Miracle-dz/UniFAR-FTUs huggingface dataset:
On the method of modi®ed equations. I: Asymptotic analysis of the Euler forward dierence method

The method of modi®ed equations is studied as a technique for the analysis of ®nite dierence equations. The non-uniqueness of the modi®ed equation of a dierence method is stressed and three kinds of modi®ed equations are introduced. The ®rst modi®ed or equivalent equation is the natural pseudo-dierential operator associated to the original numerical method. Linear and nonlinear combinations of the equivalent equation and their derivatives yield the second modi®ed or second equivalent equation and the third modi®ed or (simply) modi®ed equation, respectively. For linear problems with constant coecients, the three kinds of modi®ed equations are equivalent among them and to the original dierence scheme. For nonlinear problems, the three kinds of modi®ed equations are asymptotically equivalent in the sense that an asymptotic analysis of these equations with the time step as small parameter yields exactly the same results. In this paper, both regular and multiple scales asymptotic techniques are used for the analysis of the Euler forward dierence method, and the resulting asymptotic expansions are veri®ed for several nonlinear, autonomous, ordinary dierential equations. It is shown that, when the resulting asymptotic expansion is uniformly valid, the asymptotic method yields very accurate results if the solution of the leading order equation is smooth and does not blow up, even for large step sizes. Ó 1999 Elsevier Science Inc. All rights reserved.
Combined Liver-Kidney Transplants: Allosensitization and Recipient Outcomes

Background. A pretransplant positive crossmatch in combined liver kidney transplants (CLK) is not considered a contraindication based on the reported immunoprotection conferred by the liver allograft. However, antibody-mediated rejection of the kidney in CLK has been reported recently. This prompted our study to investigate the impact of presensitization on CLK recipient outcomes. Methods. We examined kidney allograft and patient survival by indication of sensitization using Scientific Registry of Transplant Recipients data on CLK performed from 1995 to 2008. We defined sensitization as panel reactive antibody (PRA) more than 10% or a positive T-cell crossmatch (TXM). Results. Among 2484 CLK recipients with available PRA or TXM information, 30% had positive TXM or PRA more than 10%. Among those with TXM information, 12% had a positive crossmatch (n=234). In univariate analyses, patient (P=0.002) and overall kidney graft survival (P=0.015) were significantly diminished among sensitized patients. Differences in patient survival translated to estimated half-lives of 10.3 years among nonsensitized recipients versus 7.8 years among sensitized recipients, In multivariable Cox models, allosensitization was independently associated with patient death (adjusted hazard ratio=1.22, 95% CI, 1.04–1.43) and overall kidney graft loss (adjusted hazard ratio=1.16, 95% CI, 1.00–1.36). Conclusions. These results suggest a negative impact of presensitization on patient and overall renal allograft survival in CLK. Accordingly, presensitization may need to be considered in risk stratification and clinical management of CLK.
Nonoperative Treatment for Lumbar Spinal Stenosis: Clinical and Outcome Results and a 3-Year Survivorship Analysis

Study Design. A cohort study of nonoperatively treated patients with lumbar spinal stenosis. Objective. To assess the effectiveness of aggressive nonsurgical treatment for lumbar spinal stenosis. Background Data. While surgical treatment of lumbar spinal stenosis has been widely accepted, the natural history of this condition is poorly documented. Moreover, the effect of other available therapies is unclear. Methods. Forty-nine patients meeting radiographic and clinical criteria for spinal stenosis underwent nonsurgical intervention consisting of therapeutic exercises, analgesics, and epidural steroid injections. Patients were followed for an average of 33 months. Outcome was assessed using a recently developed patient questionnaire for assessment of patients with lumbar spinal stenosis. Survival analysis was used to assess the probability of surgical intervention over the follow-up period. Results. At 3 years following treatment, 9 of the 49 patients had undergone surgical intervention. Of the remaining 40 unoperated patients, it is reported that two suffered significant motor deterioration, one of whom still reported overall symptoms as mild improvement, and the other as definite worsening. Five of the 40 unoperated patients reported feeling overall symptoms as probably or definitely worse, 12 reported no change, 11 reported only mild improvement, and 12 reported sustained improvement. Twelve of the 40 unoperated patients also had none or only mild pain. Conclusions. The authors conclude that aggressive nonoperative treatment for spinal stenosis remains a reasonable option.
A comparison of classification methods for differentiating fronto‐temporal dementia from Alzheimer's disease using FDG‐PET imaging

Flurodeoxyglucose positron emission tomography (FDG‐PET) is being explored to determine its ability to differentiate between a diagnosis of Alzheimer's disease (AD) and fronto‐temporal dementia (FTD). We have examined statistical discrimination procedures to help achieve this purpose and compared the results to visual ratings of FDG‐PET images. The methods are applied to a data set of 48 subjects with autopsy confirmed diagnoses of AD or FTD (these subjects come from a multi‐centre collaborative study funded by the National Alzheimer's Coordinating Center). FDG‐PET images are composed of thousands of voxels (volume elements) so one is left with a situation where there are vastly more variables than subjects. Therefore, it is necessary to perform a data reduction before a statistical procedure can be applied. Approaches using both the entire image and summary statistics calculated on a number of volumes of interest (VOI) are examined. We performed the data reduction techniques of principal components analysis (PCA) and partial least‐squares (PLS) on the entire image and then used linear discriminant analysis (LDA), quadratic (QDA) or logistic regression (LR) to classify subjects as having AD or FTD. Some of these methods achieve diagnostic accuracy (as assessed by leave‐one‐out cross‐validation) that is similar to visual ratings by expert raters. Methods using PLS appear to be more successful. Averaging or using VOI data may also be helpful. Copyright © 2004 John Wiley & Sons, Ltd.
Miller-Fisher syndrome at King Chulalongkorn Memorial Hospital.

BACKGROUND Miller-Fisher syndrome (MFS), a variant of Guillain-Barré syndrome (GBS) is a self-limiting demyelinating disease of the peripheral nervous system. Clinical spectrum, natural history, prognosis, and pathogenesis of MFS are not fully documented. OBJECTIVE Probe the clinical features of MFS in a tertiary center in Thailand and compare its pattern with other Asian countries. MATERIAL AND METHOD The clinical recordings were searched from databases at King Chulalongkorn Memorial Hospital (KCMH) between 2002 and 2007. Keywords were "Miller-Fisher syndrome" and "Guillain-Barré syndrome". Cases with MFS were recruited The data regarding clinical features, course, treatments, and investigations were reviewed. Comparisons with other large Asian series were demonstrated. RESULTS Six patients (male:female; 3:3) with MFS were analyzed The incident rate is 7.7% that of GBS. The median age was 54.3 years (range 28 to 73 years). MFS frequently started with diplopia followed by ophthalmoplegia and ataxia. Other clinical symptoms included limb dysesthesia and weakness, dysphagia, dysarthria, and diffuse headache. Spontaneous recovery occurred in three patients while two patients received plasmapheresis and one received intravenous immunoglobulin (IVIG). Six months after neurological deficits, all patients were almost free of symptoms and had returned to their normal activities. CONCLUSION The incidence, clinical features, and prognosis of MFS in KCMH were comparable with the previous studies in other Asian countries. High percentage of limb dysesthesia and optic neuropathy were detected in the present series. Headache was also common among Thai MFS. Immuno-pathogenesis of MFS is well documented but immunomodulatory therapy should be considered only in some cases.
Sustained Administration of Trazodone Enhances Serotonergic Neurotransmission: In Vivo Electrophysiological Study in the Rat Brain

Despite its clinical use for more than two decades, the mechanisms by which trazodone acts as an antidepressant are not clear, because it has affinity for a variety of 5-hydroxytryptamine (5-HT; serotonin) receptors and the 5-HT transporter. This study examined the effects of sustained trazodone administration on 5-HT neurotransmission. Electrophysiological recordings were conducted in anesthetized rats. Subcutaneously implanted minipumps delivered vehicle or trazodone (10 mg/kg/day) for 2 and 14 days. A 2-day trazodone administration suppressed the firing rate of raphe 5-HT neurons, which recovered to baseline after 14 days. This was attributable to 5-HT1A autoreceptor desensitization because the suppressant effect of the 5-HT autoreceptor agonist lysergic acid diethylamide was dampened in 14-day trazodone-treated rats. Prolonged trazodone administration did not change the sensitivity of postsynaptic 5-HT1A and α2-adrenergic receptors in hippocampus, but enhanced synaptic 5-HT levels because the 5-HT1A antagonist N-{2-[4 (2-methoxyphenyl)-1-piperazinyl]ethyl}-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride (WAY-100635) enhanced hippocampal firing in treated rats, but not in controls. Trazodone administration for 14 days increased the 50% recovery time value, an index of 5-HT transporter blockade in vivo, and decreased the inhibitory function of terminal 5-HT1B autoreceptors on the electrically evoked release of 5-HT. The agonistic action of trazodone at 5-HT1A receptors was characterized as being full because it did not attenuate the inhibitory action of 5-HT when coapplied locally. The enhanced 5-HT neurotransmission by trazodone is caused in part by reuptake blockade and activation of postsynaptic 5-HT1A receptors, which may account for its effectiveness in major depression.
Schaefer's theorem for graphs

Schaefer's theorem is a complexity classification result for so-called Boolean constraint satisfaction problems: it states that every Boolean constraint satisfaction problem is either contained in one out of six classes and can be solved in polynomial time, or is NP-complete. We present an analog of this dichotomy result for the propositional logic of graphs instead of Boolean logic. In this generalization of Schaefer's result, the input consists of a set W of variables and a conjunction Phi of statements ("constraints") about these variables in the language of graphs, where each statement is taken from a fixed finite set Psi of allowed quantifier-free first-order formulas; the question is whether Phi is satisfiable in a graph. We prove that either Psi is contained in one out of 17 classes of graph formulas and the corresponding problem can be solved in polynomial time, or the problem is NP-complete. This is achieved by a universal-algebraic approach, which in turn allows us to use structural Ramsey theory. To apply the universal-algebraic approach, we formulate the computational problems under consideration as constraint satisfaction problems (CSPs) whose templates are first-order definable in the countably infinite random graph. Our method to classify the computational complexity of those CSPs produces many statements of independent mathematical interest.
Tumor necrosis factor and nitric oxide production by retinal Müller glial cells from rats exhibiting inherited retinal dystrophy

The primary cause of the inherited retinal dystrophy observed in Royal College of Surgeons (RCS) rats is located in the retinal pigmented epithelium, which is unable to phagocytize photoreceptor outer segments. We have demonstrated here that retinal Müller glial (RMG) cells obtained from RCS dystrophic rats and stimulated in vitro with lipopolysaccharide (LPS) and interferon‐gamma (IFN‐γ) accumulated higher levels of tumor necrosis factor (TNF) and inducible nitric oxide synthase (NOS II) mRNA and released in culture supernatants significantly higher amounts of TNF and nitrite compared to cells derived from nondystrophic controls. The TNF and NOS II mRNA expression and TNF and nitrite synthesis induced in RMG cells from both strains by LPS + IFN‐γ was significantly prevented by including transforming growth factor‐beta (TGF‐β) in the culture medium. Coincubation of the stimulants with an inhibitor of NOS II, NG‐monomethyl‐L‐arginine (L‐NMMA), while inhibiting nitrite synthesis, induced an increase of TNF production in supernatants from RMG cells without increasing TNF mRNA levels. The retinal dystrophy observed in RCS dystrophic rats could result from an abnormal susceptibility of RMG cells from RCS dystrophic rats to produce TNF and NO in response to stimulants. Administration of the immunomodulatory cytokine TGF‐β or inhibitors of NOS II would provide additional research avenues for photoreceptor rescue. GLIA 20:59‐69, 1997. © 1997 Wiley‐Liss, Inc.
Crystal structure of a phycourobilin-containing phycoerythrin at 1.90-A resolution.

The structure of R-phycoerythrin (R-PE) from the red alga Griffithsia monilis was solved at 1.90-A resolution by molecular replacement, using the atomic coordinates of cyanobacterial phycocyanin from Fremyella diplosiphon as a model. The crystallographic R factor for the final model is 17.5% (Rfree 22.7%) for reflections in the range 100-1.90 A. The model consists of an (alphabeta)2 dimer with an internal noncrystallographic dyad and a fragment of the gamma-polypeptide. The alpha-polypeptide (164 amino acid residues) has two covalently bound phycoerythrobilins at positions alpha82 and alpha139. The beta-polypeptide (177 residues) has two phycoerythrobilins bound to residues beta82 and beta158 and one phycourobilin covalently attached to rings A and D at residues beta50 and beta61, respectively. The electron density of the gamma-polypeptide is mostly averaged out by threefold crystallographic symmetry, but a dipeptide (Gly-Tyr) and one single Tyr could be modeled. These two tyrosine residues of the gamma-polypeptide are in close proximity to the phycoerythrobilins at position beta82 of two symmetry-related beta-polypeptides and are related by the same noncrystallographic dyad as the (alphabeta)2 dimer. Possible energy transfer pathways are discussed briefly.
Runtime mechanisms for leakage current reduction in CMOS VLSI circuits

Abstract. This paper describes two runtime mechanisms for reducing the leakage current of a CMOS circuit. In both cases, it is assumed that the system or environment produces a "sleep" signal that can be used to indicate that the circuit is in a standby mode. In the first method, the "sleep" signal is used to shift in a new set of external inputs and pre-selected internal signals into the circuit with the goal of setting the logic values of all of the internal signals so as to minimize the total leakage current in the circuit. This minimization is possible because the leakage current of a CMOS gate is a strong function of the input combination applied to its inputs. In the second method, NMOS and PMOS transistors are added to some of the gates in the circuit to increase the controllability of the internal signals of the circuit and decrease the leakage current of the gates using the "stack effect". This is, however, done carefully so that the minimum leakage is achieved subject to a delay constraint for all input-output paths in the circuit. In both cases, Boolean satisfiability is used to formulate the problems, which are subsequently solved by employing a highly efficient SAT solver. Experimental results on the circuits in the MCNC91 benchmark suite demonstrate that it is possible to reduce the leakage current by up to 70% in VLSI circuits at the expense of a very small overhead.
Assessing the genetic component of the susceptibility of mice to viral infections

Abstract Laboratory mice often exhibit wide differences in susceptibility when infected experimentally with viruses. Based on such observations, experiments have been designed to investigate the determinism of these differences at the molecular level, and a few genes that play a major role in the innate mechanisms of defence of the species toward viral aggressions have been characterised. For example, the extraordinary resistance of SJL mice to experimental infections with hepatitis virus strain A59 is the consequence of a structural alteration of a cell adhesion molecule which normally binds to the spikes of the virus, allowing its entry into the cells. If the virus cannot bind to the molecule, or if the molecule is absent, epithelial cells of the intestine and liver are not infected and mice are resistant. In the same way, most — not to say all — laboratory strains of mice are susceptible to infections with orthomyxoviruses or flaviviruses because essential molecules, the synthesis of which is normally triggered by interferon, are defective in these mice. Wild mice, by contrast — probably because they are constantly exposed to natural infections — are resistant. Finally, some mouse strains resist experimental infections by the mouse cytomegalovirus 1 (MCMV-1) because, once infected, these mice synthesise a molecule at the surface of infected cells which allows immediate recognition and killing by natural killer (NK) cells. With the exuberant development of mouse genetics and the constant generation of new mutant alleles, it is likely that many more genes with an impact on the phenotype of resistance or susceptibility will be identified in the forthcoming years. These genes are probably numerous, however, and many of them presumably interact with each other and/or have additive effects. This might slow down progress in our understanding of the innate mechanism of defence.
Heart rate detection from an electronic weighing scale

We propose a novel technique for beat-to-beat heart rate detection based on the ballistocardiographic (BCG) force signal from a subject standing on a common electronic weighing scale. The detection relies on sensing force variations related to the blood acceleration in the aorta, works even if wearing footwear and does not require any sensors attached to the body because it uses the load cells in the scale. We have devised an approach to estimate the sensitivity and frequency response of three commercial weighing scales to assess their capability to detect the BCG force signal. Static sensitivities ranged from 490 nV V−1 N−1 to 1670 nV V−1 N−1. The frequency response depended on the subject's mass but it was broad enough for heart rate estimation. We have designed an electronic pulse detection system based on off-the-shelf integrated circuits to sense heart-beat-related force variations of about 0.24 N. The signal-to-noise ratio of the main peaks of the force signal detected was higher than 30 dB. A Bland–Altman plot was used to compare the RR time intervals estimated from the ECG and BCG force signals for 17 volunteers. The error was ±21 ms, which makes the proposed technique suitable for short-term monitoring of the heart rate.
Imaging and modelling of digestion in the stomach and the duodenum

Abstract Gastroduodenal physiology is traditionally understood in terms of motor‐secretory functions and their electrical, neural and hormonal controls. In contrast, the fluid‐mechanical functions that retain and disperse particles, expose substrate to enzymes, or replenish the epithelial boundary with nutrients are little studied. Current ultrasound and magnetic resonance imaging allows to visualize processes critical to digestion like mixing, dilution, swelling, dispersion and elution. Methodological advances in fluid mechanics allow to numerically analyse the forces promoting digestion. Pressure and flow fields, the shear stresses dispersing particles or the effectiveness of bolus mixing can be computed using information on boundary movements and on the luminal contents. These technological advances promise many additional insights into the mechanical processes that promote digestion and absorption.
Semi-Supervised Method for Multi-category Emotion Recognition in Tweets

Each tweet is limited to 140 characters. This constraint surprisingly makes Twitter a more spontaneous platform to express our emotions. Detecting emotions and correctly classifying them automatically is an increasingly important task if we want to understand how large groups of people feel about an event or relevant topic. However, constructing supervised classifiers can be a daunting task because of the high manual annotation costs. We propose constructing emotion classifiers with a minimal amount of initial knowledge (e.g. A general-purpose emotion lexicon) and using a semi-supervised learning method to extend it to correctly detect more emotional tweets within a specific domain. Additionally, we show that our algorithm, Balanced Weighted Voting (or BWV) is able to overcome the imbalanced distribution of emotions in the initial labeled data. Our validation experiments show that BWV improves the performance of three initial classifiers, at least in the specific domain of sports. Furthermore, its comparison with other two learning strategies reveals its superiority in terms of macro F1-score, as well as more stable performance among different emotion categories.
The NMR structure of a stable and compact all‐β‐sheet variant of intestinal fatty acid‐binding protein

Intestinal fatty acid‐binding protein (I‐FABP) has a clam‐shaped structure that may serve as a scaffold for the design of artificial enzymes and drug carriers. In an attempt to optimize the scaffold for increased access to the interior‐binding cavity, several helix‐less variants of I‐FABP have been engineered. The solution‐state NMR structure of the first generation helix‐less variant, known as Δ17‐SG, revealed a larger‐than‐expected and structurally ill‐defined loop flanking the deletion site. We hypothesized that the presence of this loop, on balance, was energetically unfavorable for the stability of the protein. The structure exhibited no favorable pairwise or nonpolar interactions in the loop that could offset the loss of configurational entropy associated with the folding of this region of the protein. As an attempt to generate a more stable protein, we engineered a second‐generation helix‐less variant of I‐FABP (Δ27‐GG) by deleting 27 contiguous residues of the wild‐type protein and replacing them with a G‐G linker. The deletion site of this variant (D9 through N35) includes the 10 residues spanning the unstructured loop of Δ17‐SG. Chemical denaturation experiments using steady‐state fluorescence spectroscopy showed that the second‐generation helix‐less variant is energetically more stable than Δ17‐SG. The three‐dimensional structure of apo‐Δ27‐GG was solved using triple‐resonance NMR spectroscopy along with the structure calculation and refinement protocols contained in the program package ARIA/CNS. In spite of the deletion of 27 residues, the structure assumes a compact all‐β‐sheet fold with no unstructured loops and open access to the interior cavity.