Thermally activated electrostatic injection of solvated ions by a track membrane interfaced vacuum feedthrough

Electromembrane ion sources are considered as potential techniques for direct mass spectrometric sampling from ambient conditions. Interfacing of a time-of-flight mass spectrometer by means of a poly(ethylene terephthalate) track membrane requires investigation of the thermally activated processes involved. In this study, we directly attempt substantiating an activation-like performance of such track membrane-mediated interfaces. A number of KCl/glycerol solution samples were tested. A wide range of fixed, externally applied, potential drops was covered. For the charge extraction processes studied, we observe and discuss an activation term, exp(-ΔF/k(B)T), with a free-energy barrier ΔF = ΔF(0) - ΔF(Φ). The potential drop-dependent ΔF(Φ), was found to be sensitive to the varying salt concentration.     

Preproinsulin I and II mRNAs and insulin electron microscopic immunoreaction are present within the rat fetal nervous system

Insulin-like substance has been found within the nervous system. In the rat, preproinsulin II mRNA was shown within the brain and preproinsulin I mRNA within the retina. The present study demonstrates the presence of preproinsulin mRNAs within the 15, 17 and 19 day gestational age fetal rat brain, spinal cord and dorsal root ganglia (DRG), employing RNA template-specific polymerase chain reaction (RS-PCR), semi-nested PCR and RNase protection assay. Preproinsulin I mRNA was present in the 17 and 19 day gestational age brain, spinal cord and DRG, and only in the brain of the 15 day gestational age brain. Preproinsulin II mRNA was present in all the gestational ages studied in the brain, spinal cord and DRG. The RS-PCR and the semi-nested PCR demonstrated products that co-migrated with the pancreatic control. The semi-nested products were characterized as preproinsulin I and II by restriction enzyme digestion and sequence. RNase protection assay using specific cRNA for preproinsulin I and II showed a band that co-migrated with pancreatic preproinsulin I and II mRNAs, and confirmed the PCR results. In addition, insulin receptor mRNA was detected by RS-PCR. Ultrastructural studies showed insulin immunoreaction within the endoplasmic reticulum, Golgi apparatus, cytoplasm, axon, dendrites, and in relation to the synapses. Thus, we demonstrated the presence of preproinsulin I and II mRNA, insulin receptor mRNA and insulin immunoreaction within the rat fetal central and peripheral nervous system.     

Homecare

With the help of volunteers from coast to coast, operators of homemeal delivery programs are helping needy seniors preserve their dignity, environments & cherished independence, providing nourishment for bodies & souls.     

Light-Stimulated Formation and Dissociation of Supramolecular Donor–Acceptor Complexes between Eosin and Bipyridinium Azobenzenes: Design of Molecular Electronic Devices for the Piezoelectrical Transduction of Recorded Optical Signals

The photoisomerizable electron acceptors, trans-4,4′-bis(N-methylpyridinium)azobenzene, ( 1t ), and trans-3,3′-bis(N-methylpyridinium)azobenzene, ( 2t ), exhibit photoswitchable binding affinities to eosin. While the trans isomers, ( 1t ) or ( 2t ) exhibit high association affinities (K_a = 8.3 × 10³ M⁻¹ and 3.8 × 10⁴ M⁻¹, respectively), the cis isomers ( 1c ) or ( 2c ) reveal lower binding affinities (K_a = 3.4 × 10³ M⁻¹ and 1.4 × 10⁴ M⁻¹, respectively). The formation of the supramolecular donor–acceptor complexes between the eosin and the electron acceptors is associated with an absorbance change of the chromophore. This enables the cyclic spectroscopic transduction of the optically-induced formation and dissociation of the complexes upon photoisomerization between the respective trans and cis states. An eosin monolayer was assembled onto the Au-electrodes associated with a quartz piezoelectric crystal. The eosin-functionalized crystal was employed for the microgravimetric, quartz-crystal-microbalance analyses of the association of ( 1t ), ( 2t ), ( 1c ), or ( 2c ) to the crystal interface. The microgravimetric analyses allowed the characterization of the kinetics of association of the electron acceptors to the monolayer and the association constants between the isomers ( 1t ), ( 2t ), ( 1c ), and ( 2c ) with the eosin monolayer. By cyclic photoisomerization of the electron-acceptor between the trans and cis states, reversible piezoelectric transduction of the formation of the complexes with ( 1t ) or ( 2t ) at the monolayer interface, and their dissociation upon photoisomerization to ( 1c ) or ( 2c ) was accomplished.     

The expression of the urinary forms of human luteinizing hormone beta fragment in various populations as assessed by a specific immunoradiometric assay

Human gonadotrophins undergo metabolic transformations which result in the presence of several smaller, structurally and immunologically related forms of gonadotrophins in the urine. For luteinizing hormone (LH), a beta core fragment (LHbeta cf) has been isolated from the pituitary and characterized. The corresponding urinary fragment is inferred from mass spectral and immunochemical analysis of chromatographically separated urinary forms. Physicochemical characteristics, primarily mass spectral and chromatographic, indicate that the pituitary and urinary forms of LHbeta cf have a different structure, probably in the carbohydrate moieties. This communication characterizes the expression of LHbeta cf in the urine of both reproductive and post-reproductive age women and in men, employing assays highly specific for the pituitary form of the fragment. It was found that LHbeta cf is the predominant LH associated molecular form in the urine during peri-ovulatory period, peaking 1-3 days later than intact LH and reaching a concentration of approximately 600 fmol/mg creatinine, 7-fold higher than either LH or LH free beta subunit. Corresponding concentrations of human chorionic gonadotrophin (HCG) beta cf were <1% that of LHbeta cf. LHbeta cf cross-reaction with some LH or LHbeta monoclonal antibodies may well interfere with the accurate estimation of the day of the LH surge when urinary tests are utilized.     

Psychological and academic adjustment in adopted children.

Evaluated psychological and academic adjustment of 130 6–11 yr old adopted children and 130 age-matched nonadopted children using the Hahnemann Elementary School Behavior Rating Scale and a child behavior profile. Results show that adopted Ss were rated higher in psychological and school-related behavior problems and lower in social competence and school achievement than were nonadopted Ss. It is suggested that although the results support the position that the risk is greater for adopted children to develop emotional and school-related problems, the data should not be overinterpreted because the majority of adopted Ss were within the normal range of behavior. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)