[Current treatment in advanced hepatocellular carcinoma and prospects for immuno-oncology therapy]

Treatment of patients with advanced hepatocellular carcinoma (HCC) remains a huge challenge since a widely accepted therapeutic strategy has not been identified. There are some special features in patients with HCC in China, such as are mainly related to hepatitis B virus infection, often diagnosed as advanced or end-stage disease, and usually have a poorer prognosis compared with patients in western countries. Hence, appropriate treatments are urgently needed for these patients. Notably, immune-oncology therapy has been received increased attention in recent years. Based on promising results observed in clinical trials, immune-oncology therapy has been approved for treatment of various malignant diseases and brings a new hope to the treatment of advanced HCC. The review summarizes the current situation of advanced HCC treatment in China and discusses the prospects of immuno-oncology therapy.

[Identifying T-DNA insertion site(s) of transgenic plants by whole-genome resequencing]

The availability of T-DNA insertion sites is very important for plant functional genomics research and the screening and identification of transgenic plants. However, the present protocols for identifying T-DNA insertion sites, like reverse PCR and semi-random primer PCR, are not only complex and time-consuming, but also inefficient. In this paper, a DNA pool of three transgenic plants was sequenced by whole-genome resequencing, and four T-DNA insertion sites were identified by blasting using transgenic T-DNA sequences. After PCR and Southern blot analysis, the T-DNA insertion sites of the three transgenic plants were successfully confirmed, and one of the transgenic plants showed two insertion sites. In conclusion, this study established a simple, reliable and efficient method for obtaining T-DNA insertion sites in transgenic plants.

[The value of MRI in early diagnosis of dysbaric osteonecrosis]

Objective: To investigate the value of MRI in the early diagnosis of diagnosis of dysbaric osteonecrosis. Methods: Labor hygiene investigation and occupation health were examined on 52 high pressure operating personnel, were selected for the examination of both shoulders, hips and knees with X-ray and CT scan. Results: The cystic sign in dysbaric osteonecrosis as an important imaging feature, which perform in the MRI examination for T1W I sequence showed low or slightly low signal and T2W I sequence showed high signal, and X-ray and CT have a lower detection rate than MRI. The Kappa consistency test showed a high consistency with the two methods. At the same time MRI examination also can discover the bone marrow cavity necrosis early pathological change. Conclusion: MRI is an effective method for the diagnosis of early dysbaric osteonecrosis, which can improve the early diagnosis rate of dysbaric osteonecrosis.

[A 3.0 T MRI study on the alterations of the volume and morphology of fifteen subcortical nucleus in patients with early post-stroke depression]

Objective: To investigate the alterations of the volumes and 3D shapes of fifteen subcortical nucleus in patients with post-stroke depression (PSD) and to explore the pathogenesis regularity and mechanism of early PSD. Methods: From 2015 to 2017, a total of 28 patients with PSD and 18 stroke patients without depression (PSND), 13 patients with depression (De) and 11 cases of healthy volunteers (NC) were enrolled to perform 3.0 T high resolution MRI.Computer automatic segmentation and vertex analysis were used to segment and measure the volume of bilateral nucleus accumbens, caudate nucleus, putamen, globus pallidus, thalamus, hippocampus, mygdale and brainstem. Results: The volume of bilateral nucleus accumbens and bilateral thalamus, left pallidum were different among groups with statistical difference (P<0.05). The nucleus volume of the PSD group was (415±128) mm(3) (L-Nac)/(303±90) mm(3) (R-Nac), (7 590±867) mm(3) (L-Th)/(7 459±905) mm(3) (R-Th), (1 675±328) mm(3) (L-Pa), which was smaller than that of PSND group (433±100) mm(3) /(307±88) mm(3), (7 999±961) mm(3) /(7 753± 955) mm(3), (1 790±286) mm(3) and other groups.The nuclei with significantly statistical differences between inter-group were found in following: between PSD group and NC group, right accumbens and bilateral thalamus (P<0.01); between PSD group and De group, right accumbens and right thalamus (P<0.001), left accumbens, left pallidum and left thalamus (P<0.01); between PSND group and NC group, right accumbens (P<0.05); between PSND group and De group, right accumbens (P<0.001), left accumbens and right thalamus (P<0.05). Significant differences in morphology changes of nuclei (P<0.05) by F test mainly located on the top and tail of right accumbens, the anterior and middle body of right caudate nucleus, the most part of bilateral thalamus, the ventromedial body of bilateral hippocampus, the anterior and body of left caudate nucleus, especially in left thalamus. Conclusion: PSD has abnormal volume and morphological structure of subcortical nuclei, which supports the role of subcortical structures changes in the pathophysiology and pathogenesis of early PSD.

[Circulating tumor DNA and targeted therapy in colorectal cancer]

The detection of circulating tumor DNA is a quick, low cost and reliable approach of liquid biopsy of cancer. It has a wide range of applications for tumor screening because of its noninvasive, convenient and highly repeatable features. In terms of the targeted therapy in patients with colorectal cancer, serial monitoring of circulating tumor DNA, especially for the specific genetic alterations, can be used for prognosis, monitoring resistance, evaluation of therapeutic effects and screening combined targeted therapy. Therefore, it will guide more precise treatment of colorectal cancer.

[Surgical treatment of colorectal liver metastases]

Surgical resection of the metastases offers the only opportunity for long-term survival in colorectal liver metastases. However, only 10% to 20% of patients present with resectable disease, and so how to increase surgical patients has been a clinical hotspot. In addition to expanding surgical indications, two-stage hepatectomy and convertible therapy are optional. In convertible therapy, initial treatment regimen decides long-term benefit, and it is important to select appropriate patient population in addition to Ras status when anti-epithelial growth factor receptor monoclonal antibody is used. Minimally invasive surgery can also be used for liver resection and simultaneous resection, and it is safe and effective. For patients with colorectal cancer and unresectable asymptomatic liver metastases, the debate continues over the efficacy of primary resection compared to chemotherapy alone, limited by lack of prospective evidence. Therefore, multidisciplinary team assessment is essential to optimize outcomes in colorectal liver metastases.

The effects of neighborhood views containing multiple environmental features on road traffic noise perception at dwellings

The importance of non-acoustical factors including the type of visual environment on human noise perception becomes increasingly recognized. In order to reveal the relationships between long-term noise annoyance and different types of neighborhood views, 2033 questionnaire responses were collected for studying the effect of perceptions of different combinations of views of sea, urban river, greenery, and/or noise barrier on the annoyance responses from residents living in high-rise apartments in Hong Kong. The collected responses were employed to formulate a multivariate model to predict the probability of invoking a high annoyance response from residents. Results showed that views of sea, urban river, or greenery could lower the probability, while views of noise barrier could increase the probability. Views of greenery had a stronger noise moderation capability than views of sea or urban river. The presence of an interaction effect between views of water and views of noise barrier exerted a negative influence on the noise annoyance moderation capability. The probability due to exposure to an environment containing views of noise barriers and urban rivers would be even higher than that due to exposure to an environment containing views of noise barriers alone.

Evaporating metal nanocrystal arrays

Anodic aluminum oxide (AAO) substrates with a self-ordered triangular array of nanopores provide the means to fabricate multiple forms of nano materials, such as nanowires and nanoparticles. This study focuses on nanostructures that emerge in thin films of metals thermally evaporated onto the surface of AAO. Previous work showed that films of different evaporated metals assume dramatically different structures, e.g. an ordered triangular array of nearly monodisperse nanoparticles forms for lead (Pb) while a polycrystalline nanohoneycomb structure forms for silver (Ag). Here, we present investigations of the effects of substrate temperature and deposition angle that reveal the processes controlling the nano particle array formation. Our findings indicate that arrays form provided the grain nucleation density exceeds the pore density and the atomic mobility is high enough to promote grain coalescence. They introduce a method for producing films with anisotropic grain array structure. The results provide insight into the influence of substrate nano-morphology on thin film growth energetics and kinetics that can be harnessed for creating films with other novel nano-structures.

Driving a Superconductor to Insulator Transition with Random Gauge Fields

Typically the disorder that alters the interference of particle waves to produce Anderson localization is potential scattering from randomly placed impurities. Here we show that disorder in the form of random gauge fields that act directly on particle phases can also drive localization. We present evidence of a superfluid bose glass to insulator transition at a critical level of this gauge field disorder in a nano-patterned array of amorphous Bi islands. This transition shows signs of metallic transport near the critical point characterized by a resistance , indicative of a quantum phase transition. The critical disorder depends on interisland coupling in agreement with recent Quantum Monte Carlo simulations. We discuss how this disorder tuned SIT differs from the common frustration tuned SIT that also occurs in magnetic fields. Its discovery enables new high fidelity comparisons between theoretical and experimental studies of disorder effects on quantum critical systems.

Association between the AGTR1 A1166C polymorphism and risk of IgA nephropathy: a meta-analysis

Numerous studies have evaluated the association between the A1166C polymorphism in the angiotensin II type 1 receptor (AGTR1) gene and immunoglobulin A nephropathy (IgAN) risk. However, this relationship remains controversial. Our aim was to evaluate the relationship between this polymorphism and IgAN susceptibility by performing a meta-analysis. Articles were identified in the PubMed, Google Scholar, and China National Knowledge Infrastructure databases, and after selection, five eligible studies were included. Statistical analyses were carried out using Stata 12.0, combining data from all the relevant studies. The pooled odds ratios (ORs) regarding the association between the AGTR1 A1166C polymorphism and IgAN risk were not statistically significant [A vs C: OR = 0.64, 95% confidence interval (CI) = 0.24-1.68; AA vs AC+CC: OR = 1.02, 95%CI = 0.74-1.39; CC vs AC+AA: OR = 1.20, 95%CI = 0.48-2.98; AC vs AA+CC: OR = 0.96, 95%CI = 0.70-1.31]. In conclusion, the AGTR1 gene A1166C polymorphism may not be correlated with IgAN susceptibility. However, further studies should be performed to confirm this finding.

Ultrasound Findings of Intraductal Papillary Neoplasm in Bile Duct and the Added Value of Contrast-Enhanced Ultrasound

PURPOSE

To investigate the imaging features of intraductal papillary neoplasm in bile duct (IPNB) on baseline ultrasound and contrast-enhanced ultrasound (CEUS).

MATERIALS AND METHODS

The imaging features on baseline ultrasound and CEUS in 16 pathologically proven IPNB lesions in 15 patients were retrospectively analyzed. Real-time contrast specific modes and contrast agent of SonoVue were used for CEUS.

RESULTS

Bile duct dilation was present in all patients. The mean lengths for the intraductal papillary adenomas and adenocarcinomas were 2.5 ± 1.1 (range, 1.2 - 4.2 cm) and 5.6 ± 2.0 cm (range, 3.3 - 9.8 cm) (P = 0.004). Three imaging types of IPNB on ultrasound were depicted: bile duct dilation with intraductal mass (n = 8), bile duct dilation without intraductal mass (n = 3), and cystic-solid mixed type (n = 5). On CEUS, solid components of 13 lesions appeared hyper- (n = 12) or iso-enhancement (n = 1) in the arterial phase whereas all showed hypo-enhancement in the portal and late phases. For 3 lesions of bile duct dilation without intraductal mass, CEUS showed non-enhancement during all phases. Pre-surgical CEUS and conventional ultrasound made correct diagnoses in 12 (75.0 %) and 5(31.3 %) of 16 IPNBs respectively (P = 0.04). For CECT, correct diagnosis was also achieved in 12 (75.0 %) of 16 lesions (P = 1.00, in comparison with CEUS).

CONCLUSIONS

IPNB should be taken into consideration when intraductal mass or cystic-solid mass with bile duct dilation, or remarkable bile duct dilation without intraductal mass, are found on US. Intraductal mass length > 3.0 cm is more commonly found in malignant IPNB. CEUS might facilitate the diagnosis of IPNB by easily excluding the possibility of commonly found sludge, nonshadowing stones, or blood clots.

Blockade of the CXCR6 signaling inhibits growth and invasion of hepatocellular carcinoma cells through inhibition of the VEGF expression

Chemokines have been shown to play a critical role in tumor development and progression. However, little is known about the function and molecular mechanisms of CXCR6 in multiple malignancies. In the present study, we aimed to investigate the role of CXCR6 in human hepatocellular carcinoma (HCC). The expression of CXCR6 was examined by immunohistochemical assay using a tissue microarray procedure. A loss-of-function experiment was performed to explore the effects of lentivirus-mediated CXCR6 shRNA (shCXCR6) on cell proliferation and invasive potential by MTT and Transwell assays in HCC cell line (SMMC-7721). It was found that the expression of CXCR6 protein was significantly increased in HCC tissues compared with that in adjacent non-cancerous tissues (ANCT) (63.04&#x0025; vs 36.96&#x0025;, P=0.019), and correlated with the lymph-vascular space invasion in HCC patients (P=0.038). Knockdown of CXCR6 repressed cell proliferation and invasion of HCC cells followed by the down-regulation of vascular endothelial growth factor (VEGF). Taken together, our findings show that high expression of CXCR6 is positively associated with distant invasion of HCC patients, and blockade of CXCR6 signaling suppresses the growth and invasion of HCC cells through inhibition of the VEGF expression, suggesting that CXCR6 may represent a promising therapeutic target for the treatment of HCC.

A study on dysbaric osteonecrosis in caisson workers

PURPOSE

To study the effects of exposure to compressed air on tunnel workers' health and to investigate the prevalence of dysbaric osteonecrosis (DON) in caisson workers.

METHODS

128 tunnel workers were divided into the exposed group (n = 58) and the control group (n = 70), and their shoulders, hips and knees were examined with X-ray, computed tomography (CT) and magnetic resonance imaging (MRI).

RESULTS

1) 34.5% of the exposed group were diagnosed with DON based on the national diagnostic criteria of decompression sickness. 2) The incidental difference of skeletal cystic changes between the exposed group and the control group was highly statistically significant (p < 0.01). 3) CT and MRI examination could detect early onset of DON lesions, and the cystic changes shown in CT and abnormal signals in MRI were diagnostic indicators in cases.

CONCLUSION

Cystic changes in CT and abnormal signals in MRI are key imaging findings of early DON.

Ag-decorated TiO₂ nanograss for 3D SERS-active substrate with visible light self-cleaning and reactivation

The production of SERS-active substrates which are uniform, sensitive, reproducibile and durable still remains an important issue. Here, we report a strategy for the fabrication of a large-area Ag-decorated TiO₂ nanograss SERS-active substrate by a simple solvothermal approach combined with Ag evaporation. The nanograss consists of dense rutile TiO₂ nanorods of about 5 nm in diameter and the decorated Ag nanoparticles are an average of 8 nm in diameter. The Ag protrusions and gaps between them contribute to three dimensional SERS "hot spots" which can be modulated by simply controlling the Ag evaporating parameters. The Ag-decorated TiO₂ substrate is highly efficient in detecting rhodamine 6G (R6G) and 4-aminothiophenol (4-ATP) molecules and has good homogeneity. An obvious red shift and even high enhancement of b₂ vibration mode were observed in detecting 4-ATP due to the effective charge transfer from the Ag atoms to sulfur atoms. The Ag-decorated TiO₂ substrate can be easily self-cleaned and reactivated by visible light irradiation without obvious degeneration of SERS signals. Our results demonstrate that the Ag-decorated TiO₂ substrate with high and homogeneous SERS activity has potential feasibility as a sensitive SERS probe.

Observation of giant positive magnetoresistance in a Cooper pair insulator

Ultrathin amorphous Bi films, patterned with a nanohoneycomb array of holes, can exhibit an insulating phase with transport dominated by the incoherent motion of Cooper pairs (CP) of electrons between localized states. Here, we show that the magnetoresistance (MR) of this Cooper pair insulator (CPI) phase is positive and grows exponentially with decreasing temperature T, for T well below the pair formation temperature. It peaks at a field estimated to be sufficient to break the pairs and then decreases monotonically into a regime in which the film resistance assumes the T dependence appropriate for weakly localized single electron transport. We discuss how these results support proposals that the large MR peaks in other unpatterned, ultrathin film systems disclose a CPI phase and provide new insight into the CP localization.

Heritability of metabolic syndrome traits among healthy younger adults: a population based study in China

OBJECTIVE To estimate heritability of metabolic syndrome traits among healthy younger adults in a human population in China, and examine potential sex differences in heritability and parental effect on metabolic syndrome traits. METHODS Using offspring-parent regression, we estimated heritability (h(2)) of metabolic syndrome traits based on 452 child-parent triads identified from a population based random survey on metabolic syndrome among people over 15 years of age in Guangzhou, China. RESULTS Body mass index (BMI), cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG) and waist circumference (waist-C) were more heritable (h(2), 0.42-0.545), whereas systolic blood pressure (SBP), diastolic blood pressure (DBP), and triglycerides (TG) were less heritable (h(2), 0.14-0.28). Sons had pronounced increases in heritability for all traits over daughters, particularly for cholesterol (0.653 vs 0.356), FPG (0.602 vs 0.313), LDL-C (0.521 vs 0.329), and TG (0.395 vs 0.187). Offspring-mother seemed to have a higher heritability in every trait except FPG (0.67 vs 0.794) than offspring-father, most notably for DBP (0.308 vs 0.122), SBP (0.288 vs 0.146), TG (0.387 vs 0.239) and waist-C (0.581 vs 0.354). CONCLUSION We estimated the heritability of metabolic syndrome traits in a human population based on a unique population based offspring-parent sample from China, and found important evidence that the maternal and paternal effects on these traits are different and the sex difference in heritability is pronounced.

Kinetic distribution of 14C-metsulfuron-methyl residues in paddy soils under different moisture conditions

Rice paddy soils undergo several cycles of drying and wetting during a growing season. A laboratory study was conducted to determine the effect of soil moisture conditions on the distribution and kinetics of extractable and bound residues of 14C-metsulfuron-methyl in six Chinese paddy soils during 84 d of incubation at 15 degrees C with moisture contents varying from 20 to 50% of the field water-holding capacity. The amount of extractable residues consistently increased and bound residues decreased with increasing soil moisture content. At the end of the incubation experiments, extractable residues and bound residues accounted for 34.5 to 84.4% and 11.6 to 53.3% of applied radioactivity in soils, respectively. Soil pH and soil microbial biomass carbon were the most predominant factors affecting the formation and relative distribution of herbicide residues between extractable and bound residue forms. In high-pH soils, bound residues decreased and extractable residues increased, suggesting an increased leaching risk for metsulfuron-methyl in alkaline soils. High precipitation rates, along with the common practice of liming in southeastern China, may lead to enhanced herbicide leaching as well as phytotoxicity to rotation plants and should be considered in overall pest management practices.

Cobrotoxin-containing analgesic compound to treat chronic moderate to severe cancer pain: results from a randomized, double-blind, cross-over study and from an open-label study

Cobrotoxin produces intense analgesia but it has an onset of response of 1-3 h which hampers its clinical use in cancer pain. Recently, a compound analgesic formulation combining cobrotoxin, tramadol hydrochloride and ibuprofen (Compound Keluoqu, CKLQ) has become available in China. The aim of this study was to evaluate the clinical efficacy of CKLQ for moderate to severe cancer pain. A consecutive series of patients with chronic moderate to severe cancer pain was enrolled into two multicenter trials. Of the 230 eligible patients, 119 were assigned to a randomized, double-blind, cross-over study, while 111 entered an open-label study. They were all of Han-China nationality and had a mean age of 52.0 and 55.4 years and a mean body weight of 55.6 and 52.9 kg, respectively. A total of 11 patients discontinued the study, 6 (54.5%) because of insufficient pain relief and 5 due to the occurrence of adverse events. In the cross-over study, 59 patients were randomized to receive a CKLQ package with 2 CKLQ tablets (each containing 0.16 mg cobrotoxin, 25 mg tramadol hydrochloride and 50 mg ibuprofen) and 2 placebo capsules, a placebo package with 2 placebo tablets and 2 placebo capsules, and an active control package with 2 tramadol hydrochloride capsules (each containing 50 mg tramadol hydrochloride) and 2 placebo tablets (arm A), and 60 to receive a tramadol hydrochloride package, a placebo package and a CKLQ package (arm B), sequentially and only once. Patients in the open-label study only received CKLQ and were given the option to continue for up to 7 days as long as they had satisfactory pain relief. Pain response was classified as CR, PR and NC. CR was defined as 100% pain relief, with a pain score of 0 on a 0-10 VAS. PR was defined as decreased to mild pain, with a pain score of no more than 4 on a 0-10 VAS. NC was defined as pain that either remained unchanged or that was reduced from severe to moderate at baseline, with a VAS pain score of more than 4 after treatment. One hundred and eight patients completed the cross-over study with all the three drug units. The overall rate of pain relief was 93/111 (83.7%) for CKLQ, 75/110 (68.2%) for tramadol hydrochloride (P=0.011) and 39/111 (35.1%) for placebo (P<0.001). The mean duration of pain relief with CKLQ was significantly longer than that of the other two agents (P<0.001). Of the 35 patients who did not respond to tramadol hydrochloride, 27 (77.1%) responded to CKLQ, while of the 18 who did not respond to CKLQ, 8 (55.6%) achieved satisfactory pain control with tramadol hydrochloride. In the open-label study, the overall relief rate of a single-dose of CKLQ was 99/111 (89.2%). A reduction in the percentage of complete relief, an increase in that of PR and a significant decrease in duration of relief were observed after continuous treatment with at least 10 doses of CKLQ. The frequency of adverse events for CKLQ was similar to that of tramadol hydrochloride. The results of the randomized, double-blind, cross-over study and the open-label study of CKLQ in cancer patients with chronic moderate to severe cancer pain suggest that the CKLQ may be valuable for the treatment of chronic moderate to severe cancer pain. However, the tolerance of CKLQ remains to be further defined.

Molecular self-organization in cylindrical nanocavities

We studied molecular organization in cylindrical nanocavities using liquid crystals. NMR analysis shows high surface-induced ordering way above the bulk critical temperature. The surface-order evolution reveals replacement of the isotropic phase by a paranematic phase and surface-induced disordering in the nematic phase. Due to strong surface potential and nanoconfinement, complete wetting and continuous evolution of the surface-order parameter are observed through the nematic-paranematic transition. As we show, the counter-intuitive absence of complete phase transition at the interface while an abrupt phase transition was measured in the averaged order parameter is in good agreement with established theories.

Risk assessment for safety of soils and vegetables around a lead/zinc mine

Concentrations of heavy metals (Pb, Zn, Cd, Cu) were determined in soils and vegetables (chrysanthemum, spinach and four cultivars of Chinese cabbage from the area adjacent to a Pb/Zn mine in Shaoxing, Zhejiang province, China, and compared with the Chinese National Standards for Soil Environmental Quality. The accumulation of heavy metals in cabbage cv. Siyuegreen was investigated at different distances from the center of the mine. The vegetable plantation soils were polluted with Pb, Cd, Cu and Zn, especially by Pb and Cd. The levels of Pb and Cd were 20 and 30 times higher than the permitted standards, indicating that this Pb/Zn mining area is unsuitable for agricultural use. Chinese cabbage, chrysanthemum and spinach had different enrichment coefficients. The enrichment coefficient of Cd from soil to roots of chrysanthemum was >80% and from roots to leaves of cabbage cv. Shanghaigreen was >120%. These vegetables were polluted by heavy metals and could not be regarded as safe for human consumption. Environmental accumulation of heavy metals in the vegetable plantation soils was proportional to heavy metal accumulation in vegetables and both were inversely proportional to the distance from the lead/zinc mine.

Ultra-high redox enzyme signal transduction using highly ordered carbon nanotube array electrodes

We report on a highly ordered array of carbon nanotubes (CNTs) that serves as a universally direct nanoelectrode interface for redox proteins and provides an efficient conduit for electron transfer. The site-selective, covalent docking of the enzyme glucose oxidase (GO(x)) on the CNT tips is found to have a marked effect on enhancing electron transfer properties, as measured by cyclic voltammetry. A unimolecular electron transfer rate of 1500 s(-1) has been measured for this system, a value exceeding the rate of oxygen reduction by glucose oxidase. Furthermore, the redox enzyme-CNT array conjugate can be utilized as a quantitative, substrate-specific biosensor.

Site-specific assembly of DNA and appended cargo on arrayed carbon nanotubes

We describe a strategy that permits discrete regions of arrayed carbon nanotubes (CNTs) to be functionalized simultaneously and specifically with DNA oligonucleotides. The different chemical properties of two regions on single CNTs and orthogonal chemical coupling strategies have been exploited to derivatize CNTs within highly ordered arrays with multiple DNA sequences. Through duplex hybridization, we then targeted different DNA sequences with appended metal nanoparticles to distinct sites on the CNT architecture with precise spatial control. The materials generated from these studies represent the first CNTs with bipartite functionalization. The approach described provides a high level of precision in parallel and directed assembly of DNA sequences and appended cargo and is useful for the preparation of novel hybrid bionanomaterials.

Theoretical and experimental studies of carbon nanotube electromechanical coupling

We present an investigation into electromechanical coupling in carbon nanotubes by focusing on phonon frequency shifts as a result of charge injection. A nearest-neighbor, tight-binding theoretical model is accompanied by a computational explication carried out using the Vienna ab initio simulation package density functional theory code. Raman spectroscopic measurements of the electromechanic couplings under varied but controlled charge injection conditions are also carried out, and the close agreement between the model results and the measured Raman peak shifts suggests that geometrical changes of charged carbon nanotubes previously observed or speculated in different experiments can indeed originate from the simple quantum effects described herein.