Detecting nitrogen-vacancy-hydrogen centers on the nanoscale using nitrogen-vacancy centers in diamond

In diamond, nitrogen defects like the substitutional nitrogen defect (Ns) or the nitrogen-vacancy-hydrogen complex (NVH) outnumber the nitrogen vacancy (NV) defect by at least one order of magnitude creating a dense spin bath. While neutral Ns has an impact on the coherence of the NV spin state, the atomic structure of NVH reminds of a NV center decorated with a hydrogen atom. As a consequence, the formation of NVH centers could compete with that of NV centers possibly lowering the N-to-NV conversion efficiency in diamond grown with hydrogen-plasma-assisted chemical vapor deposition (CVD). Therefore, monitoring and controlling the spin bath is essential to produce and understand engineered diamond material with high NV concentrations for quantum applications. While the incorporation of Ns in diamond has been investigated on the nano- and mesoscale for years, studies concerning the influence of CVD parameters and the crystal orientation on the NVH formation have been restricted to bulk N-doped diamond providing high-enough spin numbers for electron paramagnetic resonance and optical absorption spectroscopy techniques. Here, we investigate sub-micron-thick (100)-diamond layers with nitrogen contents of (13.8 +- 1.6) ppm and (16.7 +- 3.6) ppm, and exploiting the NV centers in the layers as local nano-sensors, we demonstrate the detection of NVH- centers using double-electron-electron-resonance (DEER). To determine the NVH- densities, we quantitatively fit the hyperfine structure of NVH- and confirm the results with the DEER method usually used for determining Ns0 densities. With our experiments, we access the spin bath composition on the nanoscale and enable a fast feedback-loop in CVD recipe optimization with thin diamond layers instead of resource- and time-intensive bulk crystals.Comment: 7 pages, 3 figure

Discovery of ST1 centers in natural diamond

The ST1 center is a point defect in diamond with bright fluorescence and a mechanism for optical spin initialization and readout. The center has impressive potential for applications in diamond quantum computing as a quantum bus to a register of nuclear spins. This is because it has an exceptionally high readout contrast and, unlike the well-known nitrogen-vacancy center, it does not have a ground state electronic spin that decoheres the nuclear spins. However, its chemical structure is unknown and there are large gaps in our understanding of its properties. We present the discovery of ST1 centers in natural diamond. Our experiments identify interesting power dependence of the center's optical dynamics and reveal new electronic structure. We also present a theory of its electron-phonon interactions, which we combine with previous experiments, to shortlist likely candidates for its chemical structure

MEDDB: A medicinal plant database developed with the information gathered from tribal people in and around Madurai, Tamil Nadu

Tribal peoples are endowed with enriched traditional wisdom to use available nature resources around them. They are well versed in the usage of plant for treating various diseases. They have used powder or extract or paste form of the plant parts such as root, shoot, whole plant, fruits and leaves etc. The recipe known by the tribal people was passed on only to their family members and community through mouth to mouth practice. Hence, the knowledge is confined to particular people alone. It is always expedient to store information in the database, so that it will be accessible by everyone from everywhere. To achieve this, MEDDB has been developed, which stores the details of 110 plant species that are commonly used by tribes for fever, asthma, cold, cough, diabetes, diarrhea, dysentery, eye infections, stomach ache, wounds and snake bite. The details of each plant were collected from the literature and through web search to give comprehensive and exhaustive information. Each plant entry is compiled under the subheadings viz., common name, classification, physical characteristics, medicinal uses, active constituents, and references

Nanodiamond Theranostic for Light-Controlled Intracellular Heating and Nanoscale Temperature Sensing

[Image: see text] Temperature is an essential parameter in all biological systems, but information about the actual temperature in living cells is limited. Especially, in photothermal therapy, local intracellular temperature changes induce cell death but the local temperature gradients are not known. Highly sensitive nanothermometers would be required to measure and report local temperature changes independent of the intracellular environment, including pH or ions. Fluorescent nanodiamonds (ND) enable temperature sensing at the nanoscale independent of external conditions. Herein, we prepare ND nanothermometers coated with a nanogel shell and the photothermal agent indocyanine green serves as a heat generator and sensor. Upon irradiation, programmed cell death was induced in cancer cells with high spatial control. In parallel, the increase in local temperature was recorded by the ND nanothermometers. This approach represents a great step forward to record local temperature changes in different cellular environments inside cells and correlate these with thermal biology

Randomized Clinical Trial of High-Dose Rifampicin With or Without Levofloxacin Versus Standard of Care for Pediatric Tuberculous Meningitis: The TBM-KIDS Trial

Background. Pediatric tuberculous meningitis (TBM) commonly causes death or disability. In adults, high-dose rifampicin may reduce mortality. The role of fluoroquinolones remains unclear. There have been no antimicrobial treatment trials for pediatric TBM. Methods. TBM-KIDS was a phase 2 open-label randomized trial among children with TBM in India and Malawi. Participants received isoniazid and pyrazinamide plus: (i) high-dose rifampicin (30 mg/kg) and ethambutol (R30HZE, arm 1); (ii) high-dose rifampicin and levofloxacin (R30HZL, arm 2); or (iii) standard-dose rifampicin and ethambutol (R15HZE, arm 3) for 8 weeks, followed by 10 months of standard treatment. Functional and neurocognitive outcomes were measured longitudinally using Modified Rankin Scale (MRS) and Mullen Scales of Early Learning (MSEL). Results. Of 2487 children prescreened, 79 were screened and 37 enrolled. Median age was 72 months; 49%, 43%, and 8% had stage I, II, and III disease, respectively. Grade 3 or higher adverse events occurred in 58%, 55%, and 36% of children in arms 1, 2, and 3, with 1 death (arm 1) and 6 early treatment discontinuations (4 in arm 1, 1 each in arms 2 and 3). By week 8, all children recovered to MRS score of 0 or 1. Average MSEL scores were significantly better in arm 1 than arm 3 in fine motor, receptive language, and expressive language domains (P < .01). Conclusions. In a pediatric TBM trial, functional outcomes were excellent overall. The trend toward higher frequency of adverse events but better neurocognitive outcomes in children receiving high-dose rifampicin requires confirmation in a larger trial. Clinical Trials Registration. NCT02958709

Superintendence of antimicrobial resistance observed in bacterial flora isolated from human faecal carriage in Vellore, India

A frequent cross-sectional study was conducted to determine the patterns of antimicrobial resistance in 296 bacterial strains isolated from in-patient faecal samples of Government Vellore Medical College and Hospital, Vellore. Isolation and identification of bacterial strains were done using enrichment media, selective media, and biochemical tests. Antimicrobial susceptibility testing by the disc diffusion method and minimal inhibitory concentration method was conducted and the strains were subjected to extended spectrum beta-lactamases screening. Antibiotic sensitivity pattern of Staphylococcus spp. showed oxacillin resistance. Almost all the strains were sensitive to linezolid, vancomycin, gentamycin and chloramphenicol. In gram negative isolates ciprofloxacin and tobramycin showed better sensitivity and ceftazidime showed a higher percentage of resistance by MIC. Out of 250 isolates, Enterobacteriaceae showed positive for 86/250, 82/250 and 94/250 isolates and 3/10, 4/10 and 4/10 non-Enterobacteriaceae isolates were found to be positive for CTX-M gene, TEM gene and SHV gene, respectively. This study helps to assess/analyse the relation between the spectrum of microorganisms present in various grades of faecal carriage and their susceptibility pattern in this part of the Vellore town

Evaluation of Yield and Quality Attributes of Grafted Brinjal under Treated Paperboard Mill Effluent Irrigation and Sludge Application

Field experiment was conducted to assess the impact of paperboard mill sludge compost and treated paperboard mill effluent irrigation on growth and yield of grafted brinjal. Among the different treatment combinations, application of phosphorus enriched ETP sludge compost at 5 t ha-1 along with treated effluent through drip irrigation and recommended level of NPK (200:150:100 kg NPK ha-1) resulted the highest brinjal yield of 42.7 t ha-1. There were no adverse effects on soil properties due to sludge compost application and treated effluent irrigation. Quality attributes of the fruits which include anthocyanin content, total phenol content, ascorbic acid content, titrable acidity and protein content were not affected due to the composted sludge application along with treated effluent irrigation. Thus, the treated effluent and the composted sludge which complies with the state pollution control board norms can be used as a viable alternative source of irrigation and nutrients for grafted brinjal cultivation without adversely affecting on crop quality

Paperboard Mill Sludge Derived Nanocellulose as a Biosorbent for Hexavalent Chromium

In the present study, paperboard mill sludge derived nanocellulose as biosorbent for removal of hexavalent chromium from simulated aqueous solution prepared from potassium dichromate. The adsorbents namely, CA-NC and FA-NC were prepared through citric and formic acid hydrolyses of the nanocellulose. The prepared sorbents were utilized for the adsorption of Cr(VI), with parameters such as pH, adsorbent dosage, solute concentration and contact time played pivotal role in the study. The ideal circumstances of these parameters to perform well were notably pH of 2, with adsorbent dose of 1.5 g, solute concentration of 100 mg L-1, with a contact duration of 60 minutes. The adsorption followed pseudo second order reaction and fitted the Langmuir isotherm model indicating chemisorption coupled with monolayer adsorption of adsorbate onto the adsorbent

Nanoscale detection and real-time monitoring of free radicals in a single living cell under the stimulation of targeting moieties using a nanodiamond quantum sensor

Intracellular radicals play important roles in cell signaling and regulation of growth factors, cytokines, transcription, apoptosis, and immunomodulation, among others. To gain a more comprehensive understanding of their biological functions in a spatio-temporal perspective, there is a great need for nanoscale sensitive tools that allow real-timeiin detection of these reactive species. Currently, intracellular radical probes are based on chemical reactions that could significantly alter radical levels during detection. Due to the excellent biocompatibility and favorable photophysical properties of nitrogen-vacancy (NV‒) centers in fluorescent nanodiamonds (fNDs), the fNDs can serve as a powerful and chemically inert nanotool for intracellular radical detection. In this study, a positively charged nanogel (NG) coating was prepared to prevent the precipitation of fNDs and promote cellular internalization. After internalization of nanodiamond-nanogels (fND-NGs), different stimulators, namely somatostatin (SST), triphenylphosphonium (TPP), and trans-activator of transcription (TAT) peptide, which are widely used cell- or organelle- targeting ligands in medicine, drug delivery, and diagnostics, were applied to stimulate the cells. In parallel, the intracellular radical changes under stimulation of SST, TPP, and TAT ligands were monitored by fND-NGs in a home-built ODMR microscope. Our method allows for detecting intracellular radicals in-situ and monitoring their real-time changes during incubation with the targeting ligands in a single living cell. We believe that our method will provide insights into the generation of radical stress in cells, which could improve our fundamental understanding of the pharmacology and signaling pathways of widely used cell- and organelle-targeting ligands associated with free radicals