Density Functional Theory; A New Route for Structural and Thermodynamic Parameters Calculations

Structural and thermodynamic parameters of the studied virgin polymeric matrices poly e-caprolactone (PCL), Chitosan (Chi) and their polymer blend were investigated using theoretical density functional theory (DFT). Thermodynamic functions were calculated based on vibrational frequencies and optimized geometrical coordinates in the temperature range 25-1000 °K which cannot be amended easily. Calculated free energy was found to be convex in terms of extensive variable and concave in terms of intensive ones

Synthesis Characterization and Studies of Photodegradation of PVC Films of(4-amino-5-(2-(2,3- dimethylphenyl)aminophnyl)- 1,2,4-triazole-3-thion)with Co(II),Ni(II),Cu(II),Zn(II) and Cd(II) Matel ions

A complexes of Co(II) , Ni(II), Cu(II), Zn(II) and Cd(II)  with 4-amino-5-(2-(2,3- dimethylphenyl) aminophnyl)-1,2,4-triazole-3-thion)(L)was prepared and evaluated as a photodegradation for rigid Poly(vinyl chloride) (PVC).  Polyvinyl chloride dissolved with metal complexes in THF solvent to form PVC films of 5% (40μm) thickness containing concentrations of the complexes by weight.  These different samples were produced by the casting method from the solvent. The photodegradation of films was investigated using UV-visible spectra. The photostabilization activity of these compounds was determined by calculating the photodecomposition rate constant (Kd) for modified PVC films against a blank. Keywords: photodegradation, 1,2,4-triazole, matel complexes

Gold aggregating gold: A novel nanoparticle biosensor approach for the direct quantification of hepatitis C virus RNA in clinical samples

The affordable and reliable detection of Hepatitis C Virus (HCV) RNA is a cornerstone in the management and control of infection, affecting approximately 3% of the global population. However, the existing technologies are expensive, labor intensive and time consuming, posing significant limitations to their wide-scale exploitation, particularly in economically deprived populations. Here, we utilized the unique optical and physicochemical properties of gold nanoparticles (AuNPs) to develop a novel assay platform shown to be rapid and robust in sensing and quantifying unamplified HCV RNA in clinical samples. The assay is based on inducing aggregation of citrate AuNPs decorated with a specific nucleic acid probe. Two types of cationic AuNPs, cysteamine and CTAB capped, were compared to achieve maximum assay performance. The technology is simple, rapid, cost effective and quantitative with 93.3% sensitivity, high specificity and detection limit of 4.57 IU/µl. Finally, our data suggest that RNA folding impact the aggregation behavior of the functionalized AuNPs, with broader applications in other nucleic acid detection technologies

Gold nanoparticles - an optical biosensor for RNA quantification for cancer and neurologic disorders diagnosis

Purpose: The objective of this study is to develop a facile tool for the absolute detection and quantification of nucleic acid transcripts, using a gold nanoparticle-based optical biosensor. Topoisomerase 1 (TOP1) and tyrosyl DNA phosphodiesterase 2 (TDP2) were among the nucleic acid transcripts of choice due to their role as genomic instability biomarkers and their implication in various cancers and neurologic disorders. This opens the door to develop a simple tool that can be used for diagnosing and monitoring treatment response for such diseases, overcoming the requirements for high cost, time, and complexity of the existing technologies for the absolute quantification of transcripts of interest. Materials and methods: The TOP1 and TDP2 mRNA transcripts were first captured specifically using magnetic nanoparticles that were functionalized with TOP1- and TDP2-specific probes, respectively. The captured mRNA was then directly detected and quantified using the gold aggregating gold (GAG) assay, without the need for amplification as in existing technologies used for the quantification of transcripts. Results: A linear correlation exists between the GAG assay and the qPCR for the quantification of the TOP1 and TDP2 mRNA transcripts (101–104 copies). The detection limit of the GAG assay in mRNA quantification was up to 10 copies per reaction. Wild-type and TDP2-deficient cell lines confirmed the assay specificity and reproducibility in distinguishing between different transcripts. Conclusion: The GAG assay can be utilized as an inexpensive, rapid, simple, and sensitive tool for the absolute quantification of RNA for different applications, instead of the laborious, expensive, and sophisticated real-time PCR

Enhancement of clavulanic acid production by Streptomyces sp MU-NRC77 via mutation and medium optimization

Purpose: To enhance clavulanic acid production using UV-mutagenesis on Streptomyces sp. NRC77.Methods: UV-mutagenesis was used to study the effect of Streptomyces sp. NRC77 on CA production. Phenotypic and genotypic identification methods of the promising mutant strain were characterized. Optimization of the fermentation medium and culture conditions were investigatedResults: Out of the screened mutants, 120A3 mutant isolate was selected as promising. The phenotypic properties of 120A3 mutant showed culture characteristics similar to those of Streptomyces species. Phylogenetic analysis of 16S rRNA gene sequence indicate that this strain has similarity (99 %) to Streptomyces sp.T2-7; therefore it was suggested as Streptomyces sp. MU-NRC77 and has Gen Bank accession no. KT953342.Conclusion: Improvement of CA yield by 48 % was obtained from fermentation medium and culture condition optimization. Further optimization by addition of H2O2 and activated charcoal to the production medium increased CA yield to 646.12 and 682.94 mg/L respectively, i.e., 83 % more than that obtained prior to addition.Keywords: Clavulanic acid, Medium optimization, Phenotypic and Genotypic identification, Streptomyces sp. MU-NRC77, UV-Mutagenesi

Tension term, interchange symmetry, and the analogy of energy and tension laws of the AdS soliton solution

In this paper, we reconsider the energy and tension laws of the Ricci flat black hole by taking the contribution of the tension term into account. After this considering and inspired by the interchange symmetry between the Ricci flat black hole and the AdS soliton solution which arises from the double analytic continuation of the time and compact spatial direction, we find out the analogy of the energy and tension laws of the AdS soliton solution. Moreover, we also investigate the energy and tension laws of the boosted Ricci flat black hole, and discuss the boosted AdS soliton solution. However, although there is the same interchange symmetry between the boosted Ricci flat black hole and boosted AdS soliton, the analogy of laws of the boosted AdS soliton solution may be of no sense for the existence of the closed timelike curves and conical singularity. In spite of that, the conserved charges such as the energy and momentum of the boosted AdS soliton are well-defined, and an interesting result is that its energy is lower than that of the static AdS soliton. On the other hand, note that although the laws obtained above are the same as those of the asymptotically flat case, the underlying deduced contents are different. Thus, our results could also be considered as a simple generalization to the asymptotically AdS case. Moreover, during the calculation, we find that there may be a new way to define the gravitational tension which can come from the quasi-local stress tensor of the counter-term method.Comment: V4: 15 pages, no figure, version to appear in JHE

Ricci flat rotating black branes with a conformally invariant Maxwell source

We consider Einstein gravity coupled to an $U(1)$ gauge field for which the density is given by a power of the Maxwell Lagrangian. In $d$-dimensions the action of Maxwell field is shown to enjoy the conformal invariance if the power is chosen as $d/4$. We present a class of charge rotating solutions in Einstein-conformally invariant Maxwell gravity in the presence of a cosmological constant. These solutions may be interpreted as black brane solutions with inner and outer event horizons or an extreme black brane depending on the value of the mass parameter. Since we are considering power of the Maxwell density, the black brane solutions exist only for dimensions which are multiples of four. We compute conserved and thermodynamics quantities of the black brane solutions and show that the expression of the electric field does not depend on the dimension. Also, we obtain a Smarr-type formula and show that these conserved and thermodynamic quantities of black branes satisfy the first law of thermodynamics. Finally, we study the phase behavior of the rotating black branes and show that there is no Hawking--Page phase transition in spite of conformally invariant Maxwell field.Comment: 13 pages, one figur

Nuttier Bubbles

We construct new explicit solutions of general relativity from double analytic continuations of Taub-NUT spacetimes. This generalizes previous studies of 4-dimensional nutty bubbles. One 5-dimensional locally asymptotically AdS solution in particular has a special conformal boundary structure of $AdS_3\times S^1$. We compute its boundary stress tensor and relate it to the properties of the dual field theory. Interestingly enough, we also find consistent 6-dimensional bubble solutions that have only one timelike direction. The existence of such spacetimes with non-trivial topology is closely related to the existence of the Taub-NUT(-AdS) solutions with more than one NUT charge. Finally, we begin an investigation of generating new solutions from Taub-NUT spacetimes and nuttier bubbles. Using the so-called Hopf duality, we provide new explicit time-dependent backgrounds in six dimensions.Comment: 32 pages, 1 figure; v.3. typos corrected. Matches the published versio

Indirect measurement of anterior-posterior ground reaction forces using a minimal set of wearable inertial sensors: from healthy to hemiparetic walking

BACKGROUND: The anterior-posterior ground reaction force (AP-GRF) and propulsion and braking point metrics derived from the AP-GRF time series are indicators of locomotor function across healthy and neurological diagnostic groups. In this paper, we describe the use of a minimal set of wearable inertial measurement units (IMUs) to indirectly measure the AP-GRFs generated during healthy and hemiparetic walking. METHODS: Ten healthy individuals and five individuals with chronic post-stroke hemiparesis completed a 6-minute walk test over a walking track instrumented with six forceplates while wearing three IMUs securely attached to the pelvis, thigh, and shank. Subject-specific models driven by IMU-measured thigh and shank angles and an estimate of body acceleration provided by the pelvis IMU were used to generate indirect estimates of the AP-GRF time series. Propulsion and braking point metrics (i.e., peaks, peak timings, and impulses) were extracted from the IMU-generated time series. Peaks and impulses were expressed as % bodyweight (%bw) and peak timing was expressed as % stance phase (%sp). A 75%-25% split of 6-minute walk test data was used to train and validate the models. Indirect estimates of the AP-GRF time series and point metrics were compared to direct measurements made by the forceplates. RESULTS: Indirect measurements of the AP-GRF time series approximated the direct measurements made by forceplates, with low error and high consistency in both the healthy (RMSE= 4.5%bw; R2= 0.93) and post-stroke (RMSE= 2.64%bw; R2= 0.90) cohorts. In the healthy cohort, the average errors between indirect and direct measurements of the peak propulsion magnitude, peak propulsion timing, and propulsion impulse point estimates were 2.37%bw, 0.67%sp, and 0.43%bw. In the post-stroke cohort, the average errors for these point estimates were 1.07%bw, 1.27%sp, and 0.31%bw. Average errors for the braking estimates were higher, but comparable. CONCLUSIONS: Accurate estimates of AP-GRF metrics can be generated using three strategically mounted IMUs and subject-specific calibrations. This study advances the development of point-of-care diagnostic systems that can catalyze the routine assessment and management of propulsion and braking locomotor deficits during rehabilitation.KL2 TR001411 - NCATS NIH HHSPublished versio

Horizonless Rotating Solutions in (n+1)(n+1)-dimensional Einstein-Maxwell Gravity

We introduce two classes of rotating solutions of Einstein-Maxwell gravity in $n+1$ dimensions which are asymptotically anti-de Sitter type. They have no curvature singularity and no horizons. The first class of solutions, which has a conic singularity yields a spacetime with a longitudinal magnetic field and $k$ rotation parameters. We show that when one or more of the rotation parameters are non zero, the spinning brane has a net electric charge that is proportional to the magnitude of the rotation parameters. The second class of solutions yields a spacetime with an angular magnetic field and $$ boost parameters. We find that the net electric charge of these traveling branes with one or more nonzero boost parameters is proportional to the magnitude of the velocity of the brane. We also use the counterterm method inspired by AdS/CFT correspondence and calculate the conserved quantities of the solutions. We show that the logarithmic divergencies associated to the Weyl anomalies and matter field are zero, and the $r$ divergence of the action can be removed by the counterterm method.Comment: 14 pages, references added, Sec. II amended, an appendix added. The version to appear in Phys. Rev.