Rings, chains and planes: Variation ofT g with composition in chalcogenide glasses

We propose a microscopic, phenomenological model for the decrease in the viscosity observed at glass transition. Our model is primarily applicable to chalcogenide glasses. According to this model, the decrease in the viscosity at glass transition is mainly due to the breaking of the Van der Waals bonds in the chalcogenides. Using this model, we derive a relationship between the glass transition temperature,T _g ,and the molar volume V _m.The validity of this relation is checked using experimental data available in the literature for two binary systems (Ge-Se and As-S) and a pseudo-binary system (As ₄₀ Se _x Te _60-x .     

Modeling of quantitative relationships between physicochemical properties of active pharmaceutical ingredients and tensile strength of tablets using a boosted tree

Objectives: The aim of this study was to explore the potential of boosted tree (BT) to develop a correlation model between active pharmaceutical ingredient (API) characteristics and a tensile strength (TS) of tablets as critical quality attributes.

Methods: First, we evaluated 81 kinds of API characteristics, such as particle size distribution, bulk density, tapped density, Hausner ratio, moisture content, elastic recovery, molecular weight, and partition coefficient. Next, we prepared tablets containing 50% API, 49% microcrystalline cellulose, and 1% magnesium stearate using direct compression at 6, 8, and 10?kN, and measured TS. Then, we applied BT to our dataset to develop a correlation model. Finally, the constructed BT model was validated using k-fold cross-validation.

Results: Results showed that the BT model achieved high-performance statistics, whereas multiple regression analysis resulted in poor estimations. Sensitivity analysis of the BT model revealed that diameter of powder particles at the 10th percentile of the cumulative percentage size distribution was the most crucial factor for TS. In addition, the influences of moisture content, partition coefficients, and modal diameter were appreciably meaningful factors.

Conclusions: This study demonstrates that BT model could provide comprehensive understanding of the latent structure underlying APIs and TS of tablets.     

Hybrid Models for Breast Cancer Detection via Transfer Learning Technique

Currently, breast cancer has been a major cause of deaths in women worldwide and the World Health Organization (WHO) has confirmed this. The severity of this disease can be minimized to the large extend, if it is diagnosed properly at an early stage of the disease. Therefore, the proper treatment of a patient having cancer can be processed in better way, if it can be diagnosed properly as early as possible using the better algorithms. Moreover, it has been currently observed that the deep neural networks have delivered remarkable performance for detecting cancer in histopathological images of breast tissues. To address the above said issues, this paper presents a hybrid model using the transfer learning to study the histopathological images, which help in detection and rectification of the disease at a low cost. Extensive dataset experiments were carried out to validate the suggested hybrid model in this paper. The experimental results show that the proposed model outperformed the baseline methods, with F-scores of 0.81 for DenseNet + Logistic Regression hybrid model, (F-score: 0.73) for Visual Geometry Group (VGG) + Logistic Regression hybrid model, (F-score: 0.74) for VGG + Random Forest, (F-score: 0.79) for DenseNet + Random Forest, and (F-score: 0.79) for VGG + Densenet + Logistic Regression hybrid model on the dataset of histopathological images.     

Mathematical models for the numerical study of turbulent flows

Abstract

This paper presents (1) a brief overview of the mathematical models used in the numerical study of turbulent flows; (2) a K‐? model of turbulence; and (3) extensions of the K‐? model to account for some of the effects of compressibility, low Reynolds number, streamline curvature, and preferential stress dissipation.     

Uncatalyzed synthesis of polypyrrole with viologen side groups and its chemical properties

A substituted polypyrrole (PPr) with viologen side groups (polymer-1) was obtained from the reaction of N-aminopyrrole with 1-hexyl-1′-(2,4-dinitrophenyl)-4,4′-bipyridinium dihalide (salt-1). A model compound (model-1) was synthesized by the reaction of N-aminopyrrole with N-(2,4-dinitrophenyl)-4-(4-pyridyl)pyridinium chloride (salt-2). UV–vis spectra revealed that polymer-1 had an expanded π-conjugation system along the polymer chain: the polymer showed an onset position of absorption at a wavelength approximately 200 nm longer than the corresponding wavelength of model-1. Polymer-1 received an electrochemical oxidation of the pyrrole ring and reduction of the viologen group within the polymer.     

Hyaluronic acid-coated,prodrug-based nanostructured lipid carriers for enhanced pancreatic cancer therapy

Abstract

Context: Gemcitabine (GEM) and Baicalein (BCL) are reported to have anti-tumor effects including pancreatic cancer. Hyaluronic acid (HA) can bind to over-expressed receptors in various kinds of cancer cells.

Objective: The aim of this study is to develop prodrugs containing HA, BCL and GEM, and construct nanomedicine incorporate GEM and BCL in the core and HA on the surface. This system could target the cancer cells and co-deliver the drugs.

Methods: GEM-stearic acid lipid prodrug (GEM-SA) and hyaluronic acid-amino acid-baicalein prodrug (HA-AA-BCL) were synthesized. Then, GEM and BCL prodrug-based targeted nanostructured lipid carriers (HA-GEM-BCL NLCs) were prepared by the nanoprecipitation technique. The in vitro cytotoxicity studies of the NLCs were evaluated on AsPC1 pancreatic cancer cell line. In vivo anti-tumor effects were observed on the murine-bearing pancreatic cancer model.

Results: HA-GEM-BCL NLCs were effective in entering pancreatic cancer cells over-expressing HA receptors, and showed cytotoxicity of tumor cells in vitro. In vivo study revealed significant tumor growth inhibition ability of HA-GEM-BCL NLCs in murine pancreatic cancer model.

Conclusion: It could be concluded that HA-GEM-BCL NLCs could be featured as promising co-delivery, tumor-targeted nanomedicine for the treatment of cancers.     

Photoelectric properties of Se-doped Cd1.23Zn1.77As2 crystals

The spectral response of the photocurrent through Se-dopedCd _1.23 Zn _1.77 As ₂ single crystals was studied. The results were used to determine the band gap at absolute zero (0.540 eV) and the temperature coefficient of band gap (-0.39 meV/K). The photocurrent spectra were found to contain a photovoltaic peak attributable to Schottky barriers at the interface between the semiconductor and the metallic contact. The heights of the barriers responsible for residual conductivity were evaluated using a two-barrier model. Both surface and bulk inhomogeneities were shown to play a significant part in residual conductivity.     

Possible ionization of mercury atoms by elastic reflection in hyperthermal surface ionization experiments

An elastic collision model baed on data given by Danon et al. [Phys. Rev. Lett. 65, 2038 (1990)] was used to calculate the ionization potential of mercury atoms (V′) at the critical charge transfer distance as a function of the kinetic energy of the atoms (E). The linear dependence V′(E) obtained supports the model of surface ionization of mercury atoms by elastic reflection from a surface. Pis’ma Zh. Tekh. Fiz. 25, 42–45 (July 26, 1999)     

Sensor Network Localization,Euclidean Distance Matrix completions,and graph realization

We study Semidefinite Programming, SDP, relaxations for Sensor Network Localization, SNL, with anchors and with noisy distance information. The main point of the paper is to view SNL as a (nearest) Euclidean Distance Matrix, EDM, completion problem that does not distinguish between the anchors and the sensors. We show that there are advantages for using the well studied EDM model. In fact, the set of anchors simply corresponds to a given fixed clique for the graph of the EDM problem.     

Solidification of hesperidin nanosuspension by spray drying optimized by design of experiment (DoE)

Objective: To accelerate the determination of optimal spray drying parameters, a “Design of Experiment” (DoE) software was applied to produce well redispersible hesperidin nanocrystals.

Significance: For final solid dosage forms, aqueous liquid nanosuspensions need to be solidified, whereas spray drying is a large-scale cost-effective industrial process.

Methods: A nanosuspension with 18% (w/w) of hesperidin stabilized by 1% (w/w) of poloxamer 188 was produced by wet bead milling. The sizes of original and redispersed spray-dried nanosuspensions were determined by laser diffractometry (LD) and photon correlation spectroscopy (PCS) and used as effect parameters. In addition, light microscopy was performed to judge the redispersion quality.

Results: After a two-step design of MODDE 9, screening model and response surface model (RSM), the inlet temperature of spray dryer and the concentration of protectant (polyvinylpyrrolidone, PVP K25) were identified as the most important factors affecting the redispersion of nanocrystals. As predicted in the RSM modeling, when 5% (w/w) of PVP K25 was added in an 18% (w/w) of hesperidin nanosuspension, subsequently spray-dried at an inlet temperature of 100?°C, well redispersed solid nanocrystals with an average particle size of 276?nm were obtained. By the use of PVP K25, the saturation solubility of the redispersed nanocrystals in water was improved to 86.81?µg/ml, about 2.5-fold of the original nanosuspension. In addition, the dissolution velocity was accelerated.

Conclusions: This was attributed to the additional effects of steric stabilization on the nanocrystals and solubilization by the PVP polymer from spray drying.     

Modeling of thermally stimulated depolarization current (TSDC) using dipole–dipole interaction concept

The study of thermally stimulated depolarization current (TSDC) using the dipole–dipole interaction model is describedin this work. The dipole–dipole interaction model (DDIM) determines the TSDC peak successfully since it gives significant peak parameters (i.e. activation energy (E{\bf \textit{E}}) and pre-exponential factor (t₀){\boldsymbol\tau}_{{\bf 0}})) in addition to the dipole–dipole interaction strength parameter (d_i){\bf \textit{d}}_{{\bf i}}). Application of this model to study the peak parameters of some polymeric systems is presented.     

High-speed impact of electromagnetically sensitive fabric and induced projectile spin

This work deals with the dynamic contact of a rigid body with a deformable electromagnetically sensitive fabric structure, represented by a network model. Of particular interest are the electromagnetically induced forces generated on the fabric, which are proportional to the external electric field (E ^EXT ) and the velocity crossed with the external magnetic field (v × B ^EXT ). These forces transmit reactions to the rigid contacting object, which can induce rotational motion. Modeling and simulation of this effect can be useful in ballistic shielding applications, because the rotation of an incoming, ogival, projectile allows it to be more easily impeded. A modular formulation for the deformation of impacted fabric structures, represented by a network model, is developed in this paper, characterized by (1) stretching of interconnected yarn networks, described by simple constitutive relations, including yarn damage, (2) interaction with impacting objects, incorporating contact with friction and (3) electromagnetic sensitivity and actuation, demonstrating how the Lorentz force can be harnessed to break symmetric deformation patterns in order to induce spin onto an incoming object, whether that object is electromagnetically sensitive or not.     

The Model Calculation of the Phase (P-T) Diagram for Fullerene C60

Abstract

A detailed theoretical study of the phase (P-T) diagram of fullerene C₆₀ is carried out using both the thermodynamic principles and the calculated model based on the rigid molecules interacting via the (n-m) potential model.     

Nonlinear quantum optical computing via measurement

Abstract

We show how the measurement induced model of quantum computation proposed by Raussendorf and Briegel (2001, Phys. Rev. Letts., 86, 5188) can be adapted to a nonlinear optical interaction. This optical implementation requires a Kerr nonlinearity, a single photon source, a single photon detector and fast feed forward. Although nondeterministic optical quantum information proposals such as that suggested by KLM (2001, Nature, 409, 46) do not require a Kerr nonlinearity they do require complex reconfigurable optical networks. The proposal in this paper has the benefit of a single static optical layout with fixed device parameters, where the algorithm is defined by the final measurement procedure.     

Anti prostate cancer using PEGylated bombesin containing,cabazitaxel loading nano-sized drug delivery system

Context: Prostate cancer (PCa) is the second most-frequently diagnosed cancer in men. Cabazitaxel was approved for the treatment of patients with hormone-refractory metastatic prostate cancer previously treated with a docetaxel-containing regimen.

Objective: In this study, bombesin (BN), a ligand reported to specifically target GRP overexpressing prostate tumor, was applied for the construction of lipid-polymer hybrid nanoparticles (LPNs), and used for the targeted delivery of cabazitaxel (CAB) to prostate cancer.

Methods: BN-polyethylene glycol-1,2-Distearoyl-sn-glycero-3-phosphoethanolamine (BN-PEG-DSPE) was synthesized. CAB loaded, BN-PEG-DSPE contained LPNs (BN-CAB-LPNs) were prepared. Their particle size, zeta potential and drug encapsulation efficiency (EE) were evaluated. In vitro cytotoxicity study of BN-CAB-LPNs was tested in LNCaP human prostatic cancer cell line (LNCaP cells). In vivo anti-tumor efficacy of the carriers was evaluated on mice bearing prostate cancer model.

Results: The optimum BN-CAB-LPNs formulations had a particle size of 184.9?nm and a 26.5?mV positive surface charge. The growth of LNCaP cells in vitro was obviously inhibited. BN-CAB-LPNs also displayed better anti-tumor activity than the other formulations in vivo.

Conclusion: The results demonstrated that BN-CAB-LPNs can sufficiently deliver CAB to the cancer cells and enhance the anti-tumor capacity. Thus, BN-CAB-LPNs can be proved to be a superior nanomedicine which can achieve better therapeutic efficacy of prostate tumor.     

Cytoprotective activities of water-soluble fullerenes in zebrafish models

Using zebrafish (Danio rerio) embryos as a model system, we compared the antioxidant and cytoprotective effects of a series of new water-soluble fullerenes 1–12. Since zebrafish embryos are transparent during the first week of life, the effects of fullerenes on multiple organ systems, including CNS, PNS, and heart, could be assessed in situ. Both positively charged and negatively charged water-soluble fullerenes were added at concentrations between 1 and 500?µM to 96 well plates containing zebrafish embryos at 24–120 hours post fertilization (hpf). Direct toxicity of each fullerene compound was assessed by LC50. In addition, we assessed the ability of each fullerene to protect against toxicity induced by known chemical toxins in this system. Four different drug/chemical toxicity models were used in our study: (i) protection of neuromast hair cells from gentamicin-induced toxicity; (ii) protection of neuromast hair cells from cisplatinum-induced toxicity; (iii) protection of tyrosine hydroxylase-containing dopaminergic CNS neurons from 6-hydroxydopamine toxicity; and (iv) protection of total CNS neurons from 6-hydroxydopamine toxicity. Our results indicate that (i) positively charged water-soluble fullerenes tend to exhibit greater toxicity than negatively charged fullerenes with similar structures; (ii) toxicity varies considerably among negatively charged fullerenes from very low to moderate, depending on structural features; (iii) dendrofullerenes 2–7 (monoadducts of C₆₀) show stronger protection against cisplatinum toxicity in neuromast hair cells while then the e,e,e-trismalonic acid 1 (so called C3) shows stronger protection against gentamicin-induced cytotoxicity in the same cells; (iv) C3 (1) is relatively unstable in all aqueous solvents tested and breaks down mainly through decarboxylation reactions to form penta, tetra and tris carboxylated forms, which exhibit increased toxicity in vivo compared with C3 (1). Our findings indicate that water-soluble fullerenes can protect against chemical toxin-induced apoptotic cell death in a vertebrate, whole-animal model that may be useful for predicting the efficacy and toxicity of these compounds in mammals. Furthermore, the relative potential for pharmacologic use of these compounds varies considerably with respect to stability.     

Fabrication of solid lipid nanoparticles of lurasidone HCl for oral delivery: optimization,in vitro characterization,cell line studies and in vivo efficacy in schizophrenia

Objective: The aim of the present investigation was to investigate the efficacy of solid lipid nanoparticles (SLNs) to enhance the absorption and bioavailability of lurasidone hydrochloride (LH) following oral administration.

Methods: The LH loaded SLNs (LH-SLNs) were prepared by high pressure homogenization (HPH) method, optimized using box Behnken design and evaluated for particle size (PS), entrapment efficiency (EE), morphology, FTIR, DSC, XRD, in vitro release, ex vivo permeation, transport studies across Caco-2 cell line and in vivo pharmacokinetic and pharmacodynamic studies.

Results: The LH-SLNs had PS of 139.8?±?5.5?nm, EE of 79.10?±?2.50% and zeta potential of ?30.8?±?3.5?mV. TEM images showed that LH-SLNs had a uniform size distribution and spherical shape. The in vitro release from LH-SLNs followed the Higuchi model. The ex vivo permeability study demonstrated enhanced drug permeation from LH-SLNs (>90%) through rat intestine as compared to LH-suspension. The SLNs were found to be taken up by energy dependent, endocytic mechanism which was mediated by clathrin/caveolae-mediated endocytosis across Caco-2 cell line. The pharmacokinetic results showed that oral bioavailability of LH was improved over 5.16-fold after incorporation into SLNs as compared to LH-suspension. The pharmacodynamic study proved the antipsychotic potential of LH-SLNs in the treatment of schizophrenia.

Conclusion: It was concluded that oral administration of LH-SLNs in rats improved the bioavailability of LH via lymphatic uptake along with improved therapeutic effect in MK-801 induced schizophrenia model in rats.     

Mechanism of cube grain nucleation during recrystallization of deformed commercial purity aluminium

Cube texture is a sharp recrystallization texture component infcc metals like aluminium, copper, etc. It is described by an ideal orientation i.e. (100) (100). The subject of cube texture nucleation i.e. cube grain nucleation, from the deformed state of aluminium and copper is of scientific curiosity with concurrent technological implications. There are essentially two models currently in dispute over the mechanism of cube grain nucleation i.e. the differential stored energy model founded on the hypothesis proposed by Ridha and Hutchinson and the micro-growth selection model of Dugganet al. In this paper, calculations are made on the proposal of Ridha and Hutchinson model and the results are obtained in favour of the differential stored energy model. It is also shown that there is no need for the micro-growth model.     

Appropriate selection of an aggregation inhibitor of fine particles used for inhalation prepared by emulsion solvent diffusion

Abstract

Context: Dry powder inhaler (DPI) formulations have been developed to deliver large amounts of drugs to the lungs.

Objective: Fine particles of a poorly water-soluble drug, the model drug ONO-2921, were prepared by the emulsion solvent diffusion (ESD) method for use in a DPI.

Methods: The effects of additives on the fine particle formation of ONO-2921 were estimated when droplets of an ethanolic drug solution were dispersed into aqueous media containing various additives. Subsequently, the suspensions were freeze-dried to create powdered samples to estimate the inhalation properties using a twin impinger and an Andersen cascade impactor.

Results: This simple ESD method produced submicron-sized ONO-2921 particles (approximately 600?nm) in combination with suitable additives. In addition, the freeze-dried powder produced using additives exhibited superior in vitro inhalation properties. Among these methods, the freeze-dried powder produced with 0.50% weight/volume one type of polyvinyl alcohol (PVA-205) displayed the most efficient features in the fine particle fraction (FPF). These results could be explained by the stabilization of the ONO-2921 suspension by PVA-205, indicating that PVA-205 acts as an aggregation inhibitor of fine particles.

Conclusions: The ESD method, in combination with appropriate types and amounts of additives, may be useful for preparing a DPI suitable for delivering drugs directly to the lungs without the assistance of carrier particles.