Decay Dynamics of N, N-Dimethylthioacetamide in S3（ππ＊） State

The decay dynamics of N, N-dimethylthioacetamide after excitation to the S3（ππ＊） state was studied by using the resonance Raman spectroscopy and complete active space self- consistent field method calculations. The UV-absorption and vibrational spectra were as- signed. The A-band resonance Raman spectra were obtained in acetonitrile, methanol and water with the laser excitation wavelengths in resonance with the first intense absorption band to probe the Franck-Condon region structural dynamics. The CASSCF calculations were carried out to determine the excitation energies and optimized structures of the lower- lying singlet states and conical intersection point. The A-band structural dynamics and the corresponding decay mechanism were obtained by the analysis of the resonance Raman in- tensity pattern and the CASSCF calculated structural parameters. The major decay channel of S3,FC （ππ＊）→S3（ππ＊）/S1 （nπ＊）→S1（nπ＊） is proposed.

In vivo magnetic resonance spectroscopy of liver tumors and metastases

Primary liver cancer is the fifth most common malignancy in men and the eighth in women worldwide. The liver is also the second most common site for metastatic spread of cancer. To assist in the diagnosis of these liver lesions non-invasive advanced imaging techniques are desirable. Magnetic resonance (MR) is commonly used to identify anatomical lesions, but it is a very versatile technique and also can provide specific information on tumor pathophysiology and metabolism, in particular with the application of MR spectroscopy (MRS). This may include data on the type, grade and stage of tumors, and thus assist in further management of the disease. The purpose of this review is to summarize and discuss the available literature on proton, phosphorus and carbon-13-MRS as performed on primary liver tumors and metastases, with human applications as the main perspective. Upcoming MRSapproaches with potential applications to liver tumors are also included. Since knowledge of some technical background is indispensable to understand the results, a basic introduction of MRS and some technical issues of MRS as applied to tumors and metastases in the liver are described as well. In vivo MR spectroscopy of tumors in a metabolically active organ such as the liver has been demonstrated to provide important information on tumor metabolism, but it also is challenging as compared to applications on some other tissues, in particular in humans, mostly because of its abdominal location where movement may be a disturbing factor.

Magnetic nanoparticle-based cancer therapy

Nanoparticles（NPs） with easily modified surfaces have been playing an important role in biomedicine.As cancer is one of the major causes of death,tremendous efforts have been devoted to advance the methods of cancer diagnosis and therapy.Recently,magnetic nanoparticles（MNPs） that are responsive to a magnetic field have shown great promise in cancer therapy.Compared with traditional cancer therapy,magnetic field triggered therapeutic approaches can treat cancer in an unconventional but more effective and safer way.In this review,we will discuss the recent progress in cancer therapies based on MNPs,mainly including magnetic hyperthermia,magnetic specific targeting,magnetically controlled drug delivery,magnetofection,and magnetic switches for controlling cell fate.Some recently developed strategies such as magnetic resonance imaging（MRI） monitoring cancer therapy and magnetic tissue engineering are also addressed.

Clinical decision support systems for brain tumor characterization using advanced magnetic resonance imaging techniques

In recent years, advanced magnetic resonance imaging(MRI) techniques, such as magnetic resonance spec-troscopy, diffusion weighted imaging, diffusion tensor imaging and perfusion weighted imaging have been used in order to resolve demanding diagnostic prob-lems such as brain tumor characterization and grading, as these techniques offer a more detailed and non-invasive evaluation of the area under study. In the last decade a great effort has been made to import and utilize intelligent systems in the so-called clinical deci-sion support systems(CDSS) for automatic processing, classification, evaluation and representation of MRI data in order for advanced MRI techniques to become a part of the clinical routine, since the amount of data from the aforementioned techniques has gradually inticle is two-fold. The first is to review and evaluate the progress that has been made towards the utilization of CDSS based on data from advanced MRI techniques. The second is to analyze and propose the future work that has to be done, based on the existing problems and challenges, especially taking into account the new imaging techniques and parameters that can be intro-duced into intelligent systems to significantly improve their diagnostic specificity and clinical application.

Neuroimaging in Huntington's disease

Huntington's disease(HD) is a progressive and fatal neurodegenerative disorder caused by an expanded tri-nucleotide CAG sequence in huntingtin gene(HTT) on chromosome 4. HD manifests with chorea, cognitive and psychiatric symptoms. Although advances in genetics allow identification of individuals carrying the HD gene, much is still unknown about the mechanisms underly-ing the development of overt clinical symptoms and the transitional period between premanifestation and mani-festation of the disease. HD has no cure and patients rely only in symptomatic treatment. There is an urgent need to identify biomarkers that are able to monitor disease progression and assess the development and efficacy of novel disease modifying drugs. Over the past years, neuroimaging techniques such as magnetic resonance imaging(MRI) and positron emission tomog-raphy(PET) have provided important advances in our understanding of HD. MRI provides information about structural and functional organization of the brain, while PET can detect molecular changes in the brain. MRI and PET are able to detect changes in the brains of HD gene carriers years ahead of the manifestation of the dis-ease and have also proved to be powerful in assessingdisease progression. However, no single technique hasbeen validated as an optimal biomarker. An integrativemultimodal imaging approach, which combines differ-ent MRI and PET techniques, could be recommendedfor monitoring potential neuroprotective and preventivetherapies in HD. In this article we review the currentneuroimaging literature in HD.

A cytochrome c551 mediates the cyclic electron transport chain of the anoxygenic phototrophic bacterium Roseiflexus castenholzii

Roseiflexus castenholzii is a gram-negativefilamentous phototrophic bacterium that carries out anoxygenic photosynthesis through a cyclic electron transport chain(ETC).The ETC is composed of a reaction center(RC)–light-harvesting(LH)complex(rcRC–LH);an alternative complex III(rcACIII),which functionally re-places the cytochrome bc1/b6f complex;and the periplasmic electron acceptor auracyanin(rcAc).Although compositionally and structurally different from the bc1/b6f complex,rcACIII plays similar essential roles in oxidizing menaquinol and transferring electrons to the rcAc.However,rcACIII-mediated electron transfer(which includes both an intraprotein route and a downstream route)has not been clearly elucidated,nor have the details of cyclic ETC.Here,we identify a previously unknown monoheme cytochrome c(cyt c551)as a novel periplasmic electron acceptor of rcACIII.It reduces the light-excited rcRC–LH to complete a cyclic ETC.We also reveal the molecular mechanisms involved in the ETC using electron paramagnetic resonance(EPR),spectroelectrochemistry,and enzymatic and structural analyses.Wefind that electrons released from rcACIII-oxidized menaquinol are transferred to two alternative periplasmic electron acceptors(rcAc and cyt c551),which eventually reduce the rcRC to form the complete cyclic ETC.This work serves as a foundation for further studies of ACIII-mediated electron transfer in anoxygenic photosynthesis and broadens our under-standing of the diversity and molecular evolution of prokaryotic ETCs.

N×N optical switch based on cascaded microring reso-nators

An N×N optical switch based on cascaded microring resonators on chip is proposed.As an example,the 4×4 optical switch is further investigated.It is successfully demonstrated that its insertion loss is relatively low as 2.2 d B,the crosstalk is negligible,and the extinction ratio(ER)is as large as 130 d B.Thermal tuning is employed to make the microrings be in resonance or not,which leads to a response time of several hundred microseconds.Alternatively,doping the desired waveguide regions with p-type or n-type dopants is able to achieve a better response time of several nanoseconds.The proposed design is easily integrated to a large scale with less microring resonators,which ensures the compact size and the low power consumption.

Comparison of caspase-3 activation in tumor cells upon treatment of chemotherapeutic drugs using capillary electrophoresis

Caspases play important roles in cell apoptosis.Meas-urement of the dynamics of caspase activation in tumor cells not only facilitates understanding of the molecular mechanisms of apoptosis but also contributes to the development,screening,and evaluation of anticancer drugs that target apoptotic pathways.The fluorescence resonance energy transfer(FRET)technique provides a valuable approach for defining the dynamics of apop-tosis with high spatio-temporal resolution.However,FRET generally functions in the single-cell level and becomes ineffective when applied in the high throughput detection of caspase activation.In the cur-rent study,a FRET sensor was combined with capillary electrophoresis(CE)to achieve a high throughput method for cellular caspase detection.The FRET-based CE system is composed of a homemade CE system and a laser source for detecting the dynamics of caspase-3 in various cells expressing sensors of caspase-3 that have been treated with anticancer drugs,such as cell cycle-independent drug cisplatin and specific cell cycle drugs camptothecin and etoposide,as well as their combination with tumor necrosis factor(TNF).A posi-tive correlation between the caspase-3 activation ve-locity and drug concentration was observed when the cells were treated with cisplatin,but cells induced by camptothecin and etoposide did not show any apparent correlation with their concentrations.Moreover,differ-ent types of cells presented distinct sensitivities under the same drug treatment,and the combination treat-ment of TNF and anticancer drugs significantly accel-erated the caspase-3 activation process.Its high throughput capability and detection sensitivity make the FRET-based CE system a useful tool for investi-gating the mechanisms of anticancer drugs and anti-cancer drug screening.

Review： Tip-based vibrational spectroscopy for nanoscale analysis of emerging energy materials

Vibrational spectroscopy is one of the key instrumentations that provide non-invasive investigation of structural and chemical composition for both organic and inorganic materials. However, diffraction of light funda- mentally limits the spatial resolution of far-field vibrational spectroscopy to roughly half the wavelength. In this article, we thoroughly review the integration of atomic force microscopy （AFM） with vibrational spectroscopy to enable the nanoscale characterization of emerging energy materials, which has not been possible with far-field optical techniques. The discussed methods utilize the AFM tip as a nanoscopic tool to extract spatially resolved electronic or molecular vibrational resonance spectra of a sample illuminated by a visible or infrared （IR） light source. The absorption of light by electrons or individual functional groups within molecules leads to changes in the sample＇s thermal response, optical scattering, and atomic force interactions, all of which can be readily probed by an AFM tip. For example, photothermal induced resonance （PTIR） spectroscopy methods measure a sample＇s local thermal expansion or temperature rise. Therefore, they use the AFM tip as a thermal detector to directly relate absorbed IR light to the thermal response of a sample. Optical scattering methods based on scanning near-field optical microscopy （SNOM） correlate the spectrum of scattered near-field light with molecular vibrational modes. More recently, photo-induced force microscopy （PiFM） has been developed to measure the change of the optical force gradient due to the light absorption by molecular vibrational resonances using AFM＇s superb sensitivity in detecting tip-sample force interactions. Such recent efforts successfully breech the diffraction limit of light to provide nanoscale spatial resolution of vibrational spectroscopy,which will become a critical technique for characterizing novel energy materials.

Optical approaches in study of nanocatalysis with single-molecule and single-particle resolution

Studying the activity of individual nanocata- lysts, especially with high spatiotemporal resolution of single-molecule and single-turnover scale, is essential for the understanding of catalytic mechanism and the designing of effective catalysts. Several approaches have been developed to monitor the catalytic reaction on single catalysts. In this review, we summarized the updated progresses of several new spectroscopic and microscopic approaches, including single-molecule fluorescence microscopy, surface-enhanced Raman spectroscopy, surface plasmon resonance microscopy and X-ray microscopy, for the study of single-molecule and single-particle catalysis.

SOLVABILITY FOR m-POINT BOUNDARY VALUE PROBLEM AT RESONANCE WITH ONE-DIMENSIONAL p-LAPLACIAN

By using Mawhin＇s continuation theorem, the existence of solution for a class of m-point boundary value problem at resonance with one-dimensional p-Laplacian is obtained. An example is given to demonstrate the main result of the paper.