Bright nanowire single photon source based on SiV centers in diamond

The practical implementation of many quantum technologies relies on the development of robust and bright single photon sources that operate at room temperature. The negatively charged silicon-vacancy (SiV^-) color center in diamond is a possible candidate for such a single photon source. However, due to the high refraction index mismatch to air, color centers in diamond typically exhibit low photon out-coupling. An additional shortcoming is due to the random localization of native defects in the diamond sample. Here we demonstrate deterministic implantation of Si ions with high conversion efficiency to single SiV^- centers, targeted to fabricated nanowires. The co-localization of single SiV^- centers with the nanostructures yields a ten times higher light coupling efficiency than for single SiV^- centers in bulk diamond. This enhanced photon out-coupling, together with the intrinsic scalability of the SiV^- creation method, enables a new class of devices for integrated photonics and quantum science.

Ion implantation for deterministic single atom devices

We demonstrate a capability of deterministic doping at the single atom level using a combination of direct write focused ion beam and solid-state ion detectors. The focused ion beam system can position a single ion to within 35 nm of a targeted location and the detection system is sensitive to single low energy heavy ions. This platform can be used to deterministically fabricate single atom devices in materials where the nanostructure and ion detectors can be integrated, including donor-based qubits in Si and color centers in diamond.

Are physicians prepared for whole genome sequencing? a qualitative analysis

Although the integration of whole genome sequencing (WGS) into standard medical practice is rapidly becoming feasible, physicians may be unprepared to use it. Primary care physicians (PCPs) and cardiologists enrolled in a randomized clinical trial of WGS received genomics education before completing semi-structured interviews. Themes about preparedness were identified in transcripts through team-based consensus-coding. Data from 11 PCPs and 9 cardiologists suggested that physicians enrolled in the trial primarily to prepare themselves for widespread use of WGS in the future. PCPs were concerned about their general genomic knowledge, while cardiologists were concerned about how to interpret specific types of results and secondary findings. Both cohorts anticipated preparing extensively before disclosing results to patients by using educational resources with which they were already familiar, and both cohorts anticipated making referrals to genetics specialists as needed. A lack of laboratory guidance, time pressures, and a lack of standards contributed to feeling unprepared. Physicians had specialty-specific concerns about their preparedness to use WGS. Findings identify specific policy changes that could help physicians feel more prepared, and highlight how providers of all types will need to become familiar with interpreting WGS results.

Spectroscopic markers for uranium(vi) phosphates: a vibronic study

Uranyl phosphate minerals are studied by optical and vibrational spectroscopy which provide robust markers to discriminate among environmentally hazardous uranium phases.

Solid-state (207)Pb NMR studies of lead-group 16 and mixed transition-metal/lead-group 16 element-containing materials

(207)Pb solid-state NMR studies have been conducted on binary lead-group 16 and mixed transition-metal/lead group 16 materials, correlating the NMR chemical shifts of the materials with their structures. The experimental results show that the (207)Pb chemical shifts are strongly influenced by the local electronic structure. Data are reported for lead selenide, lead selenate, calcium plumbate, strontium plumbite, barium plumbite, lead borate, lead zirconate, lead tungstate, lead meta-tantalate, lead niobate, lead molybdate, lead meta-vanadate, lead sulfite, and lead sulfate.

207Pb NMR of minium, Pb3O4: evidence for the [Pb2]4+ ion and possible relativistic effects in the Pb-Pb bond

Solid Pb3O4 has been studied with 207Pb nuclear magnetic resonance (NMR) spectroscopy. The 207Pb NMR chemical-shift tensor of the Pb2+ site has principal values of delta11 = 1980 +/- 5 ppm, delta22 = 1540 +/- 5 ppm, and delta33 = -1108 +/- 10 ppm; delta(iso) = 804 +/- 10 ppm. The chemical-shift tensor of the Pb4+ site is axial, with principal values delta(parallel) = -1009 +/- 3 ppm and delta(perpendicular) = 1132 +/- 3 ppm; delta(iso) = -1091 +/- 3 ppm. The Pb4+-Pb2+ scalar coupling constant J(Pb-Pb) = 2.3 +/- 0.1 kHz. The main contribution to the Pb2- chemical-shift anisotropy is proposed to arise from an exchange interaction in the Pb2+-Pb2+ pairs, conventionally regarded as molecular [Pb2]4+ ions.

The Effect of Humidity on the Physical and Chemical Stability of Spray-Dried Aluminum Hydroxycarbonate

The moisture sorption isotherm of amorphous spray-dried aluminum hydroxycarbonate (SDAHC) at 25°C revealed that moisture sorption increased sharply when the relative humidity exceeded 80%. The physical and chemical stability of SDAHC was studied for 1 year at 25°C and 0, 11, 54, 84, or 100% RH. The results were interpreted to reveal that two mechanisms affect the properties of SDAHC at 25°C. The sample stored at 0% RH did not exhibit any significant changes during the 1-year study period. The surface area and rate of acid neutralization decreased when samples were stored at 11 or 54% RH, but the material remained amorphous. This change is believed to be due to aggregation and cementation of particles. Much larger changes in surface area and the rate of acid neutralization occurred in the samples aged at 84 or 100% RH. Under these humidity conditions, polymorphic transformations occurred in addition to aggregation and cementation. X-ray diffraction indicated that microcrystalline boehmite was an intermediate phase. The stable polymorph was bayerite, which is believed to form due to the high surface pH produced by water sorption at 84 or 100% RH. The moisture sorption isotherm was useful in identifying the humidity conditions which resulted in high moisture sorption. Polymorphic transformations were only detected when the SDAHC was aged under these humidity conditions.

Determination of 207Pb2+ chemical shift tensors from precise powder lineshape analysis

207Pb solid state NMR powder spectra at 296 K are presented for PbSO4, PbMoO4, PbCrO4, PbCO3, PbTiO3, PbZrO3, Pb(NO3)2, Pb(SCN)2, and PbS. Analysis for principal values of the anisotropic chemical shift tensors of the generally very broad spectra included the frequency dependent excitation of the pulse sequence used. Commonly used solid and liquid secondary shift standards for lead were studied with high precision as a function of temperature between 295 K and 315 K to establish a clean 207Pb shift scale. Errors in the existing literature are discussed.

Characterization of antacid compounds containing both aluminum and magnesium. II. Codried powders

The composition and antacid properties of six samples of codried antacids containing both aluminum and magnesium were determined. Aluminum hydroxide-magnesium carbonate codried gel and aluminum hydroxide-magnesium hydroxide codried gel were non-homogeneous, as the samples contained combinations of hydrotalcite, amorphous aluminum hydroxide, magnesium hydroxide, magnesium hydroxycarbonate, and magnesium carbonate. All samples passed the preliminary antacid test and had high acid neutralizing capacities. However, the rate of acid neutralization varied between samples. In some cases the rate of acid neutralization at a dose of 400 mg was too slow to raise the pH to 3.0 as required by the Rossett-Rice test.

Characterization of antacid compounds containing both aluminum and magnesium. I. Crystalline powders

The composition and antacid properties of 10 samples of crystalline antacids containing both aluminum and magnesium were determined. The composition was found to vary significantly, even within the same type of antacid. For example, three of four hydrotalcite samples exhibit evidence of the presence of a minor phase of amorphous aluminum hydroxide. Almagate and almagcit, which are claimed to be unique compounds, were found to be composed of hydrotalcite, magnesium hydroxycarbonate, and/or magnesium carbonate and amorphous aluminum hydroxide. All three magaldrate samples examined contained a minor phase of amorphous aluminum hydroxide. All 10 samples passed the preliminary antacid test and had high acid neutralizing capacities. However, the rate of acid neutralization varied between samples. In some cases the rate of acid neutralization at a dose of 400 mg was too slow to raise the pH to 3.0 as required by the Rossett-Rice test.

Third-party payor billing and reimbursement for nursing services: infant apnea management

This article examines the process of implementing a program for billing third-party payors for the services of the pediatric clinical nurse specialist. Factors to consider when initiating a billing program are discussed, as well as guidelines for structuring the charges, obstacles to reimbursement and strategies to overcome them, and benefits (both direct and indirect) of implementing such a program. Examples are cited from apnea management programs at two major children's hospitals in the southwestern United States. Implications are made regarding generalizing these methods to other nursing services and practices.

Keys to creating an effective ethics program

Ethics is not a box that can be checked after every employee has been through an ethics training program or has acknowledged reading the code of conduct. Ethics has to do with the basic culture and operating values of an organization.

Aluminum compounds used as adjuvants in vaccines

The structure of nine commercially manufactured aluminum-containing adjuvants was investigated by X-ray diffraction, infrared spectroscopy, transmission electron micrography, and energy dispersive spectrometry. Seven samples which were labeled as aluminum hydroxide were identified as boehmite, a crystalline aluminum oxyhydroxide [AlO(OH)]. However, the degree of crystallinity varied between the samples. Two samples which were labeled as aluminum phosphate were found to be amorphous aluminum hydroxyphosphate. Buffer anions and sulfate anions substitute for hydroxyls in the amorphous aluminum hydroxide formed by the in situ alum precipitation method. Finally, the aluminum-containing adjuvant in diphtheria and tetanus toxoid, U.S.P., produced by three manufacturers was characterized.

Dexamethasone used as an antiemetic in chemotherapy protocols inhibits natural cytotoxic (NC) cell activity

Because dexamethasone is often included as an antiemetic in chemotherapy protocols that involve cisplatin and because cisplatin has been shown to increase the in vitro lysis of tumor cells by natural cytotoxic (NC) effector cells, we determined the NC activity of 27 patients who received dexamethasone in conjunction with seven different cisplatin-based chemotherapy protocols. The results of this analysis showed that the NC activity of patients who received cisplatin-based chemotherapy protocols that included dexamethasone was reduced significantly 24 hours after treatment compared with before treatment (P less than 0.001). The addition of dexamethasone (at a concentration equivalent to the plasma level of patients treated with dexamethasone) to the in vitro assay of NC activity caused a significant decrease in NC activity compared with when dexamethasone was not added (P less than 0.001). There was no cumulative effect of dexamethasone in that the reduction of NC activity by dexamethasone was not significantly different in patients who had been treated previously at least four times and in patients who were treated for the first time. When dexamethasone was not included in the chemotherapy protocol the NC activity of 19 patients was not reduced 24 hours after treatment. These results indicate that dexamethasone causes a significant reduction in NC activity. Although the tumor surveillance role of human NC cells in vivo has not been established, the effect of dexamethasone on NC cells suggests that additional research of the effect of dexamethasone in cisplatin-based chemotherapy protocols is warranted.

Utility of d4-PGE2 as an internal standard to quantify endogenous levels of PGE1, PGE2, 19OH PGE1 and 19OH PGE2 in human seminal fluid by GC-MS-SIM

Four prostaglandins-PGE1, PGE2, 19OH PGE1 and 19OH PGE2-were quantified in human seminal fluid by GC-MS-SIM using only the internal standard, d4-PGE2. Methods and calculations were developed to minimize errors inherent in using only one internal standard for quantifying four closely related prostaglandins. Preliminary data concerning the statistical significance of the difference found between PGE and 19OH PGE levels in fertile, azospermic and oligospermic men are reported.