A remotely interrogated all-optical Rb-87 magnetometer

Atomic magnetometry was performed at Earth's magnetic field over a free-space distance of ten meters. Two laser beams aimed at a distant alkali-vapor cell excited and detected the Rb-87 magnetic resonance, allowing the magnetic field within the cell to be interrogated remotely. Operated as a driven oscillator, the magnetometer measured the geomagnetic field with less than or similar to 3.5 pT precision in a similar to 2 s data acquisition; this precision was likely limited by ambient field fluctuations. The sensor was also operated in self-oscillating mode with a 5.3 pT root Hz noise floor. Further optimization will yield a high-bandwidth, fully remote magnetometer with sub-pT sensitivity. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4747206

Environmental Factors in the Relapse and Recurrence of Inflammatory Bowel Disease:A Review of the Literature

The causes of relapse in patients with Crohn's disease (CD) and ulcerative colitis (UC) are largely unknown. This paper reviews the epidemiological and clinical data on how medications (non-steroidal anti-inflammatory drugs, estrogens and antibiotics), lifestyle factors (smoking, psychological stress, diet and air pollution) may precipitate clinical relapses and recurrence. Potential biological mechanisms include: increasing thrombotic tendency, imbalances in prostaglandin synthesis, alterations in the composition of gut microbiota, and mucosal damage causing increased permeability

Evolution and stoichiometry of heterogeneous processing in the Antarctic stratosphere

Simultaneous in situ measurements of HCl and ClO have been made for the first time in the southern hemisphere, allowing a systematic study of the processes governing chlorine activation between 15 and 20 km in the 1994 Antarctic winter. Data for several other gases (O_3, NO, NO_y, OH, HO_2, N_(2)O, CH_4, CO, H_(2)O, CFCs), particulates, and meteorological parameters were collected from the ER-2 aircraft out of New Zealand as part of the 1994 Airborne Southern Hemisphere Ozone Experiment/Measurements of Atmospheric Effects of Stratospheric Aircraft (ASHOE/MAESA) campaign. Observations from the ER-2 in the fall (April–May), prior to polar night, show that chlorine activation begins with 60–75% of inorganic chlorine as HCl. By midwinter (July–August), near-total removal of HCl is observed. The wintertime loss of HCl in air recently exposed to extreme temperatures is found to be correlated with high levels of reactive chlorine (ClO and its dimer, Cl_(2)O_2) in the linear fashion expected from the stoichiometry of the heterogeneous reaction of hydrochloric acid with chlorine nitrate on polar stratospheric clouds (PSCs): HCl + ClONO_2 → Cl_2 + HNO_3. To constrain the role of different heterogeneous reactions and PSC types, we have used a photochemical trajectory model which includes heterogeneous sulfate and PSC chemistry. Model calculations of the evolution of reactive gases are compared with the in situ observations. In addition, simultaneous measurements of OH and HO_2 are used as a diagnostic for the occurrence of the heterogeneous reaction HOCl + HCl → Cl_2 + H_(2)O, which contributes to suppressed levels of HO_x inside the vortex. It is shown that the amount of chlorine activation is not strongly dependent on the composition of PSCs. However, HO_x levels exhibit different signatures depending on the type of heterogeneous surfaces that affected chlorine activation. Furthermore, this analysis implies that in the edge region of the Antarctic vortex, the observed near-total removal of HCl can result from latitudinal excursions of air parcels in and out of sunlight during the winter, which photochemically resupply HOCl and ClONO_2 as oxidation partners for HCl

Charged and Hydrophobic Surfaces on the A Chain of Shiga-Like Toxin 1 Recognize the C-Terminal Domain of Ribosomal Stalk Proteins

Shiga-like toxins are ribosome-inactivating proteins (RIP) produced by pathogenic E. coli strains that are responsible for hemorrhagic colitis and hemolytic uremic syndrome. The catalytic A1 chain of Shiga-like toxin 1 (SLT-1), a representative RIP, first docks onto a conserved peptide SD[D/E]DMGFGLFD located at the C-terminus of all three eukaryotic ribosomal stalk proteins and halts protein synthesis through the depurination of an adenine base in the sarcin-ricin loop of 28S rRNA. Here, we report that the A1 chain of SLT-1 rapidly binds to and dissociates from the C-terminal peptide with a monomeric dissociation constant of 13 µM. An alanine scan performed on the conserved peptide revealed that the SLT-1 A1 chain interacts with the anionic tripeptide DDD and the hydrophobic tetrapeptide motif FGLF within its sequence. Based on these 2 peptide motifs, SLT-1 A1 variants were generated that displayed decreased affinities for the stalk protein C-terminus and also correlated with reduced ribosome-inactivating activities in relation to the wild-type A1 chain. The toxin-peptide interaction and subsequent toxicity were shown to be mediated by cationic and hydrophobic docking surfaces on the SLT-1 catalytic domain. These docking surfaces are located on the opposite face of the catalytic cleft and suggest that the docking of the A1 chain to SDDDMGFGLFD may reorient its catalytic domain to face its RNA substrate. More importantly, both the delineated A1 chain ribosomal docking surfaces and the ribosomal peptide itself represent a target and a scaffold, respectively, for the design of generic inhibitors to block the action of RIPs

Durability of fire retardant treated wood products at humid and exterior conditions. Review of literature

Fire retardants may considerably improve the fire properties of wood products, but the durability, e.g. in exterior applications, has not been addressed fully. This paper reviews the existing knowledge and experience mainly from the USA with the aim of supporting further development in Europe. The review is concentrated on pressure impregnated fire retardant treated wood products which have the best opportunities for increased durabilit

Kartlegging av miljøgifter i sedimenter i Indre Drammensfjorden 1993

Totalt 18 sedimentstasjoner i indre fjordområde og 2 løsmasseprøver fra Holmen i utløpet av Drammenselva ble undersøkt for innholdet av miljøgifter. I tillegg er det foretatt evaluering av en rekke mulige forurensningskilder, samt nærmere karakterisering av ren tjæreprøve fra Gilhusbukta. Hovedresultatene viser at belastningen mht. tungmetaller er liten til moderat i sedimentene og samlet viser metallene maksimalt tilstandsklasse III. Flere ulike kilder til tungmetallforekomstene kan antydes. Av de organiske miljøgiftene er forekomstene av PCB mest markert, og antyder tilstandsklasse III-IV for store deler av fjorden. PAH forekommer i svært høye konsentrasjoner, men har hovedsakelig en begrenset og lokal utbredelse. Både PCB og PAH forekomstene kan stamme fra flere ulike kilder i indre del av fjorden. Av andre klororganiske forbindelser ble kun DDT registrert i forhøyde konsentrasjoner og synes å være knyttet til Lierelva. Oljeforurensningen (THC) var mer moderat og var mest framtredende i elva utenfor Holmen. Referansestasjonen utenfor Sandtangen, synes å ligge i et akkumulasjonsområde for forurensninger i fjorden, da det gjennomgående ble registrert høye konsentrasjoner her for alle miljøgiftene. Løsmasseprøvene fra Holmen var ikke forurenset

Kartlegging av miljøgifter i sedimenter i Indre Drammensfjorden 1993

Totalt 18 sedimentstasjoner i indre fjordområde og 2 løsmasseprøver fra Holmen i utløpet av Drammenselva ble undersøkt for innholdet av miljøgifter. I tillegg er det foretatt evaluering av en rekke mulige forurensningskilder, samt nærmere karakterisering av ren tjæreprøve fra Gilhusbukta. Hovedresultatene viser at belastningen mht. tungmetaller er liten til moderat i sedimentene og samlet viser metallene maksimalt tilstandsklasse III. Flere ulike kilder til tungmetallforekomstene kan antydes. Av de organiske miljøgiftene er forekomstene av PCB mest markert, og antyder tilstandsklasse III-IV for store deler av fjorden. PAH forekommer i svært høye konsentrasjoner, men har hovedsakelig en begrenset og lokal utbredelse. Både PCB og PAH forekomstene kan stamme fra flere ulike kilder i indre del av fjorden. Av andre klororganiske forbindelser ble kun DDT registrert i forhøyde konsentrasjoner og synes å være knyttet til Lierelva. Oljeforurensningen (THC) var mer moderat og var mest framtredende i elva utenfor Holmen. Referansestasjonen utenfor Sandtangen, synes å ligge i et akkumulasjonsområde for forurensninger i fjorden, da det gjennomgående ble registrert høye konsentrasjoner her for alle miljøgiftene. Løsmasseprøvene fra Holmen var ikke forurenset.Fylkesmannen i Buskerud, Miljøvernavdelinge