2,564 research outputs found
Low Velocity Granular Drag in Reduced Gravity
We probe the dependence of the low velocity drag force in granular materials
on the effective gravitational acceleration (geff) through studies of spherical
granular materials saturated within fluids of varying density. We vary geff by
a factor of 20, and we find that the granular drag is proportional to geff,
i.e., that the granular drag follows the expected relation Fprobe = {\eta}
{\rho}grain geff dprobe hprobe^2 for the drag force, Fprobe on a vertical
cylinder with depth of insertion, hprobe, diameter dprobe, moving through
grains of density {\rho}grain, and where {\eta} is a dimensionless constant.
This dimensionless constant shows no systematic variation over four orders of
magnitude in effective grain weight, demonstrating that the relation holds over
that entire range to within the precision of our data
25-Hydroxy vitamin-D, obesity, and associated variables as predictors of breast cancer risk and tamoxifen benefit in NSABP-P1.
Observational studies suggest that host factors are associated with breast cancer risk. The influence of obesity, vitamin-D status, insulin resistance, inflammation, and elevated adipocytokines in women at high risk of breast cancer is unknown. The NSABP-P1 trial population was used for a nested case-control study. Cases were drawn from those who developed invasive breast cancer and controls selected from unaffected participants (≤4 per case) matched for age, race, 5 year Gail score, and geographic location of clinical center as a surrogate for latitude. Fasting serum banked at trial enrolment was assayed for 25-hydroxy vitamin-D (25OHD), insulin, leptin (adipocytokine), and C-reactive protein (CRP, marker of inflammation). Logistic regression was used to test for associations between study variables and the risk of invasive breast cancer. Two hundred and thirty-one cases were matched with 856 controls. Mean age was 54, and 49% were premenopausal. There were negative correlations for 25OHD with body mass index (BMI), insulin, CRP, and leptin. BMI ≥ 25 kg/m(2) was associated with higher breast cancer risk (odds ratio [OR] 1.45, p = 0.02) and tamoxifen treatment was associated with lower risk (OR = 0.44, p < 0.001). Suboptimal 25OHD (<72 nmol/l) did not influence breast cancer risk (OR = 1.06, p = 0.76). When evaluated as continuous variables, 25OHD, insulin, CRP, and leptin levels were not associated with breast cancer risk (all p > 0.34). In this high risk population, higher BMI was associated with a greater breast cancer risk. Serum levels of 25OHD, insulin, CRP, and leptin were not independent predictors of either breast cancer risk or tamoxifen benefit
Yield, impact and fracture performance of injected metallic looking polypropylene parts
Innovation, cost and weight reduction are some factors for the replacement of metals by plastics.
Plastics continue to offer attractive solutions for design engineers. The metallic effect obtained by incorporation
of metal particles in polymers by injection moulding has the advantage of eliminating postprocessing
techniques reducing production cost and time. Nevertheless, undesired defects in the final appearance
of parts are common. These defects occur due to inhomogeneous orientation and anisotropy of the metal
particles. Very few studies are reporting the influence of metallic particles on the morphology development of
PP parts. Therefore, this study is focused on the production of parts made of PP/metallic pigments (aluminium)
by injection moulding in order to understand the influence of metallic particles on the aesthetic, morphological
and mechanical properties of the parts
Multiportal Combined Transorbital and Transnasal Endoscopic Resection of Fibrous Dysplasia
Introduction Historically, access to the anterior skull base was achieved with open procedures. The paradigms to this approach were challenged with the advent of minimally disruptive endoscopic surgical techniques and supporting technology. The next step in the evolution of minimally disruptive surgery was the combination of multiportal endoscopic surgery. Results The patient was an 18-year-old man who presented with right-sided proptosis. Further diagnostic tests revealed a fibrous dysplasia (FD) occupying the skull base and orbit. The lesion was successfully resected. Conclusions The location of the tumor in this case was challenging, in which surgeons at some centers would have opted to have performed as an open procedure instead of endoscopically. The combined transnasal/transorbital approach is an uncommonly used technique that we have used to remove this tumor successfully. The patient also had a unique disease (FD) in a unique location that was treated without complications. This case report highlights how surgeons may use an expanded armamentarium in dealing with complex pathologies
The cardiac torsion as a sensitive index of heart pathology: A model study.
The torsional behaviour of the heart (i.e. the mutual rotation of the cardiac base and apex) was proved to be sensitive to alterations of some cardiovascular parameters, i.e. preload, afterload and contractility. Moreover, pathologies which affect the fibers architecture and cardiac geometry were proved to alter the cardiac torsion pattern. For these reasons, cardiac torsion represents a sensitive index of ventricular performance. The aim of this work is to provide further insight into physiological and pathological alterations of the cardiac torsion by means of computational analyses, combining a structural model of the two ventricles with simple lumped parameter models of both the systemic and the pulmonary circulations. Starting from diagnostic images, a 3D anatomy based geometry of the two ventricles was reconstructed. The myocytes orientation in the ventricles was assigned according to literature data and the myocardium was modelled as an anisotropic hyperelastic material. Both the active and the passive phases of the cardiac cycle were modelled, and different clinical conditions were simulated. The results in terms of alterations of the cardiac torsion in the presence of pathologies are in agreement with experimental literature data. The use of a computational approach allowed the investigation of the stresses and strains in the ventricular wall as well as of the global hemodynamic parameters in the presence of the considered pathologies. Furthermore, the model outcomes highlight how for specific pathological conditions, an altered torsional pattern of the ventricles can be present, encouraging the use of the ventricular torsion in the clinical practice.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jmbbm.2015.10.00
Use of anakinra in severe COVID-19: a case report
Coronavirus Disease 19 is a global healthcare emergency with high lethality rate. Relevant inflammatory cytokine storm is associated with severity of disease and IL1 inhibition is a cornerstone treatment for hyperinflammatory diseases. We present here the case of a patient with critical COVID-19 successfully treated with IL-1 receptor antagonist (anakinra)
Intellectual abilities, language comprehension, speech, and motor function in children with spinal muscular atrophy type 1
Background: Spinal muscular atrophy (SMA) is a chronic, neuromuscular disease characterized by degeneration of
spinal cord motor neurons, resulting in progressive muscular atrophy and weakness. SMA1 is the most severe form
characterized by significant bulbar, respiratory, and motor dysfunction. SMA1 prevents children from speaking a clearly
understandable and fluent language, with their communication being mainly characterized by eye movements,
guttural sounds, and anarthria (type 1a); severe dysarthria (type 1b); and nasal voice and dyslalia (type 1c).
The aim of this study was to analyze for the first time cognitive functions, language comprehension, and speech in
natural history SMA1 children according to age and subtypes, to develop cognitive and language benchmarks that
provide outcomes for the clinical medication trials that are changing SMA1 course/trajectory.
Methods: This is a retrospective study including 22 children with SMA1 (10 affected by subtype 1a-1b: AB and 12 by
1c: C) aged 3–11 years in clinical stable condition with a coded way to communicate “yes” and “no”. Data from the
following assessments have been retrieved from patient charts: one-dimensional Raven test (RCPM), to evaluate
cognitive development (IQ); ALS Severity Score (ALSSS) to evaluate speech disturbances; Brown Bellugy modified for
Italian standards (TCGB) to evaluate language comprehension; and Children’s Hospital of Philadelphia Infant Test of
Neuromuscular Disorders (CHOP-INTEND) to assess motor functioning.
Results: SMA 1AB and 1C children were similar in age, with the former characterized by lower CHOP-INTEND scores
compared to the latter. All 22 children had collaborated to RCPM and their median IQ was 120 with no difference (p =
0.945) between AB and C. Global median score of the speech domain of the ALSSS was 5; however, it was 2 in AB
children, being significantly lower than C (6.5, p < 0.001).
TCGB test had been completed by 13 children, with morphosyntactic comprehension being in the normal range (50).
Although ALSSS did not correlate with both IQ and TCGB, it had a strong (p < 0.001) correlation with CHOP-INTEND described by an exponential rise to maximum.
Conclusions: Although speech and motor function were severely compromised, children with SMA1 showed general
intelligence and language comprehension in the normal range. Speech impairment was strictly related to global motor
impairment
Fluorescein for resection of high-grade gliomas: A safety study control in a single center and review of the literature
Background: The importance of a complete resection of high-grade gliomas (HGGs) has been highlighted in scientific literature, in order to limit tumor recurrence and above all to improve disease-free survival rates. Several fluorescent biomarkers have been tested to improve intraoperative identification of residual tumor; 5-aminolevulinic acid (5-ALA) and fluorescein sodium (FS) are now starting to play a central role in glioma surgery. We performed a retrospective analysis on 47 patients operated for HGGs. Here we report our preliminary data. Methods: Data of 47 consecutive patients with HGG have been collected in our study (25 males, 22 females; mean age: 60.3 years, range: 27-86 years). Fluorescein (5 mg/kg of body weight) was injected intravenously right after the induction of general anesthesia. A YELLOW 560 filter was used on an OPMI Pentero 900 microscope (Carl Zeiss Meditec, Oberkochen, Germany) to complete a microsurgical tumor removal. Glioma resection and quality of life were evaluated preoperative and postoperatively. Results: Gross total resection (GTR) was achieved in 53.2% (n = 25) of patients. A subtotal resection (STR) (>95%) was achieved in 29.8% (n = 14), while a partial resection (PR) (<95%) was obtained in 17% (n = 8) of patients. Overall, in 83% (n = 39) of patients who underwent fluorescence-guided surgery the resection rate achieved was >95%. No adverse effects correlated to fluorescein have been recorded. Conclusion: Fluorescein seems to be safe and effective in the resection of HGGs, allowing a high rate of gross total removal of contrast enhanced areas
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