Dipole Moment Studies. VII. Dipole Moments of the Halofluorophosphines

Dipole moment measurements have been made on a series of halophosphines using gas phase heterodyne beat methods. Values obtained are: PF3, 1.00±0.03 D; PF2Cl, 0.93±0.01 D; PFCl2, 0.86±0.05 D; PF2Br, 0.83±0.05 D; and PF2I, 0.85±0.06 D. The value for PF3 is in reasonable agreement with the microwave value [R. G. Schulman et al., Phys. Rev. 78, 145 (1950)], of 1.025±0.009 D. Molecular moments for the mixed halophosphines are approximated reasonably well by the vector sum of P‐X moments, but the value for PF2H cannot be estimated in this way. An explanation is offered in terms of a polarization model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70347/2/JCPSA6-57-12-5372-1.pd

Dipole Moment of Difluorophosphine

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70678/2/JCPSA6-46-10-4159-1.pd

Dipole Moment Studies. V. The Dipole Moments of the Methylphosphine Boranes

Dipole moments of methylphosphine borane, dimethylphosphine borane, and trimethylphosphine borane were determined in benzene solution. After correction for solvent effects the values obtained were: CH3PH2BH3, 4.58 D; (CH3)2PHBH3, 4.78 D; (CH3)3PBH3, 4.97 D. The variation in these moments is interpreted in terms of a polarization model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70185/2/JCPSA6-57-12-5365-1.pd

Dipole Moment Studies. VI. Dipole Moments of the Propylphosphines

The dipole moments of mono‐n‐propylphosphine and mono‐i‐propylphosphine, as measured in the gas phase with a heterodyne beat apparatus, are 1.09±0.06 and 1.22±0.03 D, respectively. The moments of mono‐n‐propylphosphine, di‐n‐propylphosphine, and tri‐n‐propylphosphine as measured in benzene solution and corrected for solvent effect are 1.17±0.05, 1.22±0.05, and 1.16±0.08 D, respectively. The moments for mono‐i‐propylphosphine, di‐i‐propylphosphine, and tri‐i‐propylphosphine as measured in benzene solution and corrected for solvent effects are 1.13±0.03, 1.32±0.12, and 1.32±0.04 D, respectively. Discrepancies between gas phase and solution values are considered, and values for each series are discussed in terms of a bond polarization model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70575/2/JCPSA6-57-12-5367-1.pd

Removal of terrestrial DOC in aquatic ecosystems of a temperate river network

Surface waters play a potentially important role in the global carbon balance. Dissolved organic carbon (DOC) fluxes are a major transfer of terrestrial carbon to river systems, and the fate of DOC in aquatic systems is poorly constrained. We used a unique combination of spatially distributed sampling of three DOC fractions throughout a river network and modeling to quantify the net removal of terrestrial DOC during a summer base flow period. We found that aquatic reactivity of terrestrial DOC leading to net loss is low, closer to conservative chloride than to reactive nitrogen. Net removal occurred mainly from the hydrophobic organic acid fraction, while hydrophilic and transphilic acids showed no net change, indicating that partitioning of bulk DOC into different fractions is critical for understanding terrestrial DOC removal. These findings suggest that river systems may have only a modest ability to alter the amounts of terrestrial DOC delivered to coastal zones

Bringing Molecular Biology to Bear on Adhesion Prevention: Postsurgical Adhesion Reduction Using Intraperitoneal Inoculation of Hyaluronic Acid–Inducing Adenoviral Vector in a Murine Model

Objective: Seprafilm (Genzyme, Cambridge, MA) an absorbable adhesion barrier incorporating hyaluronic acid (HA), a high molecular mass glycosaminoglycan and important component of the extracellular matrix, has been shown to prevent adhesions in both experimental models and human subjects. Yet, the application of HA as a sheet at the time of surgery has several important logistic limitations. Recently, our laboratory has identified and cloned the genes encoding murine hyaluronic acid synthase 2 (mHAS2) and 3 (mHAS3) and engineered adenoviruses incorporating these genes, which, on intraperitoneal injection, significantly increases HA in peritoneal fluid. We hypothesized that intraperitoneal gene therapy with mHAS2 or mHAS3 via an adenoviral vector prior to a standardized cecal abrasion surgery would lead to a reduction in postoperative adhesion severity. Methods: Mice were assigned to one of four groups: (1) intraperitoneal inoculation with adenovirus encoding mHAS2; (2) mHAS3; (3) a control reporter adenovirus (RV) encoding GFP; or (4) intraoperative placement of a commercially available and murine-validated hyaluronic acid adhesion barrier (Seprafilm, SF). An a priori sample size calculation was performed. Mice in groups 1, 2, and 3 underwent injection of 2 x 107 viral particles in 1 ml of fluid on day -1. Sham injection was performed on group 4 SF mice. On day 0, laparotomy was performed in random sequence by surgeon blinded to the experimental group. On day 7, adhesion scores (0-3) were assigned independently by two blinded investigators. Results: Mean adhesion scores (n = 247) were 0.68 (mHAS2), 0.91 (mHAS3), 1.28 (RV), and 0.47 (SF). Pairwise comparisons using Wilcoxon rank-sum test revealed significant reduction in severity of adhesions between mHAS2, mHAS3, and SF compared to RV (p = 0.0004, 0.039, and 0.0001, respectively). Significance persisted despite correction for multiple comparisons (p = 0.0002, Kruskal-Wallis). There was a direct relationship between intraperitoneal HA concentration and adhesion reduction. Only one death (RV) was secondary to adhesive disease; differential risk of death between groups was statistically significant (p = 0.008) (highest in mHAS2 group). Conclusions: In a dose-response relationship, an intraperitoneal gene therapy approach to adhesion prevention in a murine model was successful, with adenoviruses most productive of HA resulting in the most significant reduction in adhesion scores compared to empty virus (RV). Although SF best reduced postoperative adhesions, the adenoviral gene delivery approach may prove to be more effective in clinical use when peritoneal injury is less localized or at laparoscopy where the application of SF is not possible. Further studies to elucidate the reason for the differential death rates (time bias may have played a role) and to validate results are in progress

Taxon-specific multiplex-PCR for quick, easy, and accurate identification of encyrtid and aphelinid parasitoid species attacking soft scale insects in California citrus groves

Citricola scale, Coccus pseudomagnoliarum Kuwana (Hemiptera: Coccidae), is a serious pest of citrus in California's San Joaquin Valley, but not in southern California where a complex of Metaphycus spp. Mercet (Hymenoptera: Encyrtidae) suppress it. This has created interest in using these (and other Metaphycus) species for biological control in the San Joaquin Valley. A critical step in assessing an organism's potential for biological control is the ability to accurately identify it. For Metaphycus spp., this currently requires slide mounted adult specimens and expert taxonomic knowledge. We present a simple, quick and accurate method to identify any life stage of the ten major parasitoids of soft scales in California citrus, based on amplification of ribosomal DNA, using the polymerase chain reaction (PCR). Three multiplex-PCR protocols amplify products of taxon-specific sizes, allowing direct diagnosis of taxa accommodated by the PCR, and reducing identification time to a fraction of that of existing methods

Variational Approach to Hard Sphere Segregation Under Gravity

It is demonstrated that the minimization of the free energy functional for hard spheres and hard disks yields the result that excited granular materials under gravity segregate not only in the widely known "Brazil nut" fashion, i.e. with the larger particles rising to the top, but also in reverse "Brazil nut" fashion. Specifically, the local density approximation is used to investigate the crossover between the two types of segregation occurring in the liquid state, and the results are found to agree qualitatively with previously published results of simulation and of a simple model based on condensation.Comment: 10 pages, 3 figure

Impaired cellular immune response in rats exposed perinatally to Baltic Sea herring oil or 2,3,7,8-TCDD

While the immunotoxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been well established, the effects of complex environmental mixtures of polyhalogenated aromatic hydrocarbons (PHAHs) are poorly understood. Many PHAHs, including the polychlorinated-biphenyls (PCBs), -dibenzofurans (PCDFs), and dibenzo-p-dioxins (PCDDs), possess 'dioxin-like' activities, and accumulate in the aquatic food chain. Organisms occupying high trophic levels may therefore be exposed to concentrations which may present an immunotoxic risk. In this study, pregnant PVG rats were administered a daily oral dose of 1 ml of the following during pregnancy and lactation: (1) oil extracted from herring caught in the relatively uncontaminated Atlantic Ocean; (2) oil extracted from herring caught in the contaminated Baltic Sea; or (3) the Atlantic herring oil extract spiked with 2,3,7,8-TCDD. The daily intakes of aryl hydrocarbon (Ah)-receptor dependent toxic equivalents (TEQ) for mothers were 0.3 in the Atlantic group, 2.1 in the Baltic group, and 134 ng/kg body wt. in the 2,3,7,8-TCDD positive control group. Immune function and host resistance to rat cytomegalovirus (RCMV) we