Type-II Dirac Photons at Metasurfaces

Topological characteristics of energy bands, such as Dirac and Weyl nodes, have attracted substantial interest in condensed matter systems as well as in classical wave systems. Among these energy bands, the type-II Dirac point is a nodal degeneracy with tilted conical dispersion, leading to a peculiar crossing dispersion in the constant-energy plane. Such nodal points have recently been found in electronic materials. The analogous topological feature in photonic systems remains a theoretical curiosity, with experimental realization expected to be challenging. Here, we experimentally realize the type-II Dirac point using a planar metasurface architecture, where the band degeneracy point is protected by the underlying mirror symmetry of the metasurface. Gapless edge modes are found and measured at the boundary between the different domains of the symmetry-broken metasurface. Our Letter shows that metasurfaces are simple and practical platforms for realizing electromagnetic type-II Dirac points, and their planar structure is a distinct advantage that facilitates applications in two-dimensional topological photonics.

[Development of Positioning and Navigation System Using for C-arm X-ray Apparatus for Minimally Invasive Surgeries]

On account of the problem that traditional C-arm X-ray apparatus cannot provide precise route guidance for minimally invasive surgeries, we designed and developed a laser positioning and navigation system based on C-arm X-ray apparatus, which can achieve precise positioning function and reduce the exposure of doctors and patients to radiation in minimally invasive surgeries under the linear guidance of a laser beam. Furthermore, this system can enhance the refinement level of surgical operation in minimally invasive surgeries.

pH-Sensitive Micelles Based on Star Copolymer Ad-(PCL-b-PDEAEMA-b-PPEGMA)₄ for Controlled Drug Delivery

Enhancing drug loading efficacy and stability of polymeric micelles remains a grand challenge. Here we develop adamantane-based star copolymers adamantane-[poly(ε-caprolactone)-b-poly(2-(diethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate)]₄ (Ad-(PCL-b-PDEAEMA-b-PPEGMA)₄) and their self-assembled micelles for controlled drug delivery. Results show that the polymers have excellent stability in solution with low critical micelle concentration (CMC) (0.0025⁻0.0034 mg/mL) and the apparent base dissociation constant (pKb) of the polymers is from 5.31 to 6.05. Dynamic light scattering analysis exhibits the great environmental response capability of the pH-sensitive micelles according to particle sizes and zeta potentials. With the synergy effect of the adamantane and hydrophobic block, the micelles display the high Doxorubicin (DOX) loading efficacy (up to 22.4%). The DOX release study shows that the micelles are capable of controlled release for drug. This work indicates the Ad-(PCL-b-PDEAEMA-b-PPEGMA)₄ micelles may provide new guidelines for drug control and release system in overcoming cancer treatment.

Efficient nitrogen fixation to ammonia on MXenes

Nitrogen can be easily adsorbed onto the surfaces of Mo₂C and W₂C MXenes, and then the nitrogen is effectively converted to ammonia.

[Diagnostic value of endobronchial ultrasonography with a guide sheath for peripheral pulmonary ground glass opacity]

Objective: To explore the diagnostic value of endobronchial ultrasonography with a guide sheath (EBUS-GS) for peripheral pulmonary ground glass opacity (GGO). Methods: The clinical data of 27 consecutive patients with 27 GGOs diagnosed by EBUS-GS between November 2014 to December 2015 in our Cancer Hospital were retrospectively analyzed. The average age of these 27 patients, including 9 males and 18 females, was 59±11 years. The median lesion size of the 27 GGOs was 2.9±1.2 cm, including 24 mixed GGOs and 3 pure GGOs. EBUS images of all 27 GGOs were evaluated, cytological, histological and combination diagnosis analyzed, and complications observed. Results: Under thin bronchoscope, 2 out of 27 cases showed bronchial stenosis, 1 showed bronchial stenosis with mucosal swelling, and the other 24 did not show abnormalities. Twenty-five out of 27 GGOs were found by EBUS, including 22 cases of mGGO and 3 of pGGO. In these ultrasonic images of 22 mGGOs, 18 showed mixed blizzard sign, 3 showed diffusely heterogeneous acoustic shadow and 1showed blizzard sign. Ultrasonic images of 3 pGGOs all appeared as blizzard sign. Twenty-six cytological specimens were obtained, and 16 were diagnosed clearly. All 27 histological specimens were collected, and 18 were diagnosed clearly. Nineteen of 27 cases were diagnosed by combination of cytological and histological specimens. One complication of EBUS-GS with mild bleeding was observed, and hemorrhage was terminated by conservative treatment. Conclusions: EBUS-GS is valuable for GGO diagnosis with less complications and higher safety. GGO ultrasonic image manifested as mixed blizzard sign, blizzard sign or diffusely heterogeneous acoustic shadow.

A Point Temperature Sensor Based on Upconversion Emission in Er3+/Yb3+ Codoped Tellurite-Zinc-Niobium Glass

Er3+/Yb3+ codoped tellurite-zinc-niobium (TZNb) glass was prepared by the melt-quenching method and used for the construction of a point all-fiber temperature sensor. The glass thermal stability and network structural properties were studied by differential thermal analysis and Raman spectrum, respectively. High glass transition temperature is beneficial to widen the working temperature range. The dependence of fluorescence intensity ratio (FIR) of green upconversion emissions on the surrounding temperature from 276 to 363 K was experimentally investigated and the maximum temperature sensitivity is 95 × 10-4 K-1 at 363 K. Strong green upconversion emission, broad temperature measurement range and high sensitivity indicate this point temperature sensor is a promising optical device for application on optical temperature sensing.

Association of CXCR4, CCR7, VEGF-C and VEGF-D expression with lymph node metastasis in patients with cervical cancer

OBJECTIVE

We attempted to investigate the expression of CXCR4, CCR7, VEGF-C and VEGF-D in cervical cancer specimens, and the association between CXCR4, CCR7, VEGF-C and VEGF-D expression with the clinicopathological parameters of patients with cervical cancer.

STUDY DESIGN

57 tissue microarrays including 9 normal cervical tissues and 48 cervical cancer tissues were purchased from Biomax. The association between CXCR4, CCR7, VEGF-C and VEGF-D expression with the clinicopathological parameters were evaluated. Then immunohistochemistry was used to assess the expression of CXCR4, CCR7, VEGF-C and VEGF-D in cervical cancer specimens. Finally, Spearman correlations were used for the correlation analyses between CXCR4, CCR7, VEGF-C and VEGF-D.

RESULTS

We revealed that CXCR4 expression was significantly higher in patients with squamous cell carcinomas (P=0.002) and lymph node metastasis (P=0.038), while CCR7 expression was significantly elevated in patients with lymph node metastasis (P=0.037). VEGF-C expression was markedly up-regulated in patients exhibiting FIGO stage II-III tumors (P=0.015) and lymph node metastasis (P=0.038), while VEGF-D expression was obviously increased in patients displaying FIGO stage II-III tumors (P=0.025), squamous carcinomas (P=0.017) and lymph node metastasis (P=0.037). The correlation analysis indicated that CXCR4, CCR7, VEGF-C and VEGF-D expression have a significant correlation to each other.

CONCLUSION

These results suggested that CXCR4, CCR7, VEGF-C and VEGF-D expression might have synergistic effects on the lymph node metastasis in patients with cervical cancer.

OVCA1 expression and its correlation with the expression levels of cyclin D1 and p16 in cervical cancer and intraepithelial neoplasia

The present study aimed to examine the associations between the protein and mRNA expression levels of ovarian cancer gene 1 (OVCA1), cyclin D1 and p16 and high-risk human papillomavirus (HR-HPV) infection in cervical lesions. The protein expression levels of OVCA1, cyclin D1 and p16 in 66 cases of cervical cancer, 64 cases of cervical intraepithelial neoplasia (CIN) and 34 normal cervix tissues were detected using immunohistochemistry. The mRNA expression levels of OVCA1, cyclin D1 and p16 in cervical cancer and normal cervix cells were detected using real-time polymerase chain reaction. The results revealed that the protein expression levels of OVCA1 increased gradually, whereas its mRNA expression levels decreased gradually, in the progression from normal cervix tissue to CIN and cervical cancer (P<0.01). In addition, significant differences in the protein expression levels of OVCA1 between low-and high-level CIN, as well as between the early and advanced stages of cervical cancer, were observed (P<0.05). No significant associations were detected between the protein and mRNA expression levels of OVCA1 and the pathological type of cervical cancer or the presence of lymph node metastasis (P>0.05). The expression levels of OVCA1 mRNA and protein were positively correlated with the levels of p16 expression (P<0.01). Significant differences were also observed in the OVCA1 protein and mRNA expression levels between the HR-HPV (+) and HR-HPV (−) groups (P<0.05). Therefore, aberrant expression of OVCA1 protein and mRNA may be important during the development of cervical lesions, particularly in the early stages. In addition, the mechanisms underlying the effects of OVCA1 during cervical cancer development may involve p16 and HPV, as the levels of OVCA1 in cervical lesions were correlated with abnormal expression of p16 and HR-HPV infection.

Rapid detection of hexamethylenetetramine based on the substrate UC@SiO2@Au@Ag using SERS

UC@SiO₂@Au@Ag was employed for the first time as a SERS substrate to detect HMT.

Surface Roughening of Nickel Cobalt Phosphide Nanowire Arrays/Ni Foam for Enhanced Hydrogen Evolution Activity

Development of earth-abundant, efficient, and stable electrocatalysts for hydrogen evolution reactions (HER) in alkaline or even neutral pH electrolyte is very important for hydrogen production from water splitting. Construction of bimetal phosphides via tuning the bonding strength to hydrogen and increasing effective active sites through nanostructuring and surface engineering should lead to high HER activity. Here, ternary NiCoP nanowires (NWs) decorated by homogeneous nanoparticles have been obtained on Ni foam for a highly efficient HER property via long-term cyclic voltammetric (CV) sweeping. The electron density transfer between the positively charged Ni and Co and negatively charged P atoms, one-dimensional electron transfer channel of the NWs, and abundant active sites supplied by the nanoparticles and NWs endow the catalyst with low overpotentials of 43 and 118 mV to achieve the respective current densities of 10 and 100 mA cm^-2 together with long durability for at least 33 h in 1 M KOH. A cycled anodic dissolution-redeposition mechanism is disclosed for the formation of the NiCoP nanoparticles during the CV sweeping process. Such a surface roughening method is found to be adaptable to enhance the HER property of other phosphides, including Ni₂P nanoplates/NF, NiCoP nanoparticles/NF, and CoP NW/NF.

Temperature-Mediated Selective Growth of MoS2 /WS2 and WS2 /MoS2 Vertical Stacks on Au Foils for Direct Photocatalytic Applications

A growth-temperature-mediated two-step chemical vapor deposition strategy is designed to synthesize MoS₂ /WS₂ and WS₂ /MoS₂ stacks on Au foils. Predominantly A-A stacked MoS₂ /WS₂ and A-B stacked WS₂ /MoS₂ are selectively achieved and confirmed. Relative enhancements or reductions in photocatalytic activities of MoS₂ /WS₂ or WS₂ /MoS₂ are observed under illumination, because the type-II band alignment enables directional electron flow from electrode to active site.

Extracellular high-mobility group box 1 mediates pressure overload-induced cardiac hypertrophy and heart failure

Inflammation plays a key role in pressure overload-induced cardiac hypertrophy and heart failure, but the mechanisms have not been fully elucidated. High-mobility group box 1 (HMGB1), which is increased in myocardium under pressure overload, may be involved in pressure overload-induced cardiac injury. The objectives of this study are to determine the role of HMGB1 in cardiac hypertrophy and cardiac dysfunction under pressure overload. Pressure overload was imposed on the heart of male wild-type mice by transverse aortic constriction (TAC), while recombinant HMGB1, HMGB1 box A (a competitive antagonist of HMGB1) or PBS was injected into the LV wall. Moreover, cardiac myocytes were cultured and given sustained mechanical stress. Transthoracic echocardiography was performed after the operation and sections for histological analyses were generated from paraffin-embedded hearts. Relevant proteins and genes were detected. Cardiac HMGB1 expression was increased after TAC, which was accompanied by its translocation from nucleus to both cytoplasm and intercellular space. Exogenous HMGB1 aggravated TAC-induced cardiac hypertrophy and cardiac dysfunction, as demonstrated by echocardiographic analyses, histological analyses and foetal cardiac genes detection. Nevertheless, the aforementioned pathological change induced by TAC could partially be reversed by HMGB1 inhibition. Consistent with the in vivo observations, mechanical stress evoked the release and synthesis of HMGB1 in cultured cardiac myocytes. This study indicates that the activated and up-regulated HMGB1 in myocardium, which might partially be derived from cardiac myocytes under pressure overload, may be of crucial importance in pressure overload-induced cardiac hypertrophy and cardiac dysfunction.

Transcriptomic Changes Due to Cytoplasmic TDP-43 Expression Reveal Dysregulation of Histone Transcripts and Nuclear Chromatin

TAR DNA-binding protein 43 (TDP-43) is normally a nuclear RNA-binding protein that exhibits a range of functions including regulation of alternative splicing, RNA trafficking, and RNA stability. However, in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP), TDP-43 is abnormally phosphorylated, ubiquitinated, and cleaved, and is mislocalized to the cytoplasm where it forms distinctive aggregates. We previously developed a mouse model expressing human TDP-43 with a mutation in its nuclear localization signal (ΔNLS-hTDP-43) so that the protein preferentially localizes to the cytoplasm. These mice did not exhibit a significant number of cytoplasmic aggregates, but did display dramatic changes in gene expression as measured by microarray, suggesting that cytoplasmic TDP-43 may be associated with a toxic gain-of-function. Here, we analyze new RNA-sequencing data from the ΔNLS-hTDP-43 mouse model, together with published RNA-sequencing data obtained previously from TDP-43 antisense oligonucleotide (ASO) knockdown mice to investigate further the dysregulation of gene expression in the ΔNLS model. This analysis reveals that the transcriptomic effects of the overexpression of the ΔNLS-hTDP-43 transgene are likely due to a gain of cytoplasmic function. Moreover, cytoplasmic TDP-43 expression alters transcripts that regulate chromatin assembly, the nucleolus, lysosomal function, and histone 3' untranslated region (UTR) processing. These transcriptomic alterations correlate with observed histologic abnormalities in heterochromatin structure and nuclear size in transgenic mouse and human brains.

Compositional effects and optical properties of CdSeXTe1−X alloyed nanotube arrays

The compositional effects on the cell constant, absorption and Raman scattering were demonstrated for well-aligned CdSe_XTe_1−X (0 ≤ X ≤ 1) nanotube arrays on ITO.

A two-component pre-seeded dermal-epidermal scaffold

We have developed a bilayered dermal-epidermal scaffold for application in the treatment of full-thickness skin defects. The dermal component gels in situ and adapts to the lesion shape, delivering human dermal fibroblasts in a matrix of fibrin and cross-linked hyaluronic acid modified with a cell adhesion-promoting peptide. Fibroblasts were able to form a tridimensional matrix due to material features such as tailored mechanical properties, presence of protease-degradable elements and cell-binding ligands. The epidermal component is a robust membrane containing cross-linked hyaluronic acid and poly-l-lysine, on which keratinocytes were able to attach and to form a monolayer. Amine-aldehyde bonding at the interface between the two components allows the formation of a tightly bound composite scaffold. Both parts of the scaffold were designed to provide cell-type-specific cues to allow for cell proliferation and form a construct that mimics the skin environment.

Thermal-healable and shape memory metallosupramolecular poly(n-butyl acrylate-co-methyl methacrylate) materials

Thermal-induced shape memory and healing based on a metallosupramolecular polymer were realized.

Prevalence of herpes and respiratory viruses in induced sputum among hospitalized children with non typical bacterial community-acquired pneumonia

Objective

Few comprehensive studies have searched for viruses in infants and young children with community-acquired pneumonia (CAP) in China. The aim of this study was to investigate the roles of human herpes viruses (HHVs) and other respiratory viruses in CAP not caused by typical bacterial infection and to determine their prevalence and clinical significance.

Methods

Induced sputum (IS) samples were collected from 354 hospitalised patients (infants, n = 205; children, n = 149) with respiratory illness (CAP or non-CAP) admitted to Wenling Hospital of China. We tested for HHVs and respiratory viruses using PCR-based assays. The epidemiological profiles were also analysed.

Results

High rate of virus detection (more than 98%) and co-infection (more than 80%) were found among IS samples from 354 hospitalised infants and children with respiratory illness in this study. Of 273 CAP samples tested, CMV (91.6%), HHV-6 (50.9%), RSV (37.4%), EBV (35.5%), HBoV (28.2%), HHV-7 (18.3%) and rhinovirus (17.2%) were the most commonly detected viruses. Of 81 non- CAP samples tested, CMV (63%), RSV (49.4%), HHV-6 (42%), EBV (24.7%), HHV-7 (13.6%) and HBoV (8.6%) were the dominant viruses detected. The prevalence of several viral agents (rhinovirus, bocavirus, adenovirus and CMV) among IS samples of CAP were significantly higher than that of non-CAP control group. We also found the prevalence of RSV coinfection with HHVs was also higher among CAP group than that of non-CAP control.

Conclusions

With sensitive molecular detection techniques and IS samples, high rates of viral identification were achieved in infants and young children with respiratory illness in a rural area of China. The clinical significance of rhinovirus, bocavirus, adenovirus and HHV (especially CMV) infections should receive greater attention in future treatment and prevention studies of CAP in infants and children.

[Detection of human parvovirus B19, human bocavirus and human parvovirus 4 infections in blood samples among 95 patients with liver disease in Nanjing by nested PCR]

OBJECTIVE

To analyze the infection of human parvovirus B19, human bocavirus (HBoV) and human parvovirus 4 (PARV4) in blood samples among patients with liver disease in Nanjing by molecular detection.

METHODS

Nested PCR assays were designed and validated to detect B19, HBoV and PARV4, respectively. The assays were used to screen three parvoviruses in blood samples from 95 patients with different liver disease in Nanjing. The parvovirus infection was analyzed statistically.

RESULTS

The detection limits were 10 copies of genomic DNA equivalents per reaction for each assays and the good specificity were observed. The frequency of B19 and HBoV were 2/95 (2.1%) and 9/95 (9.5%) in blood samples respectively. No PARV4 was detected. HBoV was detected in 3/5 patients with drug-induced hepatitis.

CONCLUSION

Both B19 and HBoV infection were detected in blood from patients with liver disease.

OVCA1 inhibits the proliferation of epithelial ovarian cancer cells by decreasing cyclin D1 and increasing p16

OVCA1, a tumor suppressor gene, is deleted or lower expressed in about 80% of ovarian cancer. Over expression of OVCA1 in human ovarian cancer A2780 cells inhibits cell proliferation and arrests cells in G1 stage. However, the fact that the molecular mechanism of OVCA1 inhibits cell growth is presently elusive. Here we investigated the potential signaling pathway induced by over-expression of OVCA1. Our results show that over-expression of human OVCA1 in ovarian cancer cells A2780 leads to down-regulation of cyclin D1, and up-regulation of p16, but no effect on the expression of NF-κB. It indicates that OVCA1 could inhibit the proliferation of ovarian cancer cell A2780 by p16/cyclin D1 pathway, but not by NF-κB.

External auditory canal exostoses in white water kayakers

OBJECTIVE

In this study, the presence and severity of external auditory canal exostoses (EACE) in a group of white water kayakers related to the duration and intensity of kayaking and the number of ear infections reported were identified.

DESIGN

A community-based volunteer cross-sectional study was completed with 92 kayakers (69 men, 23 women; mean (SD) age 29.3 (8.72) years) and 65 control volunteers (37 men, 28 women; mean (SD) age 36.9 (14.9) years). After exclusions, 269 individual ears were examined (154 kayakers and 115 controls). Participants completed a questionnaire and underwent otoscopic examination. Main outcome measures were the presence and severity of EACE, the duration and frequency of kayaking and self-reported ear infections. Exclusion criteria included other cold-water exposure, known ear pathology or poor visualisation of the auditory canal.

RESULTS

The findings demonstrated that 69.5% of kayaker ears and 1.7% of the control group were found to have EACE. Severity of EACE was significantly associated with the duration (p<0.01) and frequency (p<0.05) of kayaking with 90.6% of kayakers that had participated for more than 10 years having evidence of EACE. A significant relationship also existed between the number of self-reported ear infections and the severity of EACE (p<0.01).

CONCLUSION

There is a positive relationship between the duration and frequency of white water kayaking and the presence and severity of EACE and associated ear infections.

[Study on absorption spectra and optical limiting properties of soluble polymer/multi-walled carbon nanotube composites]

Three kinds of soluble polymer grafted multi-walled carbon nanotubes (MWNTs), including poly(N-vinylcarbazole)-MWNTs (MWNTs-PVK), polystyrene-MWNTs (MWNTs-PSt) and poly(methyl methacrylate)-MWNTs (MWNTs-PMMA) were synthesized. The TEM images of these samples show that polymers are coated outside the carbon nanotubes. The UV-Vis absorption spectra of the samples in CHCl3 were taken on a HP8452 spectrophotometer at room temperature. Compared with that of MWNTs suspension, there is a characteristic absorption peak in the ultraviolet region, which can be attributed to the polymers linked covalently with MWNTs. Their nonlinear optical properties and optical limiting (OL) performances were investigated by Z-scan method with 527 nm nanosecond laser pulses. These MWNTs dissolved in chloroform possess similar optical limiting properties, which are better than that of raw MWNT suspension and C60 in toluene solution. Nonlinear refraction, nonlinear absorption and nonlinear scattering mechanism were taken into consideration for explaining the observed results. The analysis of the experimental results shows that nonlinear absorption is the dominant mechanism behind the OL performance of these samples.

The Ultrafast Dynamics and Nonlinear Optical Properties of Tribranched Styryl Derivatives Based on 1,3,5-Triazine

By using the femtosecond laser spectroscopic techniques, we have studied the ultrafast response and the nonlinear optical properties of three molecules with donor-acceptor structure (denoted as T01, T02, and T03). Two-photon absorption (2PA) cross sections measured by the open aperture Z-scan technique were determined to be 77, 90, and 410 GM for T01, T02, and T03, respectively. The relaxation dynamics of the excited states were measured by two-color femtosecond pump-probe and time-resolved photoluminescence (PL) experiments. By changing the solvent from chloroform (CHCl3) to dimethyl sulfoxide (DMSO), the transient dynamics was found changed significantly and the decay time of PL emission decreased dramatically because DMSO with large dipole moment accelerates the cross-transfer process and the nonradiative process in the molecules.

Towards a feminist global bioethics: addressing women's health concerns worldwide

In this paper I argue that a global bioethics is possible. Specifically, I present the view that there are within feminist approaches to bioethics some conceptual and methodological tools necessary to forge a bioethics that embraces the health-related concerns of both developing and developed nations equally. To support my argument I discuss some of the challenges that have historically confronted feminists. If feminists accept the idea that women are entirely the same, then feminists present as fact the fiction of the essential "Woman." Not only does "Woman" not exist, -she" obscures important racial, ethnic, cultural, and class differences among women. However, if feminists stress women's differences too much, feminists lose the power to speak coherently and cogently about gender justice, women's rights, and sexual equality in general. Analyzing the ways in which the idea of difference as well as the idea of sameness have led feminists astray, I ask whether it is possible to avoid the Scylla of absolutism (imperialism, colonialism, hegemony) on the one hand and the Charybdis of relativism (postmodernism, fragmentation, Balkanization) on the other. Finally, after reflecting upon the work of Uma Narayan, Susan Muller Okin, and Martha Nussbaum, I conclude that there is a way out of this ethical bind. By focusing on women's, children's, and men's common human needs, it is possible to lay the foundation for a just and caring global bioethics.

Just caring about women's and children's health: some feminist perspectives

This article addresses the issue of women as primary caregivers to children and the concept of "maternal practice." The idea of maternal practice guides mothers as they learn (1) how to meet their child's physical, psychological, and spiritual needs, and (2) how to make their child socially acceptable. Hindrances to maternal practice include severe poverty and disabilities of the mother. The relationship between maternal practice and the quest for health care in the U.S. is discussed. Maintaining adequate health care is more difficult when parents are poorly educated and/or impoverished. Without proper health care, poor children are less likely to be able to compete with rich children in society. Dental care is also a concern, because proper dental care is fundamental in the maintenance of overall health. Dental care is not a "luxury" but medically necessary care. Solutions include increasing the awareness of such programs as CHIP and WIC, extending Medicaid benefits to more children, and compensating health care practitioners for working with Medicaid recipients. In addition, society must think more maternally and increase health and dental care accessibility, particularly to the poor in rural areas. The article concludes with the thought that if society expects mothers to care for their children, then society must care for mothers.

Evidence against oxidative stress as mechanism of endothelial dysfunction in methionine loading model

Endothelial dysfunction reflects reduced nitric oxide (NO) bioavailability due to either reduced production, inactivation of NO, or reduced smooth muscle responsiveness. Oral methionine loading causes acute endothelial dysfunction in healthy subjects and provides a model in which to study mechanisms. Endothelial function was assessed using flow-mediated dilatation (FMD) of the brachial artery in humans. Three markers of oxidative stress were measured ex vivo in venous blood. NO responsiveness was assessed in vascular smooth muscle and platelets. Oral methionine loading induced endothelial dysfunction (FMD decreased from 2.8 +/- 0.8 to 0.3 +/- 0.3% with methionine and from 2.8 +/- 0.8 to 1.3 +/- 0.3% with placebo; P < 0.05). No significant changes in measures of plasma oxidative stress or in vascular or platelet sensitivity to submaximal doses of NO donors were detected. These data suggest that oxidative stress is not the mechanism of endothelial dysfunction after oral methionine loading. Furthermore, the preservation of vascular and platelet NO sensitivity makes a signal transduction abnormality unlikely.

Unmodified supported thiol/lipid bilayers: studies of structural disorder and conducting mechanism by cyclic voltammetry and AC impedance

Supported thiol/lipid bilayer assembly, one of the most spectacular bilayer systems in recent years, has provided a good model to study biomembranes because of its high mechanical stability. In this work, the structural and conducting property of unmodified Au supported octadecanethiol/phosphatidylcholine bilayers were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The forming process of bilayer was monitored by capacitance plane plot. The normalized membrane capacitance of supported bilayer is 0.52 microF cm(-2). Kinetically controlled voltammograms determined by Butler-Volmer equation were obtained for both thiol monolayer and thiol/lipid bilayer in linear sweep voltammetry. Results of EIS experiment indicate that collapsed sites and pinhole defects exist in thiol monolayer and lipid monolayer, respectively. The difference between the values of experimental and theoretical standard electron transfer rate constant indicates that the conducting mechanism of Au supported thiol monolayer is electron tunneling at collapsed sites. The conducting mechanism of Au supported thiol/lipid bilayer is attributed as the following: the electroactive species could diffuse through pinholes in the lipid monolayer and reach collapsed sites in thiol monolayer, where electron transfer occurs via a tunneling process. The fractional coverage of the lipid monolayer measure by EIS experiments is about 0.98 or higher.

Rotation of NMR images using the 2D chirp-z transform

A quick and accurate way to rotate and shift nuclear magnetic resonance (NMR) images using the two-dimensional chirp-z transform is presented. When the desired image grid is rotated and shifted from the original grid due to patient motion, the chirp-z transform can reconstruct NMR images directly onto the ultimate grid instead of reconstructing onto the original grid and then applying interpolation to get the final real-space image in the conventional way. The rotation angle and shift distances are embedded in the parameters of the chirp-z transform. The chirp-z transform implements discrete sinc interpolation to get values at grid points that are not exactly on the original grid when applying the inverse Fourier transform. Therefore, the chirp-z transform is more accurate than methods such as linear or bicubic interpolation and is more efficient than direct implementation of sinc interpolation because the sinc interpolation is implemented at the same time as reconstruction from k-space.

Electron transfer between ferrocene-modified Au/octadecanethiol/lipid BLM electrode and redox couples in solution

Bilayers incorporated with ferrocene consisting of self-assembled octadecanethiol and lipid monolayer on gold substrates were fabricated. Its electrochemical behaviors in solutions containing different redox couples were investigated by cyclic voltammetry and ac impedance. The transmembrane electron transfer reaction across octadecanethiol self-assembled film and an adsorbed phospholipid layer mediated by ferrocene have been observed in the solution of Fe(CN)6(3-/4-). The formal potential difference between mediator in bilayer lipid membrane (BLM) and redox couple in solution has a great impact on the transmembrane electron transfer behavior. The ferrocene-modified BLM electrodes might be useful for constructing a bilayer-based electrochemical current rectifying device.

Two- and three-dimensional image rotation using the FFT

Techniques for rotating two- and three-dimensional (2-D and 3-D) images using fast Fourier transforms (FFT's) are presented. The methods are applications of the multidimensional chirp algorithm. In the 2-D case, one chirp transformation is sufficient, requiring four 2-D FFT's, In the 3-D case, two successive chirp transformations are required, needing six 3-D FFT's.

The ethics of care: a feminist virtue ethics of care for healthcare practitioners

In this paper I seek to distinguish a feminist virtue ethics of care from (1) justice ethics, (2) narrative ethics, (3) care ethics and (4) virtue ethics. I also connect this contemporary discussion of what makes a virtue ethics of care feminist to eighteenth and nineteenth century debates about male, female, and human virtue. In conclude that by focusing on issues related to gender--primarily those related to the systems, structures, and ideologies that create and sustain patterns of male domination and female subordination--we can begin to appreciate that true care and bona-fide virtue can flourish only in societies that treat all persons with equal respect and consideration.