Strain-specific rRNA-targeted primers were designed for the quantitative detection of
Bifidobacterium infantis Y1,
B. breve Y8 and
B. longum Y10 used in a pharmaceutical probiotic product (VSL-3). ...PCR and real-time PCR techniques with the selected primers were employed for the direct enumeration of the bifidobacteria in the probiotic preparation and for studying their kinetic characteristics in batch cultures. These analysis revealed that
B. infantis Y1 was the predominant strain in the probiotic product and that its growth rate was the highest. Since
B. infantis Y1,
B. breve Y8 and
B. longum Y10 are co-cultured during the industrial production of VSL-3, the kinetic characteristics of these strains can explain their different concentrations in the probiotic preparation. A validation of the PCR quantification method was performed by identifying a representative number of isolates from the bacterial mixtures with automated ribotyping. The methodology described represents a useful tool for the specific quantitative detection of bacterial strains and species in complex mixtures such as pharmaceutical preparations, dairy starter cultures, faecal samples and biopsies.
Our X‐ray diffraction measurements reveal that Mn
2
O
3
undergoes a phase transition to the CaIrO
3
type, which is proposed for the post‐perovskite in MgSiO
3
, at 27–38 GPa and 300 K, bypassing the ...other phase transitions observed in sesquioxides. Small distortions in the polyhedra after the transition indicate that the Jahn‐Teller effect, which is strong at ambient conditions, is suppressed during the transition. The CaIrO
3
‐type phase exhibits strong preferred orientation of the (010) plane perpendicular to the loading axis before annealing whereas preferred orientation of the (100) and (110) planes was observed after annealing. The pre‐annealing texture may result from either the deformation under strong differential stresses or the phase transition. The post‐annealing texture may be related to either lower differential stresses or thermal annealing. Our result shows that the texture of the CaIrO
3
type can be sensitive to phase transition and annealing as well as differential stresses.
Recent first‐principles calculations have proposed that bulk sound speed (
V
Φ
) decreases at the perovskite (Pv) → postperovskite (PPv) transition. Yet some measurements suggest an increase in
V
Φ
...at the PPv transition in (Mg,Fe)SiO
3
and NaMgF
3
. Our new measurements on NaMgF
3
up to 50 GPa under quasi‐hydrostatic stress conditions reveal that the
V
Φ
of PPv remains lower than that of Pv near the PPv transition, consistent with a first‐principles study on NaMgF
3
. Combined with similar observations in (Mg,Fe)SiO
3
, MgGeO
3
, and CaIrO
3
, our result on NaMgF
3
suggests that the
V
Φ
decrease is a robust trend in the PPv transition and is controlled more by crystal structure than by chemical composition. Our finding also strengthens the proposal that the elastic properties of PPv can explain the small
P
‐wave increase across the D″ discontinuity and the anticorrelation between the
V
Φ
and
S
‐wave velocity anomalies in the D″ region.
Rifaximin resistance in the probiotic strain
Bifidobacterium infantis BI07 was studied to assess the use of an antibiotic–probiotic combination for clinical management of intestinal disorders. A ...rifaximin-resistant mutant was selected and a 129
bp core region of the
rpoB gene was sequenced and compared with the respective sequence of the sensitive clone. A miss-sense mutation of codon 513, producing the substitution of Gln with Arg in the protein sequence, was found. The involvement of metabolic changes associated with rifaximin resistance was also investigated by proteomic analysis performed with two-dimensional electrophoresis and mass spectrometry. The principal categories of proteins, whose expression levels varied as a consequence of rifaximin resistance, included chaperonins, regulatory factors and metabolic enzymes. The hypothesis of rifaximin inactivation by bacterial enzymatic activities was excluded, as neither structural modifications nor degradation derivates of the drug moiety was identified using liquid chromatography coupled with tandem mass spectrometry.
This study compares colposcopy referrals of 2 management strategies: oncogenic human papillomavirus (HPV)-DNA testing (Hybrid Capture 2 assay, Qiagen, Germantown, MD) and repeat cytology. In the New ...Technology in Cervical Cancer Trial, 22,708 subjects were randomly assigned to undergo both HPV and liquid-based cytologic testing. Women aged 35 to 60 years old with unsatisfactory cytologic findings were directly referred for colposcopy if the HPV test result was positive, and were referred for repeat cytologic examination if the HPV test result was negative; women aged 25 to 35 years old were referred for repeat cytologic examination independent of HPV test results. A positive or a second unsatisfactory cytologic examination referred women for colposcopy. Five hundred sixty women had unsatisfactory cytologic findings. Colposcopy referral was not significant and slightly higher with HPV testing than repeat cytologic test (9.8% vs 6.8%, P = .11). When cytologic testing was repeated 36.8% were unavailable for follow-up and most of the colposcopies were performed in HPV-negative women. For unsatisfactory cytologic findings, HPV triage is a more logical and efficient management strategy than a repeat cytologic test.
Recent studies have indicated that a significant amount of iron in MgSiO
3 perovskite (Pv) is Fe
3+ (Fe
3+/ΣFe
=
10–60%) due to crystal chemistry effects at high pressure (
P) and that Fe
3+ is more ...likely than Fe
2+ to undergo a high-spin (HS) to low-spin (LS) transition in Pv in the mantle. We have measured synchrotron Mössbauer spectroscopy (SMS), X-ray emission spectroscopy (XES), and X-ray diffraction (XRD) of Pv with all iron in Fe
3+ in the laser-heated diamond-anvil cell to over 100
GPa. Fe
3+ increases the anisotropy of the Pv unit cell, whereas Fe
2+ decreases it. In Pv synthesized above 50
GPa, Fe
3+ enters into both the dodecahedral (A) and octahedral (B) sites approximately equally, suggesting charge coupled substitution. Combining SMS and XES, we found that the LS population in the B site gradually increases with pressure up to 50–60
GPa where all Fe
3+ in the B site becomes LS, while Fe
3+ in the A site remains HS to at least 136
GPa. Fe
3+ makes Pv more compressible than Mg-endmember below 50
GPa because of the gradual spin transition in the B site together with lattice compression. The completion of the spin transition at 50–60
GPa increases bulk modulus with no associated change in density. This elasticity change can be a useful seismic probe for investigating compositional heterogeneities associated with Fe
3+.
High-pressure polymorphs of H{sub 2}O are a major component in many outer planets, extra solar bodies, and icy satellites. This study sought to examine the influence of ionic impurities on the phase ...stability, thermal expansion, and melting curve of ice VII. Powder diffraction patterns of ice VII formed from pure H{sub 2}O and 5 wt.% NaCl aqueous solutions were taken at room temperature up to 11.1 {+-} 0.3 and 26.6 {+-} 0.4 GPa, respectively. Thermal expansions, {alpha}, of all ice VII samples were recorded and modeled up to the melting point of the samples. Ice VII formed from a NaCl-bearing aqueous solution at pressures greater than 2.2 GPa and less than 500 K can be indexed by ice VII only, whereas at temperatures greater than 500 K, diffraction lines indicative of halite (NaCl) are observed and become more intense with increasing temperature and only disappear at the melting point of the high-pressure ice. This phenomenon was observed in all NaCl-bearing ice samples that were heated to greater than 500 K. The melting curves of ice VII formed from pure H{sub 2}O and a 5 wt.% NaCl aqueous solution suggest that the presence of Na{sup +} and Cl{sup -} in the ice VII structure results in a depression of the melting curve by approximately 40 K. The exsolution of halite from the NaCl-doped ice VII and the depression of the ice VII melting curve suggest that the presence of ionic impurities in ice VII may promote the formation of a self-segregating zone deep within ice-rich bodies. This zone could initiate the formation of solute-rich melt pockets that may ascend toward the surface and result in surface manifestations such as solute-bearing aqueous vents, unexplained domes/diapirism, and/or salt-rich regions.
Abstract This project tests the relationship between the acetabular cup surface characteristics and their initial stability by comparing uncemented (Trabecular Metal (TM) and Trilogy) and cemented ...polyethylene shells. We hypothesised that different surface properties of uncemented cups will influence the cup stability. Mounted directly onto host bone, TM and cemented cups were significantly more stable than Trilogy cups ( P < 0.01), with minimal difference between TM and cemented cups ( P > 0.1). On 100% graft bed, there was marginal difference between all three cup types ( P > 0.1). Incremental cavitary and segmental defects resulted in reducing stability, with cemented cups being minimally more stable ( P > 0.1). TM cups possess satisfactory initial stability in bone graft constructs. This study demonstrates that TM shells are marginally less stable than cemented cups in the absence of significant host bone contact.
Studies of materials’ properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an ...achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications.
Silica is the most abundant oxide component in the Earth mantle by weight, and stishovite, the rutile-structured (.../mnm) high-pressure phase with silica in six coordination by oxygen, is one of the ...main constituents of the basaltic layer of subducting slabs. It may also be present as a free phase in the lower mantle and at the core-mantle boundary. Pure stishovite undergoes a displacive phase transition to the ... structure (Pnnm) at ...55 GPa. Theory suggests that this transition is associated with softening of the shear modulus that could provide a significant seismic signature, but none has ever been observed in the Earth. However, stishovite in natural rocks is expected to contain up to 5 wt % ... and possibly water. Here we report the acoustic velocities, densities, and Raman frequencies of aluminum- and hydrogen-bearing stishovite with a composition close to that expected in the Earth mantle at pressures up to 43.8(3) GPa where (3) indicates an uncertainty of 0.3 GPa. The post-stishovite phase transition occurs at 24.3(5) GPa (at 298 K), far lower than for pure silica at 50-60 GPa. Our results suggest that the rutile-... transition in natural stishovite (with 5 wt % ...) should occur at ...30 GPa or ...1,000-km depth at mantle temperatures. The major changes in elastic properties across this transition could make it visible in seismic profiles and may be responsible for seismic reflectors observed at 1,000- to 1,400-km depth. (ProQuest: ... denotes formulae/symbols omitted.)
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