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This work presents the development of switchable SAW resonators fabricated on a LiNbO3 substrate, which use the Electrical Bragg Bandgap concept to control the resonance frequency. The modification of the electrical condition of electrode arrays shifts their bandgap center frequency which in turn changes the effective cavity length and resonance frequency of the resonator. This method uses the electrodes already present in SAW devices, thus reducing the complexity of potentially tunable SAW components. In this paper, the electrodes which make up the cavity mirrors are connected into IDCP's (interdigitated comb pairs), reducing the necessary number of switches for operation. Finite Element Method (FEM) simulations are used to analyze resonator operation and design difficulties are discussed. Frozen (with no possibility of switching) and switchable versions of a chosen resonator structure are fabricated to experimentally showcase resonator operation. It is found that it is possible to design switchable SAW resonators which require a single switch and present a relative frequency jump of around 2.3%. Finally frozen single cell and 4-cell ladder filters are fabricated as a proof of concept of a switchable SAW filter.
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BACKGROUND: Retrorectal tumors are uncommon lesions developed in the retrorectal space. Data on their minimally invasive resection are scarce and the optimal surgical approach for tumors below S3 remains debated. METHODS: We performed a retrospective review of consecutive patients who underwent minimally invasive resection of retrorectal tumors between 2005 and 2022 at two tertiary university hospital centers, by comparing the results obtained for lesions located above or below S3. RESULTS: Of over 41 patients identified with retrorectal tumors, surgical approach was minimally invasive for 23 patients, with laparoscopy alone in 19, with transanal excision in 2, and with combined approach in 2. Retrorectal tumor was above S3 in 11 patients (> S3 group) and below S3 in 12 patients (< S3 group). Patient characteristics and median tumor size were not significantly different between the two groups (60 vs 67 mm; p = 0.975). Overall median operative time was 131.5 min and conversion rate was 13% without significant difference between the two groups (126 vs 197 min and 18% vs 8%, respectively; p > 0.05). Final pathology was tailgut cyst (48%), schwannoma (22%), neural origin tumor (17%), gastrointestinal stromal tumor (4%), and other (19%). The 90-day complication rates were 27% and 58% in the > S3 and < S3 groups, respectively, without severe morbidity or mortality. After a median follow-up of 3.3 years, no recurrence was observed in both groups. Three patients presented chronic pain, three anal dysfunction, and three urinary dysfunction. All were successfully managed without reintervention. CONCLUSIONS: Minimally invasive surgery for retrorectal tumors can be performed safely and effectively with low morbidity and no mortality. Laparoscopic and transanal techniques alone or in combination may be recommended as the treatment of choice of benign retrorectal tumors, even for lesions below S3, in centers experienced with minimally invasive surgery.
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Laparoscopía , Neoplasias del Recto , Centros de Atención Terciaria , Humanos , Estudios Retrospectivos , Masculino , Femenino , Persona de Mediana Edad , Laparoscopía/métodos , Laparoscopía/estadística & datos numéricos , Anciano , Neoplasias del Recto/cirugía , Neoplasias del Recto/patología , Centros de Atención Terciaria/estadística & datos numéricos , Adulto , Tempo Operativo , Resultado del Tratamiento , Cirugía Endoscópica Transanal/métodos , Anciano de 80 o más Años , Recto/cirugíaRESUMEN
Venetoclax, a highly selective BCL-2 inhibitor, combined with hypomethylating agents (HMAs) azacitidine or decitabine, is approved for the treatment of newly diagnosed acute myeloid leukemia (ND AML) in patients who are ineligible to receive intensive chemotherapy. Previous clinical studies initiated venetoclax plus HMA in an inpatient setting owing to concerns of tumor lysis syndrome (TLS). This study (NCT03941964) evaluated the efficacy and safety of venetoclax plus HMA in a United States community-based outpatient setting in patients with ND AML (N = 60) who were treatment naïve for AML, ineligible to receive intensive chemotherapy, had no evidence of spontaneous TLS at screening, and were deemed as appropriate candidates for outpatient initiation of venetoclax plus HMA by the investigator. Patients received venetoclax in combination with azacitidine (75 mg/m2) or decitabine (20 mg/m2) for up to 6 cycles during the study. With a median time on study of 18.3 weeks, the best response rate of composite complete remission was 66.7%, and the overall post-baseline red blood cell (RBC) and platelet transfusion independence rate was 55.0%, consistent with results of studies in which treatment was initiated in an inpatient setting. Key adverse events included nausea, anemia, thrombocytopenia, neutropenia, and white blood cell count decrease of any grade (≥50% of patients). The observed safety profile was generally consistent with that of venetoclax plus HMA observed in inpatient AML studies. With close monitoring, 2 cases of TLS were identified, appropriately managed, and the patients were able to continue study treatment. CLINICAL TRIALS REGISTRATION: This study is registered at ClinicalTrials.gov. The registration identification number is NCT03941964.
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Protocolos de Quimioterapia Combinada Antineoplásica , Azacitidina , Compuestos Bicíclicos Heterocíclicos con Puentes , Decitabina , Leucemia Mieloide Aguda , Sulfonamidas , Humanos , Sulfonamidas/administración & dosificación , Sulfonamidas/uso terapéutico , Sulfonamidas/efectos adversos , Azacitidina/administración & dosificación , Azacitidina/uso terapéutico , Azacitidina/efectos adversos , Leucemia Mieloide Aguda/tratamiento farmacológico , Compuestos Bicíclicos Heterocíclicos con Puentes/uso terapéutico , Compuestos Bicíclicos Heterocíclicos con Puentes/administración & dosificación , Compuestos Bicíclicos Heterocíclicos con Puentes/efectos adversos , Decitabina/administración & dosificación , Decitabina/uso terapéutico , Decitabina/efectos adversos , Femenino , Masculino , Anciano , Persona de Mediana Edad , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Anciano de 80 o más Años , Adulto , Pacientes AmbulatoriosRESUMEN
BACKGROUND: In the decision to perform elective surgery, it is of great interest to have data about the outcomes of surgery to individualize patients who could safely undergo sigmoid resection. The aim of this study was to provide information on the outcomes of elective sigmoid resection for sigmoid diverticular disease (SDD) at a national level. METHODS: All consecutive patients who had elective surgery for SDD (2010-2021) were included in this retrospective, multicenter, cohort study. Patients were identified from institutional review board-approved databases in French member centers of the French Surgical Association. The endpoints of the study were the early and the long-term postoperative outcomes and an evaluation of the risk factors for 90-day severe postoperative morbidity and a definitive stoma after an elective sigmoidectomy for SDD. RESULTS: In total, 4617 patients were included. The median [IQR] age was 61 [18.0;100] years, the mean ± SD body mass index (BMI) was 26.8 ± 4 kg/m2, and 2310 (50%) were men. The indications for surgery were complicated diverticulitis in 50% and smoldering diverticulitis in 47.4%. The procedures were performed laparoscopically for 88% and with an anastomosis for 83.8%. The severe complication rate on postoperative day 90 was 11.7%, with a risk of anastomotic leakage of 4.7%. The independent risk factors in multivariate analysis were an American Society of Anesthesiologists (ASA) score ≥ 3, an open approach, and perioperative blood transfusion. Age, perioperative blood transfusion, and Hartmann's procedure were the three independent risk factors for a permanent stoma. CONCLUSIONS: This series provides a real-life picture of elective sigmoidectomy for SDD at a national level. TRIAL REGISTRATION: Comité National Information et Liberté (CNIL) (n°920361).
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Diverticulitis del Colon , Diverticulitis , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Estudios de Cohortes , Colon Sigmoide/cirugía , Diverticulitis/cirugía , Diverticulitis/complicaciones , Diverticulitis del Colon/cirugía , Diverticulitis del Colon/complicaciones , Complicaciones Posoperatorias/etiología , Estudios Retrospectivos , Factores de Riesgo , Resultado del Tratamiento , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , AncianoRESUMEN
Vascular production of nitric oxide (NO) regulates vascular tone. However, highly permeable NO entering the cardiomyocyte would profoundly impact metabolism and signalling without scavenging mechanisms. The purpose of this study was to establish mechanisms of cardiac NO scavenging. Quantitative optical studies of normoxic working hearts demonstrated that micromolar NO concentrations did not alter mitochondria redox state or respiration despite detecting NO oxidation of oxymyoglobin to metmyoglobin. These data are consistent with proposals that the myoglobin/myoglobin reductase (Mb/MbR) system is the major NO scavenging site. However, kinetic studies in intact hearts reveal a minor role (â¼9%) for the Mb/MbR system in NO scavenging. In vitro, oxygenated mitochondria studies confirm that micromolar concentrations of NO bind cytochrome oxidase (COX) and inhibit respiration. Mitochondria had a very high capacity for NO scavenging, importantly, independent of NO binding to COX. NO is also known to quickly react with reactive oxygen species (ROS) in vitro. Stimulation of NO scavenging with antimycin and its inhibition by substrate depletion are consistent with NO interacting with ROS generated in Complex I or III under aerobic conditions. Extrapolating these in vitro data to the intact heart supports the hypothesis that mitochondria are a major site of cardiac NO scavenging. KEY POINTS: Cardiomyocyte scavenging of vascular nitric oxide (NO) is critical in maintaining normal cardiac function. Myoglobin redox cycling via myoglobin reductase has been proposed as a major NO scavenging site in the heart. Non-invasive optical spectroscopy was used to monitor the effect of NO on mitochondria and myoglobin redox state in intact beating heart and isolated mitochondria. These non-invasive studies reveal myoglobin/myoglobin reductase plays a minor role in cardiac NO scavenging. A high capacity for NO scavenging by heart mitochondria was demonstrated, independent of cytochrome oxidase binding but dependent on oxygen and high redox potentials consistent with generation of reactive oxygen species.
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Mioglobina , Óxido Nítrico , Mioglobina/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Óxido Nítrico/metabolismo , Complejo IV de Transporte de Electrones/metabolismo , Cinética , Miocitos Cardíacos/metabolismo , Oxidación-Reducción , Mitocondrias Cardíacas/metabolismo , Consumo de OxígenoRESUMEN
INTRODUCTION: Injuries induced by falls represent the main cause of failure in the French Navy Special Forces selection course. In the present study, we made the assumption that probing the posture might contribute to predicting the risk of fall-related injury at the individual level. METHODS: Before the start of the selection course, the postural signals of 99 male soldiers were recorded using static posturography while they were instructed to maintain balance with their eyes closed. The event to be predicted was a fall-related injury during the selection course that resulted in the definitive termination of participation. Following a machine learning methodology, we designed an artificial neural network model to predict the risk of fall-related injury from the descriptors of postural signal. RESULTS: The neural network model successfully predicted with 69.9% accuracy (95% CI 69.3-70.5) the occurrence of a fall-related injury event during the selection course from the selected descriptors of the posture. The area under the curve value was 0.731 (95% CI 0.725-0.738), the sensitivity was 56.8% (95% CI 55.2-58.4) and the specificity was 77.7% (95% CI 76.8-0.78.6). CONCLUSION: If confirmed with a larger sample, these findings suggest that probing the posture using static posturography and machine learning-based analysis might contribute to inform risk assessment of fall-related injury during military training, and could ultimately lead to the development of novel programmes for personalised injury prevention in military population.
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OBJECTIVES: We investigated hospitalization and hospital mortality rates by cause during the first year of the COVID-19 pandemic in Quebec, Canada. STUDY DESIGN: Interrupted time series and decomposition analysis. METHODS: We analyzed hospital mortality during the first (February 25-August 22, 2020) and second waves (August 23, 2020-March 31, 2021), compared with 2019. We identified the cause of death and examined trends using: 1) interrupted time series analysis; 2) log-binomial regression; and 3) decomposition of cause-specific mortality. RESULTS: Hospitalization rates decreased; however, the proportion of deaths increased from 27.0 per 1000 in 2019 to 35.0 per 1000 in the first wave, for an excess of 8.0 deaths per 1000 admissions. COVID-19 was the cause of a third of excess deaths (2.6 per 1000). Other drivers of excess deaths included respiratory conditions (1.6 deaths per 1000), circulatory disorders (0.6 deaths per 1000), and cancer (0.9 deaths per 1000). COVID-19 was the cause of 58% of excess deaths in the second wave. Interrupted time series regression indicated that the proportion of deaths increased at the outset of the first wave but returned to prepandemic levels before increasing again in the second wave. Compared with 2019, the first wave was associated with 1.31 times (95% confidence interval [CI] 1.28-1.33) and the second wave with 1.17 times (95% CI 1.15-1.19) the risk of death during hospitalization. CONCLUSIONS: The pandemic was associated with a greater risk of hospital mortality. Excess deaths were driven by COVID-19 but also other causes, including respiratory conditions, circulatory disorders, and cancer.
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COVID-19 , Enfermedades Cardiovasculares , Neoplasias , Humanos , Quebec/epidemiología , Mortalidad Hospitalaria , Análisis de Series de Tiempo Interrumpido , Pandemias , HospitalizaciónRESUMEN
Goldbach's conjecture is an unsolved legendary problem. In this paper, we investigate an optimization problem as an attempt to discuss potential applications of the conjecture. In an optimization perspective, the research question, modelled from design of base components, is to select a minimum number of primes to span a given set of target even integers. We formally define the problem, propose integer programming formulations, and develop solution procedures, which are then tested through a computational study.
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This paper reports the results of the active pharmaceutical ingredient (API) fingerprint study, organised by the General European Official Medicines Control Laboratory Network (GEON), on tadalafil. A classical market surveillance study, evaluating compliance to the European Pharmacopoeia, was combined with a fingerprint study, the latter to obtain characteristic data for the different manufacturers, allowing the network laboratories to conduct authenticity tests for future samples, as well as to detect substandard and falsified samples. In total, 46 tadalafil API samples from 13 different manufacturers were collected. For all samples fingerprint data was collected through analysis of impurities and residual solvents, mass spectrometric screening, X-ray powder diffraction and proton nuclear magnetic resonance (1H-NMR). Chemometric analysis revealed that all manufacturers could be characterised based on the impurity, residual solvent and 1H-NMR data. Future suspicious samples in the network will therefore be analysed with these techniques in order to attribute the sample to one of the manufacturers. If the sample cannot be attributed, a more profound investigation will be necessary to reveal the origin of the sample. In cases where the suspect sample is claimed to be from one of the manufacturers included in this study, analysis can be limited to the test distinguishing that manufacturer.
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RGB and CYMK are two major coloring schemes currently available for light colors and pigment colors, respectively. Both systems use letter-based color codes that require a large range of values to represent different colors. The problem is that these two systems are hard to use for manipulating any operations involving combinations of colors, and they lack the capacity for inter-changeability or unification. Based on prime number theory and Goldbach's conjecture, this study presents a universal color system (C235) using a number-based structure to encode, compute and unify all colors on a color wheel. The proposed C235 system offers a unified representation for the efficient encoding and effective manipulation of color. It can be applied to designing a high-rate LCD system and colorizing objects with multiple attributes and DNA codons, opening the door to manipulating colors and lights for even broader applications.
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Development of ready-to-use biomaterials and scaffolds is vital for further advancement of scaffold-based tissue engineering in clinical practice. Scaffolds need to mimic 3D ultrastructure, have adequate mechanical strength, are biocompatible, non-immunogenic and need to promote tissue regeneration in vivo. Although decellularization of native tissues seems promising to deliver scaffolds that meet these criteria, adequate decellularization of hard, poorly penetrable and poorly diffusible tissues remains challenging whilst being a very time-consuming process. In this study, a method to decellularize hard, dense tissues using supercritical carbon-dioxide preceded by a freeze/thaw cycle and followed by several washing steps is presented, demonstrating decellularisation efficiency and substantially reduced production/handling time. Additionally, supercritical carbon-dioxide treatment was used as sterilization method, further reducing the time required to produce the final scaffold. Histological evaluation showed that, after fine-tuning of the process, a partially acellular scaffold was obtained, with preservation of glycosaminoglycans and collagen fibers, albeit that the amount of residual dsDNA was still higher then chemically decellularized tissue. Biomechanical properties of the scaffold were similar to the native, non-decellularized tissue. After sterilization with supercritical carbon-dioxide the simulated functional outcome was more similar to native trachea, when compared to sterilization using gamma irradiation. Thus, decellularization and sterilization using supercritical carbon-dioxide with washing steps is an effective method for dense cartilaginous materials, and tuneable to meet different demands in other applications, but further optimization may be required. STATEMENT OF SIGNIFICANCE: Further advancement of the use of tissue engineered tracheal constructs is restricted by the lack of the ideal scaffold. Decellularized trachea is considered a promising scaffold, but the hard, poorly diffusible tissue remains challenging while forming a very time consumable process. Decellularization using supercritical carbon dioxide (scCO2) seems promising, resulting in efficient removal of cellular material while reducing production and handling time. Addition of scCO2 as a sterilization method resulted in further time reduction while improving functional outcome in comparison with traditional sterilization methods. This study presents an promising alternative method for decellularization and sterilization of dense materials, which can be tuned to meet different demands in other applications.
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Ingeniería de Tejidos , Andamios del Tejido , Ingeniería de Tejidos/métodos , Andamios del Tejido/química , Dióxido de Carbono/química , Esterilización/métodos , Materiales Biocompatibles , Matriz ExtracelularRESUMEN
The catalytic cycle of cytochrome c oxidase (COX) couples the reduction of oxygen to the translocation of protons across the inner mitochondrial membrane and involves several intermediate states of the heme a3-CuB binuclear center with distinct absorbance properties. The absorbance maximum close to 605 nm observed during respiration is commonly assigned to the fully reduced species of hemes a or a3 (R). However, by analyzing the absorbance of isolated enzyme and mitochondria in the Soret (420-450 nm), alpha (560-630 nm) and red (630-700 nm) spectral regions, we demonstrate that the Peroxy (P) and Ferryl (F) intermediates of the binuclear center are observed during respiration, while the R form is only detectable under nearly anoxic conditions in which electrons also accumulate in the higher extinction coefficient low spin a heme. This implies that a large fraction of COX (>50 %) is active, in contrast with assumptions that assign spectral changes only to R and/or reduced heme a. The concentration dependence of the COX chromophores and reduced c-type cytochromes on the transmembrane potential (ΔΨm) was determined in isolated mitochondria during substrate or apyrase titration to hydrolyze ATP. The cytochrome c-type redox levels indicated that soluble cytochrome c is out of equilibrium with respect to both Complex III and COX. Thermodynamic analyses confirmed that reactions involving the chromophores we assign as the P and F species of COX are ΔΨm-dependent, out of equilibrium, and therefore much slower than the ΔΨm-insensitive oxidation of the R intermediate, which is undetectable due to rapid oxygen binding.
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Complejo IV de Transporte de Electrones , Mitocondrias Cardíacas , Complejo IV de Transporte de Electrones/metabolismo , Mitocondrias Cardíacas/metabolismo , Citocromos c/metabolismo , Análisis Espectral , Oxígeno/metabolismo , Hemo/metabolismoRESUMEN
PURPOSE: To study the effects of a perindopril-based regimen on cardiovascular (CV) outcomes in patients with vascular disease in relation to background statin therapy. METHODS: A pooled analysis of the randomized ADVANCE, EUROPA, and PROGRESS trials was performed to evaluate CV outcomes in 29,463 patients with vascular disease treated with perindopril-based regimens versus placebo. The primary endpoint was a composite of CV mortality, nonfatal myocardial infarction, and stroke. Multivariable Cox regression analyses were performed to assess the effects of a perindopril-based regimen versus placebo in relation to statin use. RESULTS: At randomization, 39.5% of the overall combined study population used statins. After a mean follow-up of 4.0 years (SD 1.0), the cumulative event-free survival was highest in the statin/perindopril group and lowest in the no statin/placebo group (91.2% vs. 85.6%, respectively, log-rank p < 0.001). In statin users (adjusted hazard ratio [aHR] 0.87, 95% confidence interval [CI] 0.77-0.98) and non-statin users (aHR 0.80, 95% CI 0.74-0.87), a perindopril-based regimen was associated with a significantly lower risk of the primary endpoint when compared to placebo. The additional treatment effect appeared numerically greater in non-statin users, but the observed difference was statistically nonsignificant. CONCLUSION: Our data suggest that the treatment benefits of a perindopril-based regimen in patients with vascular disease are independent of statin use.
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Human doublecortin (DCX) mutations are associated with severe brain malformations leading to aberrant neuron positioning (heterotopia), intellectual disability and epilepsy. DCX is a microtubule-associated protein which plays a key role during neurodevelopment in neuronal migration and differentiation. Dcx knockout (KO) mice show disorganized hippocampal pyramidal neurons. The CA2/CA3 pyramidal cell layer is present as two abnormal layers and disorganized CA3 KO pyramidal neurons are also more excitable than wild-type (WT) cells. To further identify abnormalities, we characterized Dcx KO hippocampal neurons at subcellular, molecular and ultrastructural levels. Severe defects were observed in mitochondria, affecting number and distribution. Also, the Golgi apparatus was visibly abnormal, increased in volume and abnormally organized. Transcriptome analyses from laser microdissected hippocampal tissue at postnatal day 60 (P60) highlighted organelle abnormalities. Ultrastructural studies of CA3 cells performed in P60 (young adult) and > 9 months (mature) tissue showed that organelle defects are persistent throughout life. Locomotor activity and fear memory of young and mature adults were also abnormal: Dcx KO mice consistently performed less well than WT littermates, with defects becoming more severe with age. Thus, we show that disruption of a neurodevelopmentally-regulated gene can lead to permanent organelle anomalies contributing to abnormal adult behavior.
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Proteína Doblecortina/genética , Neuropéptidos , Animales , Proteínas de Dominio Doblecortina , Aparato de Golgi , Hipocampo/metabolismo , Ratones , Ratones Noqueados , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Mitocondrias/metabolismo , Mutación , Neuropéptidos/genética , Neuropéptidos/metabolismo , Células Piramidales/metabolismoRESUMEN
Positive airway pressure treatment (CPAP) is the gold standard for obstructive sleep apnea syndrome (OSAS). CPAP is highly effective, but its issue lays in poor adherence rates mainly caused by its invasive nature and related stigma. In accordance with a biopsychosocial model of CPAP adherence, psychosocial interventions have been implemented to alleviate low rates of adherence with promising results. The increase in the number of psychosocial interventions has highlighted the need to systematically evaluate their effectiveness. This review aims to identify psychosocial interventions used to increase CPAP adherence, to compile available data on their effectiveness, and the reasons why they are effective. Moreover, the review evaluates the impact of the interventions on sleep quality. Experimental and quasi-experimental studies testing psychosocial interventions (excluding educational only interventions) that aimed to increase CPAP adherence in adults with obstructive sleep apnea vs. no intervention or control group were included. A literature search in PsycINFO, MEDLINE, COCHRANE, EMBASE, CINAHL, and Web of Science was performed for studies published in English and French between 1980 and January 2020. Risk of bias and methodological quality were assessed using the Joanna Briggs Institute Critical Appraisal Tools. Fourteen studies were included involving 1923 participants, six trials tested a motivational intervention, three trials tested a cognitive behavioral intervention and five others tested one of the following: relaxation, exposition therapy, phone coaching, audiotape or stage-matched intervention. Thirteen studies reported a positive effect of the intervention on CPAP adherence, while one reported no effect. Psychosocial interventions for CPAP adherence appear effective at increasing sleep quality, but more studies are needed to test this hypothesis. Reasons for the effectiveness of the interventions were pooled into five categories: time related, the intervention's adaptability, the patient's characteristics, the intervention's nature and characteristics and the intervention's specifics and target. The current review raises a significant gap between the biomedical and psychosocial domains. In fact, even in a psychosocial intervention study, the interpretation of the results revolves around biomedical models and very little consideration is given to biopsychosocial models. Our findings demonstrate the importance of examining the relationship between psychosocial variables and CPAP adherence to better tailor interventions to increase CPAP adherence.
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Presión de las Vías Aéreas Positiva Contínua , Apnea Obstructiva del Sueño , Adulto , Humanos , Cooperación del Paciente , Intervención Psicosocial , Apnea Obstructiva del Sueño/psicología , Apnea Obstructiva del Sueño/terapia , Calidad del Sueño , Cumplimiento y Adherencia al TratamientoRESUMEN
Using data from both the US and UK we examine the survival and mortality of companies in both the early stage or start-up and mature phases. The shape of the mortality curve is broadly similar to that of humans. Even small single cellular organisms such as rotifers have a similar shape. The mortality falls in the early stages in a hyperbolic manner until around 20-30 years when it begins to rise broadly according to the Gompertz exponential law. To explain in simple terms these features we adapt the MinMax model introduced by the authors elsewhere to explain the shape of the human mortality curve.
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Through its Active Pharmaceutical Ingredient Working Group (API-WG) the General European Official Medicines Control Laboratory (OMCL) Network (GEON), co-ordinated by the European Directorate for the Quality of Medicines & HealthCare (EDQM), regularly organises market surveillance studies for specific APIs for conformity to their monograph in the European Pharmacopoeia. During the past years some studies were combined with a fingerprint study of the APIs. The idea is to obtain a fingerprint for each manufacturer of the API under investigation, allowing the OMCL network to identify future samples as well as to detect substandard and falsified APIs. This paper reports the results of the latest fingerprint study, organised on sildenafil citrate API samples. Seventy-nine samples from 14 different manufacturers were collected throughout the Network. Fingerprint data was collected through Mid-Infrared spectroscopy, Raman spectroscopy, liquid chromatography for related substances, gas chromatography for residual solvents, X-ray diffraction and Nuclear Magnetic Resonance (NMR) spectroscopy. Chemometrics applied to the collected data showed that all manufacturers could be discriminated based on the data of only three of these tests, i.e. gas chromatography for residual solvents, X-ray diffraction and proton NMR. Suspicious API samples for sildenafil citrate will therefore be analysed in the future with the selected techniques in order to link the sample to a manufacturer or demonstrate the absence of such link. If the sample cannot be attributed to one of the manufacturers, further analysis and research on provenance and identity will be required. Of course, if the suspected sample claims to originate from one of the manufacturers included in the study, analysis can be limited to the test distinguishing this manufacturer.
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Quimiometría , Cloruro de Polivinilo , Análisis por Conglomerados , Espectroscopía de Resonancia Magnética , Citrato de SildenafilRESUMEN
Like drug products, Active Pharmaceutical Ingredients (APIs) are subject to substandard and falsification issues, which represent a threat to patient health. In order to monitor the quality of drug substances and prevent the use of non-compliant APIs, Official Medicine Control Laboratories work together in a European network developing coordinated strategies and programmes. The API working group proposed a market surveillance study on omeprazole and omeprazole magnesium with the objectives of controlling the pharmaceutical quality of samples, checking compliance with the monographs of the European Pharmacopoeia, and collecting analytical fingerprints that could be further used to differentiate manufacturing sources for future authenticity investigations. The study described in this article reports the analysis carried out by 7 European laboratories on 28 samples from 11 manufacturers with 5 analytical techniques (related substances with HPLC, residual solvents with GC-MS, near infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and X-ray powder diffractometry). The large amount of resulting analytical data were centralized and treated with two chemometric methods: Principal Component Analysis and Hierarchical Clustering Analysis. Data were analyzed separately and in combination (data fusion), allowing us to conclude that NMR and XRPD were suitable to differentiate samples originating from 9 out of 11 manufacturers. Analytical fingerprints associated with chemometrics were demonstrated to be a valuable methodology to discriminate manufacturers of omeprazole and omeprazole magnesium APIs and detect future substandard and falsified APIs.
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Medicamentos Falsificados , Quimiometría , Humanos , Espectroscopía de Resonancia Magnética , Omeprazol , Análisis de Componente PrincipalRESUMEN
AIM OF THE STUDY: Treatment for rectal cancer is very standardized. However, for total mesorectal excision (TME) with positive margins at microscopic pathological examination (classified R1 ), there is no consensus regarding management. The objective of this update was, through a review of the literature, to identify the most suitable management to improve overall survival and/or recurrence-free survival after R1 TME for rectal cancer. PATIENTS AND METHODS: Published national quality guidelines and original studies were searched on Pubmed. Only studies and recommendations concerning the specific management of patients who had undergone R1 TME resection were selected. RESULTS: Five original non-randomized studies and seven published national quality guidelines were selected for review. For patients who have undergone R1 TME resection, the French and European published guidelines issued a Grade A recommendation in favor of post-operative radio-chemotherapy (RCT) for those in whom it had not already been performed pre-operatively. The French and European guidelines recommendation for adjuvant chemotherapy was based only on expert agreement. The original studies emphasized the survival benefit of adjuvant chemotherapy, as opposed to post-operative RCT, which did not seem to improve survival. Salvage surgery was not recommended in any of the studies. CONCLUSION: After R1 TME resection for rectal cancer, adjuvant chemotherapy seems to be indicated when feasible, whereas post-operative RCT and salvage surgery do not appear to improve patient survival.