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The increased penetrations from variable renewable generation (VRG), such as solar and wind, into power systems, growing the flexibility requirements for managing the uncertainty and variability of output power. These flexibility requirements can be achieved by many flexibility options. However, quantifying the flexibility available and required in a power system is a complicated problem. The paper reviews different flexibility metrics that measure the flexibility available from each conventional generator and that measure the flexibility available and needed by a power system at either planning and operational stages. Due to the dynamics of power systems, no flexibility metric has been taken as a standard. Accordingly, for high variable renewable generation shares, it is necessary to have a deeper understanding of power ramping scale as well as times when collective ramp events are most likely to occur. The paper introduces a method for power ramping analysis that will be demonstrated by analysing the output power of aggregated Belgian wind farms. In addition, the ramp characteristic indicators have been proposed for comparing the ramping behaviour of VRG in different years or between different countries. [ABSTRACT FROM AUTHOR]

Background: Rheumatoid arthritis (RA) disease activity, associated comorbidities, and therapy-related side effects impair the physical, social, and emotional dimensions of the patient's health. Presently, the ongoing COVID-19 pandemic has been associated with a broad range of psychosocial disorders in various populations. Patients with RA are especially vulnerable to such effects., Objectives: Detect the prevalence of recent COVID-19 infection among patients with RA, assess depression and anxiety in these patients and their associated factors during the COVID-19 pandemic and their potential relation to disease activity., Design and Methods: This is a cross-sectional study conducted on 120 adult Egyptian patients diagnosed with RA during the COVID-19 pandemic. The prevalence of recent COVID-19 infection among the patients was evaluated. The patients underwent psychological assessment using the Hamilton Depression Rating Scale (Ham-D) and the Hamilton Anxiety Rating Scale (Ham-A) to measure levels of depression and anxiety levels. The RA disease activity was assessed using Disease Activity Score (DAS) Das-28-ESR., Results: This study encompasses a total of 120 RA patients. The prevalence of patients with a recent history of COVID-19 infection was 40.8%. Both groups exhibited significantly elevated mean scores on the Das-28-ESR scale and also scored higher on measures of depression and anxiety. Interestingly, the COVID-19 group exhibited a higher percentage of unmarried individuals, had educational attainment below the university level, and were unemployed. Patients with recent COVID-19 had significantly lower numbers of children, higher disease duration, higher Das-28-ESR scores, and elevated depression and anxiety scores. The statistical analysis revealed that the COVID-19 infection and disease duration were significant predictors of depression and anxiety. The results also exhibited that the depression score was positively correlated with age and DAS scores., Conclusions: It was observed that patients diagnosed with RA revealed a higher prevalence of COVID-19 infection. The occurrence of depression and anxiety was observed to be widespread among patients diagnosed with RA and, more significantly, prevalent in RA patients who had a recent COVID-19 and had a higher level of disease activity. The occurrence of COVID-19 and disease duration were identified as factors that can anticipate the development of depression and anxiety., Competing Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.)

Objectives: This study aimed to evaluate depression and anxiety in patients with systemic lupus erythematosus (SLE) in the post-coronavirus disease-2019 (COVID-19) period and their potential association with the disease activity and related organ damage., Patients and Methods: This is a case-control study including 120 adult Egyptian patients with SLE: sixty patients with SLE who were proven previously to be positive for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) by polymerase chain reaction (PCR) and recovered during the 3 months prior to the study were included in the case group and an equal number of age- and sex-matched patients with SLE and no evidence of SARS-CoV-2 infection were included in the control group. Patients' clinical history was collected, and they underwent clinical evaluation, including SLE disease activity, damage assessment, and psychological assessment., Results: The mean depression and anxiety scores were significantly higher in cases than in the control group. Both scores showed a significant positive correlation with age, disease duration, the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index for SLE (SDI), and SLE disease activity index (SLEDAI) and a significant negative correlation with education years. Hierarchical multivariate regression analyses revealed that COVID-19 infection was a predictor for severe depression and moderate-to-severe anxiety., Conclusions: Patients with SLE, who are already vulnerable to physiological stressors, are especially predisposed to more risk of anxiety and depression when they are contracted with COVID-19 disease. Furthermore, anxiety and depression are associated with SLE activity and damage scores, and COVID-19 infection is a significant predictor for their severity. These results suggest that healthcare providers should give special attention to the mental health of SLE patients, especially during the COVID-19 pandemic.

Objective: This study investigated the mechanical and in vitro biological properties (in immortalized human dental pulp stem cells (ihDPSCs)) of bioactive glass nanoparticle (BGN)-incorporated glass ionomer cement (GIC) with or without chitosan as a binder., Methods: After the BGNs were synthesized and characterized, three experimental GICs and a control (conventional GIC) that differed in the additive incorporated into a commercial GIC liquid (Hy-bond, Shofu, Japan) were produced: BG5 (5wt% of BGNs), CL0.5 (0.5wt% of chitosan), and BG5+CL0.5 (5wt% of BGNs and 0.5wt% of chitosan). After the net setting time was determined, weight change and bioactivity were analyzed in simulated body fluid (SBF) at 37°C. Mechanical properties (compressive strength, diametral tensile strength, flexural strength and modulus) were measured according to the incubation time (up to 28 days) in SBF. Cytotoxicity (1day) and biomineralization (14 days), assessed by alizarin red staining, were investigated using an extract from GIC and ihDPSCs. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's post hoc test; p<0.05., Results: BGNs were sol-gel synthesized to be approximately 42nm in diameter with a spherical morphology and amorphous structure. After the bioactivity and suspension ability of the BGNs were confirmed, all the experimental GIC groups had setting times of less than 6min and approximately 1% weight loss after 28days of incubation. In addition, BGNs incorporated into GIC (BG5 and BG5+CL0.5) exhibited surface bioactivity. The mechanical properties were increased in the BGN-incorporated GICs compared to those in the control (p<0.05). Without cytotoxicity, the biomineralization capacity was ranked in the order BG5, BG5+CL0.5, control, and CL0.5 (p<0.05)., Significance: BGN-incorporated GIC showed enhanced mechanical properties such as compressive, diametral tensile and flexural strength as well as in vitro biomineralization properties in ihDPSCs without cytotoxicity. Therefore, the developed BGN-incorporated GIC is a promising restorative dental material, although further in vivo investigation is needed before clinical application., (Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

In nature inorganic-organic building units create multifunctional hierarchical architectures. Organic silk protein is particularly attractive in this respect because of its micro-nanoscale structural blocks that are attributed to sophisticated hierarchical assembly imparting flexibility and compressibility to designed biohybrid materials. In the present study, aqueous silk fibroin is assembled to form nano/microtopography on inorganic silica surface via a facile diffusion-limited aggregation process. This process is driven by electrostatic interaction and only possible at a specified aminated surface chemistry. The self-assembled topography depends on the age and concentration of protein solution as well as on the surface charge distribution of the template. The self-assembled silk trails closely resemble natural cypress leaf architecture, which is considered a structural analogue of neuronal cortex. This assembled surface significantly enhances anchorage of neuronal cell and cytoskeletal extensions, providing an effective nano/microtopographical cue for cellular recognition and guidance.

The preparation of the ideal smart drug-delivery systems were successfully achieved by the in situ co-polymerization of a vinyl group-functionalized mesoporous silica nanoparticle (f-MSN) with 1-butyl-3-vinyl imidazolium bromide (BVIm) and N-isopropylacrylamide (NIPAAm) monomers. The thickness of the capping copolymer layer, poly(NIPAAm-co-BVIm) (p-NIBIm), was controlled at between 2.5nm and 5nm, depending on the monomers/f-MSN ratio in the reaction solution. The finally obtained smart drug-delivery systems are named as p-MSN2.5 and p-MSN5.0 (MSNs integrated by 2.5nm and 5nm p-NIBIm layer in thickness). The key roles of the mesoporous-silica-nanoparticle (MSN) core and the p-NIBIm shell are drug-carrying (or containing) and pore-capping, respectively, and the latter has an on/off function that operates in accordance with temperature changes. According to the swelling- or shrinking-responses of the smart capping copolymer to temperature changes between 10°C and 40°C, the loading and releasing patterns of the model drug cytochrome c were studied in vitro. The developed system showed interesting performances such as a cytochrome-c-loading profile (loading capacity for 3h=26.3% and 19.8% for p-MSN2.5 and p-MSN5.0, respectively) at 10°C and a cytochrome-c-releasing profile (releasing efficiency=>95% within 3 days and 4 days for p-MSN2.5 and p-MSN5.0, respectively) at 40°C. The cytotoxicity of the drug delivery systems, p-MSN2.5 and p-MSN5.0 (in the concentration range of <0.125mg/mL without drug), for human embryonic kidney (HEK 293) cells were minimal in vitro compared with that of a blank MSN. These results may be reasonably applied in the field of specified drug delivery., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Complete reconstruction of damaged periodontal pockets, particularly regeneration of periodontal ligament (PDL) has been a significant challenge in dentistry. Tissue engineering approach utilizing PDL stem cells and scaffolding matrices offers great opportunity to this, and applying physical and mechanical cues mimicking native tissue conditions are of special importance. Here we approach to regenerate periodontal tissues by engineering PDL cells supported on a nanofibrous scaffold under a mechanical-stressed condition. PDL stem cells isolated from rats were seeded on an electrospun polycaprolactone/gelatin directionally-oriented nanofiber membrane and dynamic mechanical stress was applied to the cell/nanofiber construct, providing nanotopological and mechanical combined cues. Cells recognized the nanofiber orientation, aligning in parallel, and the mechanical stress increased the cell alignment. Importantly, the cells cultured on the oriented nanofiber combined with the mechanical stress produced significantly stimulated PDL specific markers, including periostin and tenascin with simultaneous down-regulation of osteogenesis, demonstrating the roles of topological and mechanical cues in altering phenotypic change in PDL cells. Tissue compatibility of the tissue-engineered constructs was confirmed in rat subcutaneous sites. Furthermore, in vivo regeneration of PDL and alveolar bone tissues was examined under the rat premaxillary periodontal defect models. The cell/nanofiber constructs engineered under mechanical stress showed sound integration into tissue defects and the regenerated bone volume and area were significantly improved. This study provides an effective tissue engineering approach for periodontal regeneration-culturing PDL stem cells with combinatory cues of oriented nanotopology and dynamic mechanical stretch.

A novel therapeutic scaffolding system of engineered nanocarriers within a foam matrix for the long-term and sequential delivery of growth factors is reported. Mesoporous silica nanospheres were first functionalized to have an enlarged mesopore size (12.2nm) and aminated surface, which was then shelled by a biopolymer, poly(lactic acid) (PLA) or poly(ethylene glycol) (PEG), via electrospraying. The hybrid nanocarrier was subsequently combined with collagen to produce foam scaffolds. Bovine serum albumin (BSA), used as a model protein, was effectively loaded within the enlarged nanospheres. The biopolymer shell substantially prolonged the release period of BSA (2-3weeks from shelled nanospheres vs. within 1week from bare nanospheres), and the release rate was highly dependent on the shell composition (PEG>PLA). Collagen foam scaffolding of the shelled nanocarrier further slowed down the protein release, while enabling the incorporation of a rapidly releasing protein, which is effective for sequential protein delivery. Acidic fibroblast growth factor (aFGF), loaded onto the shelled-nanocarrier scaffolds, was released over a month at a highly sustainable rate, profiling a release pattern similar to that of BSA. The biological activity of the aFGF was evidenced by the significant proliferation of osteoblastic precursor cells in the aFGF-releasing scaffolds. Furthermore, the aFGF-delivering scaffolds implanted in rat subcutaneous tissue for 2weeks showed a substantially enhanced invasion of fibroblasts with a homogeneous population. Taken together, it is concluded that the biopolymer encapsulation of mesoporous nanospheres effectively prolongs the release of growth factors over weeks to a month, providing a nanocarrier platform for a long-term growth factor delivery. Moreover, the foam scaffolding of the nanocarrier system is a potential therapeutic three-dimensional matrix for cell culture and tissue engineering., (Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

We report the ability of aminated mesoporous silica nanoparticles (MSN-NH2) with large mesopore space and positive-charged surface to deliver genes within rat mesenchymal stem cells (MSCs). The amine functionalized inorganic nanoparticles were complexed with bone morphogenetic protein-2 (BMP2) plasmid DNA (pDNA) to study their transfection efficiency in MSCs. Intracellular uptake of the complex BMP2 pDNA/MSN-NH2 occurred significantly, with a transfection efficiency of approximately 68%. Furthermore, over 66% of the transfected cells produced BMP2 protein. The osteogenic differentiation of the transfected MSCs was demonstrated by the expression of bone-related genes and proteins including bone sialoprotein, osteopontin, and osteocalcin. The MSN-NH2 delivery vehicle for BMP2 pDNA developed in this study may be a potential gene delivery system for bone tissue regeneration., (Copyright © 2012 Wiley Periodicals, Inc.)

Inorganic bioactive nanomaterials are attractive for hard tissue regeneration, including nanocomponents for bone replacement composites and nanovehicles for delivering therapeutics. Bioactive glass nanoparticles (BGn) have recently gained potential usefulness as bone and tooth regeneratives. Here we demonstrate the capacity of the BGn with mesopores to load and deliver therapeutic molecules (drugs and particularly genes). Spherical BGn with sizes of 80-90 nm were produced to obtain 3-5 nm sized mesopores through a sono-reacted sol-gel process. A simulated body fluid test of the mesoporous BGn confirmed their excellent apatite forming ability and the cellular toxicity study demonstrated their good cell viability up to 100 μg ml(-1). Small molecules like chemical drug (Na-ampicillin) and gene (small interfering RNA; siRNA) were introduced as model drugs considering the mesopore size of the nanoparticles. Moreover, amine-functionalization allowed switchable surface charge property of the BGn (from -20-30 mV to +20-30 mV). Loading of ampicillin or siRNA saturated within a few hours (~2 h) and reflected the mesopore structure. While the ampicillin released relatively rapidly (~12 h), the siRNA continued to release up to 3 days with almost zero-order kinetics. The siRNA-nanoparticles were easily taken up by the cells, with a transfection efficiency as high as ~80%. The silencing effect of siRNA delivered from the BGn, as examined by using bcl-2 model gene, showed dramatic down-regulation (~15% of control), suggesting the potential use of BGn as a new class of nanovehicles for genes. This, in conjunction with other attractive properties, including size- and mesopore-related high surface area and pore volume, tunable surface chemistry, apatite-forming ability, good cell viability and the possible ion-related stimulatory effects, will potentiate the usefulness of the BGn in hard tissue regeneration.

Electrospinning is one of the most versatile and effective tools to produce nanostructured fibers in the biomedical science fields. The nanofibrous structure with diameters from tens to hundreds of nanometers largely mimics the native extracellular matrix (ECM) of many tissues. Thus far, a range of compositions including polymers and ceramics and their composites/hybrids have been successfully applied for generating electrospun nanofibers. Different processing tools in electrospinning set-ups and assemblies are currently developed to tune the morphology and properties of nanofibers. Herein, we demonstrate the electrospinning process and the electrospun biomaterials for specific use in tissue regeneration with some examples, involving different material combinations and fiber morphologies.

It is the purpose of this study to determine the effects of Zn deficiency on the biochemical composition of testes, epididymis, and seminal vesicle of rabbits. An attempt is made to evaluate previous physiological studies and to correlate them with biochemical changes. 30 mature male Balady rabbits were used in this study. 1 group was fed a Zn-deficient diet, and 2 control groups were pair-fed or fed ad libitum a Zn-sufficient diet, all for a period of 120 d. There was significant reduction in the levels of hyaluronidase, alkaline phosphatase, acid phosphatase, lactic dehydrogenase, sialic acid, protein, and Zn of both testes and epididymis of Zn-deficient rabbits. Reduction in the level of glyceryl-phosphoryl choline in the epididymis of Zn-deficient rabbits was the best indicator of inhibition of epididymal secretory activity. In contrast, the cholesterol and glycogen contents of the testes were elevated. The results also showed in Zn-deficient rabbits significant reduction in androgen-sensitive parameters, namely fructose and citric acid in the seminal vesicle. Zn levels were decreased in the seminal vesicle. The results indicated that Zn deficiency caused inhibition of testicular, epididymal, and seminal vesicle function and, consequently, caused reductions in the biochemical composition of these organs.

Progesterone, enzymes, minerals, trace elements, and total protein were determined in the blood serum of nine non-pregnant, early, mid-, and late pregnant as well as puerperal camels, and were assessed in their relation to the reproductive state. The progesterone level followed by the copper level reaches peak values at mid-pregnancy. The zinc level decreases with increasing pregnancy, alkaline phosphatase increases. Hypocalcaemia and hypomagnesaemia occur towards the end of pregnancy; the total protein content increases. Surprisingly, the manganese level remained more or less constant.