Quadratic Corrections to Harmonic Vibrational Frequencies Outperform Linear Models

Simulating accurate infrared spectra is a longstanding problem in computational quantum chemistry. Linearly scaling harmonic frequencies to better match experimental data is a popular way of approximating anharmonic effects while simultaneously attempting to account for deficiencies in ab initio method and/or basis set. As this approach is empirical, it is also non-variational and unbounded, so it is important to separate and quantify errors as robustly as possible. Eliminating the confounding factor of methodological incompleteness enables us to explore the intrinsic accuracy of the scaling approach alone. We find that single-coefficient linear scaling methods systematically overcorrect low frequencies, while generally undercorrecting higher frequencies. A two-parameter polynomial model gives significantly better predictions without systematic bias in any spectral region, while a single-parameter quadratic scaling model is parameterized to minimize overcorrection errors while only slightly decreasing predictive power

Acute Adhesive Small Bowel Obstruction: a Comparative Analysis of Open and Laparoscopic Surgery

Background. Acute adhesive small bowel obstruction (AASBO) is a common surgical emergency requiring immediate interventions. AASBO is a usual indication for both small bowel resection and adhesiolysis. Postoperative adhesions cause 60% of small bowel obstructions.Materials and methods. An analysis of treatment outcomes is presented for 197 acute adhesive small bowel obstruction patients; 63 patients had urgent laparotomy, and 134 were scheduled for laparoscopy. The examination included physical, laboratory, radiological methods (abdominal radiography, ultrasound, CT scan), laparoscopy and intra-abdominal pressure monitoring.Results and discussion. Of 134 patients scheduled for laparoscopic adhesiolysis, only 46.2% had laparoscopy completed, and 53.8% required conversion to laparotomy. The main rationale for conversion were massive adhesions, intraoperative haemodynamic instability, a need for intestinal decompression, as well as rare complications. Laparoscopic operations were reported with the lower vs. laparotomy rates of surgical complications (6.4  vs. 12.69%), mortality (6  vs. 6.3%), shorter hospital stays (6.5 vs. 12 days) and operation times (75 vs. 118 min, respectively).Conclusion. Laparoscopic surgery in acute adhesive small bowel obstruction was feasible in 31.47% patients and in 46.2% — after a diagnostic laparoscopy; however, a thorough patients selection for laparoscopic adhesiolysis is necessary. The first estimated should be the patient’s haemodynamic stability, the severities of condition, adhesions and comorbid cardiorespiratory pathology. Grade I—II adhesions are an indication for laparoscopic surgery

Острый аппендицит: как часто выполняется «напрасная» аппендэктомия?

   Introduction. At present, medical practice lacks a unifi ed approach to the choice of therapeutic tactics for acute catarrhal appendicitis and therefore lacks understanding of negative appendectomy.   Aim. To study the incidence of negative appendectomy in acute appendicitis. Materials and methods. The methodology involved a retrospective analysis of the results of 1590 appendectomies performed from 2003 to 2005 and a prospective non-randomized study of 1112 patientsfor the period from 2018 to 2019. During the first observation period, the examination included physical and laboratory examinations, and in the second period, Alvaro scoring, ultrasound scan, and videolaparoscopy.   Results and discussion. In the first period, catarrhal forms of appendicitis were reported in 7.82 % of cases, while in the second period — in 3.04 %. The diagnoses were confi rmed pathohistologically in all cases.   Conclusion. No cases of performing negative appendectomy were reported, based on the results of clinical, endoscopic and pathomorphological examinations. However, the ambiguous interpretation of acute catarrhal appendicitis in the national clinical practice guidelines for acute appendicitis does not allow for unambiguous conclusions from the study.   Введение. На сегодня не существует общепринятого подхода в выборе лечебной тактики при остром катаральном аппендиците и, соответственно, понимания так называемой «напрасной» аппендэктомии.   Цель работы. Изучить частоту выполнения т. н. «напрасных» аппендэктомий при остром аппендиците.   Материалы и методы. Проведен ретроспективный анализ результатов 1590 аппендэктомий за 2003–2005 гг. и проспективное нерандомизированное исследование 1112 пациентов за 2018–2019 гг. За первый период наблюдения обследование включало физикальное, лабораторное исследования, во II период обследование по шкале Alvarado, УЗИ, видеолапароскопию.   Результаты и обсуждение. В первый период катаральные формы аппендицита были в 7,82 %, во II — 3,04 %, патогистологически во всех случаях диагнозы были подтверждены.   Заключение. Случаев выполнения «напрасных» аппендэктомий по результатам клинического, эндоскопического и патоморфологического исследований не выявлено, однако неоднозначная трактовка острого катарального аппендицита в национальных клинических рекомендациях по острому аппендициту не позволяет делать однозначные выводы из исследования

Острая спаечная кишечная непроходимость: сравнительный анализ открытых и лапароскопических операций

Background. Acute adhesive small bowel obstruction (AASBO) is a common surgical emergency requiring immediate interventions. AASBO is a usual indication for both small bowel resection and adhesiolysis. Postoperative adhesions cause 60% of small bowel obstructions.Materials and methods. An analysis of treatment outcomes is presented for 197 acute adhesive small bowel obstruction patients; 63 patients had urgent laparotomy, and 134 were scheduled for laparoscopy. The examination included physical, laboratory, radiological methods (abdominal radiography, ultrasound, CT scan), laparoscopy and intra-abdominal pressure monitoring.Results and discussion. Of 134 patients scheduled for laparoscopic adhesiolysis, only 46.2% had laparoscopy completed, and 53.8% required conversion to laparotomy. The main rationale for conversion were massive adhesions, intraoperative haemodynamic instability, a need for intestinal decompression, as well as rare complications. Laparoscopic operations were reported with the lower vs. laparotomy rates of surgical complications (6.4  vs. 12.69%), mortality (6  vs. 6.3%), shorter hospital stays (6.5 vs. 12 days) and operation times (75 vs. 118 min, respectively).Conclusion. Laparoscopic surgery in acute adhesive small bowel obstruction was feasible in 31.47% patients and in 46.2% — after a diagnostic laparoscopy; however, a thorough patients selection for laparoscopic adhesiolysis is necessary. The first estimated should be the patient’s haemodynamic stability, the severities of condition, adhesions and comorbid cardiorespiratory pathology. Grade I—II adhesions are an indication for laparoscopic surgery. Введение. Острая спаечная кишечная непроходимость (ОСКН) является одной из частых причин в экстренной хирургии, требующих выполнения неотложных оперативных вмешательств. ОСКН — наиболее частое показание как для резекции тонкой кишки, так и для адгезиолизиса. В 60 % причиной обструкции тонкой кишки являются послеоперационные спайки.Материалы и методы. Представлен анализ результатов лечения 197 больных с острой спаечной кишечной непроходимостью, из которых 63 пациентам была выполнена экстренная лапаротомия, 134 — планировали лапароскопические операции. В обследовании применяли физикальные, лабораторные, лучевые методы исследования (обзорная рентгенография живота, УЗИ, КТ), лапароскопию, мониторинг внутрибрюшного давления.Результаты и  обсуждение. Из 134  пациентов, запланированных на лапароскопический адгезиолизис, только у 46,2 % операция завершена лапароскопически, в 53,8 % потребовалась конверсия на лапаротомию. Основными причинами конверсии были массивный спаечный процесс, интраоперационная нестабильность гемодинамики, потребность в декомпрессии кишечника, редко — осложнения. При лапароскопических операциях отметили снижение частоты хирургических осложнений по сравнению с лапаротомией (6,4 и 12,69 %), летальности (6 и 6,3 %), сроков госпитализации (6,5 и 12 дней), сокращение продолжительности операций (75 и 118 минут соответственно).Заключение. Хирургическое лечение лапароскопическим методом больных с острой спаечной кишечной непроходимостью возможно у 31,47 % к их общему числу, в 46,2 % — после диагностической лапароскопии, но требуется тщательный отбор больных на лапароскопический адгезиолизис. Прежде всего необходимо оценить тяжесть состояния больных, стабильность гемодинамики, выраженность спаечного процесса и коморбидной кардиореспираторной патологии. Показанием к лапароскопическим операциям является спаечный процесс I– II степени.

PyVCI: A flexible open-source code for calculating accurate molecular infrared spectra

The PyVCI program package is a general purpose open-source code for simulating accurate molecular spectra, based upon force field expansions of the potential energy surface in normal mode coordinates. It includes harmonic normal coordinate analysis and vibrational configuration interaction (VCI) algorithms, implemented primarily in Python for accessibility but with time-consuming routines written in C. Coriolis coupling terms may be optionally included in the vibrational Hamiltonian. Non-negligible VCI matrix elements are stored in sparse matrix format to alleviate the diagonalization problem. CPU and memory requirements may be further controlled by algorithmic choices and/or numerical screening procedures, and recommended values are established by benchmarking using a test set of 44 molecules for which accurate analytical potential energy surfaces are available. Force fields in normal mode coordinates are obtained from the PyPES library of high quality analytical potential energy surfaces (to 6th order) or by numerical differentiation of analytic second derivatives generated using the GAMESS quantum chemical program package (to 4th order)

PyVCI: A flexible open-source code for calculating accurate molecular infrared spectra

This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018) Abstract The PyVCI program package is a general purpose open-source code for simulating accurate molecular spectra, based upon force field expansions of the potential energy surface in normal mode coordinates. It includes harmonic normal coordinate analysis and vibrational configuration interaction (VCI) algorithms, implemented primarily in Python for accessibility but with time-consuming routines written in C. Coriolis coupling terms may be optionally included in the vibrational Hamiltonian. Non-negl... Title of program: PyVCI Catalogue Id: AFAC_v1_0 Nature of problem The simulation of accurate molecular vibrational spectra is a significant and long-standing problem in computational chemistry. There are two major challenges: constructing an accurate ab initio potential energy surface and solving the nuclear vibrational problem. Both scale poorly with respect to molecular size, requiring large amounts of CPU time and memory. Versions of this program held in the CPC repository in Mendeley Data AFAC_v1_0; PyVCI; 10.1016/j.cpc.2016.02.02

PyVCI: A flexible open-source code for calculating accurate molecular infrared spectra

The PyVCI program package is a general purpose open-source code for simulating accurate molecular spectra, based upon force field expansions of the potential energy surface in normal mode coordinates. It includes harmonic normal coordinate analysis and vibrational configuration interaction (VCI) algorithms, implemented primarily in Python for accessibility but with time-consuming routines written in C. Coriolis coupling terms may be optionally included in the vibrational Hamiltonian. Non-negligible VCI matrix elements are stored in sparse matrix format to alleviate the diagonalization problem. CPU and memory requirements may be further controlled by algorithmic choices and/or numerical screening procedures, and recommended values are established by benchmarking using a test set of 44 molecules for which accurate analytical potential energy surfaces are available. Force fields in normal mode coordinates are obtained from the PyPES library of high quality analytical potential energy surfaces (to 6th order) or by numerical differentiation of analytic second derivatives generated using the GAMESS quantum chemical program package (to 4th order)

TWO-STAGE REOSTEOSYNTHESIS OF TIBIA IN THE PATIENT WITH FRACTURE NON-UNION COMPLICATED BY POSTOPERATIVE OSTEOMYELITIS

The authors present a case report of a patient with pseudarthrosis of the right tibia complicated by chronic postoperative osteomyelitis. The development of the osteomyelitis process is caused by locked intramedullary fixation of the right tibia by a retrograde nail. Unstable fixation led to the development of acute periimplant infection and osteomyelitis.A radical surgical debridement of the focus site of chronic infection was performed by removing locking screws and nail, removal of necrotic bone tissues by handling the tibial medullary cavity by special reamers. The authors used the pulse lavage with active removal of the solution for an additional sterilization of the surgical wound and medullary cavity. A reinforced spacer impregnated with vancomycin and polyvalent bacteriophage was placed in the medullary cavity to ensure local prolonged antimicrobial therapy. Instead of the removed monomer the polyvalent bacteriophage was introduced into the polymer composition including phages against the main infectious agents in patients of traumatology and orthopedics clinic.Three months after the first stage of treatment and stabilization of laboratory parameters the patient was readmitted to the clinic. The second stage of procedure included removal of spacer, closed antegrade locked internal fixation of the right tibia and talus by a nail with an antimicrobial coating of bone cement impregnated with vancomycin and a polyvalent bacteriophage. Antimicrobial coating of the nail was made intraoperatively using an original mold.Two stage procedure allowed to achieve a stable remission of chronic osteomyelitis and stable internal fixation of tibia pseudarthrosis with preservation of the supporting function of the lower limb