Hangzhou

Once an ancient capital of China, Hangzhou has transformed to a post-socialist city that faces profound changes and critical challenges in various aspects of urban development such as historical legacies, market-oriented urban economy, expansive urban spatial patterns, population management, land use restructuring, and affordable housing provision. Under the increasingly stronger market power, the city strives to reposition itself to be an important economic center in the Yangtze River Delta Region, through strategic and innovative urban growth agenda. This profile identifies some fundamental issues and processes that underscore Hangzhou’s recent urban development and presents future prospect for a coastal metropolis with regional significance.     

Chick Chorioallantoic Membrane as an In Situ Biological Membrane for Pharmaceutical Formulation Development: A Review

The use of animals in research has always been a debatable issue. Over the past few decades, efforts have been made to reduce, replace, and refine experiments for ethical use of experimental animals. The use of chick chorioallantoic membrane (CAM) was one of the proposed alternatives to the Draize rabbit ocular irritation test with several advantages including simplicity, rapidity, sensitivity, ease of performance, and cost-effectiveness. The recent use of CAM in the development of pharmaceuticals and testing models to mimic human tissue, including drug transport across CAM, will be discussed in this review.     

Rapid screening and quantification of multi-class multi-residue veterinary drugs in royal jelly by ultra performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

A simple and rapid multi-class multi-residue analytical method was developed for the screening and quantification of veterinary drugs in royal jelly by ultra performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). A total of 90 veterinary drugs investigated belonged to more than 14 families such as lincomycins, macrolides, sulfonamides, quinolones, tetracyclines, β-agonists, β-lactams, sedatives, β-receptor antagonists, sex hormones, glucocorticoids, nitroimidazoles, benzimidazoles, nitrofurans, and the others. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure was used for the sample preparation without solid-phase extraction step. The linearity, sensitivity, accuracy, repeatability, and reproducibility of the method were fully validated. The response of the detector was linear for each target compounds in wide concentration range (at least, two orders of magnitude) with correlation coefficient (R²) of 0.9921–0.9999. The range of the limit of quantification for these compounds in the royal jelly ranged from 0.21 to 20 μg/kg. The repeatability and reproducibility were in the range of 3.01–11.6% and 5.97–14.9%, respectively. The average recoveries ranged from 70.21 to 120.1% with relative standard deviation of 1.77–9.90% at three concentration levels. For the screening method, the data of the precursor and product ions of the target analytes were simultaneously acquired under the All Ions MS/MS mode in a single run. A homemade database including the elemental composition, accurate masses, retention time, isotopic pattern data of the target ions the characteristic in-source fragment ions was utilized for the confirmation and identification of the target compounds. The applicability of the screening method was verified by applying to real royal jelly samples, and certain veterinary drugs were detected in some cases.     

Development of in vitro models to demonstrate the ability of PecSys®, an in situ nasal gelling technology,to reduce nasal run-off and drip

Many of the increasing number of intranasal products available for either local or systemic action can be considered sub-optimal, most notably where nasal drip or run-off give rise to discomfort/tolerability issues or reduced/variable efficacy. PecSys, an in situ gelling technology, contains low methoxy (LM) pectin which gels due to interaction with calcium ions present in nasal fluid. PecSys is designed to spray readily, only forming a gel on contact with the mucosal surface. The present study employed two in vitro models to confirm that gelling translates into a reduced potential for drip/run-off: (i) Using an inclined TLC plate treated with a simulated nasal electrolyte solution (SNES), mean drip length [±SD, n = 10] was consistently much shorter for PecSys (1.5?±?0.4?cm) than non-gelling control (5.8?±?1.6?cm); (ii) When PecSys was sprayed into a human nasal cavity cast model coated with a substrate containing a physiologically relevant concentration of calcium, PecSys solution was retained at the site of initial deposition with minimal redistribution, and no evidence of run-off/drip anteriorly or down the throat. In contrast, non-gelling control was significantly more mobile and consistently redistributed with run-off towards the throat. Conclusion: In both models PecSys significantly reduced the potential for run-off/drip ensuring that more solution remained at the deposition site. In vivo, this enhancement of retention will provide optimum patient acceptability, modulate drug absorption and maximize the ability of drugs to be absorbed across the nasal mucosa and thus reduce variability in drug delivery.     

Synthesis of Chemically Cross-Linked Hydroxypropyl Methyl Cellulose Hydrogels and their Application in Controlled Release of 5-Amino Salicylic Acid

The objective of this study was to achieve the colon-specific delivery of an anti-ulcerative colitis drug using hydroxypropyl methyl cellulose (HPMC) hydrogels. HPMC hydrogels containing poly ethylene glycol (PEG) as cross-links have been prepared by reacting HPMC sodium salt with polyethylene glycol dichloride.

The effect of cross-linking agent on swelling behavior of HPMC-PEG hydrogels, were investigated. Swelling parameters such as equilibrium degree of swelling, swelling ratio and network parameter such as molecular mass between cross-links (M_c) were determined. The cross-linking concentrations were 0.5%, 1%, 1.5%, and 2% (based on weight of HPMC). The equilibrium swelling ratio (Q) of cross-linked HPMC hydrogels increases from 13.2 to 27.1 as the cross-linker percentage increases from 0.5% to 2%. 5-Aminosalicylic acid (5-ASA) was used as a model of an anti-inflammatory drug. Cross-linked HPMC hydrogels were found to be a promising drug delivery system for the drugs to be delivered to the colon.     

In vitro release of ketoprofen from hydrophilic matrix tablets containing cellulose polymer mixtures

The effect of cellulose ether polymer mixtures, containing both hydroxypropylcellulose (HPC) and hydroxypropylmethylcellulose (HPMC K15M or K100M), on ketoprofen (KTP) release from matrix tablets was investigated. In order to evaluate the compatibility between the matrix components, Raman spectroscopy, scanning electron microscopy (SEM), and X-ray powder diffraction (XRPD) experiments were performed. The results evidence the absence of significant intermolecular interactions that could eventually lead to an incompatibility between the drug and the different excipients. Formulations containing mixtures of polymers with both low and high viscosity grades were prepared by a direct compression method, by varying the polymer/polymer (w/w) ratio while keeping the drug amount incorporated in the solid dispersion constant (200?mg). The hardness values of different matrices were found within the range 113.8 to 154.9 N. HPLC analysis showed a drug content recovery between 99.3 and 102.1%, indicating that no KTP degradation occurred during the preparation process. All formulations attained a high hydration degree after the first hour, which is essential to allow the gel layer formation prior to tablet dissolution. Independent-model dissolution parameters such as t_10% and t_50% dissolution times, dissolution efficiency (DE), mean dissolution time (MDT), and area under curve (AUC) were calculated for all formulations. Zero-order, first-order, Higuchi, and Korsmeyer–Peppas kinetic models were employed to interpret the dissolution profiles: a predominantly Fickian diffusion release mechanism was obtained – with Korsmeyer–Peppas exponent values ranging from 0.216 to 0.555. The incorporation of HPC was thus found to play an essential role as a release modifier from HPMC containing tablets.     

Sustained release of tetracycline from polymeric periodontal inserts prepared by extrusion

The specific aim of this study was to prepare polymeric inserts containing tetracycline that are intended for intraperiodontal pocket application. The inserts were prepared by a simple extrusion method and based on mixtures of polyvinyl alcohol, glyceryl behenate, xanthan gum, carrageenan, hydroxypropyl methylcellulose, and hyaluronic acid in addition to tetracycline HCL. The inserts were characterized regarding average weight, diameter, water content, and average tetracycline content. Zero‐order release kinetics of tetracycline were observed in case of three of the four batches of the prepared inserts with release profiles that were essentially similar. The release of the drug was incomplete in all cases. This was due, as shown by the equilibrium dialysis tests, to tetracycline binding by the polymers. However, the inserts performed more than 7 days drug sustained release which indicates promising results for local delivery of tetracycline for treatment of periodontal disease. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The Complexity of Public Attitudes Toward Compact Development

Problem: The future of compact development depends in part on understanding and shaping the public's attitudes toward it. Previous studies have suggested life cycle, socioeconomic, attitudinal, and ideological dimensions to preferences regarding development patterns, but rarely have all of these factors been examined systematically across a broad, generalizable sample of respondents.

Purpose: To examine public attitudes toward compact development, we asked survey respondents to weigh four important tradeoffs between compact and sprawling growth. We assess the relative influence of a variety of individual characteristics on these attitudes.

Methods: We use results from two large-scale, randomized telephone surveys, one conducted in California in 2002 and the other in four other southwestern states in 2007. Using logistic regression, we assess which personal characteristics are associated with stated preferences regarding compact development, and illustrate their degree of influence.

Results and conclusions: Support for the compact development alternatives is significant, in some cases exceeding support for traditional, decentralized suburban patterns. However, question wording appears to matter considerably, and individuals’ beliefs about different facets of compact development are often inconsistent. Although race, income, age, and the presence of children in the household are strongly associated with some views on the four tradeoffs, only political ideology is consistently associated with opposition to compact development.

Takeaway for practice: The significant support evident for compact development may not translate into actual housing choices unless local governments and lenders do more to support the production of such housing and neighborhood environments. If, as our results suggest, a major constituency for transit-oriented and mixed-use projects is low income residents, renters, and minorities, then well crafted urban infill projects that take into account the needs of these groups will help fulfill the potential of smart growth. Advocates might also frame compact development to appeal more to political conservatives.

Research support: The 2002 survey was conducted by the Public Policy Institute of California, with financial support from the William and Flora Hewlett Foundation, James Irvine Foundation, and David and Lucille Packard Foundation. The 2007 survey was conducted and supported by the Institute for Social Science Research at Arizona State University. All views expressed are solely those of the authors, not these organizations.     

Optimisation of night-time ventilation parameters to reduce building's energy consumption by integrating DOE2 and MATLAB

We have developed an algorithm to optimise the fan flow rate by integrating DOE2 (building's energy simulation software) with MATLAB's genetic algorithm. In our developed algorithm, MATLAB can send desired values of optimisation variables for different hours to DOE2 to simulate building's energy use, and it can also receive building's energy consumption and other data from DOE2 for the optimisation. This powerful optimisation tool can be used for finding optimal solution of night-time ventilation fan flow rates and maximising energy savings. Results of optimisation are used to train a neural network to predict fan flow rates for different conditions. Night-time ventilation investigated in DOE2 considers parameters such as (1) night-time ventilation duration, (2) ventilation fan flow rate, (3) outdoor temperature, and (4) temperature difference between outdoor and indoor. Optimisation results show outdoor temperature between 10°C and 18°C and the temperature difference of more than 8°C are appropriate for night-time ventilation.     

TrkB Receptor Signalling: Implications in Neurodegenerative,Psychiatric and Proliferative Disorders

The Trk family of receptors play a wide variety of roles in physiological and disease processes in both neuronal and non-neuronal tissues. Amongst these the TrkB receptor in particular has attracted major attention due to its critical role in signalling for brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT3) and neurotrophin-4 (NT4). TrkB signalling is indispensable for the survival, development and synaptic plasticity of several subtypes of neurons in the nervous system. Substantial evidence has emerged over the last decade about the involvement of aberrant TrkB signalling and its compromise in various neuropsychiatric and degenerative conditions. Unusual changes in TrkB signalling pathway have also been observed and implicated in a range of cancers. Variations in TrkB pathway have been observed in obesity and hyperphagia related disorders as well. Both BDNF and TrkB have been shown to play critical roles in the survival of retinal ganglion cells in the retina. The ability to specifically modulate TrkB signalling can be critical in various pathological scenarios associated with this pathway. In this review, we discuss the mechanisms underlying TrkB signalling, disease implications and explore plausible ameliorative or preventive approaches.