124 research outputs found
Garvey-Kelson Relations for Nuclear Charge Radii
The Garvey-Kelson relations (GKRs) are algebraic expressions originally
developed to predict nuclear masses. In this letter we show that the GKRs
provide a fruitful framework for the prediction of other physical observables
that also display a slowly-varying dynamics. Based on this concept, we extend
the GKRs to the study of nuclear charge radii. The GKRs are tested on 455 out
of the approximately 800 nuclei whose charge radius is experimentally known. We
find a rms deviation between the GK predictions and the experimental values of
only 0.01 fm. This should be contrasted against some of the most successful
microscopic models that yield rms deviations almost three times as large.
Predictions - with reliable uncertainties - are provided for 116 nuclei whose
charge radius is presently unknown.Comment: 4 pages and 3 figure
The interplay of intrinsic and extrinsic bounded noises in genetic networks
After being considered as a nuisance to be filtered out, it became recently
clear that biochemical noise plays a complex role, often fully functional, for
a genetic network. The influence of intrinsic and extrinsic noises on genetic
networks has intensively been investigated in last ten years, though
contributions on the co-presence of both are sparse. Extrinsic noise is usually
modeled as an unbounded white or colored gaussian stochastic process, even
though realistic stochastic perturbations are clearly bounded. In this paper we
consider Gillespie-like stochastic models of nonlinear networks, i.e. the
intrinsic noise, where the model jump rates are affected by colored bounded
extrinsic noises synthesized by a suitable biochemical state-dependent Langevin
system. These systems are described by a master equation, and a simulation
algorithm to analyze them is derived. This new modeling paradigm should enlarge
the class of systems amenable at modeling.
We investigated the influence of both amplitude and autocorrelation time of a
extrinsic Sine-Wiener noise on: the Michaelis-Menten approximation of
noisy enzymatic reactions, which we show to be applicable also in co-presence
of both intrinsic and extrinsic noise, a model of enzymatic futile cycle
and a genetic toggle switch. In and we show that the
presence of a bounded extrinsic noise induces qualitative modifications in the
probability densities of the involved chemicals, where new modes emerge, thus
suggesting the possibile functional role of bounded noises
Simple Nudges for Better Password Creation
Recent security breaches have highlighted the consequences of reusing passwords across online accounts. Recent guidance on password policies by the UK government recommend an emphasis on password length over an extended character set for generating secure but memorable passwords without cognitive overload. This paper explores the role of three nudges in creating website-specific passwords: financial incentive (present vs absent), length instruction (long password vs no instruction) and stimulus (picture present vs not present). Mechanical Turk workers were asked to create a password in one of these conditions and the resulting passwords were evaluated based on character length, resistance to automated guessing attacks, and time taken to create the password. We found that users created longer passwords when asked to do so or when given a financial incentive and these longer passwords were harder to guess than passwords created with no instruction. Using a picture nudge to support password creation did not lead to passwords that were either longer or more resistant to attacks but did lead to account-specific passwords
The PREDICT study uncovers three clinical courses of acutely decompensated cirrhosis that have distinct pathophysiology
Background & Aims: Acute decompensation (AD) of cirrhosis is defined as the acute development of ascites, gastrointestinal hemorrhage, hepatic encephalopathy, infection or any combination thereof, requiring hospitalization. The presence of organ failure(s) in patients with AD defines acute-on-chronic liver failure (ACLF). The PREDICT study is a European, prospective, observational study, designed to characterize the clinical course of AD and to identify predictors of ACLF. Methods: A total of 1,071 patients with AD were enrolled. We collected detailed pre-specified information on the 3-month period prior to enrollment, and clinical and laboratory data at enrollment. Patients were then closely followed up for 3 months. Outcomes (liver transplantation and death) at 1 year were also recorded. Results: Three groups of patients were identified. Pre-ACLF patients (n = 218) developed ACLF and had 3-month and 1-year mortality rates of 53.7% and 67.4%, respectively. Unstable decompensated cirrhosis (UDC) patients (n = 233) required ≥1 readmission but did not develop ACLF and had mortality rates of 21.0% and 35.6%, respectively. Stable decompensated cirrhosis (SDC) patients (n = 620) were not readmitted, did not develop ACLF and had a 1-year mortality rate of only 9.5%. The 3 groups differed significantly regarding the grade and course of systemic inflammation (high-grade at enrollment with aggravation during follow-up in pre-ACLF; low-grade at enrollment with subsequent steady-course in UDC; and low-grade at enrollment with subsequent improvement in SDC) and the prevalence of surrogates of severe portal hypertension throughout the study (high in UDC vs. low in pre-ACLF and SDC). Conclusions: Acute decompensation without ACLF is a heterogeneous condition with 3 different clinical courses and 2 major pathophysiological mechanisms: systemic inflammation and portal hypertension. Predicting the development of ACLF remains a major future challenge. ClinicalTrials.gov number: NCT03056612. Lay summary: Herein, we describe, for the first time, 3 different clinical courses of acute decompensation (AD) of cirrhosis after hospital admission. The first clinical course includes patients who develop acute-on-chronic liver failure (ACLF) and have a high short-term risk of death – termed pre-ACLF. The second clinical course (unstable decompensated cirrhosis) includes patients requiring frequent hospitalizations unrelated to ACLF and is associated with a lower mortality risk than pre-ACLF. Finally, the third clinical course (stable decompensated cirrhosis), includes two-thirds of all patients admitted to hospital with AD – patients in this group rarely require hospital admission and have a much lower 1-year mortality risk
Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.
Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field
Facial Nerve Decompression by Middle Fossa Craniotomy in Post-Traumatic Paralysis
Objective:
To describe our experience with the middle fossa craniotomy approach for decompression (MFCD) of the labyrinthine and tympanic segments of the facial nerve in facial nerve paralysis as a complication of temporal bone fracture.
Methods:
Retrospective review of 10 cases of acute and total facial nerve paralysis after temporal bone fracture. The MFCD was performed in eight cases (six patients), and two cases did not have surgery. Demographic, clinical, and facial nerve function outcomes were assessed using the House-Brackmann (HB) grading scale.
Results:
Facial function at presentation was HB 6 for all cases. All of the MFCD cases achieved a facial function of at least HB 3. Facial functions in the two nonsurgical cases were HB 5 and HB 6. The median time for onset of recovery of function was 21 days postoperatively (range, 17-61 days). Onset of recovery within 30 days after surgery was associated with better outcome. There were no serious postoperative complications.
Conclusion:
MFCD is a safe and effective option for patients with total and acute facial paralysis after temporal bone fracture. Prompt diagnosis and management appear to be favorable predictive factors
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Phenotype/genotype correlations in a DFNB1 cohort with ethnical diversity
The aim of this study was to 1) determine the prevalence of DFNB1 in a cohort of children with prelingual nonsyndromic sensorineural hearing loss (HL), 2) study phenotype/genotype correlations, and 3) establish guidelines for genetic counseling of DFNB1.
Prospective cohort study.
A total of 119 unrelated children (107 sporadic and 12 familial cases) with prelingual nonsyndromic HL underwent mutational screening for DFNB1 in the noncoding and coding exons of GJB2, in addition to the del(GJB6-D13S1830) mutation of GJB6. Information regarding demographics, HL, developmental milestones, inner ear high resolution computed tomography, hearing habilitation, and associated phenotypic manifestations were collected in probands with biallelic pathogenic mutations.
The prevalence of DFNB1 in cases of prelingual nonsyndromic HL was 26% (25% in sporadic and 50% in familial cases). In regards to ethnicity, 19 probands were white and 12 probands of Hispanic ancestry had a mixed racial origin (black, Native-American, white). Greater allelic heterogeneity was shown with Hispanics of mixed descent exhibiting 10 of 12 GJB2 allelic variants, whereas whites had 4 of 10 allelic variants (Fisher exact test, P = .033); both ethnic groups had theGJB6 deletion. The frequency of deaf carriers of the most commonly found mutation (c.35delG) was 8% and higher than that of expected for the general population (Fisher exact test, P = .015). The hearing phenotype was variable in terms of degree of impairment (from mild to profound), onset, symmetry and progression, and there was no correlation with any specific genotype class. DFNB1 probands had normal gross motor development, and the frequency of computed tomography abnormalities of the inner ear was low at 8%. No other specific associated phenotypic manifestations were identified.
DFNB1 is the most common identifiable etiology of nonsyndromic prelingual deafness both in sporadic and familial cases in this cohort with ethnic diversity. The greater allelic variability observed in Hispanics and the high frequency of deaf probands carrying a single allelic variant of DFNB1 support extending the screening to noncoding regions of GJB2 and to the remaining DFNB1 locus. Most probands have a congenital HL that is stable, symmetrical and without associated manifestations, but the audiometric profile should not be the only criteria for offering mutational screening of DFNB1 because of the observed variability. These data can be applied to direct the clinical evaluation and effectively counsel families of children with DFNB1
Predicting depth of electrode insertion by cochlear measurements on computed tomography scans
To evaluate the effectiveness of cochlear measures obtained by high-resolution computed tomography (HRCT) scan in predicting depth of cochlear implant insertion.
Retrospective case review.
Patients who underwent cochlear implantation in an academic referral center between 2010 and 2013 were considered. Inclusion criteria included available preoperative HRCT scan and complete operative data. Subjects with labyrinthitis ossificans, cochlear hypoplasia, or major inner ear malformations were excluded. Subsequently, measures of cochlear height in the coronal plane and basal turn width in the axial plane were obtained using electronic calipers of the stored digital HRCT images by a blinded investigator. The insertion was considered deep when the electrode was placed at least 23 mm into the cochlea. Subjects were divided into those who had a deep insertion and those who did not. Regression analyses were done to associate cochlear measures with deep insertion.
A deep insertion was possible in 25 patients out of 35. There was no statistically significant association between deep insertion and age at implantation, gender, and type of cochleostomy. The mean cochlear height was 6.22 mm (standard deviation [SD] = 0.32 mm) and 5.80 mm (SD = 0.3mm) in subjects with and without deep insertion, respectively (Student t test, P = .0015). Only cochlear height showed an association with deep insertion (logistic regression, P = .0007). For a cochlear height of 6.27 mm, the probability of deep insertion was 0.90.
Linear measurements of standard CT scans of the cochlea can predict the depth of insertion and may help the selection of the appropriate electrode array preoperatively.
4. Laryngoscope, 126:1656-1661, 2016
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Malleus Handle: Determinant of Success in Ossiculoplasty
Objective Identify prognostic factors affecting outcome in ossicular chain reconstruction (OCR). Methods Retrospective case series of electronic database at an academic institution. We reviewed 209 cases of OCR performed from January 2000 through September 2007, and systematically collected demographic, clinical, audiologic, and outcome information. Univariate analyses of group differences in terms of postoperative air-bone gap (ABG) changes were evaluated by ANOVA. Multiple regression analyses were used to examine the relationship between postoperative air-bone gap (dependent variable) and the independent variables. Results There were 107 cases of OCR which met inclusion criteria (45 primary and 62 revision tympanoplasties) with an average follow-up of 19 months. There were 36 cases of chronic suppurative otitis media without cholesteatoma and 71 cases with cholesteatoma. The mean preoperative ABG was 32 ± 15 dB and the mean postoperative ABG was 23 ± 14 dB (P < 0.001). Of the independent variables analyzed, the type of procedure (i.e., tympanoplasty vs. canal-wall up vs. canal-wall down) and status of malleus handle were predictive of the success of OCR. Conclusions Favorable prognostic factors in OCR include smaller preoperative ABG and the presence of an intact malleus handle. Our findings support the practice of performing OCR at the time of the second-look procedure
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Malleus handle: determinant of success in ossiculoplasty
The purpose of this study is to identify prognostic factors affecting outcome in ossicular chain reconstruction (OCR).
This study is a retrospective case series of electronic database at an academic institution.
We reviewed 209 cases of chronic supportive otitis media performed from January 2000 through December 2007 and collected demographic, clinical, audiologic, and outcome information. Univariate analyses of group differences in terms of postoperative air-bone gap (ABG) changes were evaluated by analysis of variance. Multiple regression analyses were used to examine the relationship between postoperative ABG and the independent variables.
There were 105 cases of OCR the met the inclusion criteria (44 primary and 61 revision tympanoplasties), with an average follow-up of 19 months. The diagnoses were chronic suppurative otitis media without cholesteatoma in 36 cases and cholesteatoma in 69 cases. The mean preoperative ABG was 34 +/- 15 dB, and the mean postoperative ABG was 20 +/- 14 dB (P < 0.001). Of the independent variables analyzed, the type of procedure (ie, OCR performed during second-look tympanoplasty vs canal wall up vs canal wall down), preoperative ABG, and status of malleus handle were predictive of the success of OCR.
Favorable prognostic factors in OCR include smaller preoperative ABG and the presence of an intact malleus handle
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