Atomic-scale 3D imaging of individual dopant atoms in an oxide semiconductor.

The physical properties of semiconductors are controlled by chemical doping. In oxide semiconductors, small variations in the density of dopant atoms can completely change the local electric and magnetic responses caused by their strongly correlated electrons. In lightly doped systems, however, such variations are difficult to determine as quantitative 3D imaging of individual dopant atoms is a major challenge. We apply atom probe tomography to resolve the atomic sites that donors occupy in the small band gap semiconductor Er(Mn,Ti)O3 with a nominal Ti concentration of 0.04 at. %, map their 3D lattice positions, and quantify spatial variations. Our work enables atomic-level 3D studies of structure-property relations in lightly doped complex oxides, which is crucial to understand and control emergent dopant-driven quantum phenomena.

Oral Microbiota Transplant in Dogs with Naturally Occurring Periodontitis.

In periodontitis patients, dysbiosis of the oral microbiota is not only found at clinically diseased periodontal sites but also at clinically healthy periodontal sites, buccal mucosae, tongue, and saliva. The present study evaluated the safety and efficacy of an oral microbiota transplant (OMT) for the treatment of periodontitis in dogs. Eighteen systemically healthy beagle dogs with naturally occurring periodontitis were enrolled in the study and randomly assigned to a test or control group. A 4-y-old, periodontally healthy female beagle dog served as a universal OMT donor. To reduce periodontal inflammation, all dogs received full-mouth mechanical debridement of teeth and mucosae 2 wk before baseline. At baseline, full-mouth mechanical debridement was repeated and followed by adjunctive subgingival and oral irrigation with 0.1% NaOCl. Subsequently, test dogs were inoculated with an OMT from the healthy donor. No daily oral hygiene was performed after OMT transplantation. Adverse events were assessed throughout the observation period. Clinical examinations were performed and whole-mouth oral microbiota samples were collected at week 2, baseline, week 2, and week 12. The composition of oral microbiota samples was analyzed using high-throughput 16S ribosomal RNA gene amplicon sequencing followed by taxonomic assignment and downstream bioinformatic and statistical analyses. Results demonstrated that the intergroup difference in the primary outcome measure, probing pocket depth at week 12, was statistically insignificant. However, the single adjunctive OMT had an additional effect on the oral microbiota composition compared to the full-mouth mechanical and antimicrobial debridement alone. The OMT resulted in an "ecological shift" toward the composition of the donor microbiota, but this was transient in nature and was not observed at week 12. No local or systemic adverse events were observed throughout the study period. The results indicate that OMT may modulate the microbiota composition in dogs with naturally occurring periodontitis and can be applied safely.

Electronic properties of reduced molybdenum oxides.

The electronic properties of MoO3 and reduced molybdenum oxide phases are studied by density functional theory (DFT) alongside characterization of mixed phase MoOx films. Molybdenum oxide is utilized in compositions ranging from MoO3 to MoO2 with several intermediary phases. With increasing degree of reduction, the lattice collapses and the layered MoO3 structure is lost. This affects the electronic and optical properties, which range from the wide band gap semiconductor MoO3 to metallic MoO2. DFT is used to determine the stability of the most relevant molybdenum oxide phases, in comparison to oxygen vacancies in the layered MoO3 lattice. The non-layered phases are more stable than the layered MoO3 structure for all oxygen stoichiometries of MoOx studied where 2 ≤ x < 3. Reduction and lattice collapse leads to strong changes in the electronic density of states, especially the filling of the Mo 4d states. The DFT predictions are compared to experimental studies of molybdenum oxide films within the same range of oxygen stoichiometries. We find that whilst MoO2 is easily distinguished from MoO3, intermediate phases and phase mixtures have similar electronic structures. The effect of the different band structures is seen in the electrical conductivity and optical transmittance of the films. Insight into the oxide phase stability ranges and mixtures is not only important for understanding molybdenum oxide films for optoelectronic applications, but is also relevant to other transition metal oxides, such as WO3, which exist in analogous forms.

Stability-indicating HPLC assays for the determination of piritramide and droperidol in PCA solution.

WHAT IS KNOWN AND OBJECTIVE: A mixture of morphine and droperidol is a well-established antiemetic for reducing the risk of postoperative nausea and vomiting. A mixture of piritramide and droperidol has not yet been evaluated in this context. Our objectives were to develop a high-performance liquid chromatographic assay for piritramide and droperidol in 0·9% saline, and to establish their stability under defined storage conditions. METHODS: The separation and assay of both drugs were attempted by high performance liquid chromatography (HPLC) using a RP-select B column and a mobile phase of 57:43% v/v methanol-monosodium phosphate solution 0·05 M at a flow rate of 1·2 mL/min. UV detection at 205 and 246 nm for piritramide and droperidol were used, respectively. RESULTS AND DISCUSSION: The HPLC method was successful. Linearity was shown for piritramide from 0·075 to 0·013 mg/mL and for droperidol from 0·8 to 0·2 mg/mL. The intra- and inter-day relative standard deviation (RSD, %) was 0·27% and 0·54% for piritramide and droperidol, respectively. The two drugs were stable for at least 72 h when stored under ambient light at room temperature. WHAT IS NEW AND CONCLUSION: Seventy-five milligrams piritramide and 2·5 mg droperidol diluted to 50 ml with 0·9% saline should be suitable for clinical use. At this dilution, a Dipidolor(®) and Xomolix(®), mixture, was stable when stored under ambient light exposure at room temperature for at least 72 h.

Melting of Bi sublattice in nanosized BiFeO3 Perovskite by resonant X-ray diffraction.

Free-standing BiFeO3 perovskite particles with a size ranging from polycrystalline bulk down to 5 nm have been studied by high-energy resonant (Bi K edge) x-ray diffraction coupled to differential atomic pair distribution function analysis. Nanosized BiFeO3 particles are found to exhibit extra, i.e., beyond the usual thermal, structural disorder that increases progressively with diminishing their size. In particles of size smaller than approximately 18 nm the disorder destroys the structural coherence of the Bi sublattice and disturbs that of the Fe-based sublattice in the perovskite structure, substantially affecting the magnetoelectric properties it carries. The new structural information helps better understand the unusual behavior of perovskites structured at the nanoscale.

Prevalence of achlorhydria in a normal population and its relation to serum gastrin.

In a middle-aged group of normal subjects achlorhydria after maximal stimulation with pentagastrin was found in 12 out of 366 males (3%) and 2 out of 198 females (1%); 13 of these 14 (93%) had an elevated serum gastrin, of which nine were more than two times normal. In another 11 persons a moderately elevated serum gastrin - less than two times normal - was found in absence of achlorhydria. At least seven of them had hypochlorhydria. Of 540 persons with a normal serum gastrin one had achlorhydria. Determination of the serum gastrin appeared to be fairly reliable as a method of detecting achlorhydria.

Parietal cell antibodies in relation to basal serum gastrin in a normal population.

Parietal cell antibodies, basal gastric pH and serum gastrin were determined in 544 normal non-achlorhydric subjects. Serum gastrin was significantly higher in subjects with parietal cell antibodies, both in the group with a weakly positive and in that with a strongly positive fluorescence score. The elevated serum gastrin level in subjects with circulating parietal cell antibodies was independent of gastric pH. It is suggested that parietal cell antibodies may interfere with gastrin receptors on the membrane of the parietal cell, thus influencing the feedback mechanism between the secretion of acid and gastrin, and resulting in an increase of the basal serum gastrin level at an unchanged basal gastric pH.

Is discrimination between type A and B atrophic gastritis clinically useful in achlorhydria?

We tested the validity of the concept that chronic atrophic gastritis can be subdivided into type A and B in hospital patients and normal subjects with proven pentagastrin-refractory achlorhydria. Classification was based on the determination of the basal serum gastrin and parietal cell antibodies. Of 59 hospital patients with achlorhydria, 71% could be classified as belonging to either type A or B; for 29% the criteria for neither type were fulfilled. Of 14 asymptomatic persons with achlorhydria found in 564 normal persons, five could be classified as having type A gastritis, and one as type B gastritis. In eight (53%) persons, an elevated serum gastrin was found in the absence of parietal cell antibodies, representing an intermediate type of atrophic gastritis. Because one-third of the hospital patients and more than half the persons with achlorhydria in a normal population had to be classified as belonging to an intermediate type, the discrimination between type A and B atrophic gastritis in achlorhydria seems to be of limited practical value.