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To assess associations between disease severity in index TB patients and QuantiFERON-TB Gold Plus (QFT-Plus) results in contacts, and predictors for QFT-Plus conversion in contacts over 6–12 months.

A series of hands-on experiments including the synthesis and application of flexible, conductive silver-nanopaste were designed to gain knowledge of conductive soft nanomaterial and the synthesis and the application of silver nanopaste (Ag nanopaste). The aim of this laboratory experiment is to provide undergraduate/graduate students an introduction to flexible, conductive electronics by the preparation of silver-nanopaste-incorporated tracks. For Ag-nanopaste-based electronics, the packability of silver nanoparticles and the sintering process are two major factors that dominate the conductivity of the device. In this experiment, ethylene glycol and polyvinylpyrrolidone were utilized to synthesize Ag nanopaste from AgNO3via chemical reduction. The application of this flexible, conductive nanomaterial was demonstrated using Ag-nanopaste-incorporated tracks with a photonic sintering process. The process of photonic sintering is used in this experiment to reduce processing time. Prior to performing hands-on laboratory experiments, students learned about the properties, synthesis, and applications of flexible, conductive nanomaterials in class. A questionnaire was administered after the hands-on experiments to acquire student feedback on the course design. A simple quiz was also completed by the students before and after the hands-on experiments for evaluation.

In an aim to study the potential application toward organic light-emitting diodes, a series of boron compounds NBN-1to NBN-5bearing 1-isoquinolinyl pyrazolate, phenyl, substituted aryl, or fused biphenyl appendages were designed and synthesized. Dual emissions specified as F1and F2bands were observed for NBN-1and NBN-2in various solvents. The F1emission features solvent independence and is assigned to the intraligand ππ* transition (i.e., LE state) over the isoquinolinyl pyrazolate moiety, whereas the F2band shows significant solvatochromism, which originates from the interligand charge transfer (i.e., CT state) from isoquinolinyl to aryl appendages. In comparison, NBN-3bearing ortho-methyl on the phenyl appendages (cf. para-methyl for NBN-2) shows only F1(LE) emission. In contrast, NBN-4and NBN-5with a fused biphenyl-like appendage reveal solely the F2(CT) emission. Comprehensive time-resolved fluorescence measurements, in combination with the computational approach, let us propose the occurrence of a through-space, photoinduced electron transfer (PET) from the LE to CT states. Depending on the characteristic of aryl appendages, the energetics between LE and CT states play a key role for the locally excited LE versus interligand CT emission. A pre-equilibrium-type PET for NBN-1and NBN-2and hence dual emissions are observed, whereas the energetically unfavorable PET for NBN-3leads to the LE emission only. The highly exergonic PET for NBN-4and NBN-5renders solely the CT emission. This work thus demonstrates a strategy of facile appendage tuning of boron compounds that can afford both the LE and interligand CT emissions spanning over the entire visible spectral region.

This study discusses the strategies on sample preparation to acquire images with sufficient quality for size characterization by scanning electron microscope (SEM) using two commercial ZnO nanoparticles of different surface properties as a demonstration. The central idea is that micrometer sized aggregates of ZnO in powdered forms need to firstly be broken down to nanosized particles through an appropriate process to generate nanoparticle dispersion before being deposited on a flat surface for SEM observation. Analytical tools such as contact angle, dynamic light scattering and zeta potential have been utilized to optimize the procedure for sample preparation and to check the quality of the results. Meanwhile, measurements of zeta potential values on flat surfaces also provide critical information and save lots of time and efforts in selection of suitable substrate for particles of different properties to be attracted and kept on the surface without further aggregation. This simple, low-cost methodology can be generally applied on size characterization of commercial ZnO nanoparticles with limited information from vendors.

Hong Kong launched a publicity campaign on the use of antibiotics and antibiotic resistance in March/April 2011. Two population surveys were conducted in November 2010 (N=1569; response rate 69.2%) and June 2011 (N=1527; response rate 66.6%) before and after the campaign, respectively, to evaluate its impact. Adults aged ≥18 years were asked about their knowledge and attitude related to antibiotic use and antibiotic resistance. Information obtained from health professionals had the highest mean impact score. There was a significant increase in the proportion of respondents knowing that antibiotics could not cure influenza (from 58.0 to 65.0%; P<0.001) or viral infections (from 24.9 to 29.0%; P=0.002). Over one-quarter (27.7%) of respondents could recall the campaign, mostly through announcement of public interest (API) on television/radio. After regression analysis, age, personal hygiene practices in daily life, and the attitude that everyone had a role to play in alleviating the problem of antimicrobial resistance were found to be associated with campaign awareness.

Objective.To determine the effectiveness of World Health Organization (WHO) multimodal strategy in promoting hand hygiene (HH) among healthcare workers (HCWs) in long-term care facilities (LTCFs).Design.Cluster-randomized controlled trial.Setting.Eighteen homes for the elderly in Hong Kong were randomly allocated to 2 intervention arms and a control arm. Direct observation of HH practice was conducted by trained nurses. Either handrubbing with alcohol-based handrub (ABHR) or handwashing with liquid soap and water was counted as a compliant action. Disease notification data during 2007–2010 were used to calculate incidence rate ratio (IRR).Participants.Managers and HCWs of the participating homes.Interventions.The WHO multimodal strategy was employed. All intervention homes were supplied with ABHR (WHO formulation I), ABHR racks, pull reels, HH posters and reminders, a health talk, video clips, training materials, and performance feedback. The only difference was that intervention arms 1 and 2 were provided with slightly powdered and powderless gloves, respectively.Results.A total of 11,669 HH opportunities were observed. HH compliance increased from 27.0% to 60.6% and from 22.2% to 48.6% in intervention arms 1 and 2, respectively. Both intervention arms showed increased HH compliance after intervention compared to controls, at 21.6% compliance (both P< .001). Provision of slightly powdered versus powderless gloves did not have any significant impact on ABHR usage. Respiratory outbreaks (IRR, 0.12; 95% confidence interval [CI], 0.01–0.93; P= .04) and methicillin-resistant Staphylococcus aureusinfections requiring hospital admission (IRR, 0.61; 95% CI, 0.38–0.97; P= .04) were reduced after intervention.Conclusions.A promotion program applying the WHO multimodal strategy was effective in improving HH among HCWs in LTCFs.

A new coordination polymer, [Zn(dpe)(bdc)]⋅4H2O (ZndB; dpe=1,2‐bis(4‐pyridyl)ethane, bdc2−=dianion of benzenedicarboxylic acid), which possesses a 3D metal–organic framework (MOF) has been synthesized and structurally characterized. This 3D MOF is constructed by the assembly of helical channels filled with guest water molecules in both inner and outer regions of the channel. The resulting network also creates a 2D water layer containing hydrogen‐bonded (H2O)16rings as the basic building units. Thermogravimetric and powder X‐ray diffraction measurements of ZndB revealed a two‐step weight loss of water molecules with a reversible water adsorption/desorption process in the inner channel for the first stage, and irreversible water desorption in the outer channel for the second stage. This spongelike property is manifested by the excimer emission originating from interaction between dpe (π*) and the other dpe (π) of the proximal helical channel, which is highly sensitive to the environmental perturbation. Powder X‐ray analyses reveal that the dehydration process induces the readjustment of dpe π–π stacking distance/orientation, which results in dramatic luminescence changes from dim pale blue (λem≈470 nm) upon hydration to bright white‐light generation (broad, λem≈500–550 nm) upon water depletion, accompanied by a ≈100‐fold increase in the emission intensity.

Strategically designed salen ligand 2,3‐bis[4‐(di‐p‐tolylamino)‐2‐hydroxybenzylideneamino]maleonitrile (1), which has pronounced excited‐state charge‐transfer properties, shows a previously unrecognized form of photoisomerization. On electronic excitation (denoted by an asterisk), 1Z*→1Eisomerization takes place by rotation about the C2C3 bond, which takes on single‐bond character due to the charge‐transfer reaction. The isomerization takes place nonadiabatically from the excited‐state (1Z) to the ground‐state (1E) potential‐energy surface in the singlet manifold; 1Zand 1Eare neither thermally inconvertible at ambient temperature (25–30 °C), nor does photoinduced reverse 1E*→1Z(or 1Z*) isomerization occur. Isomers 1Zand 1Eshow very different coordination chemistry towards a ZnIIprecursor. More prominent coordination chemistry is evidenced by a derivative of 1bearing a carboxyl group, namely, N,N′‐dicyanoethenebis(salicylideneimine)dicarboxylic acid (2). Applying 2Zand its photoinduced isomer 2Eas building blocks, we then demonstrate remarkable differences in morphology (sphere‐ and needlelike nanostructure, respectively) of their infinite coordination polymers with ZnII.

We report here the study of two-photon induced luminescence of 11-mercaptoundecanoic acid functionalized quantum-sized Au nanodots (11MUA-Au nanodots). The X-ray absorption near-edge structure (XANES) measurement at the gold LIIIedge indicates that the oxidation state of the surface of 11MUA-Au nanodots is best described as Au+. The two-photon absorption (TPA) property of 11MUA-Au nanodots was then investigated via an open aperture Z-scan method. Together with a precise extinction coefficient (i.e., one-photon absorption) extracted from inductively coupled plasma mass spectrometry, the TPA cross section, σ, was deduced to be 8761 ± 175 GM (800 nm) for 11MUA-Au nanodots (diameter 1.33 ± 0.12) in water. Upon dextran encapsulation, 11MUA-Au nanodots was proved to be highly water-soluble, stable, and low in toxicity, which demonstrated its power in two-photon imaging toward human mesenchymal stem cells (hMSCs) in vitro.

Fluorescence resonant energy transfer (FRET) has been clearly demonstrated between CdSe/ZnS type I quantum dots and CdSe/ZnTe type II quantum dots by photoluminescence, time-resolved photoluminescence (TRPL), and photoluminescence excitation (PLE) measurements. The result of PLE experiment provides us concrete evidence that the emission of CdSe/ZnTe quantum dots is indeed influenced by CdSe/ZnS quantum dots. It is found that by changing the size of CdSe/ZnS quantum dots, the emission spectra of CdSe/ZnTe quantum dots can be selectively enhanced in a particular wavelength range and the emission intensity of type II quantum dots can be greatly enlarged by up to four times. Together with the large tunability of the emission energy in the infrared region, our finding provides an opportunity for creating highly efficient optoelectronic devices and bioimaging labels derived from type II quantum dots. We stress here that the large difference in emission energies between donors and acceptors in our studied system is especially useful for the development of biosensors.

A new series of quadrupolar type two‐photon absorption (2PA) chromophores 3–9bearing a core arylamine‐[a,c]phenazine‐arylamine motif are synthesized in high yields. Palladium‐catalyzed Stille coupling and CN coupling reactions are utilized to prepare target chromophores. Detailed characterization and systematic studies of these molecules, including absorption and fluorescence emission, are conducted. These compounds are found to exhibit very large 2PA cross section values, for example, ∼7000 GM at 800 nm for 8in toluene. Two‐photon‐induced fluorescence imaging is successfully demonstrated in vitro using compound‐8‐encapsulated silica nanoparticles with excellent bio‐compatibility. In combination with the capability of both one‐ and two‐photon singlet‐oxygen sensitizations, this nanocomposite demonstrates its promising potential in dual functionality toward two‐photon fluorescence imaging and two‐photon photodynamic therapy.

Single 15-crown-5 functionalized Au nanoparticles (NPs) were synthesized with assistance of silica particles. The use of silica particles renders intrinsic advantages in that each step along the product formation can be monitored by, for example, a transmission electron microscope, and large surface-to-volume ratio of silica particles leads to a better yield of Au NP attachment than the glass substrate. The as prepared Au NPs, providing access to fundamental analysis, were readily applied in K+recognition and proved to be free from aggregation. Accordingly, a sandwich type of complexation is resolved and the corresponding thermodynamics can be extracted.

We have prepared and characterized a series of osmium complexes [Os2(CO)4(fpbpy)2] (1), [Os(CO)(fpbpy)2] (2), and [Os(fpbpy)2] (3) with tridentate 6‐pyrazol‐3‐yl 2,2′‐bipyridine chelating ligands. Upon the transformation of complex 2into 3through the elimination of the CO ligand, an extremely large change in the phosphorescence wavelength from 655 to 935 nm was observed. The results are rationalized qualitatively by the strong π‐accepting character of CO, which lowers the energy of the osmium dπorbital, in combination with the lower degree of π conjugation in 2owing to the absence of one possible pyridine‐binding site. As a result, the energy gap for both intraligand π–π* charge transfer (ILCT) and metal‐to‐ligand charge transfer (MLCT) is significantly greater in 2. Firm support for this explanation was also provided by the time‐dependent DFT approach, the results of which led to the conclusion that the S0→T1transition mainly involves MLCT between the osmium center and bipyridine in combination with pyrazolate‐to‐bipyridine 3π–π* ILCT. The relatively weak near‐infrared emission can be rationalized tentatively by the energy‐gap law, according to which the radiationless deactivation may be governed by certain low‐frequency motions with a high density of states. The information provided should allow the successful design of other emissive tridentate metal complexes, the physical properties of which could be significantly different from those of complexes with only a bidentate chromophore.

We report the design and synthesis of Ir-complex functionalized CdSe/ZnS quantum dots (QDs), in which the QD plays a key role in imaging, while the Ir-complex acts as a sensitizer to produce singlet oxygen; this conceptual design presents a novel scheme in both bio-imaging and photodynamic therapy.

Bifunctional compound (VI) is synthesized for an alternative application of DSSC toward metal recognition.