one PIPAC. The median survival was 16.0 months and one year survival rate was 77.9 %. Conclusion. A new approach to the treatment of gastric cancer with PC combining systemic chemotherapy and pressurized intraperitoneal aerosol chemotherapy is a simple and save method allowing improvement of survival of patients with peritoneal dissemination of gastric cancer.Цель исследования – изучить непосредственные и отдалённые результаты применения внутрибрюшной аэрозольной химиотерапии под давлением (ВАХД) у больных с перитонеальным карциноматозом при раке желудка. Материал и методы. На первом этапе, согласно протоколу исследования, пациентам выполняли стадирующую лапароскопию, в ходе которой определяли распространённость перитонеального карциноматоза по шкале PCI с обязательной множественной биопсией брюшины и последующим гистологическим исследованием измененных участков брюшины. Лечение начинали с 4 курсов системной химиотерапии по схеме XELOX или FOLFOX. В дальнейшем больным в условиях торакоабдоминального отделения осуществляли сеансы ВАХД препаратами цисплатин и доксорубицин с интервалом 6–8 нед. Между сеансами пациенты продолжали получать системную химиотерапию по прежней схеме. Каждый сеанс ВАХД включал лапароскопию, повторную биопсию и оценку PCI. Результаты. У 102 (80,3 %) больных был первичный рак желудка с ПК, у 25 (19,7 %) – перитонеальный рецидив. PCI<10 баллов зафиксирован у 60 (47,2 %), PCI 10–18 – у 33 (26 %), PCI>18 – у 34 (26,7 %). Диффузный тип рака желудка выявлен у 114 больных (89,7 %), кишечный тип – у 6 (4,7 %), смешанный тип – у 7 (5,5 %). С 2013 г. 127 больным проведено 310 процедур ВАХД. Тяжелых осложнений и летальности не отмечено. Лечебный патоморфоз был оценен у 72 больных. У 40 (55,6 %) больных отмечен выраженный патоморфоз (PRGS 2) и у 10 (13,9%) – полный патоморфоз (PRGS 1). Выживаемость оценена у 63 % (n=80), получивших более 1 сеанса ВАХД. Медиана выживаемости составила 16,0 мес, 1-годичная выживаемость – 77,9 %. Заключение. Новый подход к лечению больных раком желудка с перитонеальным карциноматозом, сочетающий системную химиотерапию и внутрибрюшную аэрозольную химиотерапию под давлением, зарекомендовал себя как относительно простой и безопасный метод, позволяющий добиться увеличения общей выживаемости у пациентов с диссеминированным раком желудка

The russian-american gallium experiment (sage) cr neutrino source measurement

The solar neutrino capture rate measured by SAGE is well below that predicted by solar models. To check the overall experimental efficiency, we exposed 13 tonnes of Ga metal to a reactor-produced 517 kCi source of 51Cr. The ratio of the measured production rate to that predicted from the source activity is 0.95+/-0.11$stat$+0.05/-0.08$syst$. This agreement verifies that the experimental efficiency is measured correctly, establishes that there are no unknown systematic errors at the 10% level, and provides considerable evidence for the reliability of the solar neutrino measurement. © 1996 The American Physical Society

Measurement of the response of a gallium metal solar neutrino experiment to neutrinos from a [Formula Presented] source

The neutrino capture rate measured by the Russian-American Gallium Experiment is well below that predicted by solar models. To check the response of this experiment to low-energy neutrinos, a 517 kCi source of [Formula Presented]Cr was produced by irradiating 512.7 g of 92.4%-enriched [Formula Presented]Cr in a high-flux fast neutron reactor. This source, which mainly emits monoenergetic 747-keV neutrinos, was placed at the center of a 13.1 ton target of liquid gallium and the cross section for the production of [Formula Presented]Ge by the inverse beta decay [Formula Presented] was measured to be [Formula Presented] The ratio of this cross section to the theoretical cross section of Bahcall for this reaction is 0.95 ±0.12 [Formula Presented] (theor) and to the cross section of Haxton is 0.87±0.11 (expt)±0.09 (theor). This good agreement between prediction and observation implies that the overall experimental efficiency is correctly determined and provides considerable evidence for the reliability of the solar neutrino measurement. © 1999 The American Physical Society