Rapid Modeling, Prototyping, and Generation of Digital Libraries- A Theory-Based Approach

Despite some development in the area of DL architectures and systems, there is still little support for the complete life cycle of DL development, including requirements gathering, conceptual modeling, rapid prototyping, and code generation and reuse. Even when partially supported, those activities are uncorrelated within the current systems, which can lead to inconsistencies and incompleteness. Moreover, the current few existing approaches are not supported by comprehensive and formal foundations and theories, which brings problems of interoperability and makes it extremely difficult to adapt and tailor systems to specific societal preferences and needs of the target community. In this paper, having the 5S formal theoretical framework as support, we present an architecture and a family of tools that allow rapid modeling, prototyping, and generation of digital libraries. 5S stands for Streams, Structures, Spaces, Scenarios, and Societies and is our formal theory for DLs. 5SL is a domain-specific, declarative language for DL conceptual modeling. 5SGraph is a visual modeling tool that helps designers to model a digital library without knowing the theoretical foundations and the syntactical details of 5SL. Furthermore, 5SGraph maintains semantic constraints specified by a 5S metamodel and enforces these constraints over the instance model to ensure semantic consistency and correctness. 5SGraph also enables component reuse to reduce the time and efforts of designers. 5SLGen is a DL generation tool that takes specifications in 5SL and a set of component pools and generates portions of a running DL system. The outputs of 5SLGen include user interface prototypes, in a generic UI markup language, for validation of services behavior and workflow representations of the running system, generated to support the desired scenarios

Electronic Structure in Gapped Graphene with Coulomb Potential

In this paper, we numerically study the bound electron states induced by long range Coulomb impurity in gapped graphene and the quasi-bound states in supercritical region based on the lattice model. We present a detailed comparison between our numerical simulations and the prediction of the continuum model which is described by the Dirac equation in (2+1)-dimensional Quantum Electrodynamics (QED). We also use the Fano's formalism to investigate the quasi-bound state development and design an accessible experiments to test the decay of the supercritical vacuum in the gapped graphene.Comment: 5 page, 4 figure

Mass spectrometry-based multimodal approaches for the identification and quantification analysis of microplastics in food matrix

BackgroundMicroplastics (MPs) and nanoplastics (NPs) have become emerging contaminants worldwide in food matrices. However, analytical approaches for their determination have yet to be standardized. Therefore, a systematic study is urgently needed to highlight the merits of mass spectrometry (MS) based methods for these applications.PurposeThe aim of the study is to review the current status of MS-based multimodal analysis for the determination of MPs in food matrices.MethodsWeb of Science and Google Scholar databases were searched and screened until Jan. 2023. Inclusion criteria: “publication years” was set to the last decades, “English” was selected as the “language,” and “research area” was set to environmental chemistry, food analysis and polymer science. The keywords were “microplastics,” “nanoplastics,” “determination,” “identification/quantification,” and “mass spectrometry.”ResultsTraditional spectrometry techniques offer good abilities to conduct the multimodal analysis of MPs in terms of color, shape and other morphologies. However, such technologies have some limitations, in particular the relatively high limits of detection. In contrast, MS-based methods supply excellent supplements. In MS-based methods, gas chromatographic-mass spectrometry (GC-MS), and LC-MS/MS were selected as representative methods for determining MPs in the food matrices, while specialized MS methods (i.e., MALDI-ToF MS and ToF-SIMS) were considered to offer great potential in multimodal analysis of MPs especially when interfaced with the imaging systems.SignificanceThis study will contribute to gaining a deeper insight into the assessment of the exposure levels of MPs in human body, and may help build a bridge between the monitoring studies and the toxicology field

Heat Transfer and Temperature Characteristics of a Working Digital Camera

Digital cameras represented by industrial cameras are widely used as image acquisition sensors in the field of image-based mechanics measurement, and their thermal effect inevitably induces thermal-induced errors of the mechanics measurement. To deeply understand the errors, the research for digital camera’s thermal effect is necessary. This study systematically investigated the heat transfer processes and temperature characteristics of a working digital camera. Concretely, based on the temperature distribution of a typical working digital camera, the heat transfer of the working digital camera was investigated, and a model describing the temperature variation and distribution was presented and verified experimentally. With this model, the thermal equilibrium time and thermal equilibrium temperature of the camera system were calculated. Then, the influences of thermal parameters of digital camera and environmental temperature on the temperature characteristics of working digital camera were simulated and experimentally investigated. The theory analysis and experimental results demonstrate that the presented model can accurately describe the temperature characteristics and further calculate the thermal equilibrium state of working digital camera, all of which contribute to guiding mechanics measurement and thermal design based on such camera sensors

Preparation and Properties of Stereocomplex of Poly(lactic acid) and Its Amphiphilic Copolymers Containing Glucose Groups

The stereocomplex of poly(lactic acid) containing glucose groups (sc-PLAG) was prepared by solution blending from equal amounts of poly(l-lactic acid) (PLLA) and poly(d-lactic acid-co-glucose) (PDLAG), which were synthesized from l- and d-lactic acid and glucose by melt polycondensation. The methods, including 1H nuclear magnetic resonance spectroscopy (1H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), polarizing microscope (POM), scanning electron microscope (SEM), transmission electron microscope (TEM), and contact angle were used to determine the effects of the stereocomplexation of enantiomeric poly(lactic acid) (PLA) units, the amphiphilicity due to glucose residues and lactic acid units, and the interaction of glucose residues with lactic units on the crystallization performance, hydrophilicity, thermal stability, and morphology of samples. The results showed PDLAG was multi-armed, and partial OH groups of glucose residues in PDLAG might remain unreacted. The molecular weight (Mw), dispersity (Ɖ), and glucose proportion in the chain of PDLAG thereby had significant effects on sc-PLAG. There were the stereocomplexation of enantiomeric lactic units and the amphiphilic self-assembly of PDLAG in sc-PLAG, which resulted in glucose groups mainly in the surface phase and lactic units in the bulk phase. The sc-PLAG only possessed the stereocomplex crystal owing to the interaction between nearly equimolar of l-lactic units of PLLA and d-lactic units of PDLAG, and had no homo-crystallites of l- or d-lactic units, which improved the melting temperature (Tm) of sc-PLAG about 50 °C higher than that of PLLA. Glucose groups in sc-PLAG played an important role by forming heterogeneous nucleation, promoting amphiphilic self-assembly, and affecting the ordered arrangement of lactic units. The glass transition temperature (Tg), the melting temperature (Tm), crystallinity, crystallization rate, and water absorption of sc-PLAG showed similar changes with the increased glucose content in feeding. All these parameters increased at first, and the maximum appeared as glucose content in feeding about 2%, such as the maximum crystallinity of 48.8% and the maximum water absorption ratio being 11.7%. When glucose content in feeding continued increasing, all these performances showed a downward trend due to the decrease of arrangement regularity of lactic acid chains caused by glucose groups. Moreover, the contact angle of sc-PLAG decreased gradually with the increased glucose content in feeding to obtain the minimum 77.5° as the glucose content in feeding being 5%, while that of PLLA was 85.0°. The sc-PLAG possessed a regular microsphere structure, and its microspheres with a diameter of about 200 nm could be observed. In conclusion, sc-PLAG containing proper glucose amount could effectively enhance the crystallinity, hydrophilicity, and thermal stability of PLA material, which is useful for drug delivery, a scaffold for tissue engineering, and other applications of biomedicine

Microstructure and mechanical evolution of Cu-2.7Be sheets via annealing

The microstructure and mechanical properties of cold-rolled Cu-2.7Be sheets under various annealing processes and conditions were investigated in this research. The increased beryllium content in the Cu-2.7Be alloy facilitates the formation of brittle secondary phases. Consequently, the study highlights the functionality of annealed Cu-2.7Be alloys as more favorable dynodes than the traditionally used Cu-2.0Be alloys. The mechanism of recrystallization used for the transformation of Cu-2.7Be alloys was that of continuous static recrystallization (cSRX). Moreover, the relationship between the orientation of the β phases and that of the surrounding Cu-matrix was determined to be (111)α∥(110)β and (011)α∥(001)β. The β phase has a body-centered cubic (bcc) structure with a = b = c = 0.281 nm. The β phase undergoes a morphology transformation from primitive lath-shaped β particles to quadrangle-shaped β particles during the annealing process. Such transformations could potentially have an effect on the mechanical properties of Cu-2.7Be sheets. There was a noticeable decline in the yield strength of the Cu-2.7Be after annealing, and the samples annealed at 770 °C for 15 min achieved the elongation with deep and uniform dimples caused by suitable β particle sizes, appropriate grain sizes, and the maximum volume fraction of ∑3 boundaries.Published versio

Synthesis and Properties of Nitrogen-Doped Carbon Quantum Dots Using Lactic Acid as Carbon Source

Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized in a one-step hydrothermal technique utilizing L-lactic acid as that of the source of carbon and ethylenediamine as that of the source of nitrogen, and were characterized using dynamic light scattering, X-ray photoelectron spectroscopy ultraviolet-visible spectrum, Fourier-transformed infrared spectrum, high-resolution transmission electron microscopy, and fluorescence spectrum. The generated N-CQDs have a spherical structure and overall diameters ranging from 1–4 nm, and their surface comprises specific functional groups such as amino, carboxyl, and hydroxyl, resulting in greater water solubility and fluorescence. The quantum yield of N-CQDs (being 46%) is significantly higher than that of the CQDs synthesized from other biomass in literatures. Its fluorescence intensity is dependent on the excitation wavelength, and N-CQDs release blue light at 365 nm under ultraviolet light. The pH values may impact the protonation of N-CQDs surface functional groups and lead to significant fluorescence quenching of N-CQDs. Therefore, the fluorescence intensity of N-CQDs is the highest at pH 7.0, but it decreases with pH as pH values being either more than or less than pH 7.0. The N-CQDs exhibit high sensitivity to Fe3+ ions, for Fe3+ ions would decrease the fluorescence intensity of N-CQDs by 99.6%, and the influence of Fe3+ ions on N-CQDs fluorescence quenching is slightly affected by other metal ions. Moreover, the fluorescence quenching efficiency of Fe3+ ions displays an obvious linear relationship to Fe3+ concentrations in a wide range of concentrations (up to 200 µM) and with a detection limit of 1.89 µM. Therefore, the generated N-CQDs may be utilized as a robust fluorescence sensor for detecting pH and Fe3+ ions

Clinical performance of stem cell therapy in patients with acute-on-chronic liver failure: a systematic review and meta-analysis

Abstract Background Stem cell therapy has been applied in the treatment of acute-on-chronic liver failure (ACLF). However, its clinical efficiency is still debatable. The aim of this systematic review and meta-analysis is to evaluate the clinical efficiency of stem cell therapy in the treatment of ACLF. Methods The Cochrane Library, OVID, EMBASE, and PUBMED were searched to December 2017. Both randomized and non-randomized studies, assessing stem cell therapy in patients with ACLF, were included. The outcome measures were total bilirubin (TBIL), alanine transaminase (ALT), international normalized ratio (INR), albumin (ALB), and the model for end-stage liver disease (MELD) score. The quality of evidence was assessed by GRADEpro. Results Four randomized controlled trials and six non-randomized controlled trials were included. The TBIL levels significantly decreased at 1-, 3-, 12-month after the stem cell therapy (p = 0.0008; p = 0.04; p = 0.007). The ALT levels decreased significantly compared with the control group in the short-term (p < 0.00001). There was no obvious change in the INR level compared with the control groups (p = 0.64). The ALB levels increased markedly as compared with the control groups (p < 0.0001). The significant difference can be found in MELD score between stem cell therapy and control groups (p = 0.008). Further subgroup analysis for 3-month clinical performance according to the stem cell types have also been performed. Conclusion This study suggests that the clinical outcomes of stem cell therapy were satisfied in patients with ACLF in the short-term. MSCs may be better than BM-MNCs in the stem cells transplantation of ACLF. However, more attention should focus on clinical trials in large-volume centers