148 research outputs found

    A Finite Element Method for the Multiterm Time-Space Riesz Fractional Advection-Diffusion Equations in Finite Domain

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    We present an effective finite element method (FEM) for the multiterm time-space Riesz fractional advection-diffusion equations (MT-TS-RFADEs). We obtain the weak formulation of MT-TS-RFADEs and prove the existence and uniqueness of weak solution by the Lax-Milgram theorem. For multiterm time discretization, we use the Diethelm fractional backward finite difference method based on quadrature. For spatial discretization, we show the details of an FEM for such MT-TS-RFADEs. Then, stability and convergence of such numerical method are proved, and some numerical examples are given to match well with the main conclusions

    Valley vortex states and degeneracy lifting via photonic higher-band excitation

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    We demonstrate valley-dependent vortex generation in a photonic graphene. Without breaking the inversion symmetry, excitation of two equivalent valleys leads to formation of an optical vortex upon Bragg-reflection to the third valley, with its chirality determined by the valley degree of freedom. Vortex-antivortex pairs with valley-dependent topological charge flipping are also observed and corroborated by numerical simulations. Furthermore, we develop a three-band effective Hamiltonian model to describe the dynamics of the coupled valleys, and find that the commonly used two-band model is not sufficient to explain the observed vortex degeneracy lifting. Such valley-polarized vortex states arise from high-band excitation without inversion symmetry breaking or synthetic-field-induced gap opening. Our results from a photonic setting may provide insight for the study of valley contrasting and Berry-phase mediated topological phenomena in other systems

    Comparison of cold resistance physiological and biochemical features of four Herba Rhodiola seedlings under low temperature

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    AbstractTo discuss the cold resistance performance of different Herba Rhodiolae and successfully transplant Herba Rhodiolae to the Gansu plateau area for nursing, domestication and planting, this paper systematically studies six physiological and biochemical features of Rhodiola kirilowii, Rhodiola algida, Rhodiola crenulata and Herba Rhodiolae that are closely associated with cold resistance features and concludes with the cold resistance capability of Rhodiola kirilowii. In the selected six main indexes of the Herba Rhodiolae, the POD, SOD and CAT activity and MDA and Pro content in the leaf are the main physiological and biochemical indexes to indicate the cold resistance performance of four Herba Rhodiolae seedlings and can be regarded as the preliminary indexes to assess the winter performance of Herba Rhodiolae. The research work will provide the theoretical basis for the wild variants of Herba Rhodiolae and GAPJ base construction

    Bioinformatics-integrated screening of systemic sclerosis-specific expressed markers to identify therapeutic targets

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    BackgroundSystemic sclerosis (SSc) is a rare autoimmune disease characterized by extensive skin fibrosis. There are no effective treatments due to the severity, multiorgan presentation, and variable outcomes of the disease. Here, integrated bioinformatics was employed to discover tissue-specific expressed hub genes associated with SSc, determine potential competing endogenous RNAs (ceRNA) regulatory networks, and identify potential targeted drugs.MethodsIn this study, four datasets of SSc were acquired. To identify the genes specific to tissues or organs, the BioGPS web database was used. For differentially expressed genes (DEGs), functional and enrichment analyses were carried out, and hub genes were screened and shown in a network of protein-protein interactions (PPI). The potential lncRNA–miRNA–mRNA ceRNA network was constructed using the online databases. The specifically expressed hub genes and ceRNA network were validated in the SSc mouse and in normal mice. We also used the receiver operating characteristic (ROC) curve to determine the diagnostic values of effective biomarkers in SSc. Finally, the Drug-Gene Interaction Database (DGIdb) identified specific medicines linked to hub genes.ResultsThe pooled datasets identified a total of 254 DEGs. The tissue/organ-specifically expressed genes involved in this analysis are commonly found in the hematologic/immune system and bone/muscle tissue. The enrichment analysis of DEGs revealed the significant terms such as regulation of actin cytoskeleton, immune-related processes, the VEGF signaling pathway, and metabolism. Cytoscape identified six gene cluster modules and 23 hub genes. And 4 hub genes were identified, including Serpine1, CCL2, IL6, and ISG15. Consistently, the expression of Serpine1, CCL2, IL6, and ISG15 was significantly higher in the SSc mouse model than in normal mice. Eventually, we found that MALAT1-miR-206-CCL2, let-7a-5p-IL6, and miR-196a-5p-SERPINE1 may be promising RNA regulatory pathways in SSc. Besides, ten potential therapeutic drugs associated with the hub gene were identified.ConclusionsThis study revealed tissue-specific expressed genes, SERPINE1, CCL2, IL6, and ISG15, as effective biomarkers and provided new insight into the mechanisms of SSc. Potential RNA regulatory pathways, including MALAT1-miR-206-CCL2, let-7a-5p-IL6, and miR-196a-5p-SERPINE1, contribute to our knowledge of SSc. Furthermore, the analysis of drug-hub gene interactions predicted TIPLASININ, CARLUMAB and BINDARIT as candidate drugs for SSc

    DETC2005/MECH-85241 DYNAMIC MODELING AND CONTROLLER DESIGN OF A PLANAR PARALLEL 3-RRR COMPLIANT MICROMANIPULATOR

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    ABSTRACT This paper presents control system formulations of a planar parallel 3-RRR parallel compliant micromanipulator. The design methodology is illustrated with one of such designs constructed at Beijing University of Aeronautics and Astronautics, China. Compliant joints and motion-amplifying mechanism allow rapid and accurate response as well as larger workspace. The three PZT actuators attached on the linkages produce the bending moments. The sensor is a CCD camera feeding back the tool point position. The plant is the equations of motion which can be formulated using the Lagrangian method and dynamics software. The system dynamic model was developed with ADAMS which can export the nonlinear and linearized control plant to Matlab Simulink. Overall dynamic behavior of the manipulator will be illustrated through simulations with Matlab Simulink Toolbox. After comparison of two different control plans, the controller obtained from LQR method was chosen to achieve the control objectives. Closed-loop performance in response to a step reference was plotted. Bode plots of the sensitivity and complementary sensitivity showed their relation to the step response. Gain and phase margins was computed

    Isolation and Identification of Black Yeasts by Enrichment on Atmospheres of Monoaromatic Hydrocarbons

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    Black yeast members of the Herpotrichiellaceae present a complex ecological behavior: They are often isolated from rather extreme environments polluted with aromatic hydrocarbons, while they are also regularly involved in human opportunistic infections. A selective technique to promote the in vitro growth of herpotrichiellaceous fungi was applied to investigate their ecophysiology. Samples from natural ecological niches and man-made environments that might contain black yeasts were enriched on an inert solid support at low humidity and under a controlled atmosphere rich in volatile aromatic hydrocarbons. Benzene, toluene, and xylene were provided separately as the sole carbon and energy source via the gas phase. The assayed isolation protocol was highly specific toward mesophilic Exophiala species (70 strains of this genus out of 71 isolates). Those were obtained predominantly from creosote-treated railway ties (53 strains), but isolates were also found on wild berries (11 strains) and in guano-rich soil samples (six strains). Most of the isolates were obtained on toluene (43 strains), but enrichments on xylene and benzene also yielded herpotrichiellaceous fungi (17 and 10 isolates, respectively). Based upon morphological characterizations and DNA sequences of the full internal transcriber spacers (ITS) and the 8.5S rRNA genes, the majority of the obtained isolates were affiliated to the recently described species Exophiala xenobiotica (32 strains) and Exophiala bergeri (nine strains). Members of two other phylogenetic groups (24 and two strains, respectively) somewhat related to E. bergeri were also found, and a last group (three strains) corresponded to an undescribed Exophiala species

    Utilizing 505(b)(2) Regulatory Pathway for New Drug Applications: An Overview on the Advanced Formulation Approach and Challenges

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    More than 50% of approved drugs on the market contain poorly water-soluble APIs, which typically are associated with poor bioavailability, suboptimal drug delivery, ineffective drug efficacy, and side effects. This creates a huge opportunity in generating 505(b)(2) products, which address unmet medical needs by applying formulation technologies to overcome those difficulties. A key feature of the 505(b)(2) pathway is the 505(b)(2) sponsor can rely upon clinical data or literature produced by other companies. The 505(b)(2) pathway allows manufacturers to acquire FDA approval without performing all the work required with a traditional NDA. The 505(b)(2) strategy can be an option to improve existing drug products with a new indication, dosage form, dosing regimen, strength, combination with other products, new route of administration, elimination of food effect, switching from a prescription drugs (Rx) to an over-the-counter (OTC), non-prescription product that differs from the OTC monograph, and orphan drug indications. Both generic and brand companies are turning to more complex 505(b)(2) products to avoid the commoditized generic competition. Revitalization of older marketed drug products using innovative drug delivery technologies or platforms can provide new marketing exclusivity and new patent protection, and thus offer an effective tool for product life cycle management

    Therapeutic Effect of Vagus Nerve Stimulation on Depressive-Like Behavior, Hyperglycemia and Insulin Receptor Expression in Zucker Fatty Rats

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    Depression and type 2 diabetes (T2D) are common comorbid diseases and highly prevalent in the clinical setting with an unclarified mechanism. Zucker diabetic fatty (ZDF, fa/fa) rats natively develop T2D with hyperglycemia and hyperinsulinemia. Here we studied whether ZDF rats also innately develop depression, what a correlation is between depression and T2D, whether insulin receptor (IR) expression is involved in, and whether transcutaneous auricular vagus nerve stimulation (taVNS) would be beneficial in amelioration of the comorbidity. Six week old male ZDF and Zucker lean (ZL, fa/+) littermates were randomly divided into naïve (ZDF, n = 6; ZL, n = 7) and taVNS (ZDF-taVNS, n = 8; ZL-taVNS, n = 6) groups. Once daily 30 min-taVNS sessions were administrated under anesthesia for 34 consecutive days in taVNS groups. Blood glucose levels were tested weekly, and plasma glycosylated hemoglobin (HbAlc) level and immobility time in forced swimming test were determined on day 35 in all groups. The expression of insulin receptor (IR) in various tissues was also detected by immunostaining and Western blot. We found that naïve ZDF rats developed hyperglycemia steadily. These ZDF rats showed a strong positive correlation between longer immobility time and higher plasma HbAlC level. Long term taVNS treatment simultaneously prevented the development of depression-like behavior and progression of hyperglycemia in ZDF rats. The expression of IR in various tissues of naïve ZDF rats is lower than in naïve ZL and long-term taVNS treated ZDF rats. Collectively, our results indicate that in ZDF rats, i) depression and T2D develop simultaneously, ii) immobility time and HbAlc concentrations are highly and positively correlated, iii) a low expression of IR may be involved in the comorbidity of depression and T2D, and iv) taVNS is antidiabetic and antidepressive possibly through IR expression upregulation

    Transcutaneous Auricular Vagus Nerve Stimulation Triggers Melatonin Secretion and Is Antidepressive in Zucker Diabetic Fatty Rats

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    Decreased circulating melatonin is implicated in depression. We recently found that Zucker diabetic fatty rats (ZDF, fa/fa) develop depression-like behaviors and that transcutaneous auricular vagus nerve stimulation (taVNS) is antidepressive in ZDF rats. Here we studied whether the ZDF rats could be used as a depression rodent model and whether the antidepressive effect of taVNS is mediated through modulation of melatonin secretion. Adult male ZDF and Zucker lean (ZL, fa/+) littermates were used. 30 min-taVNS procedures (2/15 Hz, 2 mA) were administered once daily under anesthesia for 34 consecutive days in pineal intact ZDF (n = 8) and ZL (n = 6) rats, as well as in pinealectomized ZDF rats (n = 8). Forced swimming test (FST) was used to determine depression-like behavior and ELISA to detect plasma melatonin concentration on day 35. We found that naïve ZDF rats had a longer immobility time in FST and that long-term (34 days) taVNS treatment ameliorated the depression-like behavior. In both pineal intact and pinealectomized ZDF rats, taVNS induced acute melatonin secretion, both during and after the taVNS session. A low melatonin level is related to the poor FST performance in ZDF rats (R = −0.544) in contrast to ZL rats (R = 0.247). In conclusion, our results show that ZDF rats are ideal candidates of innate depression and that taVNS is antidepressive through triggering melatonin secretion and increasing its production
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