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Showing papers by "Hong Kong University of Science and Technology published in 2009"


Journal ArticleDOI
TL;DR: The restriction of intramolecular rotation is identified as a main cause for the AIE effect and a series of new fluorescent and phosphorescent AIE systems with emission colours covering the entire visible spectral region and luminescence quantum yields up to unity are developed.

3,324 citations


Journal ArticleDOI
TL;DR: This article examined the relative importance of many factors in the capital structure decisions of publicly traded American firms from 1950 to 2003 and found that the most reliable factors for explaining market leverage are: median industry leverage, market-to-book assets ratio (−), tangibility (+), profits (−), log of assets (+), and expected inflation (+).
Abstract: This paper examines the relative importance of many factors in the capital structure decisions of publicly traded American firms from 1950 to 2003. The most reliable factors for explaining market leverage are: median industry leverage (+ effect on leverage), market-to-book assets ratio (−), tangibility (+), profits (−), log of assets (+), and expected inflation (+). In addition, we find that dividend-paying firms tend to have lower leverage. When considering book leverage, somewhat similar effects are found. However, for book leverage, the impact of firm size, the market-to-book ratio, and the effect of inflation are not reliable. The empirical evidence seems reasonably consistent with some versions of the trade-off theory of capital structure.

2,380 citations


Journal ArticleDOI
TL;DR: Examples of the design and biomedical application of multifunctional magnetic nanoparticles are reviewed, indicating that such nanoparticles could be applied to biological medical problems such as protein purification, bacterial detection, and toxin decorporation.
Abstract: The combination of nanotechnology and molecular biology has developed into an emerging research area: nanobiotechnology. Magnetic nanoparticles are well-established nanomaterials that offer controlled size, ability to be manipulated externally, and enhancement of contrast in magnetic resonance imaging (MRI). As a result, these nanoparticles could have many applications in biology and medicine, including protein purification, drug delivery, and medical imaging. Because of the potential benefits of multimodal functionality in biomedical applications, researchers would like to design and fabricate multifunctional magnetic nanoparticles. Currently, there are two strategies to fabricate magnetic nanoparticle-based multifunctional nanostructures. The first, molecular functionalization, involves attaching antibodies, proteins, and dyes to the magnetic nanoparticles. The other method integrates the magnetic nanoparticles with other functional nanocomponents, such as quantum dots (QDs) or metallic nanoparticles. Because they can exhibit several features synergistically and deliver more than one function simultaneously, such multifunctional magnetic nanoparticles could have unique advantages in biomedical applications. In this Account, we review examples of the design and biomedical application of multifunctional magnetic nanoparticles. After their conjugation with proper ligands, antibodies, or proteins, the biofunctional magnetic nanoparticles exhibit highly selective binding. These results indicate that such nanoparticles could be applied to biological medical problems such as protein purification, bacterial detection, and toxin decorporation. The hybrid nanostructures, which combine magnetic nanoparticles with other nanocomponents, exhibit paramagnetism alongside features such as fluorescence or enhanced optical contrast. Such structures could provide a platform for enhanced medical imaging and controlled drug delivery. We expect that the combination of unique structural characteristics and integrated functions of multicomponent magnetic nanoparticles will attract increasing research interest and could lead to new opportunities in nanomedicine.

1,754 citations


Journal ArticleDOI
TL;DR: This paper examined the relationship between employee creativity and job performance and identified two learning-related personal and situational variables (employee learning orientation and situational factors) and found that they are related to job performance.
Abstract: We examined the relationship between employee creativity and job performance. Furthermore, we identified two learning-related personal and situational variables—employee learning orientation and tr...

1,430 citations


Journal ArticleDOI
28 Apr 2009
TL;DR: The use of cooperative spectrum sensing in cognitive radio systems to enhance the reliability of detecting primary users and a cognitive space-time-frequency coding technique that can opportunistically adjust its coding structure by adapting itself to the dynamic spectrum environment are considered.
Abstract: Cognitive radio is an exciting emerging technology that has the potential of dealing with the stringent requirement and scarcity of the radio spectrum. Such revolutionary and transforming technology represents a paradigm shift in the design of wireless systems, as it will allow the agile and efficient utilization of the radio spectrum by offering distributed terminals or radio cells the ability of radio sensing, self-adaptation, and dynamic spectrum sharing. Cooperative communications and networking is another new communication technology paradigm that allows distributed terminals in a wireless network to collaborate through some distributed transmission or signal processing so as to realize a new form of space diversity to combat the detrimental effects of fading channels. In this paper, we consider the application of these technologies to spectrum sensing and spectrum sharing. One of the most important challenges for cognitive radio systems is to identify the presence of primary (licensed) users over a wide range of spectrum at a particular time and specific geographic location. We consider the use of cooperative spectrum sensing in cognitive radio systems to enhance the reliability of detecting primary users. We shall describe spectrum sensing for cognitive radios and propose robust cooperative spectrum sensing techniques for a practical framework employing cognitive radios. We also investigate cooperative communications for spectrum sharing in a cognitive wireless relay network. To exploit the maximum spectrum opportunities, we present a cognitive space-time-frequency coding technique that can opportunistically adjust its coding structure by adapting itself to the dynamic spectrum environment.

1,176 citations


Journal ArticleDOI
TL;DR: This work aims to demonstrate the efforts towards in-situ applicability of EMMARM, which aims to provide real-time information about the physical properties of Macromolecular Synthesis and Functionalization.
Abstract: Department of Chemistry, William Mong Institute of Nano Science and Technology, Bioengineering Graduate Program, The Hong Kong University of Science & Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, China, and Department of Polymer Science and Engineering, Key Laboratory of Macromolecular Synthesis and Functionalization of the Ministry of Education, Institute of Biomedical Macromolecules, Zhejiang University, Hangzhou 310027, China

1,042 citations


Journal ArticleDOI
09 Oct 2009-PLOS ONE
TL;DR: The primers recommended in this report shall facilitate a comprehensive and reliable survey of bacterial diversity in metagenomic studies, and the three predominant phyla, Firmicutes, Gemmatimonadetes and Proteobacteria, are best covered by the predicted primers.
Abstract: Bacterial 16S ribosomal DNA (rDNA) amplicons have been widely used in the classification of uncultured bacteria inhabiting environmental niches. Primers targeting conservative regions of the rDNAs are used to generate amplicons of variant regions that are informative in taxonomic assignment. One problem is that the percentage coverage and application scope of the primers used in previous studies are largely unknown. In this study, conservative fragments of available rDNA sequences were first mined and then used to search for candidate primers within the fragments by measuring the coverage rate defined as the percentage of bacterial sequences containing the target. Thirty predicted primers with a high coverage rate (>90%) were identified, which were basically located in the same conservative regions as known primers in previous reports, whereas 30% of the known primers were associated with a coverage rate of <90%. The application scope of the primers was also examined by calculating the percentages of failed detections in bacterial phyla. Primers A519–539, E969–983, E1063–1081, U515 and E517, are highly recommended because of their high coverage in almost all phyla. As expected, the three predominant phyla, Firmicutes, Gemmatimonadetes and Proteobacteria, are best covered by the predicted primers. The primers recommended in this report shall facilitate a comprehensive and reliable survey of bacterial diversity in metagenomic studies.

981 citations


Journal ArticleDOI
TL;DR: In this paper, the authors summarized recent research on and development of semiconductor-based photocatalyst materials that are applicable to environmental remediation and/or chemical synthesis purposes, including the incorporation of noble metal nanoclusters onto the surface of semiconducted particles.
Abstract: This feature article summarizes recent research on and development of semiconductor-based photocatalyst materials that are applicable to environmental remediation and/or chemical synthesis purposes. A wide variety of TiO2 particles and/or films have been studied during the past 30 years because they are the most stable and powerful photocatalysts leading to the degradation of various organic pollutants. The photocatalytic performance of other semiconductor materials such as ZnO, SnO2, WO3, Fe2O3 and CdS has also been intensively investigated. A general limitation in the efficiency of any photocatalytic process is the recombination of the photogenerated charge carriers, i.e., of electrons and holes, following bandgap illumination. Considerable efforts have been made to suppress this recombination and hence to enhance the charge carrier separation and the overall efficiency by means of coupling of different semiconductors with desirable matching of their electronic band structures, or incorporation of noble metal nanoclusters onto the surface of semiconductor photocatalyst particles. Modification of the physicochemical properties, such as particle size, surface area, porosity and/or crystallinity of the semiconductor materials, and optimization of the experimental conditions, such as pH, illumination conditions and/or catalyst loading, during photocatalytic reactions have also been carefully addressed to achieve high reaction rates or yields. To utilize solar energy more efficiently, i.e., to extend the optical absorption of the mostly UV-sensitive photocatalysts into the visible light range, numerous research groups have contributed to the development of novel visible light active photocatalysts. With the application of semiconductors with narrower bandgaps such as CdS, Fe2O3 and WO3 being straightforward choices, doping of wide bandgap semiconductors like TiO2 has been the most popular technique to enhance the catalysts' optical absorption abilities. Research on mixed-oxide-based semiconductor photocatalysts with deliberately modulated band structures has also attracted tremendous attention in the past decade, concentrating on, for example, the generation of H2 and/or O2 from H2O splitting, and the degradation of organic pollutants under visible light irradiation. Both theoretical calculations and experimental results have convincingly shown that the developed materials can serve as highly efficient photocatalysts that are both environmentally and economically significant.

869 citations


Journal ArticleDOI
TL;DR: The authors found that firms located in counties with higher levels of religiosity display lower degrees of risk exposure, as measured by variances in equity returns or returns on assets, and that chief executive officers are more likely to join a firm with a similar religious environment as in their previous firm when they switch employers.

856 citations


Journal ArticleDOI
TL;DR: In this article, a new expiratory droplet investigation system (EDIS) was used to conduct the most comprehensive program of study to date, of the dilution corrected droplet size distributions produced during different respiratory activities.

850 citations


Journal ArticleDOI
TL;DR: This paper found that individual follower's "power distance" orientation and their group's shared perceptions of tra... using 560 followers and 174 leaders in the People's Republic of China and United States.
Abstract: Using 560 followers and 174 leaders in the People's Republic of China and United States, we found that individual follower's “power distance” orientation and their group's shared perceptions of tra...

Journal ArticleDOI
TL;DR: Boron dipyrromethene (BODIPY) derivatives 1 and 2 consisting of donor and acceptor units with dual photoresponses to solvent polarity and luminogen aggregation are developed through taking advantage of twisted intramolecular charge transfer (TICT) and aggregation-induced emission (AIE) processes as discussed by the authors.
Abstract: Boron dipyrromethene (BODIPY) derivatives 1 and 2 consisting of donor and acceptor units with dual photoresponses to solvent polarity and luminogen aggregation are developed through taking advantage of twisted intramolecular charge transfer (TICT) and aggregation-induced emission (AIE) processes. In nonpolar solvents, the locally excited (LE) states of the BODIPY luminogens emit intense green lights. Increasing solvent polarity brings the luminogens from the LE state to the TICT state, causing a large bathochromic shift in the emission color but a dramatic decrease in the emission efficiency. The red emission is greatly boosted by aggregate formation or AIE effect: addition of large amounts of water into the solutions of 1 and 2 in the polar solvents causes the luminogens to aggregate supramolecularly and to emit efficiently. The emission can be enhanced by increasing solvent viscosity and decreasing solution temperature, indicating that the AIE effect is caused by the restriction of the intramolecular ro...

Journal ArticleDOI
TL;DR: The proposed features are robust to image rotation, less sensitive to histogram equalization and noise, and achieves the highest classification accuracy in various texture databases and image conditions.
Abstract: This paper proposes a novel approach to extract image features for texture classification. The proposed features are robust to image rotation, less sensitive to histogram equalization and noise. It comprises of two sets of features: dominant local binary patterns (DLBP) in a texture image and the supplementary features extracted by using the circularly symmetric Gabor filter responses. The dominant local binary pattern method makes use of the most frequently occurred patterns to capture descriptive textural information, while the Gabor-based features aim at supplying additional global textural information to the DLBP features. Through experiments, the proposed approach has been intensively evaluated by applying a large number of classification tests to histogram-equalized, randomly rotated and noise corrupted images in Outex, Brodatz, Meastex, and CUReT texture image databases. Our method has also been compared with six published texture features in the experiments. It is experimentally demonstrated that the proposed method achieves the highest classification accuracy in various texture databases and image conditions.

Journal ArticleDOI
TL;DR: In this paper, the mechanism of the ethanol oxidation reaction on a palladium electrode was studied using the cyclic voltammetry method, and the Tafel slope was found to be 130mV/dec−1 at lower potentials, which suggests that the adsorption of OH− ions follows the Temkin-type isotherm on the Pd electrode.

Journal ArticleDOI
TL;DR: The optimal voting rule for any detector applied to cooperative spectrum sensing is derived and the detection threshold when energy detection is employed, and a fast spectrum sensing algorithm is proposed for a large network which requires fewer than the total number of cognitive radios while satisfying a given error bound.
Abstract: We consider cooperative spectrum sensing in which multiple cognitive radios collaboratively detect the spectrum holes through energy detection and investigate the optimality of cooperative spectrum sensing with an aim to optimize the detection performance in an efficient and implementable way. We derive the optimal voting rule for any detector applied to cooperative spectrum sensing. We also optimize the detection threshold when energy detection is employed. Finally, we propose a fast spectrum sensing algorithm for a large network which requires fewer than the total number of cognitive radios in cooperative spectrum sensing while satisfying a given error bound.

Journal ArticleDOI
TL;DR: The size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured using the interferometric Mie imaging and particle image velocimetry techniques to avoid air sampling losses.

Journal ArticleDOI
TL;DR: In this article, the authors examine whether differences in legal protection affect the size, maturity, and inter-rate spread on loans to borrowers in 48 countries and show that variation in enforceability of contracts matters a great deal more to how loans are structured and how they are priced.
Abstract: We examine whether differences in legal protection affect the size, maturity, and inter est rate spread on loans to borrowers in 48 countries. Results show that banks respond to poor enforceability of contracts by reducing loan amounts, shortening loan maturi ties, and increasing loan spreads. These effects are both statistically significant and economically large. While stronger creditor rights reduce spreads, they do not seem to matter for loan size and maturity. Overall, we show that variation in enforceability of contracts matters a great deal more to how loans are structured and how they are priced. THE EXTENT TO WHICH PROPERTY RIGHTS are protected in a country is an impor tant consideration in determining what loans are offered to firms, how these loans are structured, and how they are priced. Property rights protection af fects a lender's incentives to monitor and its ability to recontract. Declining credit quality often results in lenders raising interest rates, demanding more collateral, shortening loan maturity, and further restricting future activities. This recontracting is costly when property rights are poorly enforced. Poor en forcement lowers recovery rates and increases the time spent in repossessing collateral following default.' In addition to enforcement, the legal rights that lenders have in reorgani zation and liquidation procedures are also important. Differences in creditor rights matter to loan contracting because laws determine who controls the in solvency process and who has rights to the property of a bankrupt firm. How do differences in creditor rights and contract enforceability affect the amount banks lend to firms, the maturity of the loans they make, and the interest rate spreads they charge? Are laws and enforcement equally important to the loan

Journal ArticleDOI
TL;DR: Three control methods—iterative learning control, repetitive control (RC), and run-to-run control (R2R)—are studied and compared and some promising fields for learning-type control are revealed.

Journal ArticleDOI
TL;DR: Experimental signatures of Majorana fermion edge states, which form at the interface between a superconductor and the surface of a topological insulator, are described.
Abstract: We describe experimental signatures of Majorana fermion edge states, which form at the interface between a superconductor and the surface of a topological insulator. If a lead couples to the Majorana fermions through electron tunneling, the Majorana fermions induce resonant Andreev reflections from the lead to the grounded superconductor. The linear tunneling conductance is 0 (2e(2)/h) if there is an even (odd) number of vortices in the superconductor. Similar resonance occurs for tunneling into the zero mode in the vortex core. We also study the current and noise of a two-lead device.

Journal ArticleDOI
TL;DR: This work extends the concept of cloaking as a special form of illusion to the wider realm of illusion optics by using a remote device that can transform the scattered light outside a virtual boundary into that of the object chosen for the illusion, irrespective of the profile and direction of the incident light.
Abstract: We propose to use transformation optics to generate a general illusion such that an arbitrary object appears to be like some other object of our choice. This is achieved by using a remote device that can transform the scattered light outside a virtual boundary into that of the object chosen for the illusion, irrespective of the profile and direction of the incident light. This type of illusion device also enables people to see through walls. Our work extends the concept of cloaking as a special form of illusion to the wider realm of illusion optics.

Journal ArticleDOI
TL;DR: This paper examined the effect of a firm's relations with its non-financial stakeholders, including its employees, suppliers, customers, and communities, on the persistence of both superior and inferior financial performance.
Abstract: We examine the effect of a firm's relations with its nonfinancial stakeholders, including its employees, suppliers, customers, and communities, on the persistence of both superior and inferior financial performance. In particular, integrating and extending the resource-based view of the firm and stakeholder management literatures, we develop the arguments that good stakeholder relations not only enable a firm with superior financial performance to sustain its competitive advantage for a longer period of time, but more importantly, also help poorly performing firms to recover from disadvantageous positions more quickly. The arguments are supported by the analysis of a series of first-order autoregressive models. Our findings further suggest that the positive effect of good stakeholder relations on the persistence of superior performance is not as strong as that of some other firm resources, such as technological knowledge, but it is the only factor examined that promises to help a firm recover from inferior performance. Therefore, the role of positive stakeholder relations in helping poorly performing firms recover is found to be more critical than its role in helping superior firms sustain their performance advantage. Copyright © 2009 John Wiley & Sons, Ltd.

Journal ArticleDOI
TL;DR: An invisibility cloak operating at a finite frequency that can cloak an object with a prespecified shape and size within a certain distance outside the shell is proposed.
Abstract: Based on the concept of complementary media, we propose an invisibility cloak operating at a finite frequency that can cloak an object with a prespecified shape and size within a certain distance outside the shell. The cloak is comprised of a dielectric core and an "antiobject" embedded inside a negative index shell. The cloaked object is not blinded by the cloaking shell since it lies outside the cloak. Full-wave simulations in two dimensions have been performed to verify the cloaking effect.

Journal ArticleDOI
TL;DR: The authors tested a multilevel model of high-performance work systems (HPWS) using data obtained from 324 managers and 522 employees in 76 Japanese establishments, and found that the relationships between establishment-level HPWS and employee job satisfaction and affective commitment were fully mediated by establishmentlevel concern for employees climate, which shed new light on the mechanisms through which HPWS impacts employee outcomes and serve to bridge between macro and micro perspectives of human resource management.
Abstract: Drawing on emerging multilevel theorizing in human resources management, we tested a multilevel model of high-performance work systems (HPWS), using data obtained from 324 managers and 522 employees in 76 Japanese establishments Results from cross-level analyses indicated that the relationships between establishment-level HPWS and employee job satisfaction and affective commitment were fully mediated by establishment-level concern for employees climate These results shed new light on the mechanisms through which HPWS impacts employee outcomes and serve to bridge between macro and micro perspectives of human resource management The research and practice implications of the findings are discussed

Journal ArticleDOI
TL;DR: For example, the authors analyzes empirically what explains the low profitability of Chinese banks for the period 1997-2004 and finds that better capitalized banks tend to be more profitable.
Abstract: This paper analyzes empirically what explains the low profitability of Chinese banks for the period 1997-2004. We find that better capitalized banks tend to be more profitable. The same is true for banks with a relatively larger share of deposits and for more X-efficient banks. In addition, a less concentrated banking system increases bank profitability, which basically reflects that the four state-owned commercial banks - China’s largest banks - have been the main drag for system’s profitability. We find the same negative influence for China’s development banks (so called Policy Banks), which are fully state-owned. Instead, more market oriented banks, such as joint-stock commercial banks, tend to be more profitable, which again points to the influence of government intervention in explaining bank performance in China. These findings should not come as a surprise for a banking system which has long been functioning as a mechanism for transferring huge savings to meet public policy goals.

Proceedings ArticleDOI
11 Oct 2009
TL;DR: Aspects of ClearView that make it particularly appropriate for this context include its ability to generate patches without human intervention, apply and remove patchesto and from running applications without requiring restarts or otherwise perturbing the execution, and identify and discard ineffective or damaging patches by evaluating the continued behavior of patched applications.
Abstract: We present ClearView, a system for automatically patching errors in deployed software. ClearView works on stripped Windows x86 binaries without any need for source code, debugging information, or other external information, and without human intervention.ClearView (1) observes normal executions to learn invariants thatcharacterize the application's normal behavior, (2) uses error detectors to distinguish normal executions from erroneous executions, (3) identifies violations of learned invariants that occur during erroneous executions, (4) generates candidate repair patches that enforce selected invariants by changing the state or flow of control to make the invariant true, and (5) observes the continued execution of patched applications to select the most successful patch.ClearView is designed to correct errors in software with high availability requirements. Aspects of ClearView that make it particularly appropriate for this context include its ability to generate patches without human intervention, apply and remove patchesto and from running applications without requiring restarts or otherwise perturbing the execution, and identify and discard ineffective or damaging patches by evaluating the continued behavior of patched applications.ClearView was evaluated in a Red Team exercise designed to test its ability to successfully survive attacks that exploit security vulnerabilities. A hostile external Red Team developed ten code injection exploits and used these exploits to repeatedly attack an application protected by ClearView. ClearView detected and blocked all of the attacks. For seven of the ten exploits, ClearView automatically generated patches that corrected the error, enabling the application to survive the attacks and continue on to successfully process subsequent inputs. Finally, the Red Team attempted to make Clear-View apply an undesirable patch, but ClearView's patch evaluation mechanism enabled ClearView to identify and discard both ineffective patches and damaging patches.

Journal ArticleDOI
TL;DR: In this paper, the authors examined the effect of firm-level corporate governance on the cost of equity capital in emerging markets and how the effect is influenced by country-level legal protection of investors.

Journal ArticleDOI
01 Aug 2009
TL;DR: This paper proposes k-automorphism to protect against multiple structural attacks and develops an algorithm (called KM) that ensures k-Automorphism and discusses an extension of KM to handle "dynamic" releases of the data.
Abstract: The growing popularity of social networks has generated interesting data management and data mining problems. An important concern in the release of these data for study is their privacy, since social networks usually contain personal information. Simply removing all identifiable personal information (such as names and social security number) before releasing the data is insufficient. It is easy for an attacker to identify the target by performing different structural queries. In this paper we propose k-automorphism to protect against multiple structural attacks and develop an algorithm (called KM) that ensures k-automorphism. We also discuss an extension of KM to handle "dynamic" releases of the data. Extensive experiments show that the algorithm performs well in terms of protection it provides.

Proceedings ArticleDOI
24 Aug 2009
TL;DR: A graph model based on Markov chains is introduced, which captures bug tossing history and reveals developer networks which can be used to discover team structures and to find suitable experts for a new task.
Abstract: bug report is typically assigned to a single developer who is then responsible for fixing the bug. In Mozilla and Eclipse, between 37%-44% of bug reports are "tossed" (reassigned) to other developers, for example because the bug has been assigned by accident or another developer with additional expertise is needed. In any case, tossing increases the time-to-correction for a bug. In this paper, we introduce a graph model based on Markov chains, which captures bug tossing history. This model has several desirable qualities. First, it reveals developer networks which can be used to discover team structures and to find suitable experts for a new task. Second, it helps to better assign developers to bug reports. In our experiments with 445,000 bug reports, our model reduced tossing events, by up to 72%. In addition, the model increased the prediction accuracy by up to 23 percentage points compared to traditional bug triaging approaches.

Journal ArticleDOI
TL;DR: Both the small Ag cluster size and the unique structure of TiO2 nanoparticles supporting highly dispersed Ag clusters are identified to be the sources of a superior bactericidal performance of the RTILs-derived Ag/TiO2.
Abstract: The antimicrobial properties of Ag-based materials have been actively investigated recently. In such materials, control of the size of the Ag particles is critical to their bactericidal performance. A novel one-pot sol−gel scheme is described here. It incorporates room-temperature ionic liquids (RTILs) to synthesize Ag/TiO2 nanocomposite powders. The presence of RTILs is indispensable to the control of the size of the Ag particles. Highly dispersed, metallic Ag nanoclusters are formed on the TiO2 nanoparticle surface after calcination of the gel. The average cluster size of Ag can be controlled to be below 5 nm with high Ag loading (7.4wt%). Antibacterial tests using 7.4wt% Ag/TiO2 on 105 CFU/mL Escherichia coli (E. coli) strains incubated on Luria−Bertani (LB)/agar plates show that bacterial growth was inhibited by 98.8% at an Ag concentration of 1.2 μg/mL. Complete inhibition was achieved at 2.4 μg(Ag)/mL. At this concentration, a 3.9wt% Ag/TiO2 sample, with a smaller Ag cluster size (<3 nm), completely...

Journal ArticleDOI
TL;DR: This tutorial review aims to introduce a new kind of biomaterials-molecular hydrogels of therapeutic agents, based on the molecular self-assembly in water, which can be beneficial in three aspects: the therapeutic agents become "self-deliverable" in the form of hydrogelators of drugs, and the exploration of molecular hydrogles of drugs may ultimately lead to bioactive molecules that have dual or multiple roles.
Abstract: This tutorial review aims to introduce a new kind of biomaterials—molecular hydrogels of therapeutic agents. Based on the molecular self-assembly in water, it is possible to transform therapeutic agents into analogues that form hydrogels without compromising their pharmacological efficacy. This transformation can be beneficial in three aspects: (i) the therapeutic agents become “self-deliverable” in the form of hydrogels; (ii) the self-assembly of hydrogelators of drugs might confer new and useful properties such as multivalency or high local densities; (iii) the exploration of molecular hydrogels of drugs may ultimately lead to bioactive molecules that have dual or multiple roles. By summarizing the reports on the molecular hydrogels made from clinical used drugs or other bioactive molecules, this article presents representative molecular hydrogels of therapeutics and outlines the promises and challenges for developing this new class of biomaterials.