Feasibility analysis of China's medical insurance coverage of assisted reproductive technology

There are millions of patients experiencing infertility in China, but assisted reproductive technology (ART) is performed at the patient's expense and is difficult to afford. With the sharp decline in China's birth rate, there is a growing controversy over the inclusion of ART in medical insurance (MI). This study aims to explore the feasibility of ART coverage by MI for the first time. We obtained basic data such as the prevalence of infertility, the cost of ART, and the success rate in China with the method of meta-analysis and consulting the government bulletin. Then, we calculated the number of infertile couples in China and the total financial expenditure of MI covering ART. Finally, we discussed the feasibility of coverage, and analyzed the population growth and economic benefits after coverage. According to our research results, it was estimated that there were 4.102-11.792 million infertile couples in China, with an annual increase of 1.189-1.867 million. If MI covered ART, the fund would pay 72.313-207.878 billion yuan, accounting for 2-6% of the current fund balance, and the subsequent annual payment would be 20.961-32.913 billion yuan, accounting for 4-7% of the annual fund balance. This was assuming that all infertile couples would undergo ART, and the actual cost would be lower. The financial input‒output ratio would be 13.022. Benefiting from the inclusion of ART in MI coverage, there would be 3.348-9.624 million new live infants, and 8-13% newborns would be born every year thereafter, which means that by 2050, 37-65 million people would be born. Due to its affordable cost, high cost-effectiveness and favourable population growth, it may be feasible to include ART in MI.

[Mediating effect of resilience on nursing occupational risk and job performance in nurses]

Objective: To analyze Nursing Occupational Risk, the relationship between resilience and job performance, and investigate the mediating effects of resilience on Nursing Occupational Risk and job performance. Methods: 406 nurses from33 clinical departments of Chengdu first-class hospital were recruited by randomsampling method. Thier Nursing Occupational Risk, resilience and job performance were interviewed by nursing occupational risk assessment questionnaire, the Scale of medical staff resilience and the job performance questionnaire, and analyze the relationship between variables. Results: The clinical nurses＇ resilience is 82.98±10.05, the clinical nurses' job performance is 145.79±23.55; here was a positive correlation between clinical nurses' resilience and job performance (P<0.05) ; three variable of resilience can explain 33.2% of the variation of clinical nurses job performance; in the highest the Nursing Occupational risk, resilience served to mediate the relationship between Nursing Occupational Risk and job performance, which was 56.77% of the total effect respective. Conclusion: resilience are closely related to job performance. Resilience plays mediating role in the relationships between Nursing Occupational Risk and job performance, three dimensions of resilience can predict nurses' job performance. Improving the resilience of nurses can effectively improve their job performance.

Driving under the influence of psychoactive substances - A historical review

Important events in the history of driving under the influence of alcohol (DUI) and/or other drugs (DUID) are reviewed covering a period of approximately 100 years. This coincides with major developments in the pharmaceutical industry and the exponential growth in motor transportation worldwide. DUID constitutes an interaction between the driver, the motor-driven vehicle, and one or more psychoactive (mind-altering) substances. In this connection, it is important to differentiate between drugs intended and used for medical purposes (prescription or licit drugs) and recreational drugs of abuse (illicit drugs). All chemicals with a mechanism of action in the central nervous system (brain and spinal cord) are potentially dangerous to use when skilled tasks, such as driving, are performed. The evidence necessary to charge a person with drug-impaired driving has evolved over many years and initially rested on a driver's own admissions and observations made about the driving by police officers or eyewitnesses. Somewhat later, all suspects were examined by a physician, whose task was to ask questions about any recent ingestion of alcohol and/or other drugs and to administer various clinical tests of impairment. By the 1940s-1950s, the driver was asked to provide samples of blood, breath, or urine for toxicological analysis, although the test results served only to verify the type of drug causing impairment of the driver. The current trend in DUID legislation is toward zero-tolerance or concentration per se statutes, which are much more pragmatic, because behavioral evidence of impairment is no longer a lynchpin in the prosecution case. This legal framework puts considerable emphasis on the results of toxicological analysis; therefore, the methods used must be accurate, precise, and fit for forensic purposes. Many traffic delinquents charged with DUI or DUID suffer from a substance use and/or personality disorder, with high recidivism rates. In addition to conventional penalties and sanctions for drug-related traffic crimes, many offenders would probably benefit from a medical intervention, such as counseling, rehabilitation, and treatment for substance use disorder, which often coexists with a mental health problem.

Evidence for negative thermal expansion in the superconducting precursor phase SmFeAsO

The fluorine-doped rare-earth iron oxypnictide series SmFeAsO1-x F x (0 [Formula: see text] 0.10) was investigated with high resolution powder x-ray scattering. In agreement with previous studies (Margadonna et al 2009 Phys. Rev. B. 79 014503), the parent compound SmFeAsO exhibits a tetragonal-to-orthorhombic structural distortion at [Formula: see text]  =  130 K which is rapidly suppressed by [Formula: see text] 0.10 deep within the superconducting dome. The change in unit cell symmetry is followed by a previously unreported magnetoelastic distortion at 120 K. The temperature dependence of the thermal expansion coefficient [Formula: see text] reveals a rich phase diagram for SmFeAsO: (i) a global minimum at 125 K corresponds to the opening of a spin-density wave instability as measured by pump-probe femtosecond spectroscopy (Mertelj et al 2010 Phys. Rev. B 81 224504) whilst (ii) a global maximum at 110 K corresponds to magnetic ordering of the Sm and Fe sublattices as measured by magnetic x-ray scattering (Nandi et al 2011 Phys. Rev. B 84 055419). At much lower temperatures than [Formula: see text], SmFeAsO exhibits a significant negative thermal expansion on the order of  -40 ppm · K-1 in contrast to the behaviour of other rare-earth oxypnictides such as PrFeAsO (Kimber et al 2008 Phys. Rev. B 78 140503) and the actinide oxypnictide NpFeAsO (Klimczuk et al 2012 Phys. Rev. B 85 174506) where the onset of [Formula: see text] 0 only appears in the vicinity of magnetic ordering. Correlating this feature with the temperature and doping dependence of the resistivity and the unit cell parameters, we interpret the negative thermal expansion as being indicative of the possible condensation of itinerant electrons accompanying the opening of a SDW gap, consistent with transport measurements (Tropeano et al 2009 Supercond. Sci. Technol. 22 034004).

[A concentration-response observation of hydromorphone combined with ropivacaine in labor analgesia]

Objective: To investigate the median effective dose (ED(50)) of hydromorphone and the appropriate concentration of ropivacaine combined with hydromorphone in epidural labor analgesia. Methods: One hundred and forty nulliparous women undergoing labor selected for delivery with epidural analgesia were enrolled in our hospital from January to June 2016. The first of top 50 women received 0.12% ropivacaine plus 20 μg/ml hydromorphone complex solution, then sequential women were used the modified sequential method to determine the ED(50) and ED(95) of hydromorphone. The other 90 women were randomly divided and receieved 0.08% ropivacaine and 15 μg/ml hydromorphone(H1 group), 0.10% ropivacaine and 15 μg/ml hydromorphone (H2 group), 0.12% ropivacaine and 15 μg/ml hydromorphone (group H3) respectively for epidural labor analgesia. In the course of labor, block levels of epidural analgesia, the Bromage scores, analgesia scores and fetal heart rate-uterine concraction were monitored. In addition, onset time of anesthesia, labor time, mode of delivery, cases of increased oxytocin using, neonatal Apgar score, incidence of nausea and vomiting, itching and fetal heart reduction were recorded. Results: The ED(50) and ED(95) values of hydromorphone were 10.49 (95% CI: 8.89-11.79) and 15.15 (95% CI: 13.25-22.25) μg/ml respectively. The onset time in group H1 was significantly longer than those in group H2 and H3((14.23±3.82) , ( 11.32±2.16), (10.83±2.56)min, respectively), the difference was statistically significant (t=5.854, 6.212, all P<0.05). Analgesic VAS score at 30, 60 and 90 min time points in H1 group was significantly higher than that in H2 group and H3 group (all P<0.05). VAS score at withdrawal in H1 group was significantly higher than that in group H3 ( (3.25±0.75) vs (0.27±0.12) ), the difference was statistically significant ( t=9.314, P<0.05). VAS scores at the fourth, fifth, sixth contractions after analgesia in H1 group were significantly higher than those in H2 and H3 groups (all P<0.05). The incidence of motor nerve block in group H3 was higher than that in group H1 and group H2 (26.67%, 6.66%, 3.33%, respectively), the difference was statistically significant (χ(2)=6.413, 4.320, all P<0.05). Conclusions: 0.10% ropivacaine combined with 15 μg/ml hydromorphone has a good analgesic effect, slight motor block, high safety and worthy clinical application for labor analgesia.

Chemical derivatization for forensic drug analysis by GC- and LC-MS

Utilizing chemical derivatization (CD) to improve gas chromatographic (GC) and GC-mass spectrometric (MS) analysis of drugs has been abundantly studied and widely practiced, while in liquid chromatography (LC) and LC-MS, application of CD approaches is still at an early stage. Silylation, acylation, and alkylation are common CD reactions, long adopted by GC and GC-MS (including GC-MS/MS) methodologies, to improve analytes' stability and/or to optimize their extraction/separation and detection efficiencies. Highly polar and nonvolatile analytes are not amenable to GC-MS analysis without the CD step; however, CD can improve LC-MS analysis of highly polar analytes, especially those with low molecular weights. Many CD reagents developed for GC and GC-MS applications are also effective in LC-MS. Other CD reagents are developed for LC-MS to enhance analytes' performance under electrospray and atmospheric pressure ionization sources. Certain CD reagents are designed to facilitate analytes' fragmentation (upon collision-induced dissociation) in generating intense product ions for sensitive MS/MS detection. In this review, various CD reagents, reaction types, and application examples are presented and discussed, with emphases on GC-MS and LC-MS analysis of drugs of abuse.

Dynamical skyrmion state in a spin current nano-oscillator with perpendicular magnetic anisotropy

We study the spectral characteristics of spin current nano-oscillators based on the Pt/[Co/Ni] magnetic multilayer with perpendicular magnetic anisotropy. By varying the applied magnetic field and current, both localized and propagating spin wave modes of the oscillation are achieved. At small fields, we observe an abrupt onset of the modulation sidebands. We use micromagnetic simulations to identify this state as a dynamical magnetic skyrmion stabilized in the active device region by spin current injection, whose current-induced dynamics is accompanied by the gyrotropic motion of the core due to the skew deflection. Our results demonstrate a practical route for controllable skyrmion manipulation by spin current in magnetic thin films.

Spectral characteristics of the microwave emission by the spin Hall nano-oscillator

We utilized microwave spectroscopy to study the magnetization oscillations locally induced in a Permalloy film by a pure spin current, which is generated due to the spin Hall effect in an adjacent Pt layer. The oscillation frequency is lower than the ferromagnetic resonance of Permalloy, indicating that the oscillation forms a self-localized nonpropagating spin-wave soliton. At cryogenic temperatures, the spectral characteristics are remarkably similar to the traditional spin-torque nano-oscillators driven by spin-polarized currents. However, the linewidth of the oscillation increases exponentially with temperature and an additional peak appears in the spectrum below the ferromagnetic resonance, suggesting that the spectral characteristics are determined by interplay between two localized dynamical states.

Difference in weight loss based on ethnicity, age and comorbidity status in a publicly funded adult weight management centre: 1-year results

Limited evidence is available on the effectiveness of publicly funded weight loss (WL) clinics. We examined the 1-year WL outcomes and investigated predictors of WL and discontinuation of 1566 overweight and obese adults, who attended the Wharton Medical Clinic (WMC) weight management centre for at least 6 months. Overall, 42.7% (n = 669) of the entire sample achieved a ≥5%WL over the entire follow-up period from July 2008 to February 2012. On average, patients lost 5.6 ± 7.2 kg (5.0 ± 6.3%) of initial body weight (BW), while a subsample of patients attending the clinic for at least 1 year had a mean weight reduction of 6.6 ± 7.9 kg (5.9 ± 7.2%) of BW. Older patients were more likely to achieve a greater WL in comparison with young patients while White patients and those without type 2 diabetes (T2D) lost almost twice as much weight and %BW in comparison with Asian patients and patients with T2D, respectively (P < 0.05). Discontinuing patients did not differ in terms of sex, body mass index, education and smoking status from those who continued treatment (P > 0.05). Results of this study demonstrate that the WMC provides a practical model for clinically effective lifestyle-based treatment, accessible to a wide range of demographically diverse adults.

Measurements of the anisotropic in-plane resistivity of underdoped FeAs-based pnictide superconductors

We systematically investigated the in-plane resistivity anisotropy of electron-underdoped EuFe(2-x)Co(x)As(2) and BaFe(2-x)Co(x)As(2) and hole-underdoped Ba(1-x)K(x)Fe(2)As(2). Large in-plane resistivity anisotropy was found in the former samples, while tiny in-plane resistivity anisotropy was detected in the latter ones. When it is detected, the anisotropy starts above the structural transition temperature and increases smoothly through it. As the temperature is lowered further, the anisotropy takes a dramatic enhancement through the magnetic transition temperature. We found that the anisotropy is universally tied to the presence of T-linear behavior of resistivity. Our results demonstrate that the nematic state is caused by electronic degrees of freedom, and the microscopic orbital involvement in the magnetically ordered state must be fundamentally different between the hole- and electron-doped materials.

The pharmacokinetics of C-glycosyl flavones of Hawthorn leaf flavonoids in rat after single dose oral administration

Hawthorn leaf flavonoids (HLF) are used in the treatment of cardiovascular diseases. Various potential pharmacodynamic effects have been observed for vitexin-4''-O-glucoside (VOG) and vitexin-2''-O-rhamnoside (VOR) which are the main constituents of HLF. The aim of this study was to investigate the pharmacokinetics of VOG and VOR when a single dose of HLF was administrated orally. The levels of VOG and VOR in plasma, tissues (heart, liver, spleen, lung, kidney and brain), bile, urine and feces were measured by HPLC-UV. The results showed that VOG and VOR have the similar pharmacokinetics. Both of them were absorbed quickly into plasma with maximal plasma concentrations of VOG and VOR being reached within 0.75 h. The mean elimination half-life (t(1/2)) of VOG and VOR were 2.53 h and 2.32 h, respectively. High levels of tissue distribution of VOG and VOR were observed in liver and kidney. No VOG and VOR were detected in brain tissue. There was no long-term accumulation of VOG and VOR in rat tissues examined. The total recovery of the dose in 24 hours was 64.91% (0.70% in urine; 64.21% in feces) for VOG and 89.01% (0.72% in urine; 88.29% in feces) for VOR. The cumulative VOG and VOR excreted in bile represented 0.58% and 13.38% of the doses, respectively. VOG and VOR in HLF were not efficiently absorbed in the rodent gastrointestinal tract.

Evidence for competing magnetic and superconducting phases in superconducting Eu 1-x Sr x Fe 2-y Co y As 2 single crystals

In single crystals of Eu(1-x)Sr(x)Fe(2-y)Co(y)As(2), Co doping suppresses spin-density wave (SDW) ordering and induces a superconducting transition. A resistivity reentrance due to the antiferromagnetic ordering of Eu(2+) spins is observed, indicating the competition between antiferromagnetism (AFM) and superconductivity (SC). It is striking that the resistivity reentrance can be completely suppressed by a small magnetic field due to a field-induced metamagnetic transition from AFM to ferromagnetism (FM). The resistivity reentrance can also be suppressed by the substitution of Eu(2+) ions with nonmagnetic Ba(2+)/Sr(2+) to completely destroy the AFM ordering. These results indicate that the AFM order appears destructive to SC, while FM can coexist with the superconductivity. Further we find that magnon excitation exists in AFM ordering and can be suppressed by an applied field. Coexistence of SC from the FeAs layer and the inner field produced by the ferromagnetic Eu(2+) layer suggest a possible p-wave component in the superconducting order parameter.

Doping dependent nonlinear Hall effect in SmFeAsO(1-x)F(x)

We report the Hall resistivity, ρ(xy), of polycrystalline SmFeAsO(1-x)F(x) for four different fluorine concentrations from the onset of superconductivity through the collapse of the structural phase transition. For the two more highly doped samples, ρ(xy) is linear in magnetic field up to 50 T with only weak temperature dependence, reminiscent of a simple Fermi liquid. For the lightly doped samples with x<0.15, we find a low temperature regime characterized as ρ(xy)(H) being both nonlinear in magnetic field and strongly temperature-dependent even though the Hall angle is small. The onset temperature for this nonlinear regime is in the vicinity of the structural phase (SPT)/magnetic ordering (MO) transitions. The temperature dependence of the Hall resistivity is consistent with a thermal activation of carriers across an energy gap. The evolution of the energy gap with doping is reported.

Transport properties and the large anisotropic magnetoresistance of Cu(x)NbS(2) single crystals

The transport properties of Cu(x)NbS(2) (x = 0.09, 0.44 and 0.55) single crystals were systematically studied. The in-plane and out-of-plane resistivities decrease with increasing Cu content, and a transition with hysteresis shows up for the crystals with x = 0.44 and 0.55. The thermopower and Hall coefficient of Cu(x)NbS(2) show opposite signs, indicating that there are two kinds of carriers in this system. The angular dependences of the in-plane magnetoresistance (MR(ab) = (ρ(ab)(H)-ρ(ab)(0))/ρ(ab)(0) × 100%) at different temperatures were also studied. The single crystals with x = 0.44 and 0.55 show a strong anisotropic MR(ab). For the x = 0.55 sample, MR(ab) reaches 80% with a magnetic field of 14 T applied along the c-axis, while MR(ab) is less than 5% for the magnetic field applied within the ab-plane. These results can be well understood in the light of the anisotropic Fermi surface in the multiband system.

Mass Spectra and Cross-Contribution of Ion Intensity Between Drug Analytes and Their Isotopically Labelled Analogs - Benzodiazepines and Their Derivatives

With GC-MS as the preferred method and isotopically labeled analogs (ILAs) of the analytes as the internal standards (ISs) of choice for quantitative determination of drugs/metabolites in biological specimens, one important aspect associated with chemical derivatization (CD) is that the CD products derived from the analyte and the selected IS must generate ions suitable for designating the analyte and the IS. These ions must not have significant cross-contribution (CC), i.e., ISs' contribution to the intensities of the ions designating the analytes, and vice versa. With this in mind, the authors have reviewed literature and information provided by manufacturers, searching for suitable CD reagents, CD methods, and ILAs of the analytes related to the following 18 benzodiazepines: oxazepam, diazepam, nordiazepam, nitrazepam, temazepam, clonazepam, 7-aminoclonazepam, prazepam, lorazepam, flunitrazepam, 7-aminoflunitrazepam, N-desalkylflurazepam, N-desmethylflunitrazepam, 2-hydroxyethylflurazepam, estazolam, alprazolam, α-hydroxyalprazolam, and α-hydroxytriazolam. These analytes and ILAs were derivatized with various derivatization groups, followed by GC-MS analysis. The resulting mass spectrometric data are systematically presented in two forms: (a) full-scan mass spectra; and (b) CC data of ion-pairs with potential for designating the analytes and their respective ILAs (candidates of ISs in quantitative analytical protocols). Many of these full-scan mass spectra are not yet available in the literature and should be of reference value to laboratories engaged in the analysis of these drugs/metabolites. Full-scan MS data were further used to select ion-pairs with potential for designating the analytes and ISs in quantitative analysis protocols. The CC data of these ion-pairs were evaluated using data collected in selected ion monitoring mode and systematically tabulated, making the data readily available for analysts searching for this important analytical parameter.

Superconductivity at 56 K in samarium-doped SrFeAsF

We synthesized the samples Sr(1-x)Sm(x)FFeAs with a ZrCuSiAs-type structure. These samples were characterized by resistivity and susceptibility. It is found that substitution of rare earth metal for alkaline earth metal in this system suppresses the anomaly in resistivity and induces superconductivity. Superconductivity at 56 K in nominal composition Sr(0.5)Sm(0.5)FFeAs is realized, indicating that the superconducting transition temperatures in the iron arsenide fluorides can reach as high as that in oxypnictides with the same structure.

Coexistence of static magnetism and superconductivity in SmFeAsO(1-x)F(x) as revealed by muon spin rotation

The recent observation of superconductivity with critical temperatures (Tc) up to 55 K in the pnictide RFeAsO(1-x)F(x), where R is a lanthanide, marks the first discovery of a non-copper-oxide-based layered high-Tc superconductor. It has raised the suspicion that these new materials share a similar pairing mechanism to the cuprate superconductors, as both families exhibit superconductivity following charge doping of a magnetic parent material. In this context, it is important to follow the evolution of the microscopic magnetic properties of the pnictides with doping and hence to determine whether magnetic correlations coexist with superconductivity. Here, we present a muon spin rotation study on SmFeAsO(1-x)F(x), with x=0-0.30 that shows that, as in the cuprates, static magnetism persists well into the superconducting regime. This analogy is quite surprising as the parent compounds of the two families have rather different magnetic ground states: itinerant spin density wave for the pnictides contrasted with the Mott-Hubbard insulator in the cuprates. Our findings therefore suggest that the proximity to magnetic order and associated soft magnetic fluctuations, rather than strong electronic correlations in the vicinity of a Mott-Hubbard transition, may be the key ingredients of high-Tc superconductors.

Fruit quality, antioxidant contents and activity, and antiproliferative activity of strawberry fruit stored in elevated CO2 atmospheres

The effects of CO2 in the storage atmosphere on color, firmness, ascorbic acid (AA), anthocyanins, flavonoids, phenolics, total antioxidant activity, and antiproliferative activity of strawberry fruit have been investigated. "Northeaster" and "Earliglow" strawberries were stored in air or in 20% CO2 (in air) at 3 degrees C for 20 d. Color changes in Northeaster were delayed more by CO2 treatment than in Earliglow. Firmness of CO2-stored fruit increased slightly compared with those stored in air. The increases in total and reduced AA concentrations during air storage were usually prevented by CO2 storage in both cultivars. Dehydroascorbic acid (DHA) concentrations increased during CO2 storage. Anthocyanins and flavonoids, and total antioxidant activity of both cultivars were higher in air-stored fruit than in CO2-stored fruit. The total phenolic concentration was lower in CO2-stored Earliglow fruit than in air, but storage treatment did not affect that of Northeaster. A 40 mg/mL concentration of Northeaster strawberry extract inhibited about 80% of HepG2 human liver cancer cell proliferation. CO2 treatment did not affect the antiproliferative activity of strawberry fruits, but antiproliferative activity was greater at harvest than after storage.

Anisotropy in the electrical resistivity and susceptibility of superconducting BaFe2As2 single crystals

We report that sizable single crystals of BaFe2As2 have been grown with the self-flux method. Measurements and anisotropy of intrinsic transport and magnetic properties from high-quality single crystal are first presented. The resistivity anisotropy (rho{c}/rho{ab}) is as large as 150 and independent of temperature. In contrast to the susceptibility behavior observed in polycrystalline samples, no Curie-Weiss behavior is observed, and a linear-T dependent susceptibility occurs from the spin-density-wave transition temperature, (T{s}), to 700 K. This result suggests that strong antiferromagnetic correlations are present well above T{s}. A twofold symmetry of susceptibility in the ab plane indicates a stripelike spin structure as observed by neutron scattering. The resistivity minimum is strongly dependent on the magnetic field, suggesting that the upturn of the resistivity at low temperatures should be related to spin fluctuation.

Magnetotransport properties in K(0.50)CoO(2) single crystals

We have measured susceptibility and angle-dependent magnetoresistance (AMR) on K(0.50)CoO(2) single crystals. A possible magnetic structure similar to that of Na(0.5)CoO(2), a G-type anti-ferromagnetic (AF) structure (both in-plane and inter-plane are AF), is proposed. At ∼20 K, a loop is observed between zero-field-cooled (ZFC) and field-cooled (FC) susceptibility. The absolute value of magnetoresistance (MR) at 20 K is much larger than other cases with H applied within the ab plane. This could arise from the magnetic field being applied in the ab plane, leading to spin-flop of the small magnetic moment of Co(3.5-δ) sites at 20 K to form in-plane ferromagnetic ordering, as observed in Na(0.52)CoO(2).

Coexistence of magnetic fluctuations and superconductivity in the pnictide high temperature superconductor SmFeAsO1-xFx measured by muon spin rotation

Muon spin rotation experiments were performed on the pnictide high temperature superconductor SmFeAsO1-xFx with x=0.18 and 0.3. We observed an unusual enhancement of slow spin fluctuations in the vicinity of the superconducting transition which suggests that the spin fluctuations contribute to the formation of an unconventional superconducting state. An estimate of the in-plane penetration depth lambda ab(0)=190(5) nm was obtained, which confirms that the pnictide superconductors obey an Uemura-style relationship between Tc and lambda ab(0);(-2).

Superconducting energy gap and c-axis plasma frequency of (Nd,Sm)FeAsO0.82F0.18 superconductors from infrared ellipsometry

We present far-infrared ellipsometric measurements of polycrystalline samples of the pnictide superconductor RFeAsO0.82F0.18 (R=Nd and Sm). We find evidence that the electronic properties are strongly anisotropic such that the optical spectra are dominated by the weakly conducting c-axis response similar to the cuprate high-temperature superconductors. We deduce an upper limit of the c-axis superconducting plasma frequency of omega pl,c(SC)< or =260 cm(-1) corresponding to a lower limit of the c-axis magnetic penetration depth of lambda c > or =6 microm and lambda c/lambda ab > or =30 as compared to lambda ab=185 nm from muon spin rotation [A. Drew, arXiv:0805.1042 [Phys. Rev. Lett. (to be published)]]. We also observe a gaplike suppression of the conductivity in the superconducting state with a shoulderlike feature at omegaSC* approximately 300 cm(-1) and spectral shape which is consistent with an unconventional order parameter with 2Delta approximately omegaSC* approximately 37 meV.

Anomalous transport properties and phase diagram of the FeAs-based SmFeAsO1-xFx superconductors

We report the detailed phase diagram and anomalous transport properties of Fe-based high-T_{c} superconductors SmFeAsO1-xFx. It is found that superconductivity emerges at x approximately 0.07, and optimal doping takes place in the x approximately 0.20 sample with the highest T_{c} approximately 54 K. T_{c} increases monotonically with doping; the anomaly in resistivity from structural phase or spin-density-wave order is rapidly suppressed, suggesting a quantum critical point around x approximately 0.14. As manifestations, a linear temperature dependence of the resistivity shows up at high temperatures in the x<0.14 regime but at low temperatures just above T_{c} in the x>0.14 regime; a drop in carrier density evidenced by a pronounced rise in the Hall coefficient is observed below the temperature of the anomaly peak in resistivity. A scaling behavior is observed between the Hall angle and temperature: cottheta_{H} proportional, variantT;{1.5} for all samples with different x in SmFeAsO1-xFx system.

Mass Spectra and Cross-Contribution of Ion Intensity Between Drug Analytes and Their Isotopically Labelled Analogs - Common Opioids and Their Derivatives

For the quantitation of most drugs and their metabolites, GC-MS is currently the preferred method and isotopically labeled analogs of the analytes are the internal standards (ISs) of choice. Under this analytical setting, chemical derivatization (CD) plays a critical role in the sample preparation process. In addition to meeting the conventional objectives of CD, products derived from the selected CD method must generate ions suitable for designating the analyte and the IS; these ions cannot have significant cross-contribution (CC), i.e., contribution to the intensity of the ions designating the analyte by the IS, and vice versa. With this in mind, the authors have reviewed literature and information provided by manufacturers, searching for suitable CD reagents, CD methods, and isotopically labeled analogs of the analytes related to the following 11 opioids: heroin, 6-acetylmorphine, morphine, hydromorphone, oxymorphone, 6-acetylcodeine, codeine, hydrocodone, dihydrocodeine, oxycodone, and noroxycodone. These analytes and ISs were derivatized with various derivatization groups, followed by GCMS analysis. The resulting MS data are systematically presented in two forms: (a) full-scan mass spectra; and (b) CC data of ion-pairs with potential for designating the analytes and their respective ISs. Many (if not most) of these full-scan mass spectra are not yet available in the literature and should be of reference value to laboratories engaged in the analysis of these drugs/metabolites. Full-scan MS data were further used to select ion-pairs with potential for designating the analytes and ISs in quantitative analysis protocols. The CC data of these ion-pairs were evaluated using data collected in selected ion monitoring mode and systematically tabulated, readily available for analysts searching for this important analytical parameter.

Superconductivity at 43 K in SmFeAsO1-xFx

Since the discovery of high-transition-temperature (high-T(c)) superconductivity in layered copper oxides, extensive effort has been devoted to exploring the origins of this phenomenon. A T(c) higher than 40 K (about the theoretical maximum predicted from Bardeen-Cooper-Schrieffer theory), however, has been obtained only in the copper oxide superconductors. The highest reported value for non-copper-oxide bulk superconductivity is T(c) = 39 K in MgB(2) (ref. 2). The layered rare-earth metal oxypnictides LnOFeAs (where Ln is La-Nd, Sm and Gd) are now attracting attention following the discovery of superconductivity at 26 K in the iron-based LaO(1-x)F(x)FeAs (ref. 3). Here we report the discovery of bulk superconductivity in the related compound SmFeAsO(1-x)F(x), which has a ZrCuSiAs-type structure. Resistivity and magnetization measurements reveal a transition temperature as high as 43 K. This provides a new material base for studying the origin of high-temperature superconductivity.

Two new flavanes and bioactive compounds fromDaphne tanguticaMaxim

Two new flavanes, named daphneflavan B (1) and daphneflavan C (2), along with two known biflavonoids, daphnodorin D(1) (3) and daphnodorin D(2) (4), were isolated from the roots of Daphne tangutica Maxim. Their structures were established on the basis of chemical, physicochemical, and spectroscopic evidences. Two compounds 3 and 4 were noted to have the most marked antitumor activity in vivo assay.

Two new chemical constituents fromDaphne odoraThunb. var.marginata

Two new phenolic constituents, daphnenone (1) and daphneone (2), were isolated from the stem bark of Daphne odora Thunb. var. marginata. Their structures were established on the basis of spectroscopic analysis. Compounds 1 and 2 were tested for cytotoxic activity by MTT assays on five human tumour cell lines, K562, A549, MCF-7, LOVO and HepG2. Compound 1 showed obvious cytotoxic activity against all the five cell lines.

Two new xanthones from Hypericum japonicum

Two new xanthones, 1,6-dihydroxyisojacereubin-5-O-beta-D-glucoside (1) and 3,6,7-tri-hydroxy-1-methoxy-xanthone (2), were isolated from Hypericum japonicum. The structural elucidation of the isolated compounds were primarily based on HREIMS, EIMS, UV, IR, 1D-, and 2D-NMR analyses, including COSY, HMQC, HMBC, and NOESY correlations.

Mass spectrometric data characteristics of commonly abused amphetamines with sequential derivatization at two active sites

There have been reports on improved chromatographic parameters derived from the incorporation of sequential derivatization in preparing biological specimens for the analysis of opiates. This current study was designed to characterize the mass spectrometric data resulting from sequential derivatizations of commonly abused amphetamines (along with all commercially available deuterated analogs) containing two active sites, i.e., amphetamine, methylenedioxyamphetamine, phenylpropanolamine. The first derivatization groups included in this study were trifluoroacetyl, pentafluoropropionyl, and heptafluorobutyryl, while t-butyldimethylsilyl was used as the second derivatization group. Products resulting from the first step and the two-step derivatization processes were analyzed by GC-MS. Full-scan mass spectrometric data were used to select ions with potential for designating the analytes and their respective isotopically labeled analogs in quantitative analysis protocols. Selected ion monitoring data were then collected and assessed to determine the quality of these ions when one or two different derivatization groups were incorporated in the sample preparation processes. A total of 77 full-scan mass spectra and 8 ion intensity cross-contribution tables, representing various forms of derivatization and isotopic analogs of the three amphetamines, are systematically presented for reference. Evaluations of these data concluded that many, but not all, products derived from "double derivatization" (sequential derivatization with two derivatization groups), generate ions of higher quality than those derived from "single derivatization".

Two new iridoids from roots of Patrinia scabra Bunge

Two new iridoids 1,3-dimethyloxy-7-hydroxymethyl-4-(3-methyl-butyryloxymethyl)-1-hydrocyclopenta-4,7-diene[c]pyran-6-one (1) and 1,3-dimethyloxy-7-hydroxymethyl-4-methyloxymethyl-1-hydrocyclopenta-4,7-diene[c]pyran-6-one (2) were isolated from the roots of Patrinia scabra Bunge. The structure elucidation of the isolated compounds was based primarily on HRESIMS, EIMS, IR, UV, 1D- and 2D-NMR analyses, including COSY, HMQC, HMBC and NOESY correlations, as well as X-ray crystallographic analysis.

Correlation of Drug-Testing Results - Immunoassay versus Gas Chromatography-Mass Spectrometry

The need for and prevalence of workplace drug-testing programs mandate the development of an effective and efficient two-step test strategy. Successful implementation of the two-step test strategy relies on the establishment of a reasonable correlation between the preliminary and the confirmatory test data and the selection of an appropriate cutoff for each test step. Correlations of test data derived form these two test steps were most commonly studied qualitatively by comparing the positive/negative test result concluded by these two test steps; however, when instrument-based immunoassays (IA) are used in the preliminary test step, the resulting "semiquantitative" and "apparent" concentration of the targeted analyte can be quantitatively correlated to the analyte concentration as determined by gas chromatography-mass spectrometry (GC-MS). Specimens selected for quantitative correlation studies should be clinical specimens with the distributions of metabolites similar to that present in test specimens; if the resulting correlation data are to be used for selecting appropriate/corresponding cutoffs for these two test steps, the concentrations of the targeted analyte in these specimens should also be within a narrow range centering on the proposed GC-MS cutoff concentration. Among the very significant number of reports correlating IA and GC-MS test data, cannabis and urine are the most common drug category and test specimen studied. The degree of correlation between IA and the GC-MS test data varies with the IA reagent manufacturers, and even with manufacture dates/lots of those supplied by the same manufacturer. The most important factors underlying the observed degree of correlation are undoubtedly the cross-reacting characteristics of the antibody and the metabolite distribution pattern of the drug of concern. Over time, specificities of IA reagents have been optimized so that the two-step test strategy can be most effectively and efficiently applied using the cutoffs mandated by workplace drug-testing programs. The nature of correlation and the selection of appropriate/corresponding cutoffs between IA and GC-MS test data derived from alternate biological matrices are yet to be fully understood and established.

Mass Spectrometric Data of Commonly Abused Amphetamines and Their Derivatives - Cross Contribution of Ion Intensity between the Analytes and Their Isotopically Labeled Analogs

With GC-MS as the preferred method and isotopically labeled analogs of the analytes as the internal standards (ISs) of choice for the analysis of drugs/metabolites in biological specimens, one important aspect associated with chemical derivatization (CD) is that the CD products derived from the analyte and the selected IS must generate ions suitable for designating the analyte and the IS; these ions cannot have significant crosscontribution (CC), i.e., contribution to the intensity of the ion designated for the analyte by the IS, and vice versa. With this in mind, the authors have reviewed literature and commercial information on common CD reagents and methods and conducted a thorough search of isotopically labeled analogs of commonly abused amphetamine-type drugs/metabolites that are commercially available. These ISs and analytes were then derivatized with various derivatization groups. These CD products were then analyzed by GC-MS and the resulting MS data are presented here in two forms: (a) systematic presentation of full-scan spectra; and (b) tabulation of CC data for ions with potential for designating the ISs and analytes. Many (if not most) of these full-scan spectra are not yet available in the literature and should be of daily reference value to forensic and clinical laboratories that are engaged in the analysis of these drugs/metabolites. Full-scan MS data were further used to select ion-pairs with potential for designating the analytes and ISs in quantitative analysis protocols. The CC data of these ion-pairs were evaluated using data collected under the SIM mode and summarized in table format. These data should save enormous amounts of time and efforts for practicing laboratories in their search for this analytical parameter.

Localization of angiotensin II in pig ovary and its effects on oocyte maturation in vitro

The renin-angiotensin system (RAS) has been found in mammalian ovarian tissue; however, its physiological role is unclear. This study examined the content of angiotensin II (Ang II) in porcine follicular fluid (pFF), Ang II localization and its receptors in ovary, and the effects of Ang II on porcine oocyte maturation. The concentrations of Ang II were 6951.82 +/- 1295.83, 3502.99 +/- 679.10, 3147.89 +/- 690.60, and 2545.92 +/- 407.01 pg/ml in pFF from small, medium, large, and extra-large follicles, respectively. In addition, Ang II was found on zona pellucidae (ZP) and granulosa cells by immunoreactive staining. The distribution of AT1, an Ang II receptor subtype, was in accordance with that of Ang II. However, AT2, another Ang II receptor, was mainly distributed in the stroma and thecal layers of follicles. When oocytes were cultured in media containing various concentrations of Ang II, a higher (P<0.05) proportion of oocytes reached metaphase II (MII) in the medium with 100 ng/ml (87.0%) than without Ang II (61%). When oocytes from different sizes of follicles were separately cultured in media containing 100 ng/ml Ang II, maturation rates were significantly higher in oocytes from small (61.5%) and medium (85.1%) follicles than that of their controls (45.1 and 72.6%, respectively). However, addition of Ang II inhibited nuclear maturation in oocytes from large follicles (77.8% versus 87.3%). Fertilization and male pronuclear (MPN) formation rates of oocytes matured in medium containing 100 or 1000 ng/ml of Ang II were higher (P<0.05) than that of oocytes matured in medium containing 0 or 10 ng/ml Ang II. Glutathione content in oocytes cultured for 44 h in medium containing 100 or 1000 ng/ml of Ang II was also higher (P<0.01) than that of oocytes cultured in medium containing 0 or 10 ng/ml Ang II. In conclusion, Ang II was present in porcine ovaries and may regulate follicle growth and oocyte maturation.

[Studies on synthesis and degradation of collagen at transcription level in liver fibrosis of rabbits with schistosomiasis japonica]

OBJECTIVE

To study the synthesis and degradation of collagen at the transcription level during liver fibrosis in rabbits with schistosomiasis japonica.

METHODS

New Zealand rabbits infected with Schistosoma japonicum cercariae were served as animal models of liver fibrosis. The liver specimens were collected through operations at 4, 6, 8, 10, 12, 16, 20, 24 and 28 weeks after infection. Type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels of liver tissue were detected by RT-PCR plus dot blotting, and the size of egg granulomas and the degree of liver fibrosis were measured by histopathological examinations.

RESULTS

Type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels increased simultaneously in the early stage after the infection, mostly reaching their peaks at 10 weeks after infection. Compared with normal controls, type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels increased by 12.0-, 11.0-, 6.6-, 10.0- and 11.0-fold, respectively, coinciding with the changes of egg granulomas. Thereafter, both collagen and collagenase mRNA levels decreased. Types I, III and IV collagen mRNA levels declined to 2-fold to 3-fold compared with normal controls (P < 0.05), while MMP-1 and MMP-9 mRNA levels declined to normal level (P > 0.05) at 28 weeks. This study showed that the synthesis and degradation of collagen remained dynamic balance in the early stage of schistosomiasis, while in the later stage the metabolism of collagen synthesis was higher than that of collagen degradation.

CONCLUSION

It was confirmed at the transcription level that when the metabolism of collagen synthesis was higher than that of collagen degradation in rabbits with schistosomiasis japonica, liver fibrosis might be produced.

The enrichment of a ruminal bacterium (Megasphaera elsdenii YJ-4) that produces the trans-10, cis-12 isomer of conjugated linoleic acid

AIMS

To isolate predominant ruminal bacteria that produce trans-10, cis-12 conjugated linoleic acid (CLA) from linoleic acid (LA).

METHODS AND RESULTS

Mixed bacteria from ruminal contents of a cow fed grain were enriched with DL-lactate and trypticase. They produced more trans-10, cis-12 CLA than those that were not enriched (7 vs 2 microg mg protein(-1), P < 0.05). Enrichments had an abundance of large cocci that produced trans-10, cis-12 CLA from LA. Strain YJ-4 produced the most trans-10, cis-12 CLA (approx. 7 microg mg protein(-1)) and 16S rDNA sequencing indicated that YJ-4 was a strain of Megasphaera elsdenii. Megasphaera elsdenii T81 produced approx. 4 microg trans-10, cis-12 CLA mg protein(-1) while strains B159, AW106 and JL1 produced < 0.5 microg mg protein(-1). The trans-10, cis-12 CLA production of YJ-4 was first order with respect to cell concentration (0-800 microg protein ml(-1)), but kinetics were not first order with respect to substrate concentration.

CONCLUSIONS

Some M. elsdenii strains produce significant amounts of trans-10, cis-12 CLA.

SIGNIFICANCE AND IMPACT OF THE STUDY

Trans-10, cis-12 CLA appears to cause milk fat depression in cattle fed diets supplemented with grain and polyunsaturated fatty acids, but predominant ruminal bacteria that produced trans-10, cis-12 CLA from LA had not previously been isolated.

Early events involved in the development of insulin resistance in Zucker fatty rat

AIM

To clarify the mechanism by which insulin resistance develops in obesity, Zucker fatty rats (ZFR) and lean litter mates (ZLR) were temporally subjected to oral glucose tolerance tests (OGTT) at 6 and 15 weeks of age.

METHOD

As candidates for causative factors of insulin resistance, plasma leptin, free fatty acids (FFA) and tumor necrosis factor (TNF)-alpha levels were evaluated.

RESULTS

There was no difference in the body weight between the two groups at 6 weeks of age, but ZFR were significantly heavier than ZLR at 15 weeks of age. At 6 weeks of age, blood glucose levels and area under the curve of glucose (AUCg) during OGTT were not significantly different between the two groups, while plasma insulin levels and area under the curve of insulin (AUCi) in the ZFR group were significantly higher than those in the ZLR group. At 15 weeks of age, the blood glucose levels and AUCg as well as plasma insulin levels and AUCi in the ZFR group during OGTT were significantly higher than those in the ZLR group. The ratio of fasting insulin to glucose in the ZFR group was significantly higher than that in the ZLR group at 6 and 15 weeks of age. Peripheral and portal plasma leptin and FFA levels were significantly higher in ZFR than ZLR both at 6 weeks and 15 weeks of age. Meanwhile, at 6 weeks, plasma TNF-alpha levels and expression of TNF-alpha protein in subcutaneous and visceral fat tissues were similar in both groups; however at 15 weeks, these were significantly higher in the ZFR group than the ZLR group.

CONCLUSION

These results suggest that FFA rather than TNF-alpha may play an important role in early events involved in the development of insulin resistance and TNF-alpha accelerates insulin resistance together with FFA in the later stage.

An organic self-regulating microfluidic system

In this paper we present an organic feedback scheme that merges microfluidics and responsive materials to address several limitations of current microfluidic systems. By using in situ fabrication and by taking advantage of microscale phenomena (e.g., laminar flow, short diffusion times), we have demonstrated feedback control of the output pH in a completely organic system. The system autonomously regulates an output stream at pH 7 under a range of input flow conditions. A single responsive hydrogel component performs the functionality of traditional feedback system components. Vertically stacked laminar flow is used to improve the time response of the hydrogel actuator. A star shaped orifice is utilized to improve the flow characteristics of the membrane/orifice valve. By changing the chemistry of the hydrogel component, the system can be altered to regulate flow based on hydrogels sensitive to temperature, light, biological/molecular, and others.

Mechanistic studies on the use of 2H- and 13C-analogues as internal standards in selected ion monitoring GC-MS quantitative determination--butalbital example

As a part of our study on the use of isotopic analogues as the internal standard (IS) for the quantitation of drug analytes, this article reports on the performance characteristics of 2H5-butalbital and 13C4-butalbital with particular focus on (1) determining and comparing the effectiveness of the 2H- and 13C-analogues in serving as the ISs for quantitation; (2) understanding the "cross-contribution" phenomenon underlying the effectiveness of selected ion pairs used for quantitation purpose; and (3) examining whether the same characteristics, observed in our preliminary report for the secobarbital/2H5-secobarbital/13C4-secobarbital system, also exist in the butalbital/2H5-butalbital/13C4-butalbital system. Adapting similar procedures applied to our previous study on the secobarbital system, we observed that (1) both labeled analogues (13C4-butalbital and 2H5-butalbital) cause more significant cross-contributions to ions designated for butalbital than butalbital to the labeled analogues; (2) compared to 2H5-butalbital, 13C4-butalbital appears to cause less cross-contributions to ions designated for butalbital; (3) cross-contribution between the following ion pairs are minimal: m/z 200/196, 199/195, 185/181 (13C4-butalbital as the IS) and m/z 201/196 (2H5-butalbital as the IS). It is also concluded that the butalbital/2H5-butalbital system exhibits the same concentration dependency phenomenon observed in the secobarbital/ 2H5-secobarbital system, that is, ratios of ion pairs designated for these two isotopic analogues (resulting from routine gas chromatography-mass spectrometry protocol) increase as their concentrations are diluted. (In parallel with the secobarbital/13C4-secobarbital system, the butalbital/13C4-butalbital system does not exhibit this phenomenon.)

Isotopic analogs as internal standards for quantitative analyses by GC/MS--evaluation of cross-contribution to ions designated for the analyte and the isotopic internal standard

Isotopic analogs of the analytes are currently preferred internal standards (IS) for quantitative analyses of drugs and their metabolites in biological matrices by GC/MS procedures. Contributions of the analyte and the IS to the intensities of ions designated for the IS and the analyte, respectively--an undesirable phenomenon termed "cross-contribution"--greatly weakens the effectiveness of this approach. The cross-contribution phenomenon has been, in the past, evaluated by a "direct measurement" approach, in which intensities of interested ions were measured in two separate experiments using equal quantities of the analyte and the IS. Alternate procedures that may generate improved results are hereby studied. For the "improved direct measurement" approach, ion intensity data derived from the previously reported direct measurement procedure are first normalized before being used to calculate the extent of cross-contribution. An "internal standard" approach is also developed, in which a set amount of a third compound is incorporated into these two separate experiments, thus allowing corrections of ion intensity data that are imbedded with variations inherent to separate experiments. Finally, a "standard addition" approach, involving a series "addition" of "standards", generates multiple data points; thus, providing a mechanism to validate the resulting cross-contribution data. Secobarbital/(2)H(5)-secobarbital and secobarbital/(13)C(4)-secobarbital pairs are adapted as the exemplar systems for this study.

Spectra interference between diquat and paraquat by second derivative spectrophotometry

A rapid and accurate method, combining solid-phase extraction and second-order derivative spectrophotomety approaches, is developed for the simultaneous determination of diquat (DQ) and paraquat (PQ) in blood, tissue and urine samples. Supernatant resulting from the precipitation of protein (with trichloroacetic acid) in plasma and tissue or Amberlite IRA-401 resin treated urine are passed through a mini-column packed with Wakogel gel (Silica gel). Analytes are then eluted with a non-organic solvent, 0.2mol/l HCl solution containing 2mol/l NH(4)Cl. UV spectrum of the eluent in 220-350nm range provides effective screen to detect the presence of DQ and/or PQ. In the presence of DQ or PQ alone, the analyte present is quantitated by conventional zero- or second-order derivative spectrophotometry. The calibration curve in the 0.1-5.0mg/l range for either analyte obeys Beer's law. When both DQ and PQ are present, their concentrations are determined by the peak amplitudes of their respective second-derivative spectra after the addition of alkaline dithionite reagent. Interference is negligible when the DQ/PQ concentration ratio is within the 5.0-0.2 range. Using a 2-ml of sample size, the detection limits for DQ and PQ in plasma are 0.02 and 0.005mg/l. The corresponding detection limits for urine samples (10ml sample size) are 0.004 and 0.001mg/l. Recoveries of DQ and PQ in triplicate plasma and urine samples spiked with 0.5mg/l of analytes are 93 and 85%. The precision of the proposed method resulting from triplicate study of spiked urine samples varies from 3.2 to 4.6% at 0.5mg/l of DQ and PQ, respectively.

Isotopic analogues as internal standards for quantitative analyses of drugs and metabolites by GC-MS--nonlinear calibration approaches

In order to achieve accurate quantitation of drugs and metabolites (analytes) in complex matrices, 2H- (and less commonly 13C-) labeled analogues of the analytes are now routinely adapted as the internal standards (IS) using linear calibration models to fit data generated by selected ion monitoring gas chromatography-mass spectrometry (GC-MS) protocols. In this study, the effects of cross-contribution (contribution of the IS to the intensity of the ion designated for the analyte and vice versa) on the linearity of the calibration data are examined. Nonlinear approaches that may address this problem are also studied. Two ion pairs (one with least and one with significant cross-contribution) from each of the following analyte/IS pairs are used as the exemplar systems for this study: butalbital/13C4-butalbital, butalbital/2H5-butalbital, secobarbital/13C4-secobarbital, and secobarbital/2H5-secobarbital. Analyte/IS ion intensity ratios of a series of standard solutions are correlated with the analyte/IS concentration ratios using one-point, multiple-point (unweighted and weighted) linear, and hyperbolic functions. The one-point calibration approach produces excellent calibration results in treating data derived from ion pairs with no significant cross contribution. In cases where significant cross-contribution exists, results derived from the one-point approach show, as expected, significant deviations at both ends of the concentration range. With the cross-contribution phenomenon accounted for, the hyperbolic calibration model is clearly more effective in fitting calibration data at both the lower and higher analyte concentration ends, thus significantly lowering the detection limit and extending the calibration range to a higher level. However, the calibration range cannot be extended indefinitely. At the low concentration end, noise-to-signal ratio and the cross-contribution of the IS to the intensity of the ion designated for the analyte, however insignificant, will incrementally reduce the quality of the observed ion intensity and intensity ratio data. At the high concentration end, detection saturation and the cross-contribution of the analyte to the intensity of the ion designated for the IS, however insignificant, will incrementally decrease the "slope" of the calibration curve. Thus, acceptable sensitivity (increase in analyte/IS ion-pair intensity ratio per unit increase in analyte concentration) of the calibration curve will become the limiting factor.

Animal experiment and clinical study of effect of gamma-interferon on hepatic fibrosis

AIM

To evaluate the antifibrotic effect of different doses of recombinant human Gamma-Interferon (IFN-gamma) in two rat models of hepatic fibrosis, and to observe its effect on moderate chronic hepatitis B virus fibrosis.

METHODS

Hepatic fibrosis was successfully induced in 150 and 196 rats by subcutaneous injection of carbon tetrachloride (CCl4) and intraperitoneal injection of dimethylnitrosamine (DMN), respectively. Each of the two model groups was divided into: (1) fibrotic model group; (2) colchicine treatment group (0.1 mg/kg/day, gastrogavage for 8 weeks); (3) high-dose IFN-gamma group (15 MU/kg per day, i.m. for 8 weeks); (4) medium-dose IFN-gamma group (5 MU/kg daily, i.m. for 8 weeks); and (5) Y low-dose IFN-gamma group (1.67 MU/kg daily, i.m. for 8 weeks). Another group of 10 rats without any treatment was used as normal controls. At the end of the experiment, semi-quantitative histopathological scores of inflammation and fibrosis, liver alpha smooth muscle actin (alpha-SMA) expression level, liver hydroxyl proline content and serum hyaluronic acid levels were compared. And 47 medium chronic hepatitis B viral fibrosis patients were studied. They were given IFN-gamma treatment, 100 MU/day i.m. for the first three months and 100 MU qod i.m. for the next six months. Semi-quantitative pathological scores of inflammation and fibrosis and serum hepatic fibrosis indices were compared within the 9 months.

RESULTS

In animal experiment, the pathological fibrosis scores and liver hydroxyl proline content were found to be significantly lower in rats treated with different doses of IFN-gamma as compared with rats in fibrotic model group induced by either CCl4 or DMN, in a dose-dependent manner. For CCl4-induced model, pathological fibrosis scores in high, medium and low doses IFN-gamma groups were 5.10 +/- 2.88, 7.70 +/- 3.53 and 8.00 +/- 3.30, respectively, but the score was 14.60 +/- 7.82 in fibrotic model group. Hydroxyl proline contents were 2.83 +/- 1.18, 3.59 +/- 1.22 and 4.80 +/- 1.62, in the three IFN-gamma groups, and 10.01 +/- 3.23 in fibrotic model group. The difference was statistically significant (P<0.01). Similar results were found in DMN-induced model. Pathological fibrosis scores were 6.30 +/- 0.48, 8.10 +/- 2.72 and 8.30 +/- 2.58, in high, medium and low doses IFN-gamma groups, and 12.60 +/- 3.57 in fibrotic model group. Hydroxyl proline contents were 2.72 +/- 0.58, 3.14 +/- 0.71 and 3.62 +/- 1.02, in the three IFN-gamma groups, and 12.79 +/- 1.54 in fibrotic model group. The difference was statistically significant (P<0.01). Serum hepatic fibrosis indices decreased significantly in the 47 patients after IFN-gamma treatment (HA: 433.38 +/- 373.00 vs 281.57 +/- 220.48; LN: 161.22 +/- 41.02 vs 146 +/- 35 +/- 44. 67; PC III: 192.59 +/- 89.95 vs 156.98 +/- 49.22; C-I: 156.30 +/- 44.01 vs 139.14 +/- 34.47) and the differences between the four indices were significant (P <0.05). Thirty-three patients received two liver biopsies, one before and one after IFN-gamma treatment. In thirty of 33 patients IFN-gamma had better effects according to semi-quantitative pathological scores (8.40 +/- 5.83 vs 5.30 +/- 4.05, P<0.05).

CONCLUSION

All the three doses of IFN-gamma are effective in treating rat liver fibrosis induced by either CCl4 or DMN, the higher the dose, the better the effect. And IFN-gamma is effective for patients with moderate chronic hepatitis B viral fibrosis.

Oral nicotine administration decreases tumor necrosis factor-alpha expression in fat tissues in obese rats

To investigate the effect of oral nicotine administration on insulin resistance and insulin secretion in an animal model of obesity, Zucker fatty rats were administered nicotine tartrate dihydrate orally through tap water (4.6 mg/kg/d, N group). Plasma nicotine concentrations in N group were 33.67 +/- 10.49 ng/mL. The control (C) group consisted of pair-fed control rats. After 8 weeks of nicotine administration, both groups of rats were administered glucose (2 g/kg) orally in an anesthetized state, and blood was collected for glucose and plasma insulin measurements. The pancreases were isolated and perfused in vitro under pentobarbital anesthesia 1 week after glucose administration. The fat tissues were excised. The levels of tumor necrosis factor (TNF)-alpha protein were assessed using enzyme-linked immunosorbent assay (ELISA) or Western blot analysis. Serum leptin levels were measured using radioimmunoassay (RIA). Blood glucose levels in N group were significantly lower than in C group before and 120 minutes after glucose administration. The insulin secretion from the isolated perfused pancreases of N group appeared to be decreased compared with C group, but there was no significant difference. Histologic examination showed that the mean size of the pancreatic islets in N group was significantly smaller than in C group. The composition ratios of alpha and beta cell mass of the pancreatic islets and fibroelastic tissues were not altered by nicotine administration. Portal TNF-alpha levels were comparable to peripheral levels in both groups. There were no significant differences in peripheral serum levels of TNF-alpha, free fatty acids (FFA), or leptin levels between N and C group. The TNF-alpha levels in visceral fat tissues in N group were significantly lower than those in C group. These results suggest that oral nicotine administration reduces insulin resistance in obese diabetic rats by decreasing production of TNF-alpha in the visceral fat tissues. Decreased islet size may be a secondary phenomenon induced by ameliorated insulin resistance, because the cellularity and fibroelastic tissues were not affected by the nicotine.

Microfluidic tectonics: a comprehensive construction platform for microfluidic systems

A microfluidic platform for the construction of microscale components and autonomous systems is presented. The platform combines liquid-phase photopolymerization, lithography, and laminar flow to allow the creation of complex and autonomous microfluidic systems. The fabrication of channels, actuators, valves, sensors, and systems is demonstrated. Construction times can be as short as 10 min, providing ultrarapid prototyping of microfluidic systems.

Effect of linoleic acid concentration on conjugated linoleic acid production by Butyrivibrio fibrisolvens A38

Butyrivibrio fibrisolvens A38 inocula were inhibited by as little as 15 microM linoleic acid (LA), but growing cultures tolerated 10-fold more LA before growth was inhibited. Growing cultures did not produce significant amounts of cis-9, trans-11 conjugated linoleic acid (CLA) until the LA concentration was high enough to inhibit biohydrogenation, growth was inhibited, and lysis was enhanced. Washed-cell suspensions that were incubated anaerobically with 350 microM LA converted most of the LA to hydrogenated products, and little CLA was detected. When the washed-cell suspensions were incubated aerobically, biohydrogenation was inhibited, CLA production was at least twofold greater, and CLA persisted. The LA isomerase reaction was very rapid, but the LA isomerase did not recycle like a normal enzyme to catalyze more substrate. Cells that were preincubated with CLA lost their ability to produce more CLA from LA, and the CLA accumulation was directly proportional (r(2) = 0.98) to the initial cell density. Growing cells were as sensitive to CLA as LA, the LA isomerase and reductases of biohydrogenation were linked, and free CLA was not released. Because growing cultures of B. fibrisolvens A38 did not produce significant amounts of CLA until the LA concentration was high, biohydrogenation was arrested, and the cell density had declined, the flow of CLA from the rumen may be due to LA-dependent bacterial inactivation, death, or lysis.

trans-10,cis-12-conjugated linoleic acid isomer exhibits stronger oxyradical scavenging capacity than cis-9,trans-11-conjugated linoleic acid isomer

Although studies have been performed to test whether conjugated linoleic acid (CLA) acts as an antioxidant, the results were not conclusive. In addition, the CLA widely used in previous research contains 43% cis-9,trans-11 isomer, 45% trans-10,cis-12 isomer, and 10 other minor isomers. The objective of this study was to investigate the antioxidant activity of cis-9,trans-11- and trans-10, cis-12-CLA isomers using high-purity CLA isomers (>98%) by total oxyradical scavenging capacity assay (Winston, G. W.; Regoli, F.; Dugas, Jr., A. J.; Fong, J. H.; Blanchard, K. A. Free Radical Biol. Med. 1998, 24, 480-493). At all concentrations (2-200 microM), t10, c12-CLA performed as an antioxidant with a 15-min lag phase, which was more effective than c9,t11-CLA and alpha-tocopherol at lower concentrations (2 and 20 microM). On the other hand, c9,t11-CLA possessed weak antioxidant activity at 2 and 20 microM, whereas at 200 microM it acted as a strong pro-oxidant, which suggests that discrepancies of the results of the previous studies on the antioxidant properties of CLA may be due to the balance of the antioxidant properties of t10,c12-CLA and the pro-oxidant properties of c9,t11-CLA in different oxidation conditions.

[Effects on ang II receptor antagonist on experimental glomerulosclerosis]

OBJECTIVE

To observe the effects of angiotensin II receptor antagonist losartan in experimental glomerulosclerosis.

METHODS

The 5/6 nephrectomized rats were randomly divided into losartan treatment group and control group, the rats with sham operation served as normal control. Urine proteins were measured in the 2nd, 4th and 6th week after operation, and serum BUN, creatinine, total protein and albumin were measured in the 6th week following operation. Renal pathologic changes were evaluated in the 6th week.

RESULTS

Losartan not only reduced urine protein, serum creatinine and BUN(P < 0.01), but also significantly ameliorated glomerular mesangial proliferation and glomerular sclerosis.

CONCLUSION

The results suggest that losartan can retard progression of glomerulosclerosis in 5/6 nephrectomized rats.

Nephrotoxicity of high- and low-osmolar contrast media. The protective role of amlodipine in a rat model

PURPOSE

To evaluate the nephrotoxicity of high- and low-osmolar contrast media (HOCM, LOCM) on kidneys in Sprague-Dawley rats. The protective role of amlodipine was studied.

MATERIAL AND METHODS

Forty rats of both sexes were randomly divided into 5 groups (n=8/group) and glycerine for inducing renal failure was given to all rats except controls.

RESULTS

In diatrizoate-injected rats, blood urea nitrogen (BUN) and serum creatinine (SCr) were increased; levels of phospholipase A2 (PLA2), lipid peroxide (LPO) and calcium were also increased in renal tissues. There was no significant difference between LOCM (iohexol) animals and glycerol controls either in the renal levels of PLA2, LPO and calcium or in the levels of BUN and SCr. The histologic changes were milder in the LOCM animals than in the HOCM animals. In the group pretreated with amlodipine, no increase in the levels of BUN or SCr was discovered and the renal content of PLA2, LPO and calcium were significantly lower than in the HOCM group; the renal injuries induced by diatrizoate were alleviated.

CONCLUSION

The HOCM, diatrizoate, was more toxic to rat kidneys than the LOCM iohexol; PLA2, LPO and calcium load played a role in producing renal function impairment induced by diatrizoate meglumine; amlodipine protected the renal tissue from nephrotoxicity induced by diatrizoate.

[Modulation of prolactin (PRL) secretion in human uterine decidual cells at early pregnancy]

Decidualization is essential for implantation of embryo and maintenance of pregnancy in human. The mechanism of decidualization was investigated in this study by regulation of prolactin (PRL) release in cultured human decidual cells during first trimester of gestation. Progesterone significantly stimulated PRL secretion, but the effect of estrogen depended on its concentration, which was ineffective at the physiological level (10( 9) mol/L) but suppressed the stimulatory effect of progesterone at higher levels. Thus adequate proportion of estrogen and progesterone is important for the decidualization. Furthermore, RU486 dramatically inhibited PRL release, suggesting that the effect of progesterone was mediated, at least in part, through its receptor. cAMP at concentration higher than 10( 5) mol/L significantly increased PRL secretion, suggesting that the cAMP signal pathway might be involved in decidualization.