187 research outputs found
Thermal Instability of Rivlin-Ericksen Elastico-Viscous Rotating Fluid in Porous Medium in Hydromagnetics
The thermal instability of a layer of Rivlin-Ericksen elastico-viscous rotating fluid in a porous medium in hydromagnetics is considered. For stationary convection, the Rivlin-Ericksen elastico-viscous fluid behaves like an ordinary (Newtonian) fluid. The magnetic field is found to have a stabilizing effect on the thermal instability of a layer of Rivlin-Ericksen fluid in the absence of rotation whereas the medium permeability has a destabilizing effect on thermal instability of Rivlin-Ericksen fluid in the absence of rotation. Rotation always has a stabilizing effect. The magnetic field, medium permeability and rotation introduce oscillatory modes in the system, which were non-existent in their absence. The case of over stability is also considered and the sufficient conditions for the non-existence of over stability are obtained in the process. The study finds applications in geophysics, chemical technology and engineering. Among the applications in engineering disciplines one can find the food process industry, chemical process industry, solidification and centrifugal casting of metals and rotating machinery
nalisis Bauran Pemasaran Dan Kualitas Pelayanan Terhadap Kepuasan Konsumen Pada Wed Cafe Banggai
Penelitian ini bertujuan untuk mengetahui pengaruh Bauran Pemasaran dan Kualitas Pelayanan terhadap kepuasan konsumen pada Wed Cafe Banggai. Metode yang di gunakan adalah metode kuantitatif. Teknik sampling yang digunakan yaitu Purposive Sampling dengan 81 responden, metode penelitian ini menggunakan pendekatan kuantitatif dengaan pengumpulan data melalui kuesioner yang disebar kepada konsumen pada Wed Cafe Banggai, Alat uji analisis yang di gunakan dalam penelitian ini yaitu regresi linier berganda.Hasil penelitian menunjukkan bahwa variabel independent berpengaruh secara parsial terhadap variabel dependent, diperoleh nilai thitung 10,989 variabel X1 dan 6,486 variabel X2 yang lebih besar dari nilai ttabel 1,990 dengan nilai signifikan 0,05, sehingga diperoleh hubungan secara parsial dan positif dari variabel Bauran Pemasaran (X1), Kualitas Pelayanan (X2), terhadap Kepuasan Konsumen Wed Cafe Banggai. Selain itu pula diperoleh analisis hubungan positif secara simultan pada variabel independent terhadap variabel dependent. Hubungan ini menunjukan nilai Fhitung 106,174 yang melebihi nilai Ftabel sebesar 3,114 dengan tingkat signifikansi 0,05. Persentase korelasi dari variabel independent dalam mempengaruhi variabel dependent mencapai 73,1%
Covalent immobilisation of an Aspergillus niger derived endo-1,4-beta-mannanase, man26A, on glutaraldehyde-activated chitosan nanoparticles for the effective production of prebiotic MOS from soybean meal
An Aspergillus niger endo-1,4- -mannanase, Man26A, was confirmed by FTIR and XRD
to be immobilised on glutaraldehyde-activated chitosan nanoparticles via covalent bonding. The
immobilisation (%) and activity yields (%) were 82.25% and 20.75%, respectively. The biochemical
properties (pH, temperature optima, and stability) were then comparatively evaluated for both the free
and immobilised Man26A. The optimal activity of Man26A shifted to a lower pH after immobilisation
(pH 2.0–3.0, from pH 5 for the free enzyme), with the optimum temperature remaining unchanged
(60 C). The two enzymes exhibited identical thermal stability, maintaining 100% activity for the first
6 h at 55 C. Substrate-specific kinetic analysis showed that the two enzymes had similar affinities
towards locust bean gum (LBG) with varied Vmax values. In contrast, they showed various affinities
towards soybean meal (SBM) and similar Vmax values. The immobilised enzyme was then employed
in the enhancement of the functional feed/prebiotic properties of SBM from poultry feed, increasing
mannooligosaccharides (MOS) quantities. The SBM main hydrolysis products were mannobiose
(M2) and mannose (M1). The SBM-produced sugars could be utilised as a carbon source by probiotic
bacteria; Streptococcus thermophilus, Bacillus subtilis, and Lactobacillus bulgaricus. The results indicate
that the immobilised enzyme has the potential for use in the sustainable and cost-effective production
of prebiotic MOS from agricultural biomass.Rhodes University’s Research Council (RC) grant and a Rated Researcher Grant (RRG).https://www.mdpi.com/journal/agronomyam2023BiochemistryGeneticsMicrobiology and Plant Patholog
FOXD1-ALDH1A3 signaling is a determinant for the self-renewal and tumorigenicity of mesenchymal glioma stem cells
Glioma stem-like cells (GSC) with tumor-initiating activity orchestrate the cellular hierarchy in glioblastoma and engender therapeutic resistance. Recent work has divided GSC into two subtypes with a mesenchymal (MES) GSC population as the more malignant subtype. In this study, we identify the FOXD1-ALDH1A3 signaling axis as a determinant of the MES GSC phenotype. The transcription factor FOXD1 is expressed predominantly in patient-derived cultures enriched with MES, but not with the proneural GSC subtype. shRNA-mediated attenuation of FOXD1 in MES GSC ablates their clonogenicity in vitro and in vivo. Mechanistically, FOXD1 regulates the transcriptional activity of ALDH1A3, an established functional marker for MES GSC. Indeed, the functional roles of FOXD1 and ALDH1A3 are likely evolutionally conserved, insofar as RNAi-mediated attenuation of their orthologous genes in Drosophila blocks formation of brain tumors engineered in that species. In clinical specimens of high-grade glioma, the levels of expression of both FOXD1 and ALDH1A3 are inversely correlated with patient prognosis. Finally, a novel small-molecule inhibitor of ALDH we developed, termed GA11, displays potent in vivo efficacy when administered systemically in a murine GSC-derived xenograft model of glioblastoma. Collectively, our findings define a FOXD1-ALDH1A3 pathway in controling the clonogenic and tumorigenic potential of MES GSC in glioblastoma tumors
Notch Signaling Activates Yorkie Non-Cell Autonomously in Drosophila
In Drosophila imaginal epithelia, cells mutant for the endocytic neoplastic tumor suppressor gene vps25 stimulate nearby untransformed cells to express Drosophila Inhibitor-of-Apoptosis-Protein-1 (DIAP-1), conferring resistance to apoptosis non-cell autonomously. Here, we show that the non-cell autonomous induction of DIAP-1 is mediated by Yorkie, the conserved downstream effector of Hippo signaling. The non-cell autonomous induction of Yorkie is due to Notch signaling from vps25 mutant cells. Moreover, activated Notch in normal cells is sufficient to induce non-cell autonomous Yorkie activity in wing imaginal discs. Our data identify a novel mechanism by which Notch promotes cell survival non-cell autonomously and by which neoplastic tumor cells generate a supportive microenvironment for tumor growth
The Potential Involvement of E-cadherin and β-catenins in Meningioma
To investigate the potential involvements of E-cadherin and β-catenin in meningioma.Immunohistochemistry staining was performed on samples from patients with meningioma. The results were graded according to the positive ratio and intensity of tissue immunoreactivity. The expression of E-cadherin and β-catenin in meningioma was analyzed by its relationship with WHO2007 grading, invasion, peritumoral edema and postoperative recurrence.The positive rates of E-cadherin in meningioma WHO I, II, III were 92.69%, 33.33% and 0, respectively, (P<0.05); while the positive rates of β-catenin in meningioma WHO I, II, III were 82.93%, 33.33% and 20.00%, respectively, (P<0.05). The positive rate of E-cadherin in meningioma without invasion (94.12%) was higher than that with invasion (46.67%) (P<0.05). The difference in the positive rate of β-catenin between meningioma without invasion (88.24%) and meningioma with invasion (33.33%, P<0.05) was also statically significant. The positive rates of E-cadherin in meningioma with peritumoral edema 0, 1, 2, 3 were 93.75%, 85.71%, 60.00% and 0 respectively, (P<0.05); the positive rates of β-catenin in meningioma with peritumoral edema 0, 1, 2, 3 were 87.50%, 85.71%, 30.00% and 0 respectively, (P<0.01). The positive rates of E- cadherin in meningioma with postoperative recurrence were 33.33%, and the positive rate with postoperative non-recurrence was 90.00% (P<0.01). The positive rates of β-catenin in meningioma with postoperative recurrence and non-recurrence were 11.11%, 85.00%, respectively (P<0.01).The expression levels of E- cadherin and β-catenin correlated closely to the WHO 2007 grading criteria for meningioma. In atypical or malignant meningioma, the expression levels of E-cadherin and β-catenin were significantly lower. The expression levels of E- cadherin and β-catenin were also closely correlated with the invasion status of meningioma, the size of the peritumoral edema and the recurrent probabilities of the meningioma, all in an inverse correlationship. Taken together, the present study provided novel molecular targets in clinical treatments to meningioma
rst Transcriptional Activity Influences kirre mRNA Concentration in the Drosophila Pupal Retina during the Final Steps of Ommatidial Patterning
Background: Drosophila retinal architecture is laid down between 24-48 hours after puparium formation, when some of the still uncommitted interommatidial cells (IOCs) are recruited to become secondary and tertiary pigment cells while the remaining ones undergo apoptosis. This choice between survival and death requires the product of the roughest (rst) gene, an immunoglobulin superfamily transmembrane glycoprotein involved in a wide range of developmental processes. Both temporal misexpression of Rst and truncation of the protein intracytoplasmic domain, lead to severe defects in which IOCs either remain mostly undifferentiated and die late and erratically or, instead, differentiate into extra pigment cells. Intriguingly, mutants not expressing wild type protein often have normal or very mild rough eyes. Methodology/Principal Findings: By using quantitative real time PCR to examine rst transcriptional dynamics in the pupal retina, both in wild type and mutant alleles we showed that tightly regulated temporal changes in rst transcriptional rate underlie its proper function during the final steps of eye patterning. Furthermore we demonstrated that the unexpected wild type eye phenotype of mutants with low or no rst expression correlates with an upregulation in the mRNA levels of the rst paralogue kin-of-irre (kirre), which seems able to substitute for rst function in this process, similarly to their role in myoblast fusion. This compensatory upregulation of kirre mRNA levels could be directly induced in wild type pupa upon RNAi-mediated silencing of rst, indicating that expression of both genes is also coordinately regulated in physiological conditions. Conclusions/Significance: These findings suggest a general mechanism by which rst and kirre expression could be fine tuned to optimize their redundant roles during development and provide a clearer picture of how the specification of survival and apoptotic fates by differential cell adhesion during the final steps of retinal morphogenesis in insects are controlled at the transcriptional level
Identification of Retinal Transformation Hot Spots in Developing Drosophila Epithelia
Background: The retinal determination (RD) network is an evolutionarily conserved regulatory circuit that governs early events in the development of eyes throughout the animal kingdom. Ectopic expression of many members of this network leads to the transformation of non-retinal epithelia into eye tissue. An often-overlooked observation is that only particular cell-populations within a handful of tissues are capable of having their primary developmental instructions superseded and overruled. Methodology/Preliminary Findings: Here we confirm that indeed, only a discrete number of cell populations within the imaginal discs that give rise to the head, antenna, legs, wings and halteres have the cellular plasticity to have their developmental fates altered. In contrast to previous reports, we find that all transformable cell populations do not lie within the TGFb or Hedgehog signaling domains. Additionally neither signaling cascade alone is sufficient for non-retinal cell types to be converted into retinal tissue. The transformation ‘‘hot spots’ ’ that we have identified appear to coincide with several previously defined transdetermination ‘‘weak spots’’, suggesting that ectopic eye formation is less the result of one network overriding the orders of another, as previously thought, but rather is the physical manifestation of redirecting cell populations of enormous cellular plasticity. We also demonstrate that the initiation of eye formation in non-retinal tissues occurs asynchronously compared to that of the normal eye suggesting that retinal development is not under the control o
Myogenin Regulates Exercise Capacity but Is Dispensable for Skeletal Muscle Regeneration in Adult mdx Mice
Duchenne muscular dystrophy (DMD) is the most prevalent inherited childhood muscle disorder in humans. mdx mice exhibit a similar pathophysiology to the human disorder allowing for an in-depth investigation of DMD. Myogenin, a myogenic regulatory factor, is best known for its role in embryonic myogenesis, but its role in adult muscle maintenance and regeneration is still poorly understood. Here, we generated an mdx:Myogflox/flox mouse harboring a tamoxifen-inducible Cre recombinase transgene, which was used to conditionally delete Myog during adult life. After tamoxifen treatment, three groups of mice were created to study the effects of Myog deletion: mdx:Myogflox/flox mice (mdx), Myogflox/flox mice (wild-type), and mdx:MyogfloxΔ/floxΔ:Cre-ER mice (mdx:Myog-deleted). mdx:Myog-deleted mice exhibited no adverse phenotype and behaved normally. When run to exhaustion, mdx:Myog-deleted mice demonstrated an enhanced capacity for exercise compared to mdx mice, running nearly as far as wild-type mice. Moreover, these mice showed the same signature characteristics of muscle regeneration as mdx mice. Unexpectedly, we found that myogenin was dispensable for muscle regeneration. Factors associated with muscle fatigue, metabolism, and proteolysis were significantly altered in mdx:Myog-deleted mice, and this might contribute to their increased exercise capacity. Our results reveal novel functions for myogenin in adult muscle and suggest that reducing Myog expression in other muscle disease models may partially restore muscle function
Competing Activities of Heterotrimeric G Proteins in Drosophila Wing Maturation
Drosophila genome encodes six alpha-subunits of heterotrimeric G proteins. The Gαs alpha-subunit is involved in the post-eclosion wing maturation, which consists of the epithelial-mesenchymal transition and cell death, accompanied by unfolding of the pupal wing into the firm adult flight organ. Here we show that another alpha-subunit Gαo can specifically antagonize the Gαs activities by competing for the Gβ13F/Gγ1 subunits of the heterotrimeric Gs protein complex. Loss of Gβ13F, Gγ1, or Gαs, but not any other G protein subunit, results in prevention of post-eclosion cell death and failure of the wing expansion. However, cell death prevention alone is not sufficient to induce the expansion defect, suggesting that the failure of epithelial-mesenchymal transition is key to the folded wing phenotypes. Overactivation of Gαs with cholera toxin mimics expression of constitutively activated Gαs and promotes wing blistering due to precocious cell death. In contrast, co-overexpression of Gβ13F and Gγ1 does not produce wing blistering, revealing the passive role of the Gβγ in the Gαs-mediated activation of apoptosis, but hinting at the possible function of Gβγ in the epithelial-mesenchymal transition. Our results provide a comprehensive functional analysis of the heterotrimeric G protein proteome in the late stages of Drosophila wing development
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