392 research outputs found
Thermal history of diamond from Arkhangelskaya and Karpinsky-I kimberlite pipes
This work studies and compares the main morphological, structural, and mineralogical features of 350 diamond crystals from the Karpinsky-I and 300 crystals of the Arkhangelskaya kimberlite pipes. The share of crystals of octahedral habit together with individual crystals of transitional forms with sheaf-like and splintery striation is higher in the Arkhangelskaya pipe and makes 15 %. The share of cuboids and tetrahexahedroids is higher in the Karpinsky-I pipe and stands at 14 %. The share of dodecahedroids in the Arkhangelskaya and Karpinsky-I pipes are 60 % and 50 %, respectively. The indicator role of the nitrogen-vacancy N3 center active in absorption and luminescence is shown. Crystals with the N3 absorption system have predominantly octahedral habit or dissolution forms derived from the octahedra. Their thermal history is the most complex. Absorption bands of the lowest-temperature hydrogen-containing defects (3050, 3144, 3154, 3188, 3310 cm−1, 1388, 1407, 1432, 1456, 1465, 1503, 1551, 1563 cm−1), are typical for crystals without N3 system, where in the absorption spectra nitrogen is in the form of low-temperature A and C defects. The above mentioned bands are registered in the spectra of 16 % and 42 % of crystals from the Arkhangelskaya and Karpinsky-I pipes, respectively. The diamond of the studied deposits is unique in the minimum temperature (duration) of natural annealing. Based on a set of features, three populations of crystals were distinguished, differing in growth conditions, post-growth, and thermal histories. The established regularities prove the multi-stage formation of diamond deposits in the north of the East European Platform and significant differences from the diamonds of the Western Cisurals. The results suggest the possibility of the existence of primary deposits dominated by diamonds from one of the identified populations
Successfully treated osteomyelitis involving the entire ischium in a patient with lower-limb paraplegia (a case report)
Introduction: Pelvic bones, probably due to their anatomical features (deep location, good blood supply and other unknown reasons), are rarely affected by exogenous or hematogenous infections. Usually, the flora isolated from the infected pelvic bone is polymicrobial, with the most common microorganisms causing this type of infection being Staphylococcus aureus, Streptococcus, Pseudomonas aeruginosa. The ischial bone (os ischii) is the pelvic bone most often affected by infections, adjacent to deep IV degree decubitus wounds. These wounds are typical for patients with severe neurological symptoms—paraplegics or quadriplegics, as well as those with cerebral disorders, and the process may remain undiagnosed for a long time.Aim: The aim of this article is to focus on the difficulties associated with the early diagnosis of an infection affecting the entire ischial bone and the soft tissues of the adjacent pelvis, as well as the high risk to the patient if adequate treatment is not carried out.Patient and Methods: One patient, a 60-year-old man, with lower-limb paraplegia, after a spinal cord trauma dating back to 10 years ago, is presented.Results: After the applied treatment—resection, removal of the entire ischial bone, and soft tissue debridement, the surgical wound healed primarily, the bone and soft tissue infection of the pelvis was successfully managed. General intoxication of the body was prevented.Conclusion: Accurate and timely debridement, including the risky total excision of the os ischii, as well as the infected adjacent soft tissues in the pelvis, combined with appropriate drainage, may prove to be the only effective and life-saving procedure for the patient
Giant plexiform fibrohistiocytic tumor of the lower leg (a case report)
Introduction: The plexiform fibrohistiocytic tumor is rare, typical for children and adolescents, affects more often the female sex and is most often localized in the upper limb—the region of the wrist joint and the hand. The tumor originates from the subcutaneous adipose tissue, but it is possible to involve the dermis and skeletal muscle. It is characterized by slow growth and sizes between 0.5 and 8 cm, with minimal or no cellular atypism. Three histological varieties have been described: fibrohistiocytic, fibroblastic, and mixed type, which occur with almost equal frequency.Aim: The aim of this article is to present an extremely rare pathohistologically large tumor atypical for the patient’s gender, location and age, and address the surgical challenges of its removal.Patients and Methods: The presented patient is a 54-year-old man with a giant tumor formation involving the anteromedial part of the proximal lower leg, with evolution of over 25 years, and an accompanying disease—cerebral palsy.Result: After en bloc excision of the tumor formation, part of the surgical wound healed secondary. No recurrences were recorded.Conclusion: The pathohistological nature of the tumor is a prerequisite for a complete cure, but the removal of such giant soft tissue formations from the proximal and medial side of the lower leg is a real surgical challenge. The exposed large area of the tibia, with no soft tissue and periosteum, is difficult to cover by local skin plastic surgery, and at the same time it is extremely unsuitable for free plastic procedure
ANEMIC SYNDROME ASSOCIATED TO PARVOVIRUS B19 INFECTION IN PATHOLOGY PREGNANCY WOMEN
Viral infections during pregnancy on a world scale are one of the main reasons for severe complications and mortality of the mother and fetus. The post-infectious anemic syndrome is characterized by low serum iron and increased hepcidin, which is the cause for iron accumulation in the endothelial macrophage system and iron deficiency for the needs of erythropoiesis. Probably the increased hepcidin plays a protective role against the growth of microorganisms by reducing extracellular iron. On the other hand, the increased hepcidin may lead to iron deficiency and to inability for effective compensation upon oral supplementation because it suppressed intestinal iron absorption.
This study aims to determine the involvement of parvovirus B19 in the anemic syndrome development in the course of/during pathological pregnancy.
Materials and Methods: In total 47 serum samples of pregnant women with anemia hospitalized in University Obstetrics and Gynecology Hospital “Maichin Dom”,were tested. Three newborn babies were also included in the study. Serological (ELISA), molecular (PCR), and immunological (CLIA) methods were used. The statistical processing of the results is based on paired Student's t-test and Pearson's correlation.
Results and discussion: 9/47 (19.1%) of patients showed presence of B19V-IgM antibodies. B19-IgG antibodies were detected in 19/47 (40.4%) women. The PCR analysis showed presence of viral DNA in all patients with positive B19V-IgM antibodies. B19V-IgM antibodies were proved in one of the newborn and viral DNA was detected. All three babies were positive for B19V-IgG antibodies. In four of the positive patients with the three diagnostic markers for acute infection, the anemia was determined as iron-deficiency according to the low serum levels of hepcidin 2.54 ± 0.4 μg/L compared to control group of pregnant women without anemia (21.7 ± 3.1 μg/L: P<0.001). In the remaining women with a proven acute B19V infection, we found a statistically significant increased level of serum hepcidin (65.3 ± 5.7 μg/L; P<0.001) compared to non anemic pregnant women.
Conclusion: Assessment of the frequency and the grade of involvement of parvovirus B19 in the anemic syndrome development during pregnancy and determination of the serum level of hepcidin would contribute to the etiological clarification of the occurred anemic syndrome and would prevent improper iron supplementation by pregnant women
Efficiency of Finding Muon Track Trigger Primitives in CMS Cathode Strip Chambers
In the CMS Experiment, muon detection in the forward direction is accomplished by cathode strip chambers~(CSC). These detectors identify muons, provide a fast muon trigger, and give a precise measurement of the muon trajectory. There are 468 six-plane CSCs in the system. The efficiency of finding muon trigger primitives (muon track segments) was studied using~36 CMS CSCs and cosmic ray muons during the Magnet Test and Cosmic Challenge~(MTCC) exercise conducted by the~CMS experiment in~2006. In contrast to earlier studies that used muon beams to illuminate a very small chamber area (~m), results presented in this paper were obtained by many installed CSCs operating {\em in situ} over an area of ~m as a part of the~CMS experiment. The efficiency of finding 2-dimensional trigger primitives within 6-layer chambers was found to be~. These segments, found by the CSC electronics within ~ns after the passing of a muon through the chambers, are the input information for the Level-1 muon trigger and, also, are a necessary condition for chambers to be read out by the Data Acquisition System
Farmland biodiversity and agricultural management on 237 farms in 13 European and two African regions
Farmland is a major land cover type in Europe and Africa and provides habitat for numerous species. The severe decline in farmland biodiversity of the last decades has been attributed to changes in farming practices, and organic and low-input farming are assumed to mitigate detrimental effects of agricultural intensification on biodiversity. Since the farm enterprise is the primary unit of agricultural decision making, management-related effects at the field scale need to be assessed at the farm level. Therefore, in this study, data were collected on habitat characteristics, vascular plant, earthworm, spider, and bee communities and on the corresponding agricultural management in 237 farms in 13 European and two African regions. In 15 environmental and agricultural homogeneous regions, 6–20 farms with the same farm type (e.g., arable crops, grassland, or specific permanent crops) were selected. If available, an equal number of organic and non-organic farms were randomly selected. Alternatively, farms were sampled along a gradient of management intensity. For all selected farms, the entire farmed area was mapped, which resulted in total in the mapping of 11 338 units attributed to 194 standardized habitat types, provided together with additional descriptors. On each farm, one site per available habitat type was randomly selected for species diversity investigations. Species were sampled on 2115 sites and identified to the species level by expert taxonomists. Species lists and abundance estimates are provided for each site and sampling date (one date for plants and earthworms, three dates for spiders and bees). In addition, farmers provided information about their management practices in face-to-face interviews following a standardized questionnaire. Farm management indicators for each farm are available (e.g., nitrogen input, pesticide applications, or energy input). Analyses revealed a positive effect of unproductive areas and a negative effect of intensive management on biodiversity. Communities of the four taxonomic groups strongly differed in their response to habitat characteristics, agricultural management, and regional circumstances. The data has potential for further insights into interactions of farmland biodiversity and agricultural management at site, farm, and regional scale
Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials
Aims:
The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials.
Methods and Results:
Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594).
Conclusions:
GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation
A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.
The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world
D-amino acids reduce Enterococcus faecalis biofilms in vitro and in the presence of antimicrobials used for root canal treatment.
Enterococcus faecalis is the most frequent species present in post-treatment disease and plays a significant role in persistent periapical infections following root canal treatment. Its ability to persist in stressful environments is inter alia, due to its ability to form biofilms. The presence of certain D-amino acids (DAAs) has previously been shown to reduce formation of Bacillus subtilis biofilms. The aims of this investigation were to determine if DAAs disrupt biofilms in early and late growth stages for clinical E. faecalis strains and to test their efficacy in disrupting E. faecalis biofilms grown in sub-minimum inhibitory concentrations of commonly used endodontic biocides. From thirty-seven E. faecalis strains, the ten "best" biofilm producers were used to test the ability of a mixture containing D-leucine, D-methionine, D-tyrosine and D-tryptophan to reduce biofilm growth over a period of 24, 72 and 144 hours and when compared to their cognate L-Amino Acids (LAAs). We have previously shown that sub-MIC levels of tetracycline and sodium hypochlorite promotes biofilm growth in clinical strains of E. faecalis. DAAs were therefore tested for their effectiveness to reduce biofilm growth in the presence of sub-minimal concentrations of sodium hypochlorite (NaOCl-0.031%) and Odontocide™ (0.25% w/v), and in the presence of Odontopaste™ (0.25% w/v). DAAs significantly reduced biofilm formation for all strains tested in vitro, while DAAs significantly reduced biofilm formation compared to LAAs. The inhibitory effect of DAAs on biofilm formation was concentration dependent. DAAs were also shown to be effective in reducing E. faecalis biofilms in the presence of Odontopaste™ and sub-MIC levels of NaOCl and Odontocide™. The results suggest that the inclusion of DAAs into current endodontic procedures may reduce E. faecalis biofilms
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