Tag: statistics

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Detecting small flaws in two-phase Ti-6Al-4V with rough surfaces.

Ultrasonics. 2020 Mar 10;106:106128

Authors: Li X, Fu Y, Zhang F, Rao Y

Abstract
Surface roughness degrades the performance of ultrasonic methods when detecting sub-wavelength flaws. In this work, a roughness-modified doubly-scattered response (DSR) model is developed to enhance the flaw detection method for two-phase Ti-6Al-4V with rough surfaces. Extreme value statistics are used to calculate the confidence bounds of grain noise, then the bounds are treated as a time-dependent threshold for segmenting flaws in C-scan images of two-phase Ti-6Al-4V with rough surfaces. Three Ti-6Al-4V samples with different surface roughness are designed and manufactured for validating the present method; ultrasonic C-scan results show that it can distinguish sub-wavelength flaws (about 1/3 wavelength) in two-phase Ti-6Al-4V with rough surfaces, which can be extended to industry applications.

PMID: 32283418 [PubMed – as supplied by publisher]

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Adipocytokines are not associated with gestational diabetes mellitus but with pregnancy status.

Cytokine. 2020 Apr 10;131:155088

Authors: Ebert T, Gebhardt C, Scholz M, Schleinitz D, Blüher M, Stumvoll M, Kovacs P, Fasshauer M, Tönjes A

Abstract
AIMS: Adipose tissue-secreted proteins, i.e. adipocytokines, have been identified as potential mediators linking fat mass and adipose tissue dysfunction with impaired glucose homeostasis, alterations in the inflammatory status, and risk of diabetes. The aim of this study was to determine whether seven circulating adipocytokines are associated with gestational diabetes mellitus (GDM) or are altered by metabolic and weight changes during pregnancy itself.
METHODS: A panel of seven adipocytokines (i.e. adiponectin, adipocyte fatty acid-binding protein, chemerin, leptin, Pro-Enkephalin, progranulin, and Pro-Neurotensin) was quantified in serum in a cross-sectional cohort of 222 women with the following three groups matched for age and body mass index: (i) 74 pregnant women with GDM; (ii) 74 pregnant women without GDM; and (iii) 74 non-pregnant and healthy women. A stepwise statistical approach was used by performing pairwise comparisons, principal component analysis (PCA), and partial least square discriminant analysis (PLS-DA).
RESULTS: Five out of seven adipocytokines were dysregulated between pregnant and non-pregnant women, i.e. adiponectin, chemerin, leptin, Pro-Enkephalin, and progranulin. None of the adipocytokines significantly differed between GDM and non-GDM status during pregnancy. The same five adipocytokines clustered in a principal component representing pregnancy-induced effects. Fasting insulin was the most relevant parameter in the discrimination of GDM as compared to pregnant women without GDM, whereas chemerin and adiponectin were most relevant factors to discriminate pregnancy status.
CONCLUSIONS: Pregnancy status but not presence of GDM can be distinguished by the seven investigated adipocytokines in discrimination analyses.

PMID: 32283441 [PubMed – as supplied by publisher]

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EEG-based classification of lower limb motor imagery with brain network analysis.

Neuroscience. 2020 Apr 10;:

Authors: Gu L, Yu Z, Ma T, Wang H, Li Z, Fan H

Abstract
This study aims to investigate the difference in cortical signal characteristics between the left and right foot imaginary movements and to improve the classification accuracy of the experimental tasks. Raw signals were gathered from 64-channel scalp electroencephalograms of 11 healthy participants. Firstly, the cortical source model was defined with 62 regions of interest over the sensorimotor cortex (9 Brodmann areas). Secondly, functional connectivity was calculated by phase lock value for α and β rhythm networks. Thirdly, network-based statistics were applied to identify whether there existed stable and significant subnetworks that formed between the two types of motor imagery tasks. Meanwhile, ten graph theory indices were investigated for each network by t-test to determine statistical significance between tasks. Finally, sparse multinomial logistic regression (SMLR)-support vector machine (SVM), as a feature selection and classification model, was used to analyze the graph theory features. The specific time-frequency (α event-related desynchronization and β event-related synchronization) difference network between the two tasks was congregated at the midline and demonstrated significant connections in the premotor areas and primary somatosensory cortex. A few of statistically significant differences in the network properties were observed between tasks in the α and β rhythm. The SMLR-SVM classification model achieved fair discrimination accuracy between imaginary movements of the two feet (maximum 75% accuracy rate in single-trial analyses). This study reveals the network mechanism of the discrimination of the left and right foot motor imagery, which can provide a novel avenue for the BCI system by unilateral lower limb motor imagery.

PMID: 32283182 [PubMed – as supplied by publisher]

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Evolutionary analysis of SARS-CoV-2: how mutation of Non-Structural Protein 6 (NSP6) could affect viral autophagy.

J Infect. 2020 Apr 10;:

Authors: Benvenuto D, Angeletti S, Giovanetti M, Bianchi M, Pascarella S, Cauda R, Ciccozzi M, Cassone A

Abstract
BACKGROUND: SARS-CoV-2 is a new coronavirus that has spread globally, infecting more than 150000 people, and being declared pandemic by the WHO. We provide here bio-informatic, evolutionary analysis of 351 available sequences of its genome with the aim of mapping genome structural variations and the patterns of selection.
METHODS: A Maximum likelihood tree has been built and selective pressure has been investigated in order to find any mutation developed during the SARS-CoV-2 epidemic that could potentially affect clinical evolution of the infection.
FINDING: We have found in more recent isolates the presence of two mutations affecting the Non-Structural Protein 6 (NSP6) and the Open Reding Frame10 (ORF 10) adjacent regions. Amino acidic change stability analysis suggests both mutations could confer lower stability of the protein structures.
INTERPRETATION: One of the two mutations, likely developed within the genome during virus spread, could affect virus intracellular survival. Genome follow-up of SARS-CoV-2 spread is urgently needed in order to identify mutations that could significantly modify virus pathogenicity.

PMID: 32283146 [PubMed – as supplied by publisher]

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Clinical characteristics of coronavirus disease 2019 (COVID-19) in China: a systematic review and meta-analysis.

J Infect. 2020 Apr 10;:

Authors: Fu L, Wang B, Yuan T, Chen X, Ao Y, Fitzpatrick T, Li P, Zhou Y, Lin Y, Duan Q, Luo G, Fan S, Lu Y, Feng A, Zhan Y, Liang B, Cai W, Zhang L, Du X, Shu Y, Li L, Zou H

Abstract
OBJECTIVE: To better inform efforts to treat and control the current outbreak with a comprehensive characterization of COVID-19.
METHODS: We searched PubMed, EMBASE, Web of Science, and CNKI (Chinese Database) for studies published as of March 2, 2020, and we searched references of identified articles. Studies were reviewed for methodological quality. A random-effects model was used to pool results. Heterogeneity was assessed using I2. Publication bias was assessed using Egger’s test.
RESULTS: 43 studies involving 3600 patients were included. Among COVID-19 patients, fever (83.3% [95% CI 78.4-87.7]), cough (60.3% [54.2-66.3]), and fatigue (38.0% [29.8-46.5]) were the most common clinical symptoms. The most common laboratory abnormalities were elevated C-reactive protein (68.6% [58.2-78.2]), decreased lymphocyte count (57.4% [44.8-69.5]) and increased lactate dehydrogenase (51.6% [31.4-71.6]). Ground-glass opacities (80.0% [67.3-90.4]) and bilateral pneumonia (73.2% [63.4-82.1]) were the most frequently reported findings on computed tomography. The overall estimated proportion of severe cases and case-fatality rate (CFR) was 25.6% (17.4-34.9) and 3.6% (1.1-7.2), respectively. CFR and laboratory abnormalities were higher in severe cases, patients from Wuhan, and older patients, but CFR did not differ by gender.
CONCLUSIONS: The majority of COVID-19 cases are symptomatic with a moderate CFR. Patients living in Wuhan, older patients, and those with medical comorbidities tend to have more severe clinical symptoms and higher CFR.

PMID: 32283155 [PubMed – as supplied by publisher]

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Do Speakers Fully Disclose Potential Conflicts of Interest in Oral and Maxillofacial Surgery?

J Oral Maxillofac Surg. 2020 Mar 18;:

Authors: Durrani I, Ji YD, Peacock ZS

Abstract
PURPOSE: The complete disclosure of conflicts of interest is critical to providing objective and ethical continuing education. The purpose of the present study was to determine the accuracy of the disclosed financial relationships by speakers at an annual oral and maxillofacial surgery conference.
MATERIALS AND METHODS: The present retrospective cross-sectional study compared speakers’ disclosures on the American Association of Oral and Maxillofacial Surgery Dental Implant Conference 2018 website to the payments reported on the Center for Medicare and Medicaid Services Open Payments Database. The predictor variable was the number of companies reported by the speakers. The outcome variable was the number of relevant companies discovered on the Open Payments Database. Other variables evaluated included total dollar sum transferred and the type of speaker (OMS vs non-OMS). Companies providing payments to speakers on the Open Payments Database were deemed relevant if they had provided goods or services relevant to dental implants. Descriptive statistics were computed, and the Student t test was performed, with P < .05 considered to indicate statistical significance.
RESULTS: A total of 43 speakers were included (32 oral and maxillofacial surgeons [OMSs]; 74.4%). We found that 35 of the 43 speakers (81.4%) had received payments relating to dental implants on the Open Payments Database that had not been disclosed on the conference website. On average, the speakers had disclosed 0.65 ± 1.04 companies; however, 2.51 ± 1.32 relevant companies per speaker were reported on the Open Payments Database (P < .0001). The OMS speakers had disclosed 0.47 ± 0.95 company on the conference site but had 2.47 ± 1.32 companies reporting payments on the Open Payments Database (P < .0001). Non-OMS speakers had disclosed 1.18 ± 1.17 companies, with 2.64 ± 1.36 companies listed on the Open Payments Database (P = .0044).
CONCLUSIONS: Continuing education conferences offer an avenue of knowledge transfer; however, the objectivity of the information presented could be affected by undisclosed conflicts of interest. The results from the present study have demonstrated that most speakers at an annual oral and maxillofacial surgery conference have underreported payments from companies relevant to the conference topic.

PMID: 32283077 [PubMed – as supplied by publisher]

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Is It Necessary to Free the Inferior Alveolar Nerve From the Proximal Segment in the Sagittal Split Osteotomy?

J Oral Maxillofac Surg. 2020 Mar 16;:

Authors: Susarla S, Ettinger R, Dodson TB

Abstract
PURPOSE: When the inferior alveolar nerve (IAN) is contained within the proximal segment after a mandibular sagittal split osteotomy (SSO), conventional teaching is to release the nerve so that it freely enters the distal segment. However, manipulation of the IAN may cause further injury. The purpose of this study was to measure IAN neurosensory recovery in SSOs when the nerve was not freed from the proximal segment.
MATERIALS AND METHODS: This was a prospective split-mouth study of patients undergoing bilateral sagittal split osteotomy (BSSO). The sample was composed of patients who underwent a BSSO in which the IAN was intact bilaterally but freely entering the distal segment on 1 side (IANDI) and contained within the proximal segment on the other (IANPR). The outcome of interest was time to functional sensory recovery (FSR) in the IAN, measured in days. Descriptive, bivariate, and Kaplan-Meier statistics were computed. P ≤ .05 was considered statistically significant.
RESULTS: Twenty patients undergoing 40 SSOs were included as study patients. The sample’s mean age was 19.0 ± 2.4 years (range, 15 to 26 years); there were 13 female patients. Of the patients, 15 underwent BSSO whereas 5 underwent BSSO plus genioplasty. The planned mean composite 3-dimensional mandibular movements for IANDI and IANPR were 6.3 ± 2.8 mm (range, 2.5 to 12.3 mm) and 6.3 ± 2.3 mm (range, 2.7 to 10.8 mm), respectively (P = .96). All patients achieved FSR in the bilateral IAN distributions within 1 year of surgery (range, 34 to 284 days). The median times to FSR were 100 days for IANDI and 101 days for IANPR (P = .64).
CONCLUSIONS: In patients undergoing SSOs, maintaining the IAN within the proximal segment of the mandible may not affect neurosensory recovery.

PMID: 32283076 [PubMed – as supplied by publisher]