Three-Dimensional Trapping of Individual Rydberg Atoms in Ponderomotive Bottle Beam Traps.

We demonstrate three-dimensional trapping of individual Rydberg atoms in holographic optical bottle beam traps. Starting with cold, ground-state ^{87}Rb atoms held in standard optical tweezers, we excite them to nS_{1/2}, nP_{1/2}, or nD_{3/2} Rydberg states and transfer them to a hollow trap at 850 nm. For principal quantum numbers 60≤n≤90, the measured trapping time coincides with the Rydberg state lifetime in a 300 K environment. We show that these traps are compatible with quantum information and simulation tasks by performing single qubit microwave Rabi flopping, as well as by measuring the interaction-induced, coherent spin-exchange dynamics between two trapped Rydberg atoms separated by 40 µm. These results will find applications in the realization of high-fidelity quantum simulations and quantum logic operations with Rydberg atoms.

Environmental and management influences on temporal variability of near saturated soil hydraulic properties.

Structural porosity is a decisive property for soil productivity and soil environmental functions. Hydraulic properties in the structural range vary over time in response to management and environmental influences. Although this is widely recognized, there are few field studies that determine dominant driving forces underlying hydraulic property dynamics. During a three year field experiment we measured temporal variability of soil hydraulic properties by tension infiltrometry. Soil properties were characterized by hydraulic conductivity, effective macroporosity and Kosugi's lognormal pore size distribution model. Management related influences comprised three soil cover treatment (mustard and rye vs. fallow) and an initial mechanical soil disturbance with a rotary harrow. Environmental driving forces were derived from meteorological and soil moisture data. Soil hydraulic parameters varied over time by around one order of magnitude. The coefficient of variation of soil hydraulic conductivity K(h) decreased from 69.5% at saturation to 42.1% in the more unsaturated range (- 10 cm pressure head). A slight increase in the Kosugi parameter showing pore heterogeneity was observed under the rye cover crop, reflecting an enhanced structural porosity. The other hydraulic parameters were not significantly influenced by the soil cover treatments. Seedbed preparation with a rotary harrow resulted in a fourfold increase in macroporosity and hydraulic conductivity next to saturation, and homogenized the pore radius distribution. Re-consolidation after mechanical loosening lasted over 18 months until the soil returned to its initial state. The post-tillage trend of soil settlement could be approximated by an exponential decay function. Among environmental factors, wetting-drying cycles were identified as dominant driving force explaining short term hydraulic property changes within the season (r2 = 0.43 to 0.59). Our results suggested that beside considering average management induced changes in soil properties (e.g. cover crop introduction), a dynamic approach to hydrological modeling is required to capture over-seasonal (tillage driven) and short term (environmental driven) variability in hydraulic parameters.

Field quantification of wetting-drying cycles to predict temporal changes of soil pore size distribution.

Wetting-drying (WD) cycles substantially influence structure related soil properties and processes. Most studies on WD effects are based on controlled cycles under laboratory conditions. Our objective was the quantification of WD cycles from field water content measurements and the analysis of their relation to the temporal drift in the soil pore size distribution. Parameters of the Kosugi hydraulic property model (rm,Kosugi, σKosugi) were derived by inverse optimization from tension infiltrometer measurements. Spectral analysis was used to calculate WD cycle intensity, number and duration from water content time series. WD cycle intensity was the best predictor (r2 = 0.53-0.57) for the temporal drift in median pore radius (rm,Kosugi) and pore radius standard deviation (σKosugi). At lower soil moisture conditions the effect of cycle intensity was reduced. A bivariate regression model was derived with WD intensity and a meteorological indicator for drying periods (ET0, climatic water balance deficit) as predictor variables. This model showed that WD enhanced macroporosity (higher rm,Kosugi) while decreasing pore heterogeneity (lower σKosugi). A drying period with high cumulative values of ET0 or a strong climatic water balance deficit on the contrary reduced rm,Kosugi while slightly increasing σKosugi due to higher frequency at small pore radius classes. The two parameter regression model was applied to predict the time course of soil pore size distribution parameters. The observed system dynamics was captured substantially better by the calculated values compared to a static representation with averaged hydraulic parameters. The study showed that spectral analysis is an adequate approach for the quantification of field WD pattern and that WD intensity is a key factor for the temporal dynamics of the soil pore size distribution.

Physical and functional association of the high affinity immunoglobulin G receptor (Fc gamma RI) with the kinases Hck and Lyn.

The high affinity immunoglobulin G (IgG) receptor Fc gamma RI (CD64) is expressed constitutively on monocytes and macrophages, and is inducible on neutrophils. Fc gamma RI has recently been shown to be associated with the signal transducing gamma subunit of the high-affinity IgE receptor (Fc epsilon RI gamma). Induction of cytoplasmic protein tyrosine phosphorylation by Fc gamma RI cross-linking is known to be important in mediating Fc gamma RI-coupled effector functions. Recently, syk has been implicated in this role. We now report that the src-type kinases hck and lyn are physically and functionally associated with Fc gamma RI. Hck and lyn coimmunoprecipitated with Fc gamma RI from detergent lysates of normal human monocytes and of the monocytic line THP-1. Hck and lyn showed rapidly increased phosphorylation and increased exogenous substrate kinase activity after cross-linking of Fc gamma RI. These results demonstrate both physical and functional association of the Fc gamma RI/Fc epsilon RI gamma receptor complex with hck and lyn, and suggest a potential signal transducing role for these kinases in monocyte/macrophage activation.

The staphylococcal toxic shock syndrome toxin 1 triggers B cell proliferation and differentiation via major histocompatibility complex-unrestricted cognate T/B cell interaction.

The Staphylococcus aureus exotoxin toxic shock syndrome toxin 1 (TSST-1) is a potent activator of T cells and monocytes. We have recently demonstrated that TSST-1 is a superantigen that binds monomorphic determinants on MHC class II molecules. In the present study, we have examined the effect of TSST-1 on the activation and differentiation of high density human tonsillar B cells. TSST-1 bound to tonsilar B cells with high affinity and saturation kinetics. This binding was effectively inhibited by a combination of anti-HLA-DR and anti-HLA-DQ mAbs. Treatment of purified B cells with TSST-1 failed to induce B cell proliferation or Ig production. However, in the presence of irradiated T cells, TSST-1 induced resting B cells to proliferate and differentiate into Ig secretory cells. TSST-1 mimicked nominal antigen in that its induction of B cell responses was strictly dependent on physical contact between T and B cells, and was profoundly inhibited by anti-MHC class II mAbs, anti-CD3 mAbs, and, to a lesser extent, by anti-CD18 mAbs. However, unlike nominal antigen, TSST-1-mediated T/B cell interactions were MHC unrestricted. These results suggest that TSST-1 induces T cell-dependent B cell proliferation and differentiation by virtue of its ability to mediate MHC-unrestricted cognate T/B cell interaction via the TCR/CD3 complex and MHC class II antigens.

The CD4 molecule is not always required for the T cell response to bacterial enterotoxins.

T cells respond in a V beta-restricted fashion to bacterial enterotoxins bound to major histocompatibility complex (MHC) class II molecules. The requirement for CD4 in MHC class II-restricted T cell responses is very well established. We have assessed the role of CD4 in the T cell response to the bacterial enterotoxins Staphylococcal enterotoxin A (SEA), SEB, and toxic shock syndrome toxin 1. Three CD4- murine T cell hybridomas were transfected with the human CD4 molecule and assayed for interleukin 2 production in the presence of accessory cells bearing human MHC class II molecules and of the appropriate enterotoxin. The results clearly indicate that CD4- cells responded even to suboptimal concentrations of enterotoxin(s) equally well as CD4+ cells. Furthermore, expression of CD4 did not result in the acquisition of previously undetectable reactivity to enterotoxins. These results suggest that unlike the case with antigen-specific responses, formation of a T cell receptor-CD3/CD4 supramolecular complex is not always essential for T cell activation by bacterial enterotoxins.

Bioavailable iron and heme metabolism in Plasmodium falciparum.

Iron metabolism is essential for cell function and potentially toxic because iron can catalyze oxygen radical production. Malaria-attributable anemia and iron deficiency anemia coincide as being treatable diseases in the developing world. In absolute amounts, more than 95% of Plasmodium metal biochemistry occurs in the acidic digestive vacuole where heme released from hemoglobin catabolism forms heme crystals. The antimalarial quinolines interfere with crystallization. Despite the completion of the Plasmodium genome, many 'gene gaps' exist in components of the metal pathways described in mammalian or yeast cells. Present evidence suggests that parasite bioavailable iron originates from a labile erythrocyte cytosolic pool rather than from abundant heme iron. Indeed the parasite has to make its own heme within two separate organelles, the mitochondrion and the apicomplast. Paradoxically, despite the abundance of iron within the erythrocyte, iron chelators are cytocidal to the Plasmodium parasite. Hemozoin has become a sensitive biomarker for laser desorption mass spectrometry detection of Plasmodium infection in both mice and humans.

L-System model for the growth of arbuscular mycorrhizal fungi, both within and outside of their host roots.

Development of arbuscular mycorrhizal fungal colonization of roots and the surrounding soil is the central process of mycorrhizal symbiosis, important for ecosystem functioning and commercial inoculum applications. To improve mechanistic understanding of this highly spatially and temporarily dynamic process, we developed a three-dimensional model taking into account growth of the roots and hyphae. It is for the first time that infection within the root system is simulated dynamically and in a spatially resolved way. Comparison between data measured in a calibration experiment and simulated results showed a good fit. Our simulations showed that the position of the fungal inoculum affects the sensitivity of hyphal growth parameters. Variation in speed of secondary infection and hyphal lifetime had a different effect on root infection and hyphal length, respectively, depending on whether the inoculum was concentrated or dispersed. For other parameters (branching rate, distance between entry points), the relative effect was the same independent of inoculum placement. The model also indicated that maximum root colonization levels well below 100%, often observed experimentally, may be a result of differential spread of roots and hyphae, besides intrinsic plant control, particularly upon localized placement of inoculum and slow secondary infection.

Molecular biomarkers for aflatoxins and their application to human liver cancer.

The rationale for developing molecular biomarkers to monitor and assess risk from human exposure to aflatoxins have been justified by the association of these carcinogens with human liver cancer, a disease that causes at least 250000 deaths world-wide each year. The goal of our research has been the development of aflatoxin biomarkers based upon the knowledge of the biochemistry and toxicology of aflatoxins gleaned from both experimental and human studies. These biomarkers have been subsequently utilized in experimental chemoprotection models to provide data on the modulation of these markers under different situations of disease risk. Several of the aflatoxin specific biomarkers have been validated in epidemiologic studies and are now available to use as intermediate biomarkers in chemoprotection trials. This systematic approach provides encouragement for preventive interventions and should serve as a template for the development, validation and application of other chemical-specific biomarkers to cancer or other chronic diseases.

Correction of neutropenia and hypogammaglobulinemia in X-linked hyper-IgM syndrome by allogeneic bone marrow transplantation.

X-linked hyper-IgM (X-HIM) syndrome is a primary immunodeficiency disease characterized by defects in both cellular and humoral immunity. X-HIM is caused by mutations in the gene for CD40 ligand (CD40L), a T cell membrane protein that mediates T cell-dependent immune functions. We report the case of a 6-year-old male with X-HIM due to an intronic mutation resulting in aberrant CD40L RNA splicing and absence of detectable CD40L protein. The patient had a history of multiple infectious complications and chronic neutropenia requiring treatment with recombinant granulocyte colony-stimulating factor, and underwent allogeneic bone marrow transplantation from an HLA-matched sibling donor. Following successful engraftment, T cell CD40L expression and immunoglobulin isotype switching were reconstituted and neutropenia resolved. Allogeneic bone marrow transplantation can correct neutropenia and reconstitute immune function in X-HIM.

Microscopic cut-through of cancer in the surgical treatment of squamous carcinoma of the tongue. Prognostic and therapeutic implications.

A retrospective review was carried out of the records of 268 patients with a pathologically proved diagnosis of squamous carcinoma of the tongue treated by glossectomy at M.D. Anderson Hospital and Tumor Institute from January 1, 1970 through December 31, 1979. Pathologic findings found on frozen section analysis were correlated with the TNM stage of the tumor, histologic characteristics, perineural invasion, type of treatment, local recurrence, and survival rate. Thirty-eight patients with squamous carcinoma of the oral tongue and 16 patients with tumors of the base of the tongue had initially positive frozen section margins. Forty-one of these patients had margins that were negative at the completion of surgery. Thirteen patients never had negative margins. Positive mucosal margins were more common in smaller tumors and positive muscular margins were more common in larger tumors. Patients with perineural invasion and larger tumors had a higher percentage of positive margins. Those patients with initially positive margins that were rendered negative at the completion of the procedure and treated with surgery only had a significantly increased local recurrence rate and reduced survival compared with patients similarly treated with initially negative margins. Tumor stage, location (muscular versus mucosal) of positive margins, and the presence of perineural invasion were not significant in predicting local recurrence or decreased survival. If all patients with microscopically positive margins are considered for postoperative radiotherapy, then the routine use of intraoperative frozen section examination of the margins of resection in squamous carcinoma of the tongue may not be justified.

Gonotrophic development in the rodent bot fly Cuterebra fontinella (Diptera: Oestridae).

The gonotrophic development of Cuterebra fontinella Clark begins after the larval-pupal molt, the point at which winter diapause often occurs in many Cuterebra spp. Adult females emerge with their eggs at stage 3 and require an additional 5 d to complete oogenesis. Other species of Cuterebra also may have similar developmental sequences and require a period of several days after eclosion to complete development of their ova.

New procedures to enhance survival of third-instar Hypoderma lineatum (Villers) (Diptera: Oestridae) in artificial media.

New techniques for the maturation of late third instars of the common cattle grub, Hypoderma lineatum (Villers), in artificial media are described. Larvae were held in either 24-well culture plates with media plus penicillin, streptomycin sulfate, nystatin, and chloramphenicol or in small salve jars on Perlite and media plus the same antibiotics. Chloramphenicol was not always necessary in the jars. Survival to pupariation of young third instars increased from 5% without nystatin and chloramphenicol to 73% when the two antibiotics were present in the culture plates. The survival of mature third instats to pupariation increased from approximately 53 to 80% after addition of nystati and chloramphenicol to the culture plates. Survival to pupariation of more mature grubs was similar in the jar and culture plate techniques. The former was more convenient, but the young grubs did not survive well in the jars.

Intra-puparial development in Oestrus ovis (Diptera: Oestridae).

The phenology of intrapuparial development in Oestrus ovis L. is described, based on 302 specimens collected from the head cavities of goats and reared in the laboratory at a photoperiod of 12:12 (L:D) h and 32 and 16 degrees C. Dissection and histology of puparia at pupariation and at 3, 6, 9, 12, 15, 18, 21, 24, 30, 36, 42, 48, 66, and 72 h after pupariation and every day of the intra-puparial period showed that pupariation was achieved in approximately 12 h in heavily pigmented larvae (range, 2-46 h in postfeeding period). Larval-pupal apolysis began immediately after pupariation and was completed by 18-36 h after pupariation (prepupal period). The cryptocephalic pupa was found from this time to the 5th d, when head eversion occurred. Pupal-adult apolysis was initiated before head eversion and completed by day 7. The pharate adult presented progressive coloration in compound eyes (transparent, white, yellow, orange, red, brown, silver) while integumental pigmentation and sclerotization were in progress. Adult emergence occurred at 22 and 23 d in males and females, respectively. Changes in the weekly puparial weight of specimens reared under both field and laboratory conditions was described. It was concluded that although the intra-puparial development of O. ovis displayed some unique characteristics, it was essentially similar to other cyclorraphous flies. The actual pupal period of O. ovis lasted from the 2-7 d post-pupariation, whereas approximately two-thirds of the intra-puparial period was used for the maturation of the pharate adult.

Gonotrophic development in Oestrus ovis (Diptera: Oestridae).

Microanatomical characteristics and the size of the ovaries of Oestrus ovis L. during development were related to the intrapuparial-phenological stadia. Mature 3rd instars were collected from the head cavities of slaughtered goats, and pupae were reared under laboratory conditions. The length of freshly dissected ovaries and follicles were measured daily after pupal-adult apolysis to emergence. Ovarian tissue was stained using the PAS-Picroindigocarmine techniques. Oocyte development was classified according to a six-stage scale previously used in oestrid species. Shortly after pupal-adult apolysis, the single primary follicle is still unseparated from the germarium. In early white-eyed pharate adults, the primary follicle of stage 1 separates from the germarium, the nurse cells and oocyte are surrounded by a layer of cuboidal follicular cells, and the remaining oogonia degenerate. Oocytes in stage 2 initiate yolk deposition becoming ovoid, and this occurs when pharate adults have white-yellow to orange eyes. Oocytes in stage 3 are mainly vitellogenic, during the orange to red-eye stage. In stage 4, oocytes complete vitellogenesis and nurse cells degenerate when pupae achieve 90-96% of development. Mature oocytes of stage 5 can be found at emergence. Ovaries and ovarioles increase in size because of yolk deposition. O. ovis begins oogenesis as pharate adults, whereas vitellogenesis occurs during 55-96% of pupal development. Females emerge with one life-long complement of eggs ready to be fertilized, similar to other species of the Family Oestridae.

Use of sterile insect releases in an IPM program for control of Hypoderma lineatum and H. bovis (Diptera: Oestridae): a pilot test.

A joint Canadian-U.S. pilot test study was conducted for 4 yr on about 3,800 km2 on the Montana-Alberta border to determine the effect of sterile male releases on Hypoderma lineatum (Villers) and H. bovis (L.) populations remaining after initial chemical treatments. Chemical treatments initially reduced populations, making sterile male releases more efficient. Insect material for release was obtained from yearling animals held in confinement, an expensive, labor-intensive method of production. Sterile males of H. lineatum were released in one-half of the study area and sterile males of H. bovis were released in the other half. The unsterilized species in each half served as a control. Although the number of sterile males released was limited (265-462 yr), each species was eliminated in its respective release area, whereas the control species was not.

Technique for age-grading late third-instar Hypoderma lineatum (Diptera: Oestridae).

Three developmental phases are described for age-grading third-instar Hypoderma lineatum (Villers) based on color and development of the posterior spiracles. Early Phase 1 (P1) larvae are white in appearance, and their kidney-shaped posterior spiracular plates have no melanization. By the end of this phase, the cuticle has become yellow, and the margins of the spiracular plates begin to melanize. The cuticle of P2 larvae continues darkening from yellow to tan to light brown and is accompanied by a progressive melanization of the spiracular plates. The third phase, P3, has a cuticle that is not black like larvae that are ready to emerge from the hides for pupation, but the posterior spiracular plates are fully developed and melanized without a space between the two plates.

Experimental bovine hypodermosis in Spain.

An experimental survey was carried out in western Spain to investigate both the chronobiology of Hypoderma spp. and the immunoresponse of their bovine hosts. This study was initiated with a new system of obtaining Hypoderma spp. larvae directly from their host, including the eclosion of adults from their pupae, infestation under natural but controlled conditions, and confirmation of the resulting infection. This survey was carried out over 2 cattle grub seasons; it was possible to infest and reinfest the experimental animals and to monitor them by both parasitological methods and by an enzyme-linked immunosorbent assay. This method permitted the evaluation of the development of anti-Hypoderma antibodies during the experiment. The experimental design also enabled us to establish the period of detectable H. lineatum infection to be from December until the end of April with the largest number of warbles observed during March and April. After a pupal period of < 30 d, adults were seen in April and May. Hypoderma bovis (de Geer) showed a delay of 2 m.o. relative to H. lineatum (de Villiers). This study reports a completed biological life cycle of Hypoderma spp. under controlled conditions in both natural and experimental environments.

Factors affecting the larvipositional activity of Oestrus ovis gravid females (Diptera: oestridae).

Observations of fly strikes or larvipositions (n=68 in 21 days of observation) were carried out in a herd of goats during the spring in Baja California Sur, Mexico in order to identify the climatic conditions favoring larviposition activity of gravid Oestrus ovis L. flies, as well as to investigate whether a mixture of some potentially useful compounds was involved in this behavior. Hand-caught, tethered flies (n=43) were either exposed or unexposed to a combination of carbon dioxide, humidity, 1-octen-3-ol, butyric, propionic, acetic acid and acetone released from movable sheep and goat dummies under open field and cage conditions. Fly strikes occurred at temperatures greater than 20 degrees C, but mainly between 25 and 28 degrees C and from 116 to 838W m(-2) of solar irradiance. Few or no strikes were seen under moderate or strong wind, but did occur in a wide range of relative humidity. The chemicals applied did not improve the capacity of animal dummies to induce the flies to larviposit, but very irregular behavior was observed. Fourteen larvipositions were made on the dummies lacking chemical stimuli, so visual ability and movement by the dummies was very important in stimulation of the flies. Temperature appeared to be the main factor determining fly activity, but wind and solar irradiance also played important roles. Characteristics of O. ovis larviposition are discussed.

Moxidectin: systemic activity against common cattle grubs (Hypoderma lineatum) (Diptera: Oestridae) and trichostrongyle nematodes in cattle.

Moxidectin, a systemic insecticide, was evaluated for its efficacy against the migrating first instars of the common cattle grub, Hypoderma lineatum, and against nematode egg production in beef cattle. It was observed that all three levels (0.1, 0.2 and 0.4 mg moxidectin kg-1) were 100% effective against cattle grubs when administered as a s.c. injection. The same levels of treatment were very effective (90-100%) in reducing trichostrongyle nematode egg production. However, there was a slight indication that at least one species, Cooperia oncophora, was not completely eliminated, as it was observed that small numbers of eggs began to appear after 2 weeks post-treatment when there had been no opportunity for reinfection.