Discover and publish cutting edge, open research.

Browse 13,847 multi-disciplinary research preprints

Most recent

Zhaomeng Zhuang

and 3 more

Objective To analyze the effect of nasopharyngeal ventilation on the detection rate of colorectal polyps in 200 middle-aged and elderly overweight patients during painless colonoscopy. Methods A total of 100 patients aged 50-75 years, body mass index (BMI) ≥24 or abdominal circumference ≥85 cm in males and ≥82 cm in females, without underlying diseases, who underwent nasopharyngeal ventilation during painless colonoscopy at physical examinations in our hospital from 2019 to 2020, were selected as the observation subjects (n = 100). The control sample area was determined by propensity matching according to the basic information characteristics presented by the observation group. 100 patients received mask oxygen at physical examinations were randomly selected in the control group (n = 100). Results The verification analysis after matching indicated that there were no intraoperative and postoperative adverse reactions, the number of intraoperative limb movements was less than 1, and the intestinal peristalsis intervals were more than 5s in both groups, without atropine intervention. Colonoscopy was performed by senior endoscopists with a withdrawal time of 6-8 min. When the intraoperative SpO2 was lower than 90% but higher than 85%, the patients in the observation group underwent nasopharyngeal ventilation while those in the control group received mask oxygen assisted chin-lift. As a result, the SpO2 was maintained higher than 90%. The detection rate of colorectal polyps was compared between the two groups. Conclusion The detection rate of colorectal polyps in the observation group was higher than that in the control group, with a statistically significant difference. It may result from the reduction of ineffective respiratory movement and intraoperative intestinal peristalsis in middle-aged and elderly overweight patients.
Reply to Betts et al. “When are hypotheses useful in ecology and conservation?”Meredith Root-Bernstein1, 2, 3UMR CESCO, CNRS, Muséum National d’Histoire Naturelle, Paris, FranceCenter of Applied Ecology and Sustainability, Santiago, ChileInstitute of Ecology and Biodiversity, Santiago, ChileWords: 2045It is difficult to disagree with Betts et al. (2021) when they claim that hypotheses are often useful but sometimes not necessary. The difficulty with Betts et al. does not lie with any of their individual points, but rather with the lack of a clear argument giving them structure. This is not just a critique of style. It is relevant because it is an example of what I think is the real problem in ecological research. In my view, the lack of hypotheses in ecology and conservation is not just about the rise of big data approaches, or the documentation of applied work. More generally, I argue that the low use of hypotheses reflects the failure of ecology and conservation to value and develop discipline-specific forms of argument, logic and reasoning. I first address the particular nature of the hypothesis as an argument form, and then the question of whether there are specifically ecological argument forms. Finally I argue that we need a broad set of arguments and logics suitable to the broad set of phenomona in ecology, and that hypotheses are usually derived from non-hypothetico-deductive reasoning and logic. If we want more or better hypotheses, we need more and better forms of non-hypothetico-deductive ecological reasoning.A hypothesis is a form of argument structured so that it can be answered in only one of two ways: rejection or non-rejection. Hypotheses are also characterized by particular ways of framing questions that are considered legitimate, interesting, or elegant, which varies by the discipline or subject matter. I will illustrate my points about the need for forms of argument that fit a subject matter with the Betts et al. paper itself. Betts et al. present their argument about why ecologists should use hypotheses in the form of a couple of hypotheses, the predictions of which they test in a hypothetico-deductive manner on quantitative data using statistical reasoning. They structure their hypothesis as though it were an evolutionary argument: they identify potential discrete individual benefits of adopting a behaviour within a specific environment.
Objective: Investigate the cardiorespiratory effects of non-invasive neurally adjusted ventilatory assist (NIV-NAVA), non-synchronized nasal intermittent positive pressure ventilation (NIPPV), and nasal continuous positive airway pressure (NCPAP) during the critical period shortly after extubation. Hypothesis: Levels of non-invasive pressure support provided and/or presence of synchronization can affect cardiorespiratory parameters. Study design: Randomized crossover trial. Patient-subject selection: Infants with birth weight (BW) ≤ 1250g undergoing their first planned extubation were randomly assigned to all 3 modes following extubation. Methodology: Electrocardiogram and electrical activity of the diaphragm (Edi) were recorded during 30min on each mode. Analysis of heart rate variability (HRV), diaphragmatic activity (Edi area, breath area, amplitude, inspiratory and expiratory times) and respiratory variability (RV) were compared between modes. Results: 23 enrolled infants had full data recordings and analysis: median [IQR] gestational age = 25.9 weeks [25.2-26.4], BW = 760g [595-900], and post-natal age 7 [4-19] days. There were no differences in HRV parameters between modes. During NIV-NAVA and NIPPV, diaphragmatic activity was significantly lower and RV higher than NCPAP. Delivered peak inflation pressures (PIPs) were lower during NIV-NAVA than NIPPV (14 cmH2O [13-16] vs cmH2O 16 [16-17]; p<0.001). However, due to a significantly higher proportion of assisted breaths (99% [92-103] vs. 51% [38-82]; p<0.001) NIV-NAVA provided a higher mean airway pressure (MAP)(9.4 cmH2O [8.2-10.0] vs. 8.2 cmH2O [7.6-9.3]; p=0.002). Conclusions: NIV-NAVA and NIPPV applied shortly after extubation were associated with positive cardiorespiratory effects. This effect was more evident during NIV-NAVA where patient-ventilator synchronization provided a higher MAP with lower PIPs.

Chi Keong Ching

and 14 more

Background: Despite a proven mortality benefit in primary prevention (PP) patients, the utilization of implantable cardioverter-defibrillators (ICD) and cardiac resynchronization therapy-defibrillators (CRT-D) remains low in many geographies. Purpose: The objective of this analysis was to examine the mortality benefit in PP patients by guideline-indicated device type: implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D). Methods: Improve SCA was a prospective, non-randomized, non-blinded multicenter trial that enrolled patients from regions where ICD utilization is low. PP patient’s CRT-D or ICD eligibility was based upon the 2008 ACC/AHA/HRS and 2006 ESC guidelines. Mortality was assessed according to guideline-indicated device type comparing implanted and non-implanted patients. Cox proportional hazards methods were used, adjusting for known factors affecting mortality risk. Results: Among 2,618 PP patients followed for a mean of 20.8 ± 10.8 months, 1,073 were indicated for a CRT-D, and 1,545 were indicated for an ICD. PP CRT-D-indicated patients who received CRT-D therapy had a 58% risk reduction in mortality compared to those without implant (adjusted HR 0.42, 95% CI: 0.28-0.61, P<0.0001). PP patients with an ICD indication had a 43% risk reduction in mortality with an ICD implant compared with no implant (adjusted HR 0.57, 95% CI: 0.41-0.81, P=0.002). Conclusions: This analysis confirms the mortality benefit of adherence to guideline-indicated implantable defibrillation therapy for PP patients in geographies where ICD therapy was underutilized. These results affirm that medical practice should follow clinical guidelines when choosing therapy for PP patients who meet the respective defibrillator device implant indication.

Suvoshree Ghosh

and 10 more

Naadhirah Munshi

and 6 more

Recent research into starling species has revealed the existence of vocal social markers and a link between song temporal structuring and social organisation. The aim of the present study was to develop a genetic tool for understanding the population structuring and behaviour (social/parental transmission) and mating in Pale-winged Starlings (Onychognathus nabouroup), a songbird which is found in arid areas of southern Africa. Using next-generation sequencing, microsatellite markers comprising six dinucleotides, eighteen trinucleotides and twenty-four tetra-nucleotides specific to the Pale-winged Starling were isolated and developed. A total of 77 birds were sampled from the Augrabies Falls Nature Reserve in South Africa (n=53) and the Ai Ais-Richtersveld Transfrontier Park resort in Namibia (n=24), respectively. Fifteen polymorphic microsatellite markers were genotyped. The statistical programme STRUCTURE revealed four different genetic clusters within the two populations. There is low genetic divergence (mean Fst value of 0.01) between the two populations, which is supported by the mean number of effective migrants (22.45) between the populations. ML-Relate data analysis indicated that all individuals sampled from both populations have relatives within and across the two populations with three exceptions in the Augrabies Falls Nature Reserve region. Birds from either population migrate and join the other population maintaining gene flow between the two populations. Each population has a high degree of genetic diversity present between individuals. There is little inbreeding and high allelic richness in both sampled populations, which will allow them to adapt to future environmental changes. The developed microsatellites have inferred information for the success of this species. Social structure, relatedness and behaviour were inferred and regardless of genetic relationships these birds maintain a stable social environment and harbour strong social bonds between same and opposite sex group members as well as mates.

Alison Amoah

and 3 more

Background Guidelines standardise high-quality evidence-based management strategies for clinicians. Uterine fibroids are a highly prevalent condition and may exert significant morbidity. Objectives The purpose of this study was to appraise national and international uterine fibroid guidelines using the validated AGREE-II instrument. Selection Strategy An electronic database search of PubMed and EMBASE from inception to October 2020 for all published English-language uterine fibroid clinical practice guidelines was undertaken. Data Collection and Analysis 939 abstracts were screened for eligibility by two reviewers independently. Three reviewers used the AGREE-II instrument to assess guideline quality in six domains (scope and purpose, stakeholder involvement, rigour of development, clarity of presentation, applicability, and editorial independence). Recommendations were mapped to allow a narrative synthesis regarding areas of consensus and disagreement. Main Results Eight national (AAGL, SOGC 2014, ACOG, ACR, SOGC 2019, CNGOF, ASRM, and SOGC 2015) and one international guideline (RANZOG) were appraised. The highest scoring guideline was RANZOG 2001(score 56.5%). None of the guidelines met the a priori criteria for being high-quality overall (score >= 66%). There were 166 recommendations across guidelines. There were several areas of disagreement and uncertainty. Conclusions There is a need for high-quality fibroid guidelines given heterogeneity across individuals and a large range of treatment modalities available. There are also areas of controversy in the management of fibroids (e.g. Ulipristal acetate, power morcellation) which also should be addressed in any guidelines. Future guidelines should be methodologically robust to allow high-quality decision-making regarding fibroid treatments.

Browse more recent preprints

Recently published in scholarly journals

Mohammed Al-Sadawi

and 7 more

Abstract: Background: This meta-analysis assessed the relationship between Obstructive Sleep Apnea (OSA) and echocardiographic parameters of diastolic dysfunction (DD), which are used in the assessment of Heart Failure with Preserved Ejection Fraction (HFpEF). Methods: We searched the databases including Ovid MEDLINE, Ovid Embase Scopus, Web of Science, Google Scholar, and EBSCO CINAHL from inception up to December 26th, 2020. The search was not restricted to time, publication status or language. Comparisons were made between patients with OSA, diagnosed in-laboratory polysomnography (PSG) or home sleep apnea testing (HSAT), and patients without OSA in relation to established markers of diastolic dysfunction. Results: Primary search identified 2512 studies. A total of 18 studies including 2509 participants were included. The two groups were free of conventional cardiovascular risk factors. Significant structural changes were observed between the two groups. Patients with OSA exhibited greater LAVI (3.94 CI [0.8, 7.07]; p=0.000) and left ventricular mass index (11.10 CI [2.56,19.65]; p=0.000) as compared to control group. The presence of OSA was also associated with more prolonged DT (10.44 ms CI [0.71,20.16]; p=0.04), IVRT (7.85 ms CI[4.48, 11.22]; p=0.000), and lower E/A ratio (-0.62 CI [-1,-0.24]; p=0.001) suggestive of early DD. The E/e’ ratio (0.94 CI[0.44, 1.45]; p=0.000) was increased. Conclusion: An association between OSA and echocardiographic parameters of DD was detected that was independent of conventional cardiovascular risk factors. OSA may be independently associated with DD perhaps due to higher LV mass. Investigating the role of CPAP therapy in reversing or ameliorating diastolic dysfunction is recommended.

Huseyin Kazan

and 6 more

Objective: To investigate the factors, especially preoperative urinalysis, predicting postoperative early infection after retrograde intrarenal surgery (RIRS) in 1-2 cm renal stones. Methods: Of the 642 patients who underwent RIRS between September 2013 and July 2019, 289 patients with a total stone size of 1-2 cm were included in the study. Patients were divided into two groups as with and without postoperative urinary tract infection. The demographic data and perioperative findings of all patients were retrospectively reviewed. Sterile urine cultures were obtained in all patients during the preoperative 30-day period and urine analysis values were included in the data. Results: Urinary system infection (UTI) was seen in 20 (6.9%) of 289 patients. Patient demographics were similar between groups. There was no statistically significant difference between the two groups in terms of stone diameter and stone localization (median diameter 13.5 vs 15, p=0.285). Patients with postoperative UTI had a higher rate of UTI history (55% vs 20.5%, p=0.000) and longer operative times (62.5 vs 60 min., p=0.008). Rate of pyuria, leukocyte esterase and nitrite positivity were observed more frequently in patients with postoperative UTI. In multivariate analysis, UTI history, prolonged operative time, and nitrite positivity were found to be independent risk factors for postoperative UTI. Conclusion: Nitrite positivity in preoperative urinanalysis, history of UTI and prolonged operation time are the factors that predict the postoperative infection in RIRS for stones between 1-2 cm.

Gunter Sturm

and 38 more

Background: There is controversy whether taking β-blockers or ACE inhibitors (ACEI) is a risk factor for more severe systemic insect sting reactions (SSR) and whether it increases the number or severity of adverse events (AE) during venom immunotherapy (VIT). Methods: In this open, prospective, observational, multicenter trial, we recruited patients with a history of a SSR and indication for VIT. The primary objective of this study was to evaluate whether patients taking β-blockers or ACEI show more systemic AE during VIT compared to patients without such treatment. Results: In total, 1,425 patients were enrolled and VIT was performed in 1,342 patients. Of all patients included, 388 (27.2%) took antihypertensive (AHT) drugs (10.4% took β-blockers, 11.9% ACEI, 5.0% β-blockers and ACEI). Only 5.6% of patients under AHT treatment experienced systemic AE during VIT as compared with 7.4% of patients without these drugs (OR: 0.74, 95% CI: 0.43–1.22, p=0.25). The severity of the initial sting reaction was not affected by the intake of β-blockers or ACEI (OR: 1.14, 95% CI: 0.89–1.46, p=0.29). In total, 210 (17.7%) patients were re-stung during VIT and 191 (91.0%) tolerated the sting without systemic symptoms. Of the 19 patients with VIT treatment failure, 4 took β-blockers, none an ACEI. Conclusions: This trial provides robust evidence that taking β-blockers or ACEI does neither increase the frequency of systemic AE during VIT nor aggravate SSR. Moreover, results suggest that these drugs do not impair effectiveness of VIT. (Funded by Medical University of Graz, Austria; number, NCT04269629)

Nazanin Kermani

and 12 more

Background. Patients with severe asthma may have a greater risk of dying from COVID-19 disease. Angiotensin converting enzyme-2 (ACE2) and the enzyme proteases, transmembrane protease serine 2 (TMPRSS2) and FURIN, are needed for viral attachment and invasion into host cells. Methods. We examined microarray mRNA expression of ACE2, TMPRSS2 and FURIN in sputum, bronchial brushing and bronchial biopsies of the European U-BIOPRED cohort. Clinical parameters and molecular phenotypes, including asthma severity, sputum inflammatory cells, lung functions, oral corticosteroid (OCS) use, and transcriptomic-associated clusters, were examined in relation to gene expression levels. Results. ACE2 levels were significantly increased in sputum of severe asthma compared to mild-moderate asthma. In multivariate analyses, sputum ACE2 levels were positively associated with OCS use and male gender. Sputum FURIN levels were significantly related to neutrophils (%) and the presence of severe asthma. In bronchial brushing samples, TMPRSS2 levels were positively associated with male gender and body mass index, whereas FURIN levels with male gender and blood neutrophils. In bronchial biopsies, TMPRSS2 levels were positively related to blood neutrophils. The neutrophilic molecular phenotype characterised by high inflammasome activation expressed significantly higher FURIN levels in sputum than the eosinophilic Type 2-high or the pauci-granulocytic oxidative phosphorylation phenotypes. Conclusion. Levels of ACE2 and FURIN may differ by clinical or molecular phenotypes of asthma. Sputum FURIN expression levels were strongly associated with neutrophilic inflammation and with inflammasome activation. This might indicate the potential for a greater morbidity and mortality outcome from SARS-CoV-2 infection in neutrophilic severe asthma.

Mehmet Pehlivaoğlu

and 5 more

Aim: This study evaluated the effect of intracavitary levobupivacaine infusion diluted with locally applied isotonic solution for pain control in cystoscopy. Methods: Included in this study are 100 patients who had previously undergone transurethral tumor resection for bladder tumor and were followed up by cystoscopy. The patients were randomized into five groups (n = 20). In the first, second, third, and fourth groups, 4, 6, 8, and 10 mL of levobupivacaine HCl (5.0 mg/mL) were mixed with 26, 24, 22, and 20 mL of isotonic solution, respectively. Hence, the total mixture was 30 mL for each group. The fifth group was the control group. In this group, the standard method commonly used in most clinics was utilized. That is, a gel containing Cathejell-2% lidocaine (25 mg lidocaine) was applied. Cystoscopic interventions were performed with a 17.5 Fr rigid cystoscope and 0°, 30°, and 70° lens. During cystoscopy and 30 min later, the pain status of patients was assessed using the Visual Analogue Scale (VAS), and patient satisfaction was questioned. Results: The mean VAS score during and after the cystoscopy procedure was significantly lower in the levobupivacaine groups compared to the lidocaine group. In addition, patient satisfaction in the levobupivacaine groups was significantly higher than in the lidocaine group. No drug-related side-effects were observed in all groups. Conclusion: Thus, levobupivacaine is a more effective drug than lidocaine alone to control pain during cystoscopy. The use of levobupivacaine is recommended to prevent possible complications of general anesthesia by eliminating the need for the aforementioned as well as its cost-saving advantage.

Yanhui Dong

and 4 more

Groundwater age is often used to estimate groundwater recharge through a simplified analytical approach. This estimated recharge is thought to be representative of the mean recharge between the point of entry and the sampling point. However, given the complexity in actual recharge, whether the mean recharge is reasonable is still unclear. This study examined the validity of the method to estimate long-term average groundwater recharge and the possibility of obtaining reasonable spatial recharge pattern. We first validated our model in producing reasonable age distributions using a constant flux boundary condition. We then generated different flow fields and age patterns by using various spatially-varying flux boundary conditions with different magnitudes and wavelengths. Groundwater recharge was estimated and analyzed afterwards using the method at the spatial scale. We illustrated the main findings with a field example in the end. Our results suggest that we can estimate long-term average groundwater recharge with 10% error in many parts of an aquifer. The size of these areas decreases with the increase in both the amplitude and the wavelength. The chance of obtaining a reasonable groundwater recharge is higher if an age sample is collected from the middle of an aquifer and at downstream areas. Our study also indicates that the method can also be used to estimate local groundwater recharge if age samples are collected close to the water table. However, care must be taken to determine groundwater age regardless of conditions.

Xinyi Guan

and 4 more

Adriana Bustamante

and 3 more

Browse more published preprints

How it works

Upload or create your research work
You can upload Word, PDF, LaTeX as well as data, code, Jupyter Notebooks, videos, and figures. Or start a document from scratch.
Disseminate your research rapidly
Post your work as a preprint. A Digital Object Identifier (DOI) makes your research citeable and discoverable immediately.
Get published in a refereed journal
Track the status of your paper as it goes through peer review. When published, it automatically links to the publisher version.
Learn More
Featured communities
Explore More Communities

Other benefits of Authorea


A repository for any field of research, from Anthropology to Zoology


Discuss your preprints with your collaborators and the scientific community

Interactive Figures

Not just PDFs. You can publish d3.js and graphs, data, code, Jupyter notebooks

Featured templates
Featured and interactive
Journals with direct submission
Explore All Templates