Cognizant Fiber-Reinforced Polymer Composites Incorporating Seamlessly Integrated Sensing and Computing Circuitry

Structural fiber-reinforced polymer (FRP) composite materials consisting of a polymer matrix reinforced with layers of high-strength fibers are used in numerous applications, including but not limited to spacecraft, vehicles, buildings, and bridges. Researchers in the past few decades have suggested the necessary integration of sensors (e.g., fiber optic sensors) in polymer composites to enable health monitoring of composites' performance over their service lives. This work introduces an innovative cognizant composite that can self-sense, compute, and implement decisions based on sensed values. It is a critical step towards smart, resilient infrastructure. We describe a method to fabricate textile sensors with flexible circuitry and a microcontroller within the polymer composite, enabling computational operations to take place in the composite without impacting its integrity. A microstructural investigation of the sensors showed that the amount of oxidative agent and soaking time of the fabric play a major role in the adsorption of polypyrrole (PPy) on fiberglass (FG). XPS results showed that the 10 g ferric chloride solution with 6 h of soaking time had the highest degree of protonation (28%) and, therefore, higher adsorption of PPy on FG. A strain range of 30% was achieved by examining different circuitry and sensor designs for their resistance and strain resolution under mechanical loading. A microcontroller was added to the circuit and then embedded within a composite material. This composite system was tested under flexural loading to demonstrate its self-sensing, computing, and actuation capabilities. The resulting cognizant composite demonstrated the ability to read resistance values and measure strain using the embedded microcontroller and autonomously actuate an LED light when the strain exceeds a predefined limit of 2000 µε. The application of the proposed FRP system would provide in situ monitoring of structural composite components with autonomous response capabilities, as well as reduce manufacturing, production, and maintenance costs.

[Clinical and genetic analysis of cases of progressive familial intrahepatic cholestasis type 3]

Objective: To conduct clinical and genetic analysis in two cases of cholestatic liver disease to determine the specific etiology of cholestasis. Methods: Clinical data and the medical histories in family members of two cases were collected. The gene variation was detected by whole-exome sequencing technology. Sanger sequencing validation and bioinformatics analysis were performed on patients and their parents with suspected pathogenic mutations. Results: Whole-exome sequencing showed that the ABCB4 gene of case 1 (a male, 16 years old) had compound heterozygous mutations of c.646C > T from the father and c.927T > A from the mother, while the ABCB4 gene of case 2 (a female, 17 years old) had a compound heterozygous mutation of c.2784-1G > A from the father and c.646C > T from the mother. New mutation sites that had not been previously reported were c.646C > T, c.927T > A, and c.2784-1G > A. Conclusion: In this study, both cases had progressive familial intrahepatic cholestasis type 3 (PFIC-3) caused by ABCB4 gene mutations, and it also enriched the ABCB4 pathogenic variant spectrum. Whole-exome sequencing technology provides a reliable diagnostic tool for etiological analysis.

Prefabricated platinum nanomaterial matrix for MALDI-MS imaging of oligosaccharides and lipids in plant tissues

Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) can visualize the spatial distribution characteristics of molecules in tissues in situ, in which the matrix plays a key role. In this paper, we propose a platinum nanomaterial pre-coated matrix, which can be prepared in bulk by sputtering platinum nanoparticles onto slides using an ion sputterer and then used for MALDI-MS analysis by placing tissue sections on the matrix. We used this matrix for MALDI-MS imaging analysis of corn kernels and germinated wheat sections, and the results show that triacylglycerides were mainly distributed in the embryo of corn kernels and germinated wheat, and sugars were mainly distributed in the endosperm, with the highest content of disaccharides.It provides a simple and reliable experimental condition for analyzing the distribution of oligosaccharide and lipid components in plant tissues.

Evolution of Thin-Film Wrinkle Patterns on a Soft Substrate: Direct Simulations and the Effects of the Deformation History

Surface wrinkling instability in thin films attached to a compliant substrate is a well-recognized form of deformation under mechanical loading. The influence of the loading history on the formation of instability patterns has not been studied. In this work, the effects of the deformation history involving different loading sequences were investigated via comprehensive large-scale finite element simulations. We employed a recently developed embedded imperfection technique which is capable of direct numerical predictions of the surface instability patterns and eliminates the need for re-defining the imperfection after each analysis step. Attention was devoted to both uniaxial compression and biaxial compression. We show that, after the formation of wrinkles, the surface patterns could still be eliminated upon complete unloading of the elastic film-substrate structure. The loading path, however, played an important role in the temporal development of wrinkle configurations. With the same final biaxial state, different deformation histories could lead to different surface patterns. The finding brings about possibilities for creating variants of wrinkle morphologies controlled by the actual deformation path. This study also offers a mechanistic rationale for prior experimental observations.

[Clinical features of children with post-primary tuberculosis]

Objective: The aim of this study was to summarize the clinical and imaging characteristics of post-primary tuberculosis in children, so as to improve the early identification and diagnosis of post-primary tuberculosis. Methods: This was a retrospective study which enrolled children who were admitted to the Department No.2 of Respiratory Medicine, Beijing Children's Hospital Affiliated to Capital Medical University between January 2015 to December 2020 and with a diagnosis of post-primary tuberculosis. Results: A total of 30 patients were enrolled, including 10 males and 20 females. The age on admission were 13.0 (12.0, 13.3) years. Their common symptoms were cough and fever, there were 26 cases (87%) with cough and 23 cases (77%) with fever, but only 4 cases (13%) had other toxic symptoms (night sweat, weakness or weight loss) of tuberculosis other than fever. Blood examination showed that the white blood cell count was (10±3)×10⁹/L, accompanied by elevated proportion of neutrophils (0.69±0.11) and increased level of C-reactive protein (31 (15,81) mg/L). The common radiographic findings of CT were nodular or mass shadow with cavitation (19 cases (63%)), consolidation (13 cases (43%)), bronchogenic spread (12 cases (40%)), hilar or mediastinal lymphadenopathy (5 cases (17%)) in this cohort. The affected locations included the right upper lobe (21 cases (70%)), the left lower lobe (17 cases (57%)) and the right lower lobe (15 cases (50%)). Acid-fast bacillus smears and mycobacterial cultures were attempted for all cases, resulting in 33% (10/30) with smear positivity and 50% (15/30) with culture positivity. Conclusions: Post-primary tuberculosis in children has no specific clinical manifestations. Imaging of chest CT is mainly manifested as nodular shadow with cavitation, consolidation or bronchogenic spread. Accurate identification of post-primary tuberculosis is crucial for preventing the spread and early treatment of tuberculosis.

[Clinical features and early diagnostic clues of chronic granulomatous disease]

Objective: To explore the early clinical clues for diagnosis of chronic granulomatous disease (CGD). Methods: One hundred and thirty-nine children with CGD seen in Beijing Children's Hospital from January 2007 to October 2020 were included in this study. The clinical features including age of onset, first presentations, reason for being hospitalized, etiology, imaging features, clues for early diagnosis of all patients were evaluated retrospectively. According to the time of diagnosis, the patients were divided into two groups, cases diagnosed before 2015 and after 2015 and 2015. The time of diagnosis, the length of stay and the hospital charges were compared between the two groups. T test and χ² test were used for statistical analyses. Results: One hundred and nineteen of the cases were males and 20 were females. The age of onset was 4 months (8 d to 14 years), and 103 cases (74.1%) had onset before 1 year of age. The age at diagnosis was 1.8 years (21 d to 14.7 years), and the time of diagnosis delay was 1 year (7 d to 13.7 years). One hundred and thirty-five cases (97.1%) had pulmonary infection as the main reason for hospitalization, of whom 76 cases (56.3%) had positive pulmonary etiology. One hundred and thirty-six patients (97.8%) were referred cases, of whom 5 were suspected of CGD before referral, and the misdiagnosis rate was as high as 96.3% (131/136). Eight early clues for diagnosis were found, the frequency from high to low, large bacillus Callmette-Guer scar in 99 cases (70.5%), left axillary lymphadenopathy or calcification in 73 cases (52.5%), skin or other lymph node infections in 58 cases (41.7%), skin scars in 50 cases (36.0%), multiple lung nodules in 42 cases (30.2%), perianal abscess in 35 cases (25.2%), pulmonary Aspergillus infection in 26 cases (18.7%) and pulmonary Burkholderia infection in 15 cases (10.8%). A total of 120 cases of CGD were diagnosed by respiratory burst test during hospitalization, including 55 cases diagnosed before 2015 and 65 cases diagnosed after 2015. After using these 8 early diagnosis clues, the cases diagnosed after 2015 had shorter time of diagnosis and the length of stay and lower hospitalization charge than cases diagnosed before 2014, and the difference was statistically significant ((25±7) vs. (10±5) d, (29±7) vs. (18±6) d, (3.7×10⁴±1.2×10⁴) vs. (3.2×10⁴±1.2×10⁴) Yuan, t=13.763, 9.262, 2.381, all P<0.05). Conclusions: Patients with CGD are younger at onset and the diagnosis is delayed. Pulmonary infections are the most common. Large BCG scar, left axillary lymphadenopathy or calcification, skin or other lymph node infections, skin scars, multiple lung nodules, perianal abscesses, pulmonary Aspergillus infection and Burkholderia infection can help early diagnosis of CGD.

Mineral Composition and Its Control on Nanopores of Marine-Continental Transitional Shale from the Ningwu Basin, North China

There is a large difference between the sedimentary environment and maturity of organic matter between marine shale and marine-continental transitional shale. It is of great significance to discuss the effect of inorganicminerals on the pores for marine-continental transitional shale gas exploration. In this study, scanning electron microscopy (SEM), low temperature liquid nitrogen adsorption and Xray diffraction (XRD) were conducted on eight marine-continental transitional shale samples from the Ningwu Basin, Shanxi Province, China. The pore structure differences in the different minerals were discussed, and the relationship between the mineral content and pore parameters was analysed. The results show that the mineral composition of shale is dominated by clay minerals, quartz, carbonate minerals and a small amount of pyrite. The clay minerals content is between 39.5% and 77.0%, with an average of 59.9%. The quartz content ranges from 21.8% to 47.8%, with an average of 31.9%. The carbonate minerals content in shale is between 0.6% and 23.9%, and the average is 6.3%. The clay minerals are composed of mixed illite-montmorillonite layer, kaolinite and chlorite. The content of mixed illite-montmorillonite layer is between 13.8% and 27.4%, with an average of 20.4%. The kaolinite content ranges from 57.0% to 86.2%, with an average of 76.0%. The content of chlorite is between 0 and 15.6%, with an average of 5.7%. The types of pores are mainly intergranular pores and interlaminar pores, which are mostly presented as slit and parallel plates. The mixed illite-montmorillonite layer contributes more to the specific surface area, which is favourable for shale gas adsorption. The pores in kaolinite are more developed than those of the mixed illite-montmorillonite layer, but the pore diameter is relatively large. The quartz granule has a complete crystal type, and intergranular pores with a large pore size are often developed at the mineral contacts. Compared with clay minerals and quartz, the pore development in the carbonate minerals is relatively poor and develops more micro-fractures. The pyrite contributes a certain number of intergranular pores and mold pores.

[Clinical features of cystic fibrosis associated allergic bronchopulmonary aspergillosis in children]

Objective: To analyze the clinical features of cystic fibrosis (CF) associated allergic bronchopulmonary aspergillosis (ABPA) in children. Methods: A retrospective study was performed in 22 children who were diagnosed with CF associated ABPA in Beijing Children's Hospital affiliated to Capital Medical University from March 2010 to March 2020. The clinical features, imaging characteristics, laboratory results and the prognosis were reviewed. Results: A total of 22 cases met the diagnostic criterion, including 12 males and 10 females. The age of diagnosis was (10.4±2.8) years and the age of onset was (5.5±4.4) years. Clinical manifestations included cough and expectoration (22 cases), recurrent wheezing (15 cases), hemoptysis (7 cases), failure to thrive (12 cases), pancreatitis (10 cases), hepatomegaly (7 cases), splenomegaly (4 cases) and steatorrhea (4 cases). CT scans of all the patients showed pulmonary infiltrates and central bronchiectasis, combined with mucoid impaction in 17 cases and high density mucus plug in 12 cases. Eosinophilia was found in 18 patients. Total IgE and serum levels of A. fumigatus-specific IgE were elevated in all 22 patients. Positive culture of sputum or bronchoalvedar lauage fluid for fungus were in 15 cases, with single Aspergillus infection in 8 cases and mixed Aspergillus infection in 3 cases. The predominant bacteria found in the airways were Pseudomonas aeruginosa (17 cases), followed by staphylococcas. aureus (6 cases) and stenotrophomonas. maltophilia (5 cases). Pulmonary function revealed obstructive ventilation dysfunction in 4 cases, mixed dysfunction in 11 cases, and small airway dysfunction in 4 cases. Regarding the treatment, 3 were treated only with systemic corticosteroid, while the remaining 19 cases also received antifungal agents.The follow up continued for 1-7 years, and 6 maintained remission, 10 had recurrent episodes, 1 died, and 5 lost to follow up. Conclusions: CF associated ABPA is extremely rare in China. The overlapping clinical, radiographic, and immunologic features of these two diseases make the diagnosis challenging. Systemic corticosteroids are considered the first-line therapy for these patients, and adjuvant antifungal agents may be helpful. Recurrence rate in our center is high.

Instabilities of Thin Films on a Compliant Substrate: Direct Numerical Simulations from Surface Wrinkling to Global Buckling

For structures consisting of a thin film bonded to a compliant substrate, wrinkling of the thin film is commonly observed as a result of mechanical instability. Although this surface undulation may be an undesirable feature, the development of new functional devices has begun to take advantage of wrinkled surfaces. The wrinkled structure also serves to improve mechanical resilience of flexible devices by suppressing crack formation upon stretching and bending. If the substrate has a reduced thickness, buckling of the entire structure may also occur. It is important to develop numerical design tools for predicting both wrinkle and buckle formations. In this paper we report a comprehensive finite element-based study utilizing embedded imperfections to directly simulate instabilities. The technique overcomes current computational challenges. The temporal evolution of the wrinkling features including wavelength and amplitude, as well as the critical strains to trigger the surface undulation and overall structural buckling, can all be predicted in a straightforward manner. The effects of model dimensions, substrate thickness, boundary condition, and composite film layers are systematically analyzed. In addition to the separate wrinkling and buckling instabilities developed under their respective geometric conditions, we illustrate that concurrent wrinkling and buckling can actually occur and be directly simulated. The correlation between specimen geometry and instability modes, as well as how the deformation increment size can influence the simulation result, are also discussed.

[Value of sweat conductivity testing in the diagnosis of cystic fibrosis in children]

Objective: To assess the diagnostic value of sweat conductivity testing in Chinese children with cystic fibrosis (CF). Methods: This is a retrospective study. Sweat conductivity tests were conducted in 45 CF children (CF group) and 200 non-CF children (non-CF group) diagnosed with other chronic pulmonary diseases at the No. 2 Department of Respiratory Medicine, Beijing Children's Hospital from May 2014 to June 2018. Pearson's chi-square test was used to assess the differences between CF and non-CF groups. A receiver operating characteristic curve was constructed to calculate the best cut-off value to diagnose or rule out CF. The pulmonary function parameters (forced expiratory volume in the first second, forced vital capacity,forced expiratory flows at 75% of exhaled vital capacity) of CF children over 6 years old were analyzed. The relationship between sweat conductivity and pulmonary function was compared between the two groups (80-120mmol/L vs.>120mmol/L). Results: The age of CF group was 9 (7,12) years old, 19 males (42%) and 26 females(58%); the age of non-CF group was 8 (5,11) years old, 106 males (53%) and 94 females(47%). The results of sweat conductivity test showed that sweat conductivity in CF group 108(99, 122) mmol/L was significantly higher than that in non-CF group 43(36, 52) mmol/L (χ(2)=207, P<0.01). A cut-off value of 80 mmol/L for CF diagnosis showed a sensitivity of 93.3% and a specificity of 98.5%. The receiver operating characteristic curve analysis suggested the best conductivity cut-off value for the diagnosis of CF was at 83.5 mmol/L,with a sensitivity of 93.3% and a specificity of 100%,and an area under the curve of 0.993 (95% confidence interval 0.985-1.000). The best conductivity cut-off value to rule out CF diagnosis was at 63.5 mmol/L,with a sensitivity of 97.8% and a specificity of 90.5%. There was no correlation between the level of sweat conductivity and the extent of pulmonary function decline. Conclusions: Sweat conductivity testing can be used for the screening of CF in Chinese children. A diagnosis of CF should be considered if the value is greater than 80 mmol/L.

Biomechanical Heterogeneity of Living Cells: Comparison between Atomic Force Microscopy and Finite Element Simulation

Atomic force microscopy (AFM) indentation is a popular method for characterizing the micromechanical properties of soft materials such as living cells. However, the mechanical data obtained from deep indentation measurements can be difficult and problematic to interpret as a result of the complex geometry of a cell, the nonlinearity of indentation contact, and constitutive relations of heterogeneous hyperelastic soft components. Living MDA-MB-231 cells were indented by spherical probes to obtain morphological and mechanical data that were adopted to build an accurate finite element model (FEM) for a parametric study. Initially, a 2D-axisymmetric numerical model was constructed with the main purpose of understanding the effect of geometrical and mechanical properties of constitutive parts such as the cell body, nucleus, and lamellipodium. A series of FEM deformation fields were directly compared with atomic force spectroscopy in order to resolve the mechanical convolution of heterogeneous parts and quantify Young's modulus and the geometry of nuclei. Furthermore, a 3D finite element model was constructed to investigate indentation events located far from the axisymmetric geometry. In this framework, the joint FEM/AFM approach has provided a useful methodology and a comprehensive characterization of the heterogeneous structure of living cells, emphasizing the deconvolution of geometrical structure and the true elastic modulus of the cell nucleus.

Emodin inhibits the expression of receptor and calcitonin-gene-related peptide release in trigeminal ganglia of trigeminal neuralgia rats

Trigeminal neuralgia (TN) is one of the most intense forms of facial pain. It has been reported that the P2X₃ receptor plays a crucial role in facilitating pain transmission, and the calcitonin-gene-related peptide (CGRP) from trigeminal ganglia (TGs) might perform differing function in nociceptive afferent input transmission. The present study investigated whether emodin can affect TN pain transmission by suppressing the expression of P2X₃ receptors and CGRP in TGs. Chronic constriction injury of the infraorbital branch of the trigeminal nerve (CCI-ION) was used as TN model. The TN rats were randomly divided into the following 4 groups: (1) a sham group (Sham), (2) a sham rats treated with emodin group (TN + E), (3) a TN rats treated with 0.5% sodium carboxymethyl cellulose (CMC) as vehicle group (TN) and (4) a TN rats treated with emodin group (TN + E). The mechanical hyperalgesia threshold of TN rats was tested by Electric Von Frey filaments. The change of the expression of P2X₃ receptors and CGRP in rat's TG was detected with RT-PCR, immunohistochemical staining, and Western blotting. The phosphorylation of p38 and ERK1/2 pathway of TG was detected by Western blotting. After CCI-ION injury, the threshold of mechanical hyperalgesia for the territory of ligated infraorbital nerve in TN group decreased significantly compared with that in sham group. On day 14 after operation of CCI-ION, there was also an evident increase in the expression of P2X₃ receptors and CGRP in the TG of TN group. However after treatment with emodin, the response of mechanical hyperalgesia of TN rats was clearly increased while the enhanced expression of P2X₃ receptor and CGRP in TN rats was significantly decreased. The phosphorylation of p38 and ERK1/2 in TN group was stronger than that in Sham group. But these phosphorylation changes in the TN rats were much weaker after treatment with emodin. In conclusion, P2X₃ receptor may cooperate with CGRP in the pain transmission of TN, and emodin can inhibit the expression and activation of P2X₃ receptor and CGRP in TG to relieve TN.

[Effects of tetramethylpyrazine on trigeminal neuralgia induced by chronic constriction injury of infraorbital nerve in rats]

Trigeminal neuralgia (TN) is a kind of recurrent transient and severe pain that is limited to the trigeminal nerve in one or more branches. The clinical incidence of TN is high, which seriously affects the quality of life of the patients and is difficult to cure. The present study investigated the effects of tetramethylpyrazine (TMP) on TN induced by chronic constriction injury of the infraorbital nerve (ION-CCI) in rats. Adult male Sprague-Dawley rats were randomly assigned to four groups: sham, sham treated with TMP (Sham+TMP), TN model (TN), and TN treated with TMP (TN+TMP). The rat TN model was established by ION-CCI and TMP (50 mg/kg) was injected intraperitoneally once a day for 2 weeks after operation. The mechanical response threshold was tested by the electronic von Frey filaments. The expression of CGRP in the trigeminal ganglia (TGs) of rats on the operative side was detected by RT-PCR, immunohistochemical staining and Western blot. In 15 days after operation, TN group showed a robust decrease in mechanical response threshold as compared with sham group. From day 9 to day 15 after operation, TMP treatment significantly suppressed the TN-induced mechanical hyperalgesia (P < 0.05). On day 15 after operation, RT-PCR, immunohistochemical staining and Western blot analysis showed an obvious increase in expression level of CGRP in TGs of TN group compared with sham group, which was downregulated by TMP treatment (P < 0.05). These results suggested that TMP might have a therapeutic potential for the treatment of TN through regulating CGRP expression in the TGs.

Non-stick syringe needles: Beneficial effects of thin film metallic glass coating

This paper reports on the use of Zr-based (Zr₅₃Cu₃₃Al₉Ta₅) thin film metallic glass (TFMG) for the coating of syringe needles and compares the results with those obtained using titanium nitride and pure titanium coatings. TFMG coatings were shown to reduce insertion forces by ∼66% and retraction forces by ∼72%, when tested using polyurethane rubber block. The benefits of TFMG-coated needles were also observed when tested using muscle tissue from pigs. In nano-scratch tests, the TFMG coatings achieved a coefficient of friction (COF) of just ∼0.05, which is about one order of magnitude lower than those of other coatings. Finite-element modeling also indicates a significant reduction in injection and retraction forces. The COF can be attributed to the absence of grain boundaries in the TFMG coating as well as a smooth surface morphology and low surface free energy.

The electronic structure engineering of organic dye sensitizers for solar cells: The case of JK derivatives

The design and development of novel dye sensitizers are effective method to improve the performance of dye-sensitized solar cells (DSSCs) because dye sensitizers have significant influence on photo-to-current conversion efficiency. In the procedure of dye sensitizer design, it is very important to understand how to tune their electronic structures and related properties through the substitution of electronic donors, acceptors, and conjugated bridges in dye sensitizers. Here, the electronic structures and excited-state properties of organic JK dye sensitizers are calculated by using density functional theory (DFT) and time dependent DFT methods. Based upon the calculated results, we investigated the role of different electronic donors, acceptors, and π-conjugated bridges in the modification of electronic structures, absorption properties, as well as the free energy variations for electron injection and dye regeneration. In terms of the analysis of transition configurations and molecular orbitals, the effective chromophores which are favorable for electron injection in DSSCs are addressed. Meanwhile, considering the absorption spectra and free energy variation, the promising electronic donors, π-conjugated bridges, and acceptors are presented to design dye sensitizers.

[Evolutionary analysis of neuraminidase gene of A/H7N9 influenza virus]

In 2013, the World Health Organization reported the first case of human infection with a new influenza A (H7N9) virus in China. This has caused damage and panic within certain areas in China. Therefore, analysis of this virus with bioinformatics technology is very necessary. Neuraminidase (NA) is one of the most important antigens of the influenza virus and an important target for anti-flu drugs. In this study, the nucleotide and protein sequences of NA gene of A/H7N9 influenza viruses were retrieved from the NCBI database, and MEGA 5.0 software was employed to construct a phylogenetic tree based on the nucleotide coding sequence; BioEdit software was used to align the nucleotide and protein sequences of NA and calculate the homologies of nucleotides and amino acids and then to analyze the important mutation sites of NA gene. The results demonstrated that the spread of influenza virus H7N9 showed certain geographical and temporal relations. The H7N9 virus isolated from China in 2013 belonged to Euroasiatic serotype, and its NA stalk region hadobvious variation, which may be one of the reasons that this virus infects human. These analyses may be very helpful for understanding the evolutionary relationship and mutation trend of A/H7N9 influenza viruses.

Understanding the electronic structures and absorption properties of porphyrin sensitizers YD2 and YD2-o-C8 for dye-sensitized solar cells

The electronic structures and excitation properties of dye sensitizers determine the photon-to-current conversion efficiency of dye sensitized solar cells (DSSCs). In order to understand the different performance of porphyrin dye sensitizers YD2 and YD2-o-C8 in DSSC, their geometries and electronic structures have been studied using density functional theory (DFT), and the electronic absorption properties have been investigated via time-dependent DFT (TDDFT) with polarizable continuum model for solvent effects. The geometrical parameters indicate that YD2 and YD2-o-C8 have similar conjugate length and charge transfer (CT) distance. According to the experimental spectra, the HSE06 functional in TDDFT is the most suitable functional for describing the Q and B absorption bands of porphyrins. The transition configurations and molecular orbital analysis suggest that the diarylamino groups are major chromophores for effective CT excitations (ECTE), and therefore act as electron donor in photon-induced electron injection in DSSCs. The analysis of excited states properties and the free energy changes for electron injection support that the better performance of YD2-o-C8 in DSSCs result from the more excited states with ECTE character and the larger absolute value of free energy change for electron injection.

Ultra-long Pt nanolawns supported on TiO2-coated carbon fibers as 3D hybrid catalyst for methanol oxidation

In this study, TiO2 thin film photocatalyst on carbon fibers was used to synthesize ultra-long single crystalline Pt nanowires via a simple photoreduction route (thermally activated photoreduction). It also acted as a co-catalytic material with Pt. Taking advantage of the high-aspect ratio of the Pt nanostructure as well as the excellent catalytic activity of TiO2, this hybrid structure has the great potential as the active anode in direct methanol fuel cells. The electrochemical results indicate that TiO2 is capable of transforming CO-like poisoning species on the Pt surface during methanol oxidation and contributes to a high CO tolerance of this Pt nanowire/TiO2 hybrid structure.

Kinetic study of Pt nanocrystal deposition on Ag nanowires with clean surfaces via galvanic replacement

Without using any templates or surfactants, this study develops a high-yield process to prepare vertical Ag-Pt core-shell nanowires (NWs) by thermally assisted photoreduction of Ag NWs and successive galvanic replacement between Ag and Pt ions. The clean surface of Ag nanowires allows Pt ions to reduce and deposit on it and forms a compact sheath comprising Pt nanocrystals. The core-shell structural feature of the NWs thus produced has been demonstrated via transmission electron microscopy observation and Auger electron spectroscopy elemental analysis. Kinetic analysis suggests that the deposition of Pt is an interface-controlled reaction and is dominated by the oxidative dissolution of Ag atoms. The boundaries in between Pt nanocrystals may act as microchannels for the transport of Ag ions during galvanic replacement reactions.

Electronic structures and absorption properties of three kinds of ruthenium dye sensitizers containing bipyridine-pyrazolate for solar cells

The geometries, electronic structures and the electronic absorption spectra of three kinds of ruthenium complexes, which contain tridentate bipyridine-pyrazolate ancillary ligands, were studied using density functional theory (DFT) and time-dependent DFT. The calculated results indicate that: (1) the strong conjugated effects are formed across the pyrazoalte-bipyridine groups; (2) the interfacial electron transfer between electrode and the dye sensitizers is an electron injection processes from the excited dyes to the conduction band of TiO2; (3) the absorption bands in visible region have a mixed character of metal-to-ligand charge transfer and ligand-to-ligand charge transfer, but the main character of absorption bands near UV region ascribe to π→π* transitions; (4) introducing pyrazolate and -NCS groups are favorable for intra-molecular charge transfer, and they are main chromophores that contribute to the sensitization of photon-to-current conversion processes, but introducing -Cl and the terminal group -CF3 are unfavorable to improve the dye performance in dye sensitized solar cells.

Direct growth of ultra-long platinum nanolawns on a semiconductor photocatalyst

A template- and surfactant-free process, thermally assisted photoreduction, is developed to prepare vertically grown ultra-long Pt nanowires (NWs) (about 30-40 nm in diameter, 5-6 μm in length, and up to 80 NWs/100 μm2 in the wire density) on TiO2 coated substrates, including Si wafers and carbon fibers, with the assistance of the photocatalytic ability and semiconductor characteristics of TiO2. A remarkable aspect ratio of up to 200 can be achieved. TEM analytical results suggest that the Pt NWs are single-crystalline with a preferred 〈111〉 growth direction. The precursor adopted and the heat treatment conditions are crucial for the yield of NWs. The photoelectrons supplied by TiO2 gives rise to the formation of nano-sized Pt nuclei from salt melt or solution. The subsequent growth of NWs is supported by the thermal electrons which also generated from TiO2 during the post thermal treatment. The interactions between the ions and the electrons in the Pt/TiO2 junction are discussed in this study.

Automatic detection of the carotid artery boundary on cross-sectional MR image sequences using a circle model guided dynamic programming

Background

Systematic aerobe training has positive effects on the compliance of dedicated arterial walls. The adaptations of the arterial structure and function are associated with the blood flow-induced changes of the wall shear stress which induced vascular remodelling via nitric oxide delivered from the endothelial cell. In order to assess functional changes of the common carotid artery over time in these processes, a precise measurement technique is necessary. Before this study, a reliable, precise, and quick method to perform this work is not present.

Methods

We propose a fully automated algorithm to analyze the cross-sectional area of the carotid artery in MR image sequences. It contains two phases: (1) position detection of the carotid artery, (2) accurate boundary identification of the carotid artery. In the first phase, we use intensity, area size and shape as features to discriminate the carotid artery from other tissues and vessels. In the second phase, the directional gradient, Hough transform, and circle model guided dynamic programming are used to identify the boundary accurately.

Results

We test the system stability using contrast degraded images (contrast resolutions range from 50% to 90%). The unsigned error ranges from 2.86% ± 2.24% to 3.03% ± 2.40%. The test of noise degraded images (SNRs range from 16 to 20 dB) shows the unsigned error ranging from 2.63% ± 2.06% to 3.12% ± 2.11%. The test of raw images has an unsigned error 2.56% ± 2.10% compared to the manual tracings.

Conclusions

We have proposed an automated system which is able to detect carotid artery cross sectional boundary in MRI sequences during heart cycles. The accuracy reaches 2.56% ± 2.10% compared to the manual tracings. The system is stable, reliable and results are reproducible.

Preparation of dye waste-barium sulfate hybrid adsorbent and application in organic wastewater treatment

A new hybrid material was developed by the template-free hybridization of weak acidic pink red B (APRB, C.I. 18073) with BaSO(4). The composition and structure of the material were determined and characterized. In contrast to conventional sorbents, the hybrid material has a specific surface area of 0.89 m(2)/g, but it contains lots of negative charges and lipophilic groups as the basis of specific adsorption. The efficient removal of cationic dyes and persistent organic pollutants (POPs) indicates that it has an improved adsorption capacity and selectivity with a short removal time less than 2 min; while the hybrid sorbents fit the Langmuir isotherm model, and follow the octanol-water partition law. Instead of using APRB reagent, an APRB-producing wastewater was reused to prepare the cost-effective sorbent, and the equilibrium adsorption capacities of which reached 222 and 160 mg/g for EV and BPR, respectively. The sorbents was then used to treat three wastewater samples with satisfactory results of over 97% decolonization and 88% COD-decreasing. In addition, the hybrid sorbent was regenerated from sludge over five cycles, and its adsorption capacity was not appreciably changed. This work has developed a simple and eco-friendly method for synthesizing a practical and efficient sorbent.

Molecular characterization of Serratia marcescens strains by RFLP and sequencing of PCR-amplified 16S rDNA and 16S-23S rDNA intergenic spacer

AIMS

To establish the specific DNA patterns in 16S rDNA and 16S-23S rDNA intergenic spacer (IGS) regions from different kinds of Serratia marcescens strains using polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) and sequences analysis.

METHODS AND RESULTS

Two pairs of primers based on the 16S rDNA and 16S-23S rDNA IGS were applied to amplify the rrn operons of two kinds of S. marcescens strains. About 1500 bp for 16S rDNA and four fragments of different sizes for 16S-23S rDNA IGS were obtained. PCR-amplified fragments were analysed by RFLP and sequence analysis. Two distinct restriction patterns revealing three to five bands between two kinds of strains were detected with each specific enzyme. According to the sequence analysis, two kinds of strains showed approximately 97% sequence homology of 16S rDNA. However, there was much difference in the sequences of IGS between the two kinds of strains. Intercistronic tRNA of strains H3010 and A3 demonstrated an order of tRNA of 5'-16S-tRNA(Ala)-tRNA(Ile)-23S-3', but strain B17 harboured the tRNA of 5'-16S-tRNA(Glu)-tRNA(Ile)-23S-3'.

CONCLUSIONS

The method was specific, sensitive and accurate, providing a new technique for differentiating different strains from the same species.

SIGNIFICANCE AND IMPACT OF THE STUDY

This paper provided the first molecular characterization of 16S rDNA and 16S-23S rDNA IGS from S. marcescens strains.

Influence of interleukin-2 on Ca2+ handling in rat ventricular myocytes

In the present study, we examined the effect of interleukin-2 (IL-2) on cardiomyocyte Ca(2+) handling. The effects of steady-state and transient changes in stimulation frequency on the intracellular Ca(2+) transient were investigated in isolated ventricular myocytes by spectrofluorometry. In the steady state (0.2 Hz) IL-2 (200 U/ml) decreased the amplitude of Ca(2+) transients induced by electrical stimulation and caffeine. At 1.25 mM extracellular Ca(2+) concentration ([Ca(2+)](o)), when the stimulation frequency increased from 0.2 to 1.0 Hz, diastolic Ca(2+) level and peak intracellular Ca(2+) concentration ([Ca(2+)](i)), as well as the amplitude of the transient, increased. The positive frequency relationships of the peak and amplitude of [Ca(2+)](i) transients were blunted in the IL-2-treated myocytes. The effect of IL-2 on the electrically induced [Ca(2+)](i) transient was not normalized by increasing [Ca(2+)](o) to 2.5 mM. IL-2 inhibited the frequency relationship of caffeine-induced Ca(2+) release. Blockade of sarcoplasmic reticulum (SR) Ca(2+)-ATPase with thapsigargin resulted in a significant reduction of the amplitude-frequency relationship of the transient similar to that induced by IL-2. The restitutions were not different between control and IL-2 groups at 1.25 mM [Ca(2+)](o), which was slowed in IL-2-treated myocytes when [Ca(2+)](o) was increased to 2.5 mM. There was no difference in the recirculation fraction (RF) between control and IL-2-treated myocytes at both 1.25 and 2.5 mM [Ca(2+)](o). The effects of IL-2 on frequency relationship, restitution, and RF may be due to depressed SR functions and an increased Na(+)-Ca(2+) exchange activity, but not to any change in L-type Ca(2+) channels.

[Hydrogen peroxide augments the injury effect of iron on the isolated rat heart and cardiomyocytes]

By using Langendorff perfused rat heart and enzymatically isolated cardiomyocytes, we investigated the augmented injury effect of iron on the myocardium by hydrogen peroxide and the underlying mechanisms. Cell-permeable iron (Fe-HQ) decreased the contractile amplitude, velocity and end-diastolic cell length of the cardiomyocyte but increased the contents of lactate dehydrogenase (LDH) and creatine kinase (CK) in the coronary effluent and the myocardial malondialdehyde (MDA) while the left ventricular developed pressure (LVDP), +/-dp/dt(max), heart rate and coronary flow showed biphasic alterations. Hydrogen peroxide augmented the injury effect of iron accompanied by increases of coronary LDH, CK release and myocardial MDA content and decreases of LVDP, +/-dp/dt(max), and heart rate. Reduced glutathione could antagonize the injury effect of iron and hydrogen peroxide on the myocardium while dimethyl sulfoxide had no injury effect on the isolated heart. It is suggested that the functional injury of sulfhydryl group containing proteins may be involved in the augmentation of myocardial injury due to the increase of intracellular iron by hydrogen peroxide, but hydroxyl radicals may not.

[Effects of interleukin-2 on the isolated rat heart and the mechanism]

The purpose of the present study was to explore the biological effects and mechanism of interleukin-2 (IL-2) on the isolated rat heart. The results showed that hrIL-2 increased the number of premature ventricular contraction, heart rate, left ventricular developed pressure, left ventricular end-diastolic pressure and coronary flow in the isolated perfused rat heart. Heat inactivated hrIL-2 had no effect on the heart. Pretreatment with ryanodine canceled the positive effects of hrIL-2 on left ventricular developed pressure, left ventricular end-diastolic pressure and coronary flow but had no effects on arrhythmogenesis and tachycardia by hrIL-2. Pretreatment with nifedipine or low extracellular calcium abolished the arrhythmogenic effect of hrIL-2 and attenuated partially the augment of heart rate, left ventricular developed pressure, left ventricular end-diastolic pressure and coronary flow. It suggests that the cardiac activity of hrIL-2 depended on the integrity of its spatial structure and transmembrane influx Ca2+ and intracellularly stored Ca2+ were involved in the cardiac activity of hrIL-2.

Operant performance following tail-pinch in the rat: effects of d-amphetamine

To extend the investigation of tail-pinch induced behavioral changes, rats performing on a differential reinforcement of low rates of 10 sec (DRL10), a fixed-interval of 60 sec (F160), and a fixed-ratio of 20 (FR20) schedules were exposed to a paper clip applied to the tail. While a 10 min tail-pinch conducted 1 hr before operant sessions significantly altered the DRL10 behavior, this stressor had little effect on either F160 or FR20 responding. Marked DRL10 behavior performance changes following tail-pinch included increases in the number of lever presses, decreases in the number of the reinforcers, and disruption in the frequency distribution of inter-response times (IRT). These DRL10 operant deficits were diminished when the subject received a tail-pinch pretreatment followed by d-amphetamine treatment (0.2 and 2.0 mg/kg). In combination with biochemical data from others, the present results suggest that catecholamine systems are involved in modulation of DRL10 behavior following tail-pinch.

Grandparents in the United States and the Republic of China: a comparison of generations and cultures

Grandparent behaviors in the United States and the Republic of China are examined to identify curriculum themes for helping them adjust to their changing role. The 3,286 non-consanguineous subjects included Chinese (n = 751), African Americans (n = 777), Caucasian Americans (n = 1,086), and Mexican Americans (n = 672). Analyses were performed using 1) Generation with three levels (grandparent, parent, and grandchild) and 2) Culture with four levels (Chinese, African American, Caucasian American, and Mexican American). The results revealed significant differences in perceptions about grandparents across cultures as well as between generations within cultures. All three generations reported grandparent strengths and needs. Specific guidelines and curriculum topics are recommended for education to support grandparent development.

Arsenic trioxide-induced apoptosis and differentiation are associated respectively with mitochondrial transmembrane potential collapse and retinoic acid signaling pathways in acute promyelocytic leukemia

Recent studies showed that arsenic trioxide (As2O3) could induce apoptosis and partial differentiation of leukemic promyelocytes. Here, we addressed the possible mechanisms underlying these two different effects. 1.0 microM As2O3-induced apoptosis was associated with condensation of the mitochondrial matrix, disruption of mitochondrial transmembrane potentials (DeltaPsim) and activation of caspase-3 in acute promyelocytic leukemia (APL) cells regardless of their sensitivity to all-trans retinoic acid (ATRA). All these effects were inhibited by dithiothreitol (DTT) and enhanced by buthionine sulfoximine (BSO). Furthermore, BSO could also render HL60 and U937 cells, which had the higher cellular catalase activity, sensitive to As2O3-induced apoptosis. Surprisingly, 1.0 microM As2O3 did not induce the DeltaPsim collapse and apoptosis, while 0.1 microM As2O3 induced partial differentiation of fresh BM cells from a de novo APL patient. In this study, we also showed that 0.2 mM DTT did not block low-dose As2O3-induced NB4 cell differentiation, and 0. 10.5 microM As2O3 did not induce differentiation of ATRA-resistant NB4-derived sublines, which were confirmed by cytomorphology, expression of CD11b, CD33 and CD14 as well as NBT reduction. Another interesting finding was that 0.10.5 microM As2O3 could also induce differentiation-related changes in ATRA-sensitive HL60 cells. However, the differentiation-inducing effect could not be seen in ATRA-resistant HL60 sublines with RARalpha mutation. Moreover, low-dose As2O3 and ATRA yielded similar gene expression profiles in APL cells. These results encouraged us to hypothesize that As2O3 induces APL cell differentiation through direct or indirect activation of retinoic acid receptor-related signaling pathway(s), while DeltaPsim collapse is the common mechanism of As2O3-induced apoptosis.

Diuretics and risk of arrhythmic death in patients with left ventricular dysfunction

Background-Treatment with diuretics has been reported to increase the risk of arrhythmic death in patients with hypertension. The effect of diuretic therapy on arrhythmic death in patients with left ventricular dysfunction is unknown. Methods and Results-We conducted a retrospective analysis of 6797 patients with an ejection fraction <0.36 enrolled in the Studies Of Left Ventricular Dysfunction (SOLVD) to assess the relation between diuretic use at baseline and the subsequent risk of arrhythmic death. Participants receiving a diuretic at baseline were more likely to have an arrhythmic death than those not receiving a diuretic (3.1 vs 1.7 arrhythmic deaths per 100 person-years, P=0.001). On univariate analysis, diuretic use was associated with an increased risk of arrhythmic death (relative risk [RR] 1.85, P=0.0001). After controlling for important covariates, diuretic use remained significantly associated with an increased risk of arrhythmic death (RR 1.37, P=0.009). Only non-potassium-sparing diuretic use was independently associated with arrhythmic death (RR 1.33, P=0.02). Use of a potassium-sparing diuretic, alone or in combination with a non-potassium-sparing diuretic, was not independently associated with an increased risk of arrhythmic death (RR 0.90, P=0.6). Conclusions-In SOLVD, baseline use of a non-potassium-sparing diuretic was associated with an increased risk of arrhythmic death, whereas baseline use of a potassium-sparing diuretic was not. These data suggest that diuretic-induced electrolyte disturbances may result in fatal arrhythmias in patients with systolic left ventricular dysfunction.

Apoptosis and growth inhibition in malignant lymphocytes after treatment with arsenic trioxide at clinically achievable concentrations

BACKGROUND

Arsenic trioxide (As2O3) can induce clinical remission in patients with acute promyelocytic leukemia via induction of differentiation and programmed cell death (apoptosis). We investigated the effects of As2O3 on a panel of malignant lymphocytes to determine whether growth-inhibitory and apoptotic effects of As2O3 can be observed in these cells at clinically achievable concentrations.

METHODS

Eight malignant lymphocytic cell lines and primary cultures of lymphocytic leukemia and lymphoma cells were treated with As2O3, with or without dithiothreitol (DTT) or buthionine sulfoximine (BSO) (an inhibitor of glutathione synthesis). Apoptosis was assessed by cell morphology, flow cytometry, annexin V protein level, and terminal deoxynucleotidyl transferase labeling of DNA fragments. Cellular proliferation was determined by 5-bromo-2'-deoxyuridine incorporation into DNA and flow cytometry and by use of a mitotic arrest assay. Mitochondrial transmembrane potential (delta psi(m)) was measured by means of rhodamine 123 staining and flow cytometry. Protein expression was assessed by western blot analysis or immunofluorescence.

RESULTS

Therapeutic concentrations of As2O3 (1-2 microM) had dual effects on malignant lymphocytes: 1) inhibition of growth through adenosine triphosphate (ATP) depletion and prolongation of cell cycle time and 2) induction of apoptosis. As2O3-induced apoptosis was preceded by delta psi(m) collapse. DTT antagonized and BSO enhanced As2O3-induced ATP depletion, delta psi(m) collapse, and apoptosis. Caspase-3 activation, usually resulting from delta psi(m) collapse, was not always associated with As2O3-induced apoptosis. As2O3 induced PML (promyelocytic leukemia) protein degradation but did not modulate expression of cell cycle-related proteins, including c-myc, retinoblastoma protein, cyclin-dependent kinase 4, cyclin D1, and p53, or expression of differentiation-related antigens.

CONCLUSIONS

Substantial growth inhibition and apoptosis without evidence of differentiation were induced in most malignant lymphocytic cells treated with 1-2 microM As2O3. As2O3 may prove useful in the treatment of malignant lymphoproliferative disorders.

[HRV analysis system based on Windows 95 and its preliminary application]

Objective. To provide a real useful application system for the HRV research. Method. The acquisition, detection and analysis system of HRV signal was set up based on Windows 95. The system analyzes the HRV signal with statistic method in time domain and power spectrum in frequency domain. And the power spectrum array was also introduced into the analysis. HRV signals of some healthy persons and some patients were detected and analyzed. Result. The HRV characteristic is much more obvious in the diabetics patients. Conclusion. The system is useful in HRV signal analysis and cardiovascular research.

[Involvement of endogenous opioids in cardioprotective effects of ischemic preconditioning in the isolated rat heart]

In the present study, the relationship between the blockade of kappa-opioid receptor and ischemic preconditioning (IP) was examined and the effect of IP and prolonged ischemia on levels of dynorphin A1-13 (Dyn A1-13) in cardiac muscle in isolated perfused rat heart was investigated. The results are as follows: (1) IP reduced the severity of ischemia/reperfusion arrhythmia (P < 0.05) and infarct size (P < 0.01), but had no significant effect on heart rate and coronary flow (P > 0.05); (2) MR2266, kappa opioid receptor antagonist, reduced the severity of ischemia/reperfusion arrhythmia (P < 0.05) and infarct size (P < 0.01), and also enhanced the recovery of coronary flow, but had no significant effect on heart rate (P > 0.05); and (3) prolonged ischemia decreased the levels of Dyn A1-13 (P < 0.05), which was more marked in the unpreconditioned hearts. The results suggest: (1) MR2266 can "mimic" cardioprotective effect of IP in reducing the severity of arrhythmias and limiting infarct size of cardiac muscle; (2) ischemia causes release of endogenous kappa opioids, which can be attenuated by IP; and (3) the cardioprotective effects of IP in rat heart involves endogenous kappa opioids.

Decreased affinity of K-receptor binding during reperfusion following ischaemic preconditioning in the rat heart

The effects of ischaemic preconditioning with three cycles of ischaemia of 3 min and reperfusion of 5 min each cycle on ventricular fibrillation threshold (VFT) and ventricular fibrillation (VF), and binding properties of tritiated U69,593, a selective kappa opioid-receptor (k-receptor) agonist, during subsequent ischaemia and/or reperfusion were studied in the rat heart. It was found that ischaemic preconditioning significantly enhanced the VFT values during ischaemic and reperfusion. VF during the subsequent reperfusion period was also significantly reduced. The Kd of the [3H]U69,593 binding sites in the sarcolemma of the heart at 5 min of reperfusion was significantly increased following ischaemic preconditioning. The Bmax was, however, not altered after the preconditioning. The study provides evidence for the first time suggesting that the cardioprotective effects of ischaemic preconditioning may be related to a reduction in affinity of the K-receptor binding.

Grandparents in Taiwan: a three-generational study

Grandparents in the Republic of China want to remain influential, but social policy has not provided them with education to fulfill their changing role. The performance of grandparents was examined to determine suitable content for an intervention program. A sample of 751 non-consanguineous participants from urban and rural Taiwan included 234 grandparents, 241 parents, and 276 grandchildren. Each generation was administered a separate version of the Grandparent Strengths and Needs Inventory that was translated into Mandarin. Respondents identified favorable qualities of grandparents as well as aspects of their relationships in which growth was necessary. Multivariate analysis of variance, univariate analysis of variance, Scheffé and t-tests were used to analyze scores, confirm results, and facilitate interpretation. All three generations described aspects of grandparent success and specific realms of learning they should acquire to become more effective. Significant main effects that influenced responses about grandparent performance were generation, gender of grandchild, age of grandchild, frequency of grandchild care by grandparent, generations living together, and amount of time grandparent and grandchild spent together. Considerations were recommended to improve behavior of grandparents and guide the development of educational programs for them.

Effects of an indene-derivative, TN-871, on synaptic transmission in a sympathetic ganglion: presynaptic actions on neurotransmitter release

Intracellular recordings were made from bullfrog sympathetic ganglion cells to elucidate effects of 2-n-butyl-1-(4-methylpiperazinyl)-5,6-methylenedioxyindene.2 HCl (TN-871) on synaptic transmission. TN-871 at 30 nM augmented cholinergic nicotinic fast excitatory postsynaptic potentials (fast EPSPs), whereas the drug at 3 microM reversibly depressed them, without affecting acetylcholine-induced depolarizations. TN-871 did not affect active and passive electrical properties of the ganglion cells. The quantal analysis method was applied to the fast EPSPs in a 0.54 mM Ca2+/7.56 mM Mg2+ Ringer's solution. The mean quantal content was significantly increased by TN-871 at 30 nM but significantly decreased at 3 microM. TN-871 at 300 nM either increased or decreased the mean quantal content. The mean quantal size of the fast EPSPs was not changed by TN-871 at the concentrations examined. Fast EPSPs in a 0.99 mM Ca2+/4.86 mM Mg2+ Ringer's solution were not affected by nicardipine, but were inhibited in amplitude by omega-conotoxin in a concentration-dependent manner. It is likely that TN-871, in high concentrations, might block omega-conotoxin-sensitive N-type calcium channels in the presynaptic terminals. These results indicate that TN-871 modulates transmitter release from preganglionic nerve terminals without changing the postsynaptic sensitivity of the ganglion cells to ACh.

Short-term, within-person variability in clinical chemistry test results. Experience from the Atherosclerosis Risk in Communities Study

We report the within-person, between-person, and methodological variances of a number of chemical analytes for free-living, middle-aged adults who participated in the Atherosclerosis Risk in Communities Study's Intraindividual Variability Study. The Atherosclerosis Risk in Communities Study is a National Institutes of Health-sponsored multicenter study of atherosclerotic risk factors. In the Atherosclerosis Risk in Communities Study and its Intraindividual Variability Study, concentrations of the following 12 chemical analytes were measured in serum from fasting individuals: sodium, calcium, potassium, creatinine, albumin, total protein, magnesium, phosphorus, urea, insulin, glucose, and urate. The analytes are listed in order of the increasing reliability coefficient (ie, the fraction that between-person variance represents of the total observed population variance), which ranged from .59 for sodium to .91 for urate. The reliability coefficient is a strong predictor of the possibility of finding statistical correlations between measured analyte concentrations and disease occurrence in an epidemiological study like the Atherosclerosis Risk in Communities Study. The within-person variance and methodological variance are also useful in computing confidence intervals for sequential laboratory test results in patients and evaluating limits for internal quality control and proficiency testing programs.

[Extracellular adenosine-5'-triphosphate increases intracellular calcium concentration of the rabbit eye suprachoroid via activation of the intracellular signal transduction]

Intracellular calcium concentration ([Ca2+]i) of the rabbit eye suprachoroid was measured with microfluorophotometry using fura-2. Adenosine-5'-triphosphate (ATP) 1-100 microM, added to a perfusing solution, elicited an increase in [Ca2+]i of the suprachoroid. This action of ATP was inhibited when preparations were perfused with a nominally zero Ca2+ Krebs solution or a high magnesium Krebs solution. The [Ca2+]i-increasing action of ATP was attenuated either by lowering temperature or by a phospholipase C inhibitor, compound 48/80. These results indicate that extracellular Ca2+ is necessary to the ATP action and also suggest that the ATP action may be mediated by the intracellular signal transduction which exerts a Ca(2+)-release from intracellular Ca(2+)-store sites. The potency order of ATP-related purine nucleotides was ATP > or = ATP-gamma-S > adenosine-5'-diphosphate (ADP). Adenosine-5'-monophosphate (AMP) and adenosine were not effective. It is concluded that P2-purinoceptors exist on the surface of the suprachoroid and are involved in mechanisms underlying the ATP-induced increase in [Ca2+]i of the suprachoroid.