Desired Period Research Articles

Mix-and-Match Assembly of Block Copolymer Blends in Solution

The chemical structure of a block copolymer (BCP) dictates the size, shape, and function of its self-assembled structure in solution. This direct correspondence demands precision synthesis of a specific BCP with optimized structural parameters to obtain the desired nanostructures with structural and functional complexity by solution self-assembly. Here we show that the binary blends of BCPs self-assemble into the desired nanostructure in solution by adjusting the composition of the blend. By modifying the structural parameters of a binary BCP blend through control of the composition, two BCPs sharing the repeating units in both polymer blocks coassemble into the desired structures, which range from spherical micelles to inverse cubic and hexagonal mesophases. These BCP blends not only allow the direct creation of complex periodic mesoporous structures of the desired periodicity and pore size but also provide nanostructures of unprecedented morphology by simple solution self-assembly without relying on the synthesis of correspondingly designed BCPs.

Abstract WMP77: Combination of Metabolic and Transcriptional Profiling Identifies Pentose Phosphate Pathway Activation by Heat Shock Protein 27 Phosphorylation During Cerebral Ischemia

Objectives: The metabolic pathophysiology of ischemic stroke remains poorly understood. We performed a comparative omics analysis to identify the effects of cerebral ischemia on metabolism of cerebral cortex in the rat model with middle cerebral artery occlusion (MCAO). Methods: MCAO was induced with suture occlusion technique. After the desired period of MCAO (30, 60, 120min), the rats were sacrificed. Tissue samples from the ischemic lesion were collected. Sham operated rats were treated in the same way except MCAO. Water-soluble metabolites were extracted and measured by gas-chromatography/mass-spectrometry (GC/MS). The obtained data were analyzed using multivariate statistics to explore metabolic pathways involved in ischemia. The associated metabolic enzymes were investigated with real-time polymerase chain reaction (RT-PCR) and Immunoblot analysis. Results: Metabolic profiling by GC/MS analysis showed clear separation between the ischemia and control group (Figure A, B). The decrease of fructose 6-phosphate and ribulose 5-phosphate suggested enhancement of the pentose phosphate pathway (PPP) during cerebral ischemia. Transcriptional profiling by microarray hybridization indicated that Toll-like receptor and mitogen-activated protein kinase (MAPK) signaling pathway were upregulated during cerebral ischemia. In relation to PPP, upregulation of heat shock protein 27 (HSP27) was observed in the MAPK signaling pathway and was confirmed through RT-PCR. Immunoblotting showed a slight increase in HSP27 protein expression and a marked increase in HSP27 phosphorylation (FigureC). Corresponding upregulation of glucose 6-phosphate dehydrogenase (G6PD) activity and an increase in the NADPH/NAD+ ratio were also observed (Figure D, E). Conclusions: G6PD activation via ischemia-induced HSP27 phosphorylation may be part of an endogenous antioxidant neuroprotection mechanism during the earliest stages of ischemia.

The Root Aqueous Extract of Entada africana Guill. et Perr. (Mimosaceae) Inhibits Implant Growth, Alleviates Dysmenorrhea, and Restores Ovarian Dynamic in a Rat Model of Endometriosis.

Entada africana (Mimosaceae) was reported to have analgesic and antioxidant properties. The present study is aimed at investigating the effects of the root aqueous extract of Entada africana (EA) on an experimental model of endometriosis. The study was performed in rats orally treated with EA at doses of 127.5, 255, and 510 mg/kg. Microgynon® 30 served as the reference substance. Estradiol valerate and oxytocin were used to induce dysmenorrhea. Endometrial implant levels of catalase and malondialdehyde (MDA) allowed estimating tissue oxidative status. Ovarian dynamic and rat sexual behavior were assessed through histological analysis of ovaries, uterus, and vagina. EA decreased dysmenorrhea at tested doses following a 7-day treatment (p < 0.001). Endometrial implant volume decreased following the three treatment periods (p < 0.05). Catalase activity (p < 0.001) and MDA level (p < 0.01) increased only following a 3-day treatment. EA also increased antral follicles, reduced luteinized unruptured follicle number (p < 0.001), and induced animals to be in the estrus phase. In conclusion, EA prevented the progress of endometriosis, reduced dysmenorrhea, promoted ovarian follicle growth, prevented anovulation, and stimulated the special period of rat sexual desire. These results suggest that Entada africana could be a promising alternative option for the treatment of endometriosis.

An Review on Floating Mucoadhesive Drug Delivery System

A gastro retentive dosage form will release the drug over an extended period in the stomach and upper gastrointestinal tract (GIT) thus enhancing the opportunity for absorption. Various approaches have been proposed to control the gastric residence of drug delivery system in the upper part of the GIT including floating drug delivery system. Formulation of Gastro-Retentive dosage forms (GRDFs) containing suitable drug candidate which would remain in stomach and/or upper part of GIT for prolonged period of time there by is maximizing the drug release at desired site within the time before GRDFs leave the stomach and or upper part of GIT. Oral route has been the adopted and most convenient route for the drug delivery. Floating dosage forms have been developed to float over GI fluids and to release the drug over a desired period of time. Floating drug delivery system also name as hydrodynamically balanced system (HBS). Bioadhesion can be defined as the process by which a natural or a synthetic polymer can adhere to a biological substrate. When the biological substrate is a mucosal layer then, the phenomenon is known as mucoadhesion.

Endocrine Regulation of Lymphocyte Trafficking In Vitro.

Lymphocyte recruitment in inflammation can be influenced by many molecules including cytokines, chemokines, and adipokines. In our lab, we have examined the effects of the adipokines leptin and adiponectin on lymphocyte migration, and observed modulation of this process. Lymphocyte behavior can be assessed in the lab under static conditions, or can be studied under flow, simulating in vivo conditions. In this chapter, in vitro methods for analyzing adhesion and migration of lymphocytes isolated from blood are described in detail. In static adhesion and migration assays, lymphocytes are allowed to settle on top of endothelial cell monolayers cultured in plates for a desired period of time. In the flow-based assay, lymphocytes are perfused over the endothelium at a continuous rate through microchannels which are commercially available. Depending on the choice of method employed, the efficiency of lymphocytes to adhere to and migrate across the endothelial cell monolayer under different conditions can be evaluated. Static assays are less complex and are of higher throughput. However, these assays provide less detailed information regarding lymphocyte behaviors. On the other hand, the flow-based assays are more difficult to perform, but are more physiologically relevant due to the presence of flow and yield more detailed information about lymphocyte activities such as capture, immobilization, and migration in real-time.

The Relationship Between Chaotic Maps and Some Chaotic Systems with Hidden Attractors

In this note, hidden attractors in chaotic maps are investigated. Although there are many new researches on hidden attractors in chaotic flows, no investigation has been done on hidden attractors in maps based on our knowledge. In addition, a new interesting chaotic map with a bifurcation diagram starting from any desired period and then continuing with period doubling is introduced in this paper.

Dynamical quantum tomography

We consider quantum state tomography with measurement procedures of the following type: First, we subject the quantum state we aim to identify to a know time evolution for a desired period of time. Afterwards we perform a measurement with a fixed measurement set-up. This procedure can then be repeated for other periods of time, the measurement set-up however remains unaltered. Given an $n$-dimensional system with suitable unitary dynamics, we show that any two states can be discriminated by performing a measurement with a set-up that has $n$ outcomes at $n+1$ points in time. Furthermore, we consider scenarios where prior information restricts the set of states to a subset of lower dimensionality. Given an $n$-dimensional system with suitable unitary dynamics and a semi-algebraic subset $\mathcal{R}$ of its state space, we show that any two states of the subset can be discriminated by performing a measurement with a set-up that has $n$ outcomes at $l$ steps of the time evolution if $(n-1)l\ge 2\dim\mathcal{R}$. In addition, by going beyond unitary dynamics, we show that one can in fact reduce to a set-up with the minimal number of two outcomes.

Graphene-like carbon with three-dimensional periodicity prepared from organic-inorganic templates for energy storage application

Free-standing, intergrown and covalently-bonded structures of three-dimensional (3D) graphene may have great advantages in electric and thermal transport properties for energy applications, but the desired symmetry and periodicity are rather hard to design and produce. Here we use an organic-inorganic template to grow an inverse.opal graphene structure by chemical vapor deposition. The symmetry-controlling temperate is a porous polymethylmethacrylate (PMMA) opal, infiltrated with inorganic cation precursors that form an interfacial phase between spheres. A graphene-like inverse opal, comprising nanometer-thick porous carbon of few-layer graphene sheets, forms on the surfaces of the porous inorganic oxide (Al2O3, MgO, SiO2) interfacial phase by templated CVD, and it remains free-standing after template removal. The three-dimensional ordered microporous and mesoporous graphene inverse opals are highly conductive with a low sheet electrical resistance of 0.35 Ω sq−1 and a large specific surface area of 972 m2 g−1. After N-doping, this inverse opal graphene exhibits a specific capacitance of 252 F g−1 that is stable over 5000 cycles, offering great potential for electrochemical energy storage applications.

Eco-friendly PEG-based controlled release nano-formulations of Mancozeb: Synthesis and bioefficacy evaluation against phytopathogenic fungi Alternaria solani and Sclerotium rolfsii

ABSTRACTControlled release (CR) nano-formulations of Mancozeb (manganese-zinc double salt of N,N-bisdithiocarbamic acid), a protective fungicide, have been prepared using laboratory-synthesized poly(ethylene glycols) (PEGs)-based functionalized amphiphilic copolymers without using any surfactants or external additives. The release kinetics of the developed Mancozeb CR formulations were studied and compared with that of commercially available 42% suspension concentrate and 75% wettable powder. Maximum amount of Mancozeb was released on 42nd day for PEG-600 and octyl chain, PEG-1000 and octyl chain, and PEG-600 and hexadecyl chain, on 35th day for PEG-1000 and hexadecyl chain, on 28th day for PEG-1500 and octyl chain, PEG-2000 and octyl chain, PEG-1500 and hexadecyl chain, and PEG-2000 and hexadecyl chain in comparison to both commercial formulations (15th day). The diffusion exponent (n value) of Mancozeb in water ranged from 0.42 to 0.62 in tested formulations. The half-release (t1/2) values ranged from 17.35 to 35.14 days, and the period of optimum availability of Mancozeb ranged from 18.54 to 35.42 days. Further, the in vitro bioefficacy evaluation of developed formulations was done against plant pathogenic fungi Alternaria solani and Sclerotium rolfsii by poison food technique. Effective dose for 50% inhibition in mgL−1 (ED50) values of developed formulations varied from 1.31 to 2.79 mg L−1 for A. solani, and 1.60 to 3.14 mg L−1 for S. rolfsii. The present methodology is simple, economical, and eco-friendly for the development of environment-friendly CR formulations of Mancozeb. These formulations can be used to optimize the release of Mancozeb to achieve disease control for the desired period depending upon the matrix of the polymer used. Importantly, the maximum amount of active ingredient remains available for a reasonable period after application. In addition, the developed CR formulations were found to be suitable for fungicidal applications, allowing use of Mancozeb in lower doses.

The vitamin-sensitive promoter PTHI11 enables pre-defined autonomous induction of recombinant protein production in Pichia pastoris.

The methylotrophic yeast Pichia pastoris is widely used for production of recombinant proteins. Here we characterize a vitamin-sensitive regulatory sequence, which can be controlled independently of the main culture medium compounds such as carbon, nitrogen, or phosphor source. The THI11 promoter (PTHI11 ) sequence derives from a gene involved in biosynthesis of thiamine. For characterization, a P. pastoris strain expressing recombinant human serum albumin under control of PTHI11 was grown in the controlled environment of a bioreactor. The thiamine sensitivity of PTHI11 was proven and specified in batch cultures containing different amounts of extracellular thiamine. Under non-repressing conditions PTHI11 offers a constitutive expression pattern with growth rate dependent product formation. Furthermore, promoter activity and thus product formation can be repressed for a desired period of time by supplementing the culture with a pre-defined amount of exogenous thiamine. Once a threshold of biomass is reached, PTHI11 driven expression starts autonomously without external intervention. Based on these findings a tailor-made process strategy was developed and experimentally verified. Additionally, we compared the THI11 promoter with the commonly used GAP promoter. In conclusion, the THI11 promoter is a versatile and easy to control regulatory sequence which enables the realization of novel protein production strategies. Biotechnol. Bioeng. 2016;113: 2633-2643. © 2016 Wiley Periodicals, Inc.

A Novel Ex Ovo Banding Technique to Alter Intracardiac Hemodynamics in an Embryonic Chicken System.

The new model presented here can be used to understand the influence of hemodynamics on specific cardiac developmental processes, at the cellular and molecular level. To alter intracardiac hemodynamics, fertilized chicken eggs are incubated in a humidified chamber to obtain embryos of the desired stage (HH17). Once this developmental stage is achieved, the embryo is maintained ex ovo and hemodynamics in the embryonic heart are altered by partially constricting the outflow tract (OFT) with a surgical suture at the junction of the OFT and ventricle (OVJ). Control embryos are also cultured ex ovo but are not subjected to the surgical intervention. Banded and control embryos are then incubated in a humidified incubator for the desired period of time, after which 2D ultrasound is employed to analyze the change in blood flow velocity at the OVJ as a result of OFT banding. Once embryos are maintained ex ovo, it is important to ensure adequate hydration in the incubation chamber so as to prevent drying and eventually embryo death. Using this new banded model, it is now possible to perform analyses of changes in the expression of key players involved in valve development and to understand the role of hemodynamics on cellular responses in vivo, which could not be achieved previously.

Laser induced birefringence in La–Ga–S–O–Gd glass polymer nanocomposites

In this work, we demonstrate a possibility to use La–Ga–S–O–Gd glass polymer nanocomposites as effective materials for photo-induced birefringence. Here we chose PVA as a photopolymer matrix. The photo-induced effects were studied using 8 ns Nd: YAG laser generating bicolor coherent light beams with wavelengths 1064, and 532 nm. The detection of the photo-induced birefringence was carried out using cw He–Ne laser at 1150 nm. The optimal concentration of the nanoglass favoring maximal changes of refractive indices is established. The photo-induced laser power density was changed up to 0.9 GW/cm2. The photo-induced beams were incident at angles varying within the 32° and 52° with respect to the nanocomposite planes. The polarizations of the beams did not play principal role. We discovered an appearance of maximal birefringence equal to about 0.078. The effect is strongly dependent on the nanoparticle sizes and is completely reversible after switching off the laser treatment within several milliseconds. Such features are useful for the recording of optical information and production of gratings with desirable periods.

Stability of plasma treated superhydrophobic surfaces under different ambient conditions

Plasma hydrophilizing of superhydrophobic substrates has become an important area of research, for example, superhydrophobic-(super)hydrophilic patterned surfaces have significant practical applications such as lab-on-chip systems, cell adhesion, and control of liquid transport. However, the stability of plasma-induced hydrophilicity is always considered as a key issue since the wettability tends to revert back to the untreated state (i.e. aging behavior). This paper focuses on the stability of plasma treated superhydrophobic surface under different ambient conditions (e.g. temperature and relative humidity). Water contact angle measurement and X-ray photoelectron spectroscopy are used to monitor the aging process. Results show that low temperature and low relative humidity are favorable to retard the aging process and that pre-storage at low temperature (−10°C) disables the treated surface to recover superhydrophobicity. When the aging is performed in water, a long-lasting hydropholicity is obtained. As the stability of plasma-induced hydrophilcity over a desired period of time is a very important issue, this work will contribute to the optimization of storage conditions of plasma treated superhydrophobic surfaces.

Hypnotic Effect of Nepeta glomerulosa on Pentobarbital-Induced Sleep in Mice

Background: Insomnia or sleeplessness is a disorder characterized by a personal incapability to falling or staying asleep for a desirable period of time, therefore disturb in quality of life. Objectives: The present study was carried out to investigate the effect of hydro-alcoholic extract of Nepeta glomerulosa and its fractions on sleep-prolonging. Materials and Methods: The extract and its fractions including ethyl acetat, n-butanol and water were injected to mice and sleep duration as well as sleep latency were recorded. Also, toxicity of the extract was determined in both in vivo and in vitro experiments. Results: The extract increased sleep duration at 50 - 200 mg/Kg. This hypnotic effect was comparable to that of induced by diazepam. N-butanol fraction could increase sleep duration. The sleep latency was decreased by the extract and n-butanol, but not by other fractions. LD50 value for Nepeta glomerulosa was found to be 2.4 g/Kg. It had no toxicity effect on viability of neuronal cells. Conclusions: Nepeta glomerulosa potentiates sleeping behaviors without any cytotoxicity. The components responsible for this effect are most likely non-polar agents which found in n-butanol fraction.

Web communication of CSR and financial performance: Study applied to catalan meat companies

Purpose: Understanding the relationship between CSR communication on corporate websites and the financial performance of Catalan meat companies.Design/methodology/approach: Qualitative and quantitative analysis of the CSR communication variables of corporate websites identifying the companies with the best CSR web communication’s practices, and economic and financial comparative analysis. It also modelled the financial returns to determine whether CSR communication, as an independent variable, affects the net profit generated in relation to the investment of the stakeholders. The analysis covered a sample of 130 Catalan meat companies.Findings and Originality/value: The report provides a diagnosis of the CSR web communication and also of the financial health of the companies in the period analyzed. The study contributes to the discussion on the relationship between CSR and financial performance.Research limitations/implications: It would be desirable extended periods of economic and financial analysis, and a more in depth study of online communication strategy incorporating the views of those responsible for the strategy and stakeholders.Practical implications: The analysis provides a better understanding of current corporate web communication and the economic and financial situation of the companies analyzed. It has practical benefits in making strategic decisions to improve the relationship with stakeholders and allows us to assess the forecast that has been made for this sector in Catalonia in the period analyzed.Social implications: The results of the study allow the industry to see the future prospects of this sector and to make the necessary changes. The results lead to improved transparency and responsible behavior.Originality/value: The analysis allows the stakeholders of the meat industry to evaluate the company’s social behavior, to assess the financial health and to take appropriate future actions.

A Wavelet Characterization of Continuous‐Time Periodically Correlated Processes with Application to Simulation

We introduce a wavelet characterization of continuous‐time periodically correlated processes based on a linear combination of infinite‐dimensional stationary processes. The finite version of this linear combination converges to the main process. The first‐order and second‐order estimators based on the wavelets are presented. Under a simple and easy algorithm, the periodically correlated process is simulated for a given autocovariance function. The proposed algorithm has two main advantages: first, it is fast, and second, it is distribution free. We indicate through four examples that the simulated data are periodically correlated with the desired period.

Optimised flexible transport mode without advanced reservations by a DES approach

Abstract: Decentralized management of an autonomous demand responsive transport system (DRTS) is studied. Clients appear in the network in a continuous Poisson stream, without any prior reservation and aiming at an immediate departure search for an adequate vehicle. When no such vehicle is available, clients decide whether to abandon the system or wait, during a desired period, for another vehicle to come. Meanwhile, vehicles travel along the network, transporting passengers while looking for potential new customers. Dynamically optimised trips are constructed adapted to the current vehicle itinerary and client preferences. Station nodes and durations are decided for idle vehicles. Client-vehicle interaction forms an asynchronous dynamical spatio-temporal system for which an event-driven approach is adopted. Developped strategies are evaluated by a made-to-measure discrete event decision tool. Involving Optimisation and Operation Research methods the best suited configuration for any demand level and system dimensioning is provided.

Framework for Assessing Effectiveness of Peak Hour Parking Restrictions: Case Study from Washington, D.C.

Roadways provide mobility for goods and services and accessibility to destinations. In urban settings such as the District of Columbia, an important element of accessibility is the ability to park on the street close to the destination. Agencies often use peak hour parking restrictions as a strategy to balance these two often-conflicting goals. The District Department of Transportation undertook a research project to develop a framework for assessing the effectiveness of existing peak hour parking restrictions and evaluating the effects of any modifications. The framework was developed, tested, and applied to two major corridors: Connecticut Avenue and Rhode Island Avenue. The corridors were modeled to simulate the existing restrictions and the alternatives. The corridor level of service was used to measure the mobility and determine the desired restriction periods. In addition, the study evaluated the effects of any restriction changes on relevant factors, such as land use, transit availability, neighborhood parking, and cut-through traffic. A policy framework and an implementation plan were developed as part of this study, and they can be applied to other corridors. These findings can be useful for jurisdictions considering the reevaluation of their peak hour parking restriction policies.

Stochastic Model of a Cold-Stand by System with Waiting for Arrival &amp;amp; Treatment of Server

The service facility or server is the key constituent to keep a system operational for desired period of time. As any eventuality with the system necessitates immediate presence of it (server) so the time point of arrival and treatment of server significantly affects the system performance. This paper works out the steady state behavior of a cold standby system equipped with two similar units and a server with elapsed arrival and treatment times following general probability distributions. It practices the theory of semi-Markov processes, regenerative point technique and Laplace transforms to derive the expressions for state transition probabilities, mean sojourn times, mean time to system failure, system availability, server busy period and expected frequencies of repairs and treatments. The profit function is also developed taking different costs and revenue in to account. For tracing wider applicability of the model for different reliability and cost-effective systems, a particular case study is also presented as an illustration.

Monitoring of chromosome dynamics of single yeast cells in a microfluidic platform with aperture cell traps.

Chromosome movement plays important roles in DNA replication, repair, genetic recombination, and epigenetic phenomena during mitosis and meiosis. In particular, chromosome movement in the nuclear space is essential for the reorganization of the nucleus. However, conventional methods for analyzing the chromosome movements in vivo have been limited by technical constraints of cell trapping, cell cultivation, oxygenation, and in situ imaging. Here, we present a simple microfluidic platform with aperture-based cell trapping arrays to monitor the chromosome dynamics in single living cells for a desired period of time. Under the optimized conditions, our microfluidic platform shows a single-cell trapping efficiency of 57%. This microfluidic approach enables in situ imaging of intracellular dynamics in living cells responding to variable input stimuli under the well-controlled microenvironment. As a validation of this microfluidic platform, we investigate the fundamental features of the dynamic cellular response of the individual cells treated with different stimuli and drug. We prove the basis for dynamic chromosome movement in single yeast cells to be the telomere and nuclear envelope ensembles that attach to and move in concert with nuclear actin cables. Therefore, these results illustrate the monitoring of cellular functions and obtaining of dynamic information at a high spatiotemporal resolution through the integration of a simple microfluidic platform.