Laboratory for Research on Enterprise and Decisions
facilityGabès, Tunisia
Research output, citation impact, and the most-cited recent papers from Laboratory for Research on Enterprise and Decisions. Aggregated across the NobleBlocks index of 300M+ scholarly works.
Top-cited papers from Laboratory for Research on Enterprise and Decisions
Deep-submicron technology is having a significant impact on permanent, intermittent, and transient classes of faults. This article discusses the main trends and challenges in circuit reliability, and explains evolving techniques for dealing with them.
Vaccinia virus immunization provides lifelong protection against smallpox, but the mechanisms of this exquisite protection are unknown. We used polychromatic flow cytometry to characterize the functional and phenotypic profile of CD8(+) T cells induced by vaccinia virus immunization in a comparative vaccine trial of modified vaccinia virus Ankara (MVA) versus Dryvax immunization in which protection was assessed against subsequent Dryvax challenge. Vaccinia virus-specific CD8(+) T cells induced by both MVA and Dryvax were highly polyfunctional; they degranulated and produced interferon gamma, interleukin 2, macrophage inflammatory protein 1beta, and tumor necrosis factor alpha after antigenic stimulation. Responding CD8(+) T cells exhibited an unusual phenotype (CD45RO(-)CD27(intermediate)). The unique phenotype and high degree of polyfunctionality induced by vaccinia virus also extended to inserted HIV gene products of recombinant NYVAC. This quality of the CD8(+) T cell response may be at least partially responsible for the profound efficacy of these vaccines in protection against smallpox and serves as a benchmark against which other vaccines can be evaluated.
The discovery of molecules that bind tightly and selectively to desired proteins continues to drive innovation at the interface of chemistry and biology. This paper describes the binding of human insulin by the synthetic receptor cucurbit[7]uril (Q7) in vitro. Isothermal titration calorimetry and fluorescence spectroscopy experiments show that Q7 binds to insulin with an equilibrium association constant of 1.5 × 10(6) M(-1) and with 50-100-fold selectivity versus proteins that are much larger but lack an N-terminal aromatic residue, and with >1000-fold selectivity versus an insulin variant lacking the N-terminal phenylalanine (Phe) residue. The crystal structure of the Q7·insulin complex shows that binding occurs at the N-terminal Phe residue and that the N-terminus unfolds to enable binding. These findings suggest that site-selective recognition is based on the properties inherent to a protein terminus, including the unique chemical epitope presented by the terminal residue and the greater freedom of the terminus to unfold, like the end of a ball of string, to accommodate binding. Insulin recognition was predicted accurately from studies on short peptides and exemplifies an approach to protein recognition by targeting the terminus.
Abstract In Parts I and II we have derived explicit formulas for the distribution limit u of the solution of the KdV equation as the coefficient of u xxx tends to zero. This formula contains n parameters β 1, …, β n whose values, as well as whose number, depends on x and t. In Section 4 we have shown that for t < t b, n=1, and the value of β, was determined. In Section 5 we have shown that the parameters β i satisfy a nonlinear system of partial differential equations. In Part III, Section 6 we show that for t large, n=3, and we determine the asymptotic behavior of β 1, β 2, β 3, and of u and u 2 , for t large. The explicit formulas show that u and u 2 are O(t −1 ) and O(t ‐2 ) respectively (see formulas (6.2) and (6.24)). In Section 7 we study initial data whose value tends to zero as x→+∞, and to ‐1 as x→−∞. If one accepts some plausible guesses about the behavior of solutions with such initial data, we derive an explicit formula for the solution and determine the large scale asymptotic behavior of the solution: equation image . The function s(ζ) is expressible in terms of complete elliptic integrals; a similar formula is derived for U 2 . In Section 8 we indicate how to extend the treatment of this series of papers to multihumped (but still negative) initial data.
Efforts to increase the relative permittivities of organic semiconducting materials and their effect on organic solar cell performance are evaluated.
Abstract In Part I* we have shown, see Theorem 2.10, that as the coefficient of u xxx tends to zero, the solution of the initial value problem for the KdV equation tends to a limit u in the distribution sense. We have expressed u by formula (3.59), where ψ x is the partial derivative with respect to x of the function ψ* defined in Theorem 3.9 as the solution of the variational problem formulated in (2.16), (2.17). ψ* is uniquely characterized by the variational condition (3.34); its partial derivatives satisfy (3.51) and (3.52), where I is the set I o defined in (3.36). In Section 4 we show that for t<t b , I consists of a single interval, and the u satisfies u t — 6 uu x = 0; here t b is the largest time interval in which (12) has a continuous solution. In Section 5 we show that when I consists of a finite number of intervals, u can be described by Whitham's averaged equation or by the multiphased averaged equations of Flaschka, Forest, and McLaughlin. Equation numbers refer to Part I.
In March 1988, there was an outbreak of infection by a strain of Salmonella saint-paul with a distinctive antigenic marker. A total of 143 reports were received between 1 March and 7 June. Preliminary investigations suggested that raw beansprouts were a possible source of infection and a case-control study confirmed the association. S. saint-paul of the epidemic type was isolated from samples of beansprouts on retail sale in different cities in the United Kingdom and from mung bean seeds on the premises of the producer who was most strongly associated with cases. In addition, Salmonella virchow PT34 was isolated from samples of raw beansprouts and was subsequently associated with seven cases of infection. Four other serotypes of salmonella were also isolated from beansprouts. On 8 April the public were advised to boil beansprouts for 15 seconds before consumption, and the premises of the one producer associated with many cases were closed. As a result of these actions there was a significant decrease in the number of infections with S. saint-paul.
Active Mo<sub>2</sub>C–C nanocomposites were synthesized using an mpg-C<sub>3</sub>N<sub>4</sub> template and demonstrated as active electrocatalysts for the hydrogen evolution reaction.
In this paper, we proposed EPP-MVSNet, a novel deep learning network for 3D reconstruction from multi-view stereo (MVS). EPP-MVSNet can accurately aggregate features at high resolution to a limited cost volume with an optimal depth range, thus, leads to effective and efficient 3D construction. Distinct from existing works which measure feature cost at discrete positions which affects the 3D reconstruction accuracy, EPP-MVSNet introduces an epipolar-assembling-based kernel that operates on adaptive intervals along epipolar lines for making full use of the image resolution. Further, we introduce an entropy-based refining strategy where the cost volume describes the space geometry with the little redundancy. Moreover, we design a light-weighted network with Pseudo-3D convolutions integrated to achieve high accuracy and efficiency. We have conducted extensive experiments on challenging datasets Tanks & Temples(TNT), ETH3D and DTU. As a result, we achieve promising results on all datasets and the highest F-Score on the online TNT intermediate benchmark. Code is available at https://gitee.com/mindspore/mindspore/tree/master/model_zoo/research/cv/eppmvsnet.
The electronic structure, lattice vibrations, and optical, dielectric and thermodynamic properties of BaTiO<sub>3</sub>/CaTiO<sub>3</sub>/SrTiO<sub>3</sub> (BT/CT/ST) ferroelectric superlattices are calculated by using first-principles calculations.
A facile method is used to prepare a series of high-performance Ni/SiO<sub>x</sub>/nitrogen-doped carbon ternary anodes for lithium-ion batteries.
Resistive Random Access Memory (ReRAM) is one of the most promising emerging memory technologies as a potential replacement for DRAM memory and/or NAND Flash. Multi-level cell (MLC) ReRAM, which can store multiple bits in a single ReRAM cell, can further improve density and reduce cost-per-bit, and therefore has recently been investigated extensively. However, the majority of the prior studies on MLC ReRAM are at the device level. The design implications for MLC ReRAM at the circuit and system levels remain to be explored. This paper aim to provide the first comprehensive investigation of the design trade-offs involved in MLC ReRAM. Our study indicates that different resistance allocation schemes, programming strategies, peripheral designs, and material selections profoundly affect the area, latency, power, and reliability of MLC ReRAM. Based on this analysis, we conduct two case studies: first we compare MLC ReRAM design against MLC phase-change memory (PCM) and multi-layer cross-point ReRAM design, and point out why multi-level ReRAM is appealing; second we further explore the design space for MLC ReRAM.
Tunneling nanotubes are actin-based cytoplasmic extensions that function as intercellular channels in a wide variety of cell types.There is a renewed and keen interest in the examination of modes of intercellular communication in cells of all types, especially in the field of cancer biology. Tunneling nanotubes -which in the literature have also been referred to as "membrane nanotubes," "'intercellular' or 'epithelial' bridges," or "cytoplasmic extensions" - are under active investigation for their role in facilitating direct intercellular communication. These structures have not, until recently, been scrutinized as a unique and previously unrecognized form of direct cell-to-cell transmission of cellular cargo in the context of human cancer. Our recent study of tunneling nanotubes in human malignant pleural mesothelioma and lung adenocarcinomas demonstrated efficient transfer of cellular contents, including proteins, Golgi vesicles, and mitochondria, between cells derived from several well-established cancer cell lines. Further, we provided effective demonstration that such nanotubes can form between primary malignant cells from human patients. For the first time, we also demonstrated the in vivo relevance of these structures in humans, having effectively imaged nanotubes in intact solid tumors from patients. Here we provide further analysis and discussion on our findings, and offer a prospective 'road map' for studying tunneling nanotubes in the context of human cancer. We hope that further understanding of the mechanisms, methods of transfer, and particularly the role of nanotubes in tumor-stromal cross-talk will lead to identification of new selective targets for cancer therapeutics.
This review discusses the extrusion process parameters and their impact on the mechanical properties of composites reinforced with lignocellulosic fibers.
Valosin containing protein (VCP) disease associated with inclusion body myopathy, Paget disease of the bone and frontotemporal dementia is a progressive autosomal dominant disorder caused by mutations in Valosin containing protein gene. To establish genotype-phenotype correlations we analyzed clinical and biochemical markers from a database of 190 members in 27 families harboring 10 missense mutations. Individuals were grouped into three categories: symptomatic, presymptomatic carriers and noncarriers. The symptomatic families were further divided into ten groups based on their VCP mutations. There was marked intra and inter-familial variation; and significant genotype-phenotype correlations were difficult to establish because of small numbers. Nevertheless when comparing the two most common mutations, R155C mutation was found to be more severe, with an earlier onset of myopathy and Paget (p = 0.03). Survival analysis of all subjects revealed an average life span after diagnosis of myopathy and Paget of 18 and 19 years respectively, and after dementia only 6 years. R155C had a reduced survival compared to the R155H mutation (p = 0.03).We identified amyotrophic lateral sclerosis (ALS) was diagnosed in 13 individuals (8.9%) and Parkinson's disease in five individuals (3%); however, there was no genotypic correlation. This study represents the largest dataset of patients with VCP disease and expands our understanding of the natural history and provides genotype-phenotype correlations in this unique disease.
Magnetically functionalized PDMS-based micropillar arrays have been successfully designed, fabricated and implanted for controllable microfluidic mixing. The arrangement of PDMS micropillar arrays inside the microchannel can be flexibly controlled by an external magnetic field. As a consequence, the flow fields inside the microchannel can be regulated at will via magnetic activation conveniently. When a microchannel is implanted with such micropillar arrays, two microstreams can be mixed easily and controllably upon the simple application of an on/off magnetic signal. Mixing efficiencies based on micropillar arrays with different densities were investigated and compared. It was found that micropillar arrays with higher density (i.e. smaller pillar pitch) would render better mixing performance. Our microfluidic system is capable of generating highly reproducible results within many cycles of mixing/non-mixing conversion. We believe that the simple mixing-triggering method together with rapid and controllable mixing control will be extraordinarily valuable for various biological or chemical applications in the future.
We have shown previously that febrile range temperatures modify cytokine production by adult macrophages. In this study, we compared the effects of moderate hyperthermia and hypothermia on the kinetics of lipopolysaccharide (LPS)-induced cytokine expression in monocytes and macrophages of newborns and adults. During culture at 40 degrees C, the initial rates of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) secretion were preserved, but the duration of secretion was shorter than the duration at 37 degrees C. TNF-alpha and IL1-beta concentrations in 24-h 40 degrees C culture supernatants were reduced 18%-50%. IL-6 concentration in 24-h 40 degrees C cultures was reduced 26%-29% in all cells except adult macrophages. At 32 degrees C, changes in early (2 h) and sustained (24 h) cytokine expression were reversed compared with those caused by hyperthermia. Culturing adult macrophages at 32 degrees C blunted early secretion of TNF-alpha and IL-6 by 69% and 65%, respectively, and increased TNF-alpha concentration at 24 h by 48% compared with levels at 37 degrees C. In adult monocytes cultured at 32 degrees C, early IL-6 and IL-1 beta secretion was decreased 64% and 51%, respectively. We speculate that the burst/suppression cytokine profile at febrile temperatures might enhance early activation of host defenses and prevent prolonged exposure to potentially cytotoxic cytokines. Hypothermia, on the other hand, may worsen outcome in infections by delaying and prolonging cytokine production.
We present a detailed study of the effects of dangling bond passivation and the comparison of different sulfide passivation processes on the properties of InGaN/GaN quantum-disk (Qdisk)-in-nanowire based light emitting diodes (NW-LEDs). Our results demonstrated the first organic sulfide passivation process for nitride nanowires (NWs). The results from Raman spectroscopy, photoluminescence (PL) measurements, and X-ray photoelectron spectroscopy (XPS) showed that octadecylthiol (ODT) effectively passivated the surface states, and altered the surface dynamic charge, and thereby recovered the band-edge emission. The effectiveness of the process with passivation duration was also studied. Moreover, we also compared the electro-optical performance of NW-LEDs emitting at green wavelength before and after ODT passivation. We have shown that the Shockley-Read-Hall (SRH) non-radiative recombination of NW-LEDs can be greatly reduced after passivation by ODT, which led to a much faster increasing trend of quantum efficiency and higher peak efficiency. Our results highlighted the possibility of employing this technique to further design and produce high performance NW-LEDs and NW-lasers.
Fibroblast growth factor (FGF) receptor (FGFR) substrate 2 (FRS2) is an adaptor protein that plays a critical role in FGFR signaling. FRS2 is located on chromosome 12q13-15 that is frequently amplified in liposarcomas. The significance of FRS2 and FGFR signaling in high-grade liposarcomas is unknown. Herein, we first comparatively examined the amplification and expression of FRS2 with CDK4 and MDM2 in dedifferentiated liposarcoma (DDLS) and undifferentiated high-grade pleomorphic sarcoma (UHGPS). Amplification and expression of the three genes were identified in 90% to 100% (9-11 of 11) of DDLS, whereas that of FRS2, CDK4, and MDM2 were observed in 55% (41 of 75), 48% (36 of 75), and 44% (33/75) of clinically diagnosed UHGPS, suggesting that these "UHGPS" may represent DDLS despite lacking histologic evidence of lipoblasts. Immunohistochemical analysis of phosphorylated FRS2 protein indicated that the FGFR/FRS2 signaling axis was generally activated in about 75% of FRS2-positive high-grade liposarcomas. Moreover, we found that FRS2 and FGFRs proteins are highly expressed and functional in three high-grade liposarcoma cell lines: FU-DDLS-1, LiSa-2, and SW872. Importantly, the FGFR selective inhibitor NVP-BGJ-398 significantly inhibited the growth of FU-DDLS-1 and LiSa-2 cells with a concomitant suppression of FGFR signal transduction. Attenuation of FRS2 protein in FU-DDLS-1 and LiSa-2 cell lines decreased the phosphorylated extracellular signal-regulated kinase 1/2 and AKT and repressed cell proliferation. These findings indicate that analysis of FRS2 in combination with CDK4 and MDM2 will more accurately characterize pathologic features of high-grade liposarcomas. Activated FGFR/FRS2 signaling may play a functional role in the development of high-grade liposarcomas, therefore, serve as a potential therapeutic target.
The precursor routes to obtain high-molecular weight poly(p-phenylene vinylene)s (PPVs) are reviewed with respect to their applicability towards specific synthesis goals and materials as well as their structural integrity.