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We investigate the reconstruction of low-count positron emission tomography (PET) projection, which is an important, but challenging, task. Using the texture feature extraction method of radiomics, i.e. the gray-level co-occurrence matrix (GLCM), texture features can be extracted from magnetic resonance imaging images with high-spatial resolution. In this work, we propose a kernel reconstruction method combining autocorrelation texture features derived from the GLCM. The new kernel function includes the correlations of both the intensity and texture features from the prior image. By regarding the GLCM as a discrete approximation of a probability density function, the asymptotically gray-level-invariant autocorrelation texture feature is generated, which can maintain the accuracy of texture features extracted from small image regions by reducing the number of quantized image gray levels. A computer simulation shows that the proposed method can effectively reduce the noise in the reconstructed image compared to the maximum likelihood expectation maximum method and improve the image quality and tumor region accuracy compared to the original kernel method for low-count PET reconstruction. A simulation study on clinical patient images also shows that the proposed method can improve the whole image quality and that the reconstruction of a high-uptake lesion is more accurate than that achieved by the original kernel method. [ABSTRACT FROM AUTHOR]

We use simple modules over the finite-dimensional solvable Lie algebras to construct many simple restricted modules over the Heisenberg-Virasoro algebra L. These modules contain the highest weight modules and Whittaker modules. Then we precisely characterize the simple restricted modules over L under certain conditions. We know that simple modules over the two dimensional non-abelian Lie algebra are classified by R. Block in [10]. We also give a complete classification of simple modules for a three dimensional solvable Lie algebra. [ABSTRACT FROM AUTHOR]

Magnesium alloy shows promise of becoming a new generation of degradable biomaterials because of its good biocompatibility and mechanical properties. This paper details the preparation of magnesium alloy by adding calcium and zinc elements to pure magnesium at a specific ratio and strengthened by solid solution treatment and extrusion. The magnesium alloy is subjected to micro-motion wear testing, in vitro degradation product analysis, and in vitro biocompatibility testing and demonstrates excellent performance. The study demonstrates that the prepared Mg-2.0Zn-1.6Ca alloy friction ring has an elliptical shape with a low friction coefficient, which notably enhances the wear resistance of the material. Furthermore, the corrosion of magnesium alloy products in simulated body fluids does not adversely affect the human body. This is because the surface of the magnesium alloy favors cell growth and has excellent antimicrobial properties. The purpose of this paper is to enhance the preparation, surface friction properties, and biocompatibility of magnesium alloys and to provide theoretical and practical guidance for the preparation, processing, and application of high-performance medical magnesium alloys. [ABSTRACT FROM AUTHOR]

Aspartate kinase (AK) is a key enzyme involved in catalyzing the first step of the aspartate-derived amino acid biosynthesis, including L-lysine and L-threonine, which is regulated by the end-metabolites through feedback inhibition. In order to accumulate the end-metabolites in the host, the feedback inhibition of AK has to be released. In this study, a chimeric aspartate kinase, which is composed of the N-terminal catalytic region from Bacillus subtilis AKII and the C-terminal region from Thermus thermophilus, was evolved through random mutagenesis and then screened using a high-throughput synthetic RNA device which comprises of an L-lysine-sensing riboswitch and a selection module. Of three evolved aspartate kinases, the best mutant BT3 showed 160 % increased in vitro activity compared to the wild-type enzyme. Recombinant Escherichia coli harboring BT3 produced 674 mg/L L-lysine in batch cultivation, similar to that produced by the strain harboring the typical commercial widely used feedback resistant aspartate kinase AKC from E. coli. The results suggested that this strategy can be extended for screening of other key enzymes involved in lysine biosynthesis pathways. [ABSTRACT FROM AUTHOR]

In this paper, we study irreducible weight modules with infinite dimensional weight spaces over the mirror Heisenberg-Virasoro algebra D. More precisely, the necessary and sufficient conditions for the tensor products of irreducible highest weight modules and irreducible modules of intermediate series over D to be irreducible are determined by using "shifting technique". This leads to a family of new irreducible weight modules over D. Then we obtain that any two such tensor products are isomorphic if and only if the corresponding highest weight modules and modules of intermediate series are isomorphic respectively. Also we discuss submodules of the tensor product module when it is not irreducible. [ABSTRACT FROM AUTHOR]

In this paper, the planar Galilean conformal algebra G\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mathcal {G}$$\end{document} is investigated, which is an infinite-dimensional extension of the finite-dimensional Galilean conformal algebra in (2+1)\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$(2+1)$$\end{document} dimensional space-time. We study simple restricted modules over G\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mathcal {G}$$\end{document}, including the highest weight modules and Whittaker modules. More precisely, we use simple modules over the finite-dimensional solvable Lie algebras to construct many simple restricted modules over G\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mathcal {G}$$\end{document}. Also, we present several equivalent descriptions for simple restricted modules over G\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mathcal {G}$$\end{document}. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) has excellent chemical stability, x-ray transmittance, and elastic modulus close to human cortical bone, which can effectively reduce the stress shielding effect. Therefore, PEEK can be used as a commonly used medical bone implant material to repair damaged bones. However, due to its low surface free energy, PEEK has a certain degree of biological inertness. Surface modification methods are urgently needed to improve this problem. Laser surface texturing is expected to improve the biological inertia of PEEK materials. In this study, an ultraviolet laser with a wavelength of 355 nm was used to construct textures on the surface of PEEK materials. By biomimetic design on the surface of PEEK materials, textures similar in depth and width to the surface topography of natural bones were processed. We explore the specific improvement of corrugated texture, single line texture, and orthogonal texture on PEEK material performance, aiming at improving the service performance of PEEK material and creating conditions for better service of PEEK material in vivo. Through the evaluation of PEEK surface contact angle, friction and wear properties, and biocompatibility, the research results show that laser surface texture treatment can improve many service properties of PEEK materials. [ABSTRACT FROM AUTHOR]

Magnesium alloy, valued for its superior mechanical properties and biocompatibility in biomaterials, faces limitations such as rapid corrosion, poor wear resistance, and unfavorable cell adhesion. To address these challenges and enhance medical magnesium alloy development, this study investigates a magnetic needle grinding process on magnesium alloy. Mg-1.6Ca-2.0Zn alloy, prepared through powder metallurgy and T6 aging treatment, undergoes milling, and magnetic grinding using various needle sizes. The impact is assessed through Vickers hardness, residual stresses, surface roughness, friction and wear tests, electrochemical assessments, and contact angle tests. Results indicate a 22.59% microhardness increase, 30.43 MPa residual compressive stress, increased surface roughness, improved wear and corrosion resistance, and improved hydrophilia after magnetic needle grinding. This research provides a theoretical foundation for advancing medical magnesium alloy industrially. [ABSTRACT FROM AUTHOR]

Aiming to realize sustainable development and reduce environmental pollution, scientists have been on searching for bio-based materials derived from renewable resources to replace petroleum-based materials. Herein, a bio-based polyimide aerogel derived from 2,5-furandicarboxylic acid was synthesized successfully via supercritical fluid drying. The bio-based polyimide aerogel had mesoporous structure and a large specific surface area (220 m2/g), which were highly advantageous to adsorption and photocatalysis. The bio-based polyimide aerogel possessed fast adsorption behavior (within 1 s), outstanding durability (200 cycles of adsorption and desorption), and a self-cleaning property. The bio-based polyimide aerogel could also realize continuous and rapid separation of organic solvent and water with the aid of a vacuum pump. Importantly, the bio-based polyimide aerogel exhibited superelastic (rapid recovery after 90% strain) and anti-fatigue performance (compressive strength remained 96% after 100 cycles). Moreover, the bio-based polyimide aerogel displayed effective photocatalytic activity under visible light. The possible degradation mechanism was also proposed, and radical quenching tests demonstrated that the generation of h+ and ·O 2 − was the key to photocatalytic degradation. Considering its environmental friendliness and excellent properties, bio-based polyimide aerogel provides a promising solution for oil/water separation and photocatalysis. [Display omitted] • Superelastic bio-based polyimide aerogel is first prepared. • Bio-based aerogel displayed effective photocatalytic activity under visible light. • The generation of h+ and ·O 2 − was the key to photocatalytic degradation. • Bio-based aerogel possessed fast adsorption behavior and a self-cleaning property. • Bio-based aerogel could realize continuous and rapid separation of oil and water. [ABSTRACT FROM AUTHOR]

Background: Major depressive disorder (MDD) is linked to degenerative and inflammatory processes in the brain. The retina, as well as the brain, originates from the ectoderm. The changes in the retina that occur in concert with MDD and sleep quality are not very clear. This study aimed to detect changes in the retinal nerve fibre layer (RNFL) and macular thickness in Chinese patients in correlation with MDD and sleep quality.Methods: Thirty-six MDD patients and 187 age- and sex-matched healthy controls were enrolled in this study. All subjects were scanned by spectral-domain optical coherence tomography (OCT) and completed the Stroop Colour-Word Test (SCWT), Pittsburgh Sleep Quality Index, and Patient Health Questionnaire-9.Results: The RNFL and macular thickness were significantly thinner and disc-area enlargement of the right eye and cup-volume enlargement of both eyes were present in MDD patients. Linear regression analysis revealed that the RNFL and macular thickness in patients with MDD were correlated with sleep quality and the severity of depression. SCWT scores were higher following expansion of the cup volume of the right eye (all p < 0.01) and in correlation with larger disc areas.Conclusions: Serious degrees of depression and insomnia in MDD patients may reflect obvious atrophy of the inner and outer rings of the right macula and enlargement of the optic disc in both eyes. These retinal structural changes might influence the visual cognition of patients with MDD. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are small molecules which serve as essential components of the innate immune system in various organisms. AMPs possess a broad spectrum of antimicrobial activities. However, the scaled production of such peptides in Escherichia coli faces many difficulties because of their small size and toxicity to the host. Here, we described a new fusion strategy to extracellularly produce significant amounts of these antimicrobial peptides in recombinant E. coli at significant amount. Employing the catalytic domain of a cellulase (Cel-CD) from Bacillus subtilis KSM-64 as the fusion partner, five recombinant antimicrobial peptides were confirmed to accumulate in the culture medium at concentrations ranging from 184 mg/L to 297 mg/L. The radical diffusion experiment demonstrated that the released model antimicrobial peptide, bombinin, had antibacterial activities against both E. coli and Staphylococcus aureus . This strategy will be suitable for the production of antimicrobial peptides and other toxicity proteins. [ABSTRACT FROM AUTHOR]

Purpose: Clinically, single radiotracer positron emission tomography (PET) imaging is a commonly used examination method; however, since each radioactive tracer reflects the information of only one kind of cell, it easily causes false negatives or false positives in disease diagnosis. Therefore, reasonably combining two or more radiotracers is recommended to improve the accuracy of diagnosis and the sensitivity and specificity of the disease when conditions permit. Methods: This paper proposes incorporating 18F‐fluorodeoxyglucose (FDG) as a higher‐quality PET image to guide the reconstruction of other lower‐count 11C‐methionine (MET) PET datasets to compensate for the lower image quality by a popular kernel algorithm. Specifically, the FDG prior is needed to extract kernel features, and these features were used to build a kernel matrix using a k‐nearest‐neighbor (kNN) search for MET image reconstruction. We created a 2‐D brain phantom to validate the proposed method by simulating sinogram data containing Poisson random noise and quantitatively compared the performance of the proposed FDG‐guided kernelized expectation maximization (KEM) method with the performance of Gaussian and non‐local means (NLM) smoothed maximum likelihood expectation maximization (MLEM), MR‐guided KEM, and multi‐guided‐S KEM algorithms. Mismatch experiments between FDG/MR and MET data were also carried out to investigate the outcomes of possible clinical situations. Results: In the simulation study, the proposed method outperformed the other algorithms by at least 3.11% in the signal‐to‐noise ratio (SNR) and 0.68% in the contrast recovery coefficient (CRC), and it reduced the mean absolute error (MAE) by 8.07%. Regarding the tumor in the reconstructed image, the proposed method contained more pathological information. Furthermore, the proposed method was still superior to the MR‐guided KEM method in the mismatch experiments. Conclusions: The proposed FDG‐guided KEM algorithm can effectively utilize and compensate for the tissue metabolism information obtained from dual‐tracer PET to maximize the advantages of PET imaging. [ABSTRACT FROM AUTHOR]

In this work, a small animal PET scanner named SIAT aPET was developed using dual-ended readout depth encoding detectors to simultaneously achieve high spatial resolution and high sensitivity. The scanner consists of four detector rings with 12 detector modules per ring; the ring diameter is 111 mm and the axial field of view (FOV) is 105.6 mm. The images are reconstructed using an ordered subset expectation maximization (OSEM) algorithm. The spatial resolution of the scanner was measured by using a 22Na point source at the center axial FOV with different radial offsets. The sensitivity of the scanner was measured at center axis of the scanner with different axial positions. The count rate performance of the system was evaluated by scanning mouse-sized and rat-sized phantoms. An ultra-micro hot-rods phantom and two mice injected with 18F-NaF and 18F-FDG were scanned on the scanner. An average depth of interaction (DOI) resolution of 1.96 mm, energy resolution of 19.1% and timing resolution of 1.20 ns were obtained for the detector. Average spatial resolutions of 0.82 mm and 1.16 mm were obtained up to a distance of 30 mm radially from the center of the FOV when reconstructing a point source in 1% and 10% warm backgrounds, respectively, using OSEM reconstruction with 16 subsets and 10 iterations. Sensitivities of 16.0% and 11.9% were achieved at center of the scanner for energy windows of 250–750 keV and 350–750 keV respectively. Peak noise equivalent count rates (NECRs) of 324 kcps and 144 kcps were obtained at an activity of 26.4 MBq for the mouse-sized and rat-sized phantoms. Rods of 1.0 mm diameter can be visually resolved from the image of the ultra-micro hot-rods phantom. The capability of the scanner was demonstrated by high quality in-vivo mouse images. [ABSTRACT FROM AUTHOR]

• The activity of a series of fluorescent compounds was investigated. • Compounds 8 and 11 reduced the cell viability of A549 lung cancer cells. • Compound 8 inhibited the activity of mTOR. • Co mpounds 8 and 11 induced apoptosis and autophagy. • Co mpound 8 induced autophagy with intact autophagic flux. Biological activities of a series of fluorescent compounds against human lung cancer cell line A549 were investigated. The results showed that (E)-1,3,3-trimethyl-2-(4-(piperidin-1-yl)styryl)-3H-indol-1-ium iodide (8) and (E)-2-(5,5-dimethyl-3-(4-(piperazin-1-yl)styryl)cyclohex-2-en-1-ylidene) malononitrile (11) could inhibit the growth of A549 cancer cells in a dose and time-dependent manner. Furthermore, compound 8 could trigger autophagy and apoptosis, but not obviously induce necrosis under the stimulatory condition. Therefore, 8 can be used as autophagy activator to investigate the regulatory mechanism of autophagy and may offer a new candidate for the treatment of lung cancer. [ABSTRACT FROM AUTHOR]

Esophageal squamous cell carcinoma (ESCC) is a dominant histological subtype of esophageal cancer with notably high incidence and mortality rates. Pemetrexed is a clinical antifolate therapeutic agent with anticancer properties. The present study aimed to understand whether pemetrexed is able to exert anticancer effects on ESCC cells, and to determine the underlying molecular mechanism. ESCC cells were treated with pemetrexed and cell survival was assessed with MTT assays. The cell cycle and apoptosis were evaluated using flow cytometry analysis, and proteins were detected using western blotting. It was demonstrated that pemetrexed inhibited cell survival and induced G0/G1 cell cycle arrest and apoptosis in human ESCC cells. Furthermore, the results demonstrated that the phorbol-12-myristate-13-acetate-induced protein 1/induced myeloid leukemia cell differentiation protein Mcl-1 axis is involved in intrinsic apoptosis induced by pemetrexed. The protein expression of endoplasmic reticulum stress markers inositol-requiring enzyme 1α, binding immunoglobulin protein and CCAAT-enhancer-binding protein homologous protein were upregulated following treatment with pemetrexed. These results suggest that pemetrexed may induce an endoplasmic reticulum stress response while activating intrinsic apoptosis. The present study provided important mechanistic insights into potential cancer treatments involving pemetrexed and enhanced the understanding of human ESCC. [ABSTRACT FROM AUTHOR]

• Docetaxel and Resveratrol were successfully encapsulated in PEGylated nanoliposomes. • High encapsulation efficiency and sustained release behavior of Docetaxel and Resveratrol were observed. • Boosted cellular uptake contributes to enhanced cytotoxicity on cancer cells. • Synergistic antitumor efficacy associated with survival benefit was observed. Combination therapy is frequently used in cancer treatments. Delivery of combined anticancer agents loaded in a nanocarrier would be a promising option for combination therapy. Here, we designed PEGylated nano-liposomes for co-delivery Docetaxel (Doc) and Resveratrol (Res) to evaluate antitumor efficiency of the combined drugs in prostate cancer. The average diameter of the liposomes was 99.67 nm with a spheral-like shape. Drug release studies showed that both drugs could synchronously leak from the liposomes in a sustained release behavior. Cellular uptake results demonstrated that liposomes could effectively deliver more cargos into cells than other formulations. Moreover, co-loaded liposomes with Doc/Res in a molar ratio of 1:2 exhibited significantly higher cytotoxicity than a mixed solution containing both drugs on cancer cells. In the study of caspase 3, we found that the combination of Doc and Res could significantly increase the activity of caspase 3 enzyme compared with Doc alone. Animal studies revealed that co-encapsulated Doc/Res in liposomes predominantly inhibited tumor growth in PC3 bearing Balb/c nude mice, as evidenced by a change in cell proliferation and apoptosis parameters. Importantly, little toxicities and prolonged survival time were observed in mice treated with liposome-loaded Doc/Res than control group exposed to liposome-free Doc/Res. These results provided evidence that loading of Doc/Res in a nano-liposome is an efficient delivery formulation for synergistic treating prostate cancer. [Display omitted] [ABSTRACT FROM AUTHOR]