Temperature dependence of the universal contact parameter in a unitary Fermi gas

The contact I, introduced by Tan, has emerged as a key parameter characterizing universal properties of strongly interacting Fermi gases. For ultracold Fermi gases near a Feshbach resonance, the contact depends upon two quantities: the interaction parameter 1/(k(F)a), where k(F) is the Fermi wave vector and a is the s-wave scattering length, and the temperature T/T(F), where T(F) is the Fermi temperature. We present the first measurements of the temperature dependence of the contact in a unitary Fermi gas using Bragg spectroscopy. The contact is seen to follow the predicted decay with temperature and shows how pair-correlations at high momentum persist well above the superfluid transition temperature.

MiR-148a promotes apoptosis by targeting Bcl-2 in colorectal cancer

Apoptosis has a vital role in maintaining tissue homeostasis, and dysregulation of the apoptotic pathway is now widely recognized as a key step in tumourigenesis. Increasingly, evidence has demonstrated that microRNA (miRNA) can exert various biological functions in tumours by targeting oncogenes or tumour suppressors. Nevertheless, the role of miRNA in apoptosis remains unclear. Here we show that ectopical expression of miR-148a can induce apoptosis in colorectal cancer cells. In addition, MYB can inhibit miR-148a by directly acting on the transcription factor binding site in miR-148a gene and miR-148a can posttranscriptionally silence Bcl-2. Subsequently, the intrinsic apoptosis pathway is activated by releasing cytochrome c, cleaving caspase 9, caspase 3 and PARP, which eventually induce cancer-cell apoptosis. These findings are part of a hitherto undocumented apoptotic regulatory pathway in which a pleiotropic transcription factor controls the expression of a miRNA and the miRNA inhibits the target, leading to activation of an intrinsic mitochondrial pathway and tumour apoptosis.

Crossover from 2D to 3D in a weakly interacting Fermi gas

We have studied the transition from two to three dimensions in a low temperature weakly interacting 6Li Fermi gas. Below a critical atom number N(2D) only the lowest transverse vibrational state of a highly anisotropic oblate trapping potential is occupied and the gas is two dimensional. Above N(2D) the Fermi gas enters the quasi-2D regime where shell structure associated with the filling of individual transverse oscillator states is apparent. This dimensional crossover is demonstrated through measurements of the cloud size and aspect ratio versus atom number.

A randomized, placebo-controlled trial (NCIC CTG MAP.2) examining the effects of exemestane on mammographic breast density, bone density, markers of bone metabolism and serum lipid levels in postmenopausal women

We hypothesized that exemestane (EXE) would reduce mammographic breast density and have unique effects on biomarkers of bone and lipid metabolism. Healthy postmenopausal women were randomized to EXE (25 mg daily) or placebo (PLAC) for 12 months and followed for a total of 24 months. The primary endpoint was change in percent breast density (PD) between the baseline and 12-month mammograms and secondary endpoints were changes in serum lipid levels, bone biomarkers, and bone mineral density (BMD). Ninety-eight women were randomized (49 to EXE; 49 to PLAC) and 65 had PD data at baseline and 12 months. Among women treated with EXE, PD was not significantly changed from baseline at 6, 12, or 24 months and was not different from PLAC. EXE was associated with significant percentage increase from baseline in N-telopeptide at 12 months compared with PLAC. No differences in percent change from baseline in BMD (lumbar spine and femoral neck) were observed between EXE and PLAC at either 12 or 24 months. Patients on EXE had a significantly larger percent decrease in total cholesterol than in the PLAC arm at 6 months and in HDL cholesterol at 3, 6, and 12 months. No significant differences in percent change in LDL or triglycerides were noted at any time point between the two treatment arms. EXE administered for 1 year to healthy postmenopausal women did not result in significant changes in mammographic density. A reversible increase in the bone resorption marker N-telopeptide without significant change in bone specific alkaline phosphatase or BMD during the 12 months treatment period and 1 year later was noted. Changes in lipid parameters on this trial were modest and reversible.

Abstract P3-13-02: Ethnicity Difference of Benign Breast Diseases in Breast Cancer and Non-Cancer Patients

Background: Breast cancer (BC) is a heterogeneous disease. Ethnicity differences in BC for Caucasian (CA) and African American (AA) women have been reported, but there is no report on ethnicity differences in benign breast diseases (BBDs) though it is known that BBDs may be precursors or risk factors of BCs. In the Clinical Breast Care Project (CBCP), a comprehensive characterization of BBDs performed on breast biopsies makes it possible to conduct a study on the ethnicity difference of BBDs between CA and AA, in the Cancer and Non-Cancer groups respectively.

Method: CA and AA patients undergoing a biopsy were selected from CBCP, totaling 1,963. A Pathology Checklist is available, reporting 131 pathologic conditions including 83 BBDs. In addition, a Core Questionnaire covering information such as demographics, medical history, risk factors, life style, etc. is completed. The Cancer group is composed of 731 CAs and 170 AAs (including in situ, invasive, and malignant NOS), and the Non-Cancer group is composed of 748 CAs and 314 AAs. BBDs with a frequency of <1% in each group were removed from the study leaving a total of 26 BBDs analyzed for the Cancer and 25 BBDs for the Non-Cancer groups. Pearson's Chi-square test was used to analyze statistical significance.

Results: The Cancer group showed 6 BBDs significantly associated with the ethnicity; 2 were more frequent in CA, i.e., fat necrosis (5.5% CA vs. 0.6% AA, p =0.011), and mild intraductal hyperplasia (6.8% CA vs. 2.4% AA, p= 0.041). The other 4 BBDs were more frequently observed in AA, which were cysts (47.2% CA vs 56.5% AA, p=0.036), multiple papillomas (8.3% CA vs 15.9% AA, p=0.005), moderate intraductal hyperplasia (18.1% CA vs 28.2% AA, p=0.004), and fibroadenomatoid nodule (5.3% CA 11.8% AA, p= 0.004). These BBDs were not significantly different in the Non-Cancer group between the two ethnicities. Six BBDs were significantly associated with the ethnicity in the Non-Cancer group. Four of them were more frequent in CA, including duct ectasia (9.5% CA vs. 3.2% AA, p=0.001), microcalcifications (35.3% CA vs. 27.4% AA, p=0.015), fibocystic changes (61.0% CA vs. 44.6% AA, p= 1.30E-06), and sclerosing adenosis (21.7% CA vs. 13.4% AA, p=0.002). The other 2 BBDs were more frequent in AA, i.e., sclerosing papilloma (0.7% CA vs 2.6% AA, p=0.025), and fibroadenoma (20.9% CA vs 29.9% AA, p=0.002). These BBDs were not significantly different in the Cancer group between the two ethnicities, for example microcalcifications were 50.1% in CA and 55.9% in AA.

Discussion: Multiple papillomas and moderate intraductal hyperplasia are moderate risk factors for BC, and in the Cancer group they were more frequently detected in AA than in CA. Microcalcification as a BC risk factor did not show ethnicity difference in the Cancer group, but was detected more frequently in CA in the Non-Cancer group. It is interesting that not a single BBD was found to be significantly associated with the ethnicity (AA and CA) across the Cancer and the Non-Cancer groups. Thus, the ethnicity difference of BBDs in AA and CA reported here not only suggests possible ethnicity-specific BC risk factors but also generates new hypotheses for future studies.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-13-02.

Abstract P3-01-04: Differential Gene Expression Analysis among Post-Menopausal Caucasian Invasive Breast Cancer, Benign and Normal Subjects

Background: Breast Cancer (BC) is the second leading cause of cancer death among women in United States. There have been studies aiming to develop a blood-based BC detection assay, but most were focused on comparing blood samples between BC and normal subjects. Including benign disease patients in the study is critical in developing a BC detection assay. In addition, BC is a heterogeneous disease with distinct characteristics being associated with ethnicity and menopausal status. Thus we designed a study to analyze gene expression, in peripheral blood samples from invasive BC, benign disease and normal subjects, stratified by menopausal status and ethnicity. Here we report the results from Caucasian postmenopausal women.

Method: Subjects were selected from the Clinical Breast Care Project (CBCP). Microarray data using Affymetrix GeneChip Human Genome U133 plus 2.0 arrays, of peripheral blood samples from pathologically confirmed invasive BC (n= 17) and benign patients (n= 17) were compared to those from normal subjects (n=17). All subjects were postmenopausal Caucasian women, matched for age. Using GenespringGX 11.0 software, the data were normalized, and QC on hybridization and internal controls were performed before filtering out probesets with the lowest 20% signal intensity in each array. Asymptotic t-test with FDR correction was used and significant pathways were obtained.

Results: Comparison of gene expression in invasive BC patients (mean±SD = 63.7±7.0 years old) vs. normal subjects (mean±SD = 63.2±7.4 years) identified 1102 significantly different genes, satisfying the thresholds of corrected p < 0.05 and Fold Change (FC) > 1.5. Of them, 1003 genes were up regulated and 99 genes were down regulated in BC patients. Comparison of gene expression in benign disease women (mean±SD = 61.4±10.4 years) vs. normal women showed 1320 significantly different genes (corrected p < 0.05, FC > 1.5), with 1121 genes being up regulated and 199 genes being down regulated in benign patients. Of the top 10 genes with highest FC values, 6 genes (MBNL1, FAR1, MDM4, ITGA4, RAB8B, and EXOC5) were common in both analyses and were up regulated. NOTCH pathway was up regulated in both benign (p=0.038) and invasive (p=0.042) groups. Similarly, IL-7 pathway was up regulated in both benign (p=0.047) and invasive (p=0.030) patients. TCR pathway (p=7.36E-04) was up regulated in benign group only. The benign vs. invasive BC subjects did not show significant differential gene expression.

Discussion: Our results provide a list of differentially expressed genes that are mostly up regulated in invasive and benign patients vs. normal subjects. NOTCH pathway is involved in cell-cell communication and angiogenesis. IL7 pathways play an important role in immune system response, cell proliferation and cell survival signaling. TCR pathway is highly significant only in benign patients and stimulation of TCR pathway induces a signaling cascade that ultimately results in activation of induced cell death. This activation could be early body response to prevent cancer development in benign subjects. When more microarray analyses are completed for this study, we hope to obtain a better understanding of the possibility of developing a blood-based BC detection assay.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-01-04.

Abstract P6-07-02: A Systems Analysis of Oscillations in the MAPK Pathway Reveals New Mechanisms of Feed-Forward and Feedback Signaling Control

Oscillations occur in diverse areas of cellular biology, from mechanotransduction to circadian control. Their physiological, pathological, and therapeutic significance in breast cancer remains undetermined, and their existence has yet to be described in the key oncogenic signaling pathways. Mathematical modeling lends itself to detailed study of these complex dynamic phenomena. We observed damped oscillations in pERK with approximately 20 minute periodicity in MCF7 breast carcinoma cell lines after stimulation with heregulin or epidermal growth factor (EGF). In order to establish mechanisms by which these oscillations might occur, we used an ordinary differential equation-based mathematical model of MAPK/PI3K signaling to simulate oscillatory behaviour in MAPK signaling. Both modification of feed-forward (HER2 overexpression) and feedback (abrogation of early gene transcription, EGFR phosphorylation by pERK, crosstalk between pAKT and RAF, and binding of pERK with SOS) loops resulted in the emergence of sustained oscillations in phospho-ERK. When these simulations were tested experimentally, MCF7 cells stably transfected with HER2 (MCF7/HER2-18) showed sustained oscillations in pERK when stimulated with heregulin, which were abrogated by inhibition of HER2 heterodimerisation with pertuzumab. Likewise, suppression of transcriptional feedback with cycloheximide resulted in sustained oscillations in pERK of increased amplitude. We have therefore described oscillations in MAPK signalling for the first time in breast cancer cell lines. Since the duration and amplitude of these oscillations is altered both by addition of the HER2 oncogene, and by inhibition of feedback control, the functional consequences of changes in oscillations may have fundamental consequences both in oncogenesis and therapeutic efficacy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-07-02.

Functional Expression and Purification of CYP93C20，a Plant Membrane-Associated Cytochrome P450 from Medicago truncatula

Plants possess very large numbers of biosynthetic cytochrome P450 enzymes. In spite of the importance of these enzymes for the synthesis of bioactive plant secondary metabolites, only two plant P450 structures has been obtained to date. Isoflavone synthase (IFS) is a membrane-associated cytochrome P450 enzyme catalyzing the entry-point reaction into isoflavonoid biosynthesis. IFS from the model legume Medicago truncatula (CYP93C20) was engineered by deleting the membrane-spanning domain and inserting a hydrophilic polypeptide in the N-terminus and a four histidine tag at the C-terminus. The truncated form exhibited dramatically enhanced expression and solubility. The engineered enzyme was expressed in Escherichia coli XL1-blue cells and was purified by Ni(2+)-NTA affinity chromatograph and size-exclusion chromatograph. The purified enzyme was characterized by enzyme assay, reduced carbon monoxide difference spectroscopy and peptide mass fingerprinting. The engineered soluble enzyme exhibited the same activity as the full length membrane-associated enzyme expressed in yeast. These studies suggest an approach for engineering plant membrane-associated P450s with enhanced expression and solubility for mechanistic and structural studies.

Universal behavior of pair correlations in a strongly interacting Fermi gas

We show that short-range pair correlations in a strongly interacting Fermi gas follow a simple universal law described by Tan's relations. This is achieved through measurements of the static structure factor which displays a universal scaling proportional to the ratio of Tan's contact to the momentum C/q. Bragg spectroscopy of ultracold 6Li atoms from a periodic optical potential is used to measure the structure factor for a wide range of momenta and interaction strengths, providing broad confirmation of this universal law. We calibrate our Bragg spectra using the f-sum rule, which is found to improve the accuracy of the structure factor measurement.

Graphene based quantum dots

Laterally localized electronic states are identified on a single layer of graphene on ruthenium by low temperature scanning tunneling spectroscopy (STS). The individual states are separated by 3 nm and comprise regions of about 90 carbon atoms. This constitutes a highly regular quantum dot-array with molecular precision. It is evidenced by quantum well resonances (QWRs) with energies that relate to the corrugation of the graphene layer. The dI/dV conductance spectra are modeled by a layer height dependent potential-well with a delta-function potential that describes the barrier for electron penetration into graphene. The resulting QWRs are strongest and lowest in energy on the isolated 'hill' regions with a diameter of 2 nm, where the graphene is decoupled from the surface.

Photonic chip based transmitter optimization and receiver demultiplexing of a 1.28 Tbit/s OTDM signal

We demonstrate chip-based Tbaud optical signal processing for all-optical performance monitoring, switching and demultiplexing based on the instantaneous Kerr nonlinearity in a dispersion-engineered As(2)S(3) planar waveguide. At the Tbaud transmitter, we use a THz bandwidth radio-frequency spectrum analyzer to perform all-optical performance monitoring and to optimize the optical time division multiplexing stages as well as mitigate impairments, for example, dispersion. At the Tbaud receiver, we demonstrate error-free demultiplexing of a 1.28 Tbit/s single wavelength, return-to-zero signal to 10 Gbit/s via four-wave mixing with negligible system penalty (< 0.5 dB). Excellent performance, including high four-wave mixing conversion efficiency and no indication of an error-floor, was achieved. Our results establish the feasibility of Tbaud signal processing using compact nonlinear planar waveguides for Tbit/s Ethernet applications.

Apoptosis induced by emodin is associated with alterations of intracellular acidification and reactive oxygen species in EC-109 cells

Emodin (1,3,8-trihydroxy-6-methylanthraquinone), a natural anthraquinone derivative found in several herbal medicines, is highly active in suppressing the proliferation of various tumor cells such as breast, hepatocellular, and lung cancer cells under in vitro conditions. The mechanism of emodin-induced apoptosis in esophagus carcinoma cells, EC-109, is not completely understood. In this study, EC-109 cells treated with emodin underwent rapid apoptosis as judged by morphological changes and flow cytometry analysis. The addition of emodin to EC-109 cells led to the inhibition of growth in a time- and dose-dependent manner. Fluorescence measurements of cells indicated that the intracellular pH (pHi) decreased significantly by 0.47-0.78 units. The results obtained from flow cytometry suggested that bursts of reactive oxygen species took place after the application of emodin. The present study indicates that emodin may be a strong anticancer drug against esophagus cancer cells by causing various early events leading to growth inhibition, including the production of reactive oxygen species and decrease of pHi, which may result in cellular apoptosis.

Establishment and evaluation of a model of a community health service in an underdeveloped area of China

OBJECTIVES

To develop and evaluate an applicable model for a community health service (CHS) in an underdeveloped area of China that ensures efficient, convenient and affordable primary healthcare access for all residents.

STUDY DESIGN

The current study was carried out in Puyang, a typical medium-sized city in central-eastern China. Based on the healthcare requirements of the residents in Puyang, a CHS network was set up and its operation was evaluated from 1999 to 2006. The system is characterized by its focus on community health education (CHE).

METHODS

Firstly, 8231 residents, selected at random, were surveyed to investigate the healthcare requirements of the local residents. Meanwhile, the operation of the pre-existing healthcare resources was investigated in Puyang. Based on the information gained, a network-based CHS system was proposed and established, with CHE as the major focus. This study compared CHS operation prior to and after establishment of the network. Finally, an analytic hierarchy process based evaluation model was applied to evaluate the operation of the CHS network.

RESULTS

There was a high prevalence (86.98 per thousand) of chronic diseases among the residents who participated in this investigation. The majority (84.39%) of the residents who had healthcare requirements resorted to professional health care; the other residents did not have access to health services. Among those residents who sought professional treatment, 71.3% visited primary healthcare institutions. This information reflects the enormous requirement for a CHS in primary health care but the lack of accessibility among the residents; this motivated the authors to establish a system to solve the problem. The improvement in CHS operation after the network was established suggests the importance of a network for optimizing the primary healthcare system. The improvement was indicated by better understanding of the residents regarding the CHS, and enhanced capability of self-monitoring for chronic diseases such as hypertension after the network was established. Moreover, the residents' knowledge of health care was significantly increased and, accordingly, the incidence of health risk behaviour was reduced after the network was established. Furthermore, the CHE index between 1999 and 2006 showed good correlation (r=0.988, p<0.005) with the CHS index, suggesting the important role of CHE in CHS development.

CONCLUSIONS

A network-characterized CHS system was established in Puyang, and improved the primary healthcare situation. This study provides a feasible model for the development of a CHS in medium and small cities in underdeveloped parts of China.

Salvianolic acid A inhibits platelet activation and arterial thrombosis via inhibition of phosphoinositide 3-kinase

BACKGROUND AND OBJECTIVE

Salvianolic acid A (SAA) is a water-soluble component from the root of Salvia miltiorrhiza Bunge, a herb that is widely used for atherothrombotic disease treatment in Asian medicine. As platelets play pivotal roles in atherothrombogenesis, we studied the effect of SAA on platelet activation and its underlying mechanisms.

METHODS AND RESULTS

SAA dose-dependently inhibited platelet aggregation induced by ADP, thrombin, collagen and U46619. It reduced ADP-enhanced platelet P-selectin expression and fibrinogen binding, which consequently hampered ADP-induced platelet-leukocyte aggregation. SAA also inhibited platelet spreading on fibrinogen, a process mediated by outside-in signaling. Under an arterial shear rate of 1000 s(-1), SAA decreased platelet adhesion on collagen surfaces by approximately 40%. Western blot analysis showed that SAA, like the phosphoinositide 3-kinase (PI3K) inhibitors LY294002 and TGX-221, potently inhibited PI3K, as shown by reduced Akt phosphorylation. The in vitro findings were further evaluated in the mouse model of arterial thrombosis, in which SAA prolonged the mesenteric arterial occlusion time in wild-type mice (35 + or - 2 min without SAA and 56 + or - 4 min with SAA; P < 0.01). Interestingly, SAA could even counteract the shortened arterial occlusion time in Ldlr(tm1Her) mutant mice (21 + or - 2 min without SAA and 45 + or - 4 min with SAA; P < 0.01).

CONCLUSIONS

SAA inhibits platelet activation via the inhibition of PI3K, and attenuates arterial thrombus formation in vivo. Our data suggest that SAA may be developed as a novel therapeutic agent for the prevention of thrombotic disorders.

Predicting human immunodeficiency virus protease cleavage sites in nonlinear projection space

HIV-1 protease has a broad and complex substrate specificity. The discovery of an accurate, robust, and rapid method for predicting the cleavage sites in proteins by HIV protease would greatly expedite the search for inhibitors of HIV protease. During the last two decades, various methods have been developed to explore the specificity of HIV protease cleavage activity. However, because little advancement has been made in the understanding of HIV-1 protease cleavage site specificity, not much progress has been reported in either extracting effective methods or maintaining high prediction accuracy. In this article, a theoretical framework is developed, based on the kernel method for dimensionality reduction and prediction for HIV-1 protease cleavage site specificity. A nonlinear dimensionality reduction kernel method, based on manifold learning, is proposed to reduce the high dimensions of protease specificity. A support vector machine is applied to predict the protease cleavage. Superior performance in comparison to that previously published in literature is obtained using numerical simulations showing that the basic specificities of the HIV-1 protease are maintained in reduction feature space, and by combining the nonlinear dimensionality reduction algorithm with a support vector machine classifier.

Lithium niobate photonic wires

LN photonic wires of cross-section dimensions down to 1 x 0.73 microm2 were fabricated by Ar milling of a single-crystalline LiNbO3 (LN) film bonded to a SiO2/LiNbO3 substrate. Mode intensity distributions, propagation losses, and group indices of refraction were measured at 1.55 microm wavelength and compared with simulation results. Moreover, effective mode indices and end face reflectivities were numerically evaluated. The waveguide of 1 microm top width is the smallest LN photonic wire reported to date; it has a mode size of approximately 0.4 microm2 (0.5 microm2) only and propagation losses of 9.9 dB/cm (12.9 dB/cm) for qTM (qTE) polarization.

An Approach To Correlate the Temporal Information To Facilitate Specimen Selection in the Breast Cancer Research Project

Background: Temporal information management is very important in translational research. In the Clinical Breast Care Project (CBCP), the information on subjects and their specimens may be collected at multiple time points using multiple instruments.All such information is stored in an in-house data warehouse. Currently, 4000+ subjects have been enrolled in the study following HIPAA-compliant IRB-approved protocols with 35,000+ specimens collected. Some of the patient's information is static but other data are time dependent. As a result, selecting samples for experiments is a challenge due to complicated temporal relationships between samples and information collected through various instruments.Methods and Results: In the CBCP, the clinical information, blood, and solid tissues of a subject may be collected at multiple time points, associated with the completion of a Core Questionnaire (CQ) for clinical information, and/or a Pathology Checklist (PC) for pathology and sample information. We have designed and implemented an algorithm to use a set of pre-defined flags to precisely describe each sample related to patient's clinical and pathology information in the temporal domain. Five categories (flags) were created to describe the relationship between the sample date (SD) and the CQ date based on whether SD is within 60 days of the CQ date or there is missing data or not. The relationship between blood samples and pathology information is more complicated. Within 90 days, any of the 15 surgical procedures might be performed on a patient and blood samples might be collected before, at the time of, or between any procedures. For some experiments, it is crucial to select blood samples taken before tumor is impacted or severely impacted. Thus, we defined a dozen categories to describe the relationship between the SD and the procedure date (PD), including when the SD is earlier than any PD, equals to the first PD, or between certain procedures. Using these flags we have characterized the relationships between SDs and CQ dates, and between SDs and PDs for all the samples and all the subjects, and stored all the information into two relational tables. The temporal criteria for sample selection are now represented by the relationships between these flags, and can be implemented through several filtering processes. The described algorithm drastically reduces the time needed for precise sample selection from several days for manual efforts to several hours.Discussion: We are in the process of developing a general data model for temporal information management. The method described here is a transitional solution that fulfills our current needs. As an initial effort some of the thresholds for categorizing different temporal conditions are arbitrary, and we are validating them with experimental results for future improvement. Nonetheless, this algorithm has greatly enhanced the efficiency of our subject and specimen selection for wet bench experiments. The same principle can be applied to the future temporal data model solution, for CBCP and other human disease studies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4173.