PHOTOACOUSTIC VISCOELASTICITY IMAGING OF BIOLOGICAL TISSUES WITH INTENSITY-MODULATED CONTINUOUS-WAVE LASER

In this paper,a novel photoacoustic viscoelasticity imaging(PAVEI)technique that provides viscoelastic infornation of biological tissues is presented.We deduced the proocess of photoacoustic(PA)ffct on the basis of thermal viscoelasticity theory and est ablished the relationship between the PA phase delay and the vicoelasticity for soft solids.By detecting the phase delay of PA signal,the viscoelasticity distribution of absorbers can be mapped.Gelatin phantoms with diferent densities and different absorption cofficients were used to verify the dependence of PA VEI measurements.Moreover,tissue mimicking phantoms mixed with fat and collagen at different concentrations were used to testify the feasibility of this technique with reli able contrast.Finally,the PAVEI was sucossfully applied to discrimination between biological tissue constituents.Our experimental results demonstrate that this novel technique has the potential for visualizing the anatomical and biomechanical properties of biological tissues.

Generation of high-energy dual-wavelength domain wall pulse with low repetition rate in an HNLF-based fiber ring laser

The generation of high-energy dual-wavelength domain wall pulse with a low repetition rate is demonstrated in a highly nonlinear fiber （HNLF）-based fiber ring laser. By introducing the intracavity birefringence-induced spectral filtering effect, the dual-wavelength lasing operation can be achieved. In order to enhance the cross coupling effect between the two lasing beams for domain wall pulse formation, a 215-m HNLF is incorporated into the laser cavity. Experimentally, it is found that the dual-wavelength domain wall pulse with a repetition rate of 77.67 kHz could be efficiently obtained through simply rotating the polarization controller （PC）. At a maximum pump power of 322 mW, the 655-nJ single pulse energy in cavity is obtained. The proposed configuration provides a simpler and more efficient way to generate high energy pulse with a low repetition rate.

Automated apoptosis identification in fluorescence imaging of nucleus based on histogram of oriented gradients of high-frequency wavelet coefficients

The automatic and accurate identification of apoptosis facilitates large-scale cell analysis.Most identification approaches using nucleus fluorescence imaging are based on specific morphological parameters.However,these parameters cannot completely describe nuclear morphology,thus limiting the identification accuracy of models.This paper proposes a new feature extraction method to improve the performance of the model for apoptosis identification.The proposed method uses a histogram of oriented gradient(HOG)of high-frequency wavelet coefficients to extract internal and edge texture information.The HOG vectors are classified using support vector machine.The experimental results demonstrate that the proposed feature extraction method well performs apoptosis identification,attaining 95:7% accuracy with low cost in terms of time.We confirmed that our method has potential applications to cell biology research.

Effects of IκBα and its mutants on NF-κB and p53 signaling pathways

AIM: To study the effects of IκBα and its mutants (IκBαM, IκBα243N, IκBαM244C) on NF-κB, p53 and their downstream target genes. The relationship of NF- κB, p53, and IκBα was further discussed.METHODS: pECFP-IκBα, pECFP-IκBαM (amino acides 1-317, Ser32, 36A), pECFP-IκBα243N (amino acides 1-243), pECFP-IκBα244C (amino acides 244-317), pEYFP-p65 and pp53-DsRed were constructed and transfected to ASTC-α-1 cells. Cells were transfected with pECFP-C1 as a control. 30 h after the transfection, location patterns of NF-κB, p53 and IκBα (IκBαM, IκBα243N, IκBα244C) were observed by a laser scanning microscope (LSM510/ConfoCor2, Zeiss). RNA extraction and reverse transcription were performed in cells transfected or co-transfected with different plasmids. Effects of IκBα and its mutants on the transprition level of NF-κB, NF-κB downstream target gene TNF-α, p53 and p53 downstream target gene Bax were observed by real time QT-PCR. In all experiments β-actin was reference. Results are expressed as the target/reference ratio of the sample divided by the target/reference ratio of the control. Different transfected cells were incubated with CCK-8 for 2 h in the incubator. Then the absorbance at 450 nm was measured by using a microplate reader. RESULTS: Cells that were transfected with p53- DsRed revealed a predominant nuclear localization. YFP-p65 mainly existed in the cytoplasm. Cells were transfected with CFP-IκBα, CFP-IκBαM, and CFP- IκBα243N respectively and revealed a predominant cytosolic localization. However, cells transfected of CFP- IκBα244C revealed a predominant nuclear localization. The mRNA levels of p65, TNF-α, p53 and Bax in CFP-IκBα transfected cells did not change significantly, while in YFP-p65/CFP-IκBα co-transfected cells, IκBα decreased the transcription of p65 downstream gene TNF-α (2.24 ± 0.503) compared with the YFP-p65/ CFP-C1 co-transfected cells (5.08 ± 0.891) (P < 0.05). Phosphorylation defective IκBα (IκBαM) decreased the transcription levels of all the four genes compared with the control (P < 0.05). The N terminus of IκBα (IκBα243N) increased the transcription of NF-κB (1.84 ± 0.176) and TNF-α (1.51 ± 0.203) a little bit. However, the C terminus of IκBα (IκBα244C) increased the transcription of NF-κB, TNF-α, p53 and Bax significantly (8.29 ± 1.662, 14.16 ± 2.121, 10.2 ± 0.621, 3.72 ± 0.346) (P < 0.05). The CCK-8 experiment also showed that IκBα244C and p53 synergistically mediate apoptosis. CONCLUSIONS: IκBα and its mutants (IκBαM, IκBα243N, IκBαM244C) have different effects on NF- κB and p53 signaling pathways, according to their different structures. IκBαM bounds with NF-κB and p53 in cytoplasm steadily, and inhibits both of the two signaling pathways. p53 and IκBα244C may be co-factor in inducing apoptosis. The C terminal of IκBα enhanced cell death, which suggests that it may be a pro-apoptotic protein existed in cells.

A review of microwave-induced thermoacoustic imaging:Excitation source,data acquisition system and biomedical applications

Microwave-induced thermoacoustic imaging(TAI)is a noninvasive modality based on the differences in microwave absorption of various biological tissues.TAI has been extensively researched in recent years,and several studies have revealed that TAI possesses advantages such as high resolution,high contrast,high imaging depth and fast imaging speed.In this paper,we reviewed the development of the TAI technique,its excitation source,data acquisition system and biomedical applications.It is believed that TAI has great potential applications in biomedical research and clinical study.

DFT Calculation of Glycine with Methanols Clusters

密度功能的理论(DFT ) 计算为中立、两性离子的 glycine-(CH3OH ) 的结构被报导 n 在哪儿 n = 16。有 16 个甲醇分子的中立、两性离子的 glycine 的簇的起始的几何学充分在 B3LYP/631+G 被优化 * 理论的水平。最低精力配置被定位，他们的氢契约结构被分析。理论预言表明甲醇喜欢近为小簇找到羧基的酸组(n 3 ) 当有衔接酸和氨基的组的甲醇的配置是喜爱的在里面时，与中立表格，两性离子的表格聚类。当在簇的甲醇分子的数字到达五和六时，二张表格趋于是 isoenergetic。

Band rules for the frequency spectra of three kinds of aperiodic photonic crystals with negative refractive index materials

By means of the theory of electromagnetic wave propagation and transfer matrix method, this paper investigates the band rules for the frequency spectra of three kinds of one-dimensional （1D） aperiodic photonic crystals （PCs）, generalized Fibonacci GF（p, 1）, GF（1,2）, and Thue Morse （TM） PCs, with negative refractive index （NRI） materials. It is found that all of these PCs can open a broad zero-n gap, TM PC possesses the largest zero-n gap, and with the increase of p, the width of the zero-n gap for GF（p, 1） PC becomes smaller. This characteristic is caused by the symmetry of the system and the open position of the zero-n gap. It is found that for GF（p, 1） PCs, the possible limit zero-n gaps open at lower frequencies with the increase of p, but for GF（1,2） and TM PCs, their limit zero-n gaps open at the same frequency. Additionally, for the tbree bottom-bands, we find the interesting perfect self-similarities of the evolution structures with the increase of generation, and obtain the corresponding subband-number formulae. Based on 11 types of evolving manners Qi （i = 1, 2,... , 11） one can plot out the detailed evolution structures of the three kinds of aperiodic PCs for any generation.

Detection of telomerase activity by combination of telomeric repeat amplification protocol and electrochemiluminescence assay

A highly sensitive telomerase detection method that combines telomeric repeat amplification protocol （TRAP） and magnetic beads based electrochemiluminescence （ECL） assay has been developed. Briefly, telomerase recognizes biotinylated telomerase synthesis primer （B-TS） and synthesizes extension products, which then serve as the templates for PCR amplification using B-TS as the forward primer and tris-（2′2′-bipyridyl） ruthenium （TBR） labeled ACX （TBR-ACX） as the reversed primer. The amplified product is captured on streptavidin-coated paramagnetic beads and detected by ECL. Telomerase positive HeLa cells were used to validate the feasibility of the method. The experimental results showed down to 10 cancer cells can be detected easily. The method is a useful tool for telomerase activity analysis due to its sensitivity, rapidity, safety, high throughput, and low cost. It can be used for screening a large amount of clinical samples.

Photonic band structures of quadrangular multiconnected networks

By means of the network equation and generalized dimensionless Floquet-Bloch theorem, this paper investigates the properties of the band number and width for quadrangular multiconnected networks （QMNs） with a different number of connected waveguide segments （NCWSs） and various matching ratio of waveguide length （MRWL）. It is found that all photonic bands are wide bands when the MRWL is integer. If the integer attribute of MRWL is broken, narrow bands will be created from the wide band near the centre of band structure. For two-segment-connected networks and three-segment-connected networks, it obtains a series of formulae of the band number and width. On the other hand, it proposes a so-called concept of two-segment-connected quantum subsystem and uses it to discuss the complexity of the band structures of QMNs. Based on these formulae, one can dominate the number, width and position of photonic bands within designed frequencies by adjusting the NCWS and MRWL. There would be potential applications for designing optical switches, optical narrow-band filters, dense wavelength-division-multiplexing devices and other correlative waveguide network devices.

An improved electrochemiluminescence polymerase chain reaction method for the detection of Fusarium wilts

An improved electrochemiluminescence polymerase chain reaction （ECL-PCR） method was developed and applied to detect Fusarium wilt. Briefly, the internal transcribed spacer （ITS） sequence of Fusarium oxysporumf, sp Cubense （FOC） was amplified by PCR. Two universal fragments, which were complimentary to Ru（bpy）3^2＋ （TBR） labeled probe and Biotin labeled probe, respectively, were connected to the tail of primers so that all the PCR products got universal sequences. Then biotin labeled probes and TBR labeled probes were hybridized with the PCR products at the same time. Through the specific interaction between biotin and streptavidin, the PCR products were captured by streptavidin coated magnetic bead and then detected by ECL assay. The experiment results showed that the healthy banana samples and infected ones can be discriminated by this ECL-PCR method. This improved ECL-PCR approach is useful in Fusarium wilt detection due to its high sensitivity, simplicity and stability.

Highly sensitive ECL-PCR method for detection of K-ras point mutation

A highly sensitive electrochemiluminescence-polymerase chain reaction (ECL-PCR) method for K-ras point mutation detection is developed. Briefly, K-ras oncogene was amplified by a Ru(bpy)3(2+) (TBR)-labeled forward and a biotin-labeled reverse primer, and followed by digestion with MvaI restriction enzyme, which only cut the wild-type amplicon containing its cutting site. The digested product was then adsorbed to the streptavidin-coated microbead through the biotin label and detected by ECL assay. The experiment results showed that the different genotypes can be clearly discriminated by ECL-PCR method. It is useful in point mutation detection, due to its sensitivity, safety, and simplicity.

Photoacoustic viscoelasticity imaging dedicated to mechanical characterization of biological tissues

Since changes in mechanical properties of biological tissues are often closely related to pathology,the viscoelastic properties are important physical parameters for medical diagnosis.A photoacoustic(PA)phase-resolved method for noninvasively characterizing the biological tissue viscoelasticity has been proposed by Gao et al.[G.Gao,S.Yang,D.Xing,\Viscoelasticity imaging of biological tissues with phase-resolved photoacoustic measurement,"Opt.Lett.36,3341–3343(2011)].The mathematical relationship between the PA phase delay and the viscosity–elasticity ratio has been theoretically deduced.Moreover,systems of PA viscoelasticity(PAVE)imaging including PAVE microscopy and PAVE endoscopy were developed,and high-PA-phase contrast images re°ecting the tissue viscoelasticity information have been successfully achieved.The PAVE method has been developed in tumor detection,atherosclerosis characterization and related vascular endoscopy.We reviewed the development of the PAVE technique and its applications in biomedical¯elds.It is believed that PAVE imaging is of great potential in both biomedical applications and clinical studies.

Pharmacokinetic Monitoring of Indocyanine Green for Tumor Detection Using Photoacoustic Imaging

We report tumor detection using a photoacoustic technique for the imaging of angiogenesis and monitoring of agent pharmacokinetics on an animal model. We take 532-nm laser pulses to excite photoacoustic signals of blood vessels with acquisition by a broadband hydrophone, and the morphological characteristics of tumor angiogenesis are successfully image depicted. Furthermore, tumor pharmacokinetics is preformed and analyzed with fast multielement photoacoustic imaging of the intravenous-injected indocyanine green （ICG）. Photoacoustic signals of ICG are excited with 805 nm laser pulses and recorded by transducer array as a function of time. The difference between the photoacoustic signal from the tumor side and that from the normal side is observed, and the ICG clearance velocity in the tumor area is found to lag behind that in the normal area. Experimental results demonstrate that photoacoustie imaging of morphological parameter and pharmacokinetics with specific agent may provide high sensitive approach for tumor detection and localization.

In Vivo Monitoring of Neovascularization in Tumour Angiogenesis by Photoacoustic Tomography

Photoacoustic tomography （PAT） is presented to in vivo monitor neovascularization in tumour angiogenesis with high resolution and high contrast images in a rat. With a circular scan system, the photoacoustic signal, generated by laser pulses at a wavelength of 532nm from a Q-switched Nd：YAG laser is captured by a hydrophone with a diameter of 1 mm and a sensitivity of 850nV/Pa. The vascular structure around the rat tumour is imaged clearly, with optimal contrast, because blood has strong absorption near this wavelength. Serial noninvasive photoacoustic images of neovascularization in tumour angiogenesis are also obtained consecutively from a growing tumour implanted under the skin of a rat over a period of two weeks. This work demonstrates that PAT can potentially provide a powerful tool for tumour angiogenesis detection in cancer research. It will bring us closer to clinical applications for tumour diagnosis and treatment monitoring.

Influence of Deviation on Optical Transmission through Aperiodic Superlattices

我们建议一个偏差模型并且在 Fibonacci 超点阵的传播系数(TC ) 上学习一台机器的相对错误和敏感的影响。为有更少层的一个系统，偏差的影响能被忽略，这被发现。当超点阵变得更复杂时，他们可以被一台机器与合适的相对错误制作并且拥有 TC 的设计价值。然而，当系统层的数字超过某批评价值时，超点阵应该仅仅由精确机器被生产。敏感的影响也被讨论。

H_(2)O_(2) INDUCES APOPTOSIS OF RABBIT CHONDROCYTES VIA BOTH THE EXTRINSIC AND THE CASPASE-INDEP ENDENT INTRINSIC PATHW AYS

Ostcoarthritis(OA),one of the most common joint discases with unknown etiology,is charac-terized by the progressive destruction of articular cartilage and the apoptosis of chondrocytes.The purpose of this study is to elucidate the molecular mechanisms of H_(2)O_(2)-mediated rabbit chon-drocytes apoptosis.CCK-8 assay showed that H_(2)O_(2) treatment induced a remarkable reduction of cell viability,which was further verified by the remarkable phosphatidylserine extemalization after H_(2)O_(2) treatment for 1 h,the typical characteristics of apoptosis.H_(2)O_(2) treatment induced a signifcant dysfunction of mitochondrial membrane potential(△ψm),but did not induce casapse-9 activation,indicating that H_(2)O_(2) treat ment induced caspase independent intrinsic apoptosis that was further verified by the fact that silencing of AIF but not inhibiting caspase-9 potently pre-vented H_(2)O_(2)-induced apoptosis.H_(2)O_(2) treatment induced a signifcant increase of caspase8 and-3 activation,and inhibition of caspase-8 or-3 significantly prevented H_(2)O_(2)-induced apoptosis,suggesting that the extrinsic pathway played an important role.Collectively,our findings demonstrate that H_(2)O_(2) induces apoptosis via both the casapse8-mediated extrinsic and the caspaseindependent intrinsic apoptosis pathways in ra bbit chondrocytes.

Effects of LPLI on microglial phagocytosis in LPS-induced neuroinflammation model

Microglial activation plays an important role in neurodegenerative diseases.Once activated,they have macrophage-like capabilities,which can be beneficial by phagocytosis and harmful by se-cretion of neurotoxins.However,the resident microglia always fail to trigger an effective pha-gocytic response to clear dead cells or Aβdeposits during the progression of neurodegeneration.Therefore,the regulation of microglial phagocytosis is considered a useful strategy in searchingfor neuroprotective treatments.In this study,our results showed that low-power laser iradiation(LPLI)(20 J/cm²)could enhance microglial phagocytic function in LPS-activated microglia.Wefound that LPLI-mediated microglial phagocytosis is a Rac-1-dependent actin-based process,that a constitutively activated form of Rac1(RaclQ61L)induced a higher level of actin pol-ymerization than cells transfected with wild-type Racl,whereas a dominant negative form ofRacl(RaclT17N)markedly suppressed actin polymerization.In addition,the involvement of Racl activation after LPLI treatment was also observed by using a Raichu fluorescence resonance energy transfer(FRET)-based biosensor.We also found that PI3K/Akt pathway was required inthe LPLI-induced Raci activation.Our research may provide a feasible therapeutic approach tocontrol the progression of neurodegenerative diseases.

Characteristics of photonic bands generated by quadrangular multiconnected networks

In this paper, by means of the network equation and generalized dimensionless Floquet-Bloch theorem, we study the influences of the number of connected waveguide segments （NCWS） between adjacent nodes and the matching ratio of waveguide length （MRWL） on the photonic bands generated by quadrangular multiconnected networks （QMNs）, and obtain a series of formulae. It is found that multicombining networks （MCNs） and repetitive combining networks （RCNs） are equivalent to each other and they can all be simplified into the simplest fundamental combining systems. It would be useful for adjusting the number, widths, and positions of photonic bands, and would possess potential applications for the designing of all-optical devices and photonic network devices.

REAL-TIME FLUORESCENCE IMAGING OF SIRT1 CYTOSOLIC TRANSLOCATION UNDER THE TREATMENT OF GROWTH FACTOR DEPRIVATION

Sirtuins comprise a family of enzymes implicated in the determination of organismal lifespan in yeast and the nematode.Human sirtuin SIRT1 has been shown to deacetylate several proteins in a NADt-dependent manner.It is reported that SIRT1 regulates physiological processes including senescence,fat metabolism,glucose homeostasis,apoptosis,and neurodegeneration.In general,SIRT1 has initially been thought to represent an exclusive nuclear protein.However,depending on the cell lines and organisms examined,a partial or temporary cytoplasmic localization was observed in murine pancreatic beta cells and neonatal rat cardiomyocytes.Since SIRT1 deacetylates both histone and nonhistone-proteins,such as a number of transcription factors,changes in subcellular localization probably play a role in the regulation of its function.In the present studies,we investigated the subcellular localization of SIRT1 in response to growth factor deprivation in African green monkey SV40-transformed kidneyfibroblast cells(COS-7).Using SIRT1-EGFPfluorescence reporter,we found that SIRT1 localized to nucleus in physiological conditions.We devised a model enabling cell senescence via growth factor deprivation and found that SIRT1 partially translocated to cytosol under the treatment,suggesting a reduced level of SIRT1 activity.We found PI3K/Akt pathway was involved in the inhibition of SIRT1's cytosolic translocation,because inhibition of these kinases significantly decreased the amount of SIRT1 maintained in nucleus.Taken together,we demonstrate that growth factor deprivation induces cytosolic translocation of SIRT1,which suggests a possible connection between cytoplasm-localized SIRT1 and the aging process and provides a new application of single moleculefluorescence imaging of the molecule events in living cells.

In vivo monitoring of microneedle-based transdermal drug delivery of insulin

Soluble microneedles(MNs)have recently become an eficient and minimally invasive tool in transdermal drug delivery because of their excellent biocompatibility and rapid dissohution.However,direct monitoring of structural and functional changes of MNs in vivo to estimate the efficieancy of insulin delivery is difficult.We monitored the dissolution of MNs to obtain structural imaging of MNs'changes by using optical coherence tomography(OCT).We also observed the effect of MNs on microvascular conditions with laser speckle contrast imaging(LSCIT)and measured the blood perfusion of skin to obtain functional imaging of MNs.We determined the performance of two soluble MN arrays made from polyvinyi alcohol(PVA)and polyvinyl alco-hol/polyvinylpyrolidone(PVA/PVP)by calculating the cross sectional areas of the micro-channels in mouse skin as a function of time.Moreover,the change in blood glucose before and after using MNs loaded with insulin was evaluated as an auxiliary means to demonstrate the ability of the soluble MNs to deliver insulin.Results showed that the structural imaging of these MNs could be observed in vivo via OCT in real time and the fumctional imaging of MNs could be showed using LSCI OCT and LSCI are potential tools in monitoring MNs structural and functional changes.