Integrated segmented IQ-modulator for orthogonal sampling and multi-level high-bandwidth signal generation.

Photonic-assisted signal processing of high-bandwidth signals emerges as a solution for challenges encountered in electronic-based processing. Here we present a concept for a compact, photonic-assisted digital-to-analog converter (DAC) and optical IQ-modulator in one single integrated device based on two innovative concepts: a segmented Mach-Zehnder modulator and orthogonal sampling. For electrically driving the modulator, only a single radio frequency oscillator and no pulse source or electrical DAC are required. The presented and simulated proof-of-concept device with six segments can generate a multi-level and high-bandwidth signal from low-bandwidth electronic drivers; e.g., we show the generation of a 120 Gbps data rate, 16-quadrature amplitude modulation (16-QAM, 30 Gbaud) signal solely based on low-bandwidth (5 GHz) non-return-to-zero (NRZ) signals. Integrated on a silicon photonic platform, the device provides fixable speed and bandwidth operations, positioning it as a viable solution for diverse communication systems.

Real-time reconfigurable on-chip photonic frequency decoder.

A group-delay-unit-based integrated silicon photonic integrated circuit (PIC) is employed as a reconfigurable analog radio frequency decoder, which provides a real-time temporal and spectral analysis of any arbitrary multi-tone signal in the micro- and mm-wave range. The circuit is based on cascaded Mach-Zehnder interferometer embedded silicon microring resonators as variable delay units. The temporal decoding of the multi-tone input signal is demonstrated by tuning the signal with respect to the ring resonator delay and resonance. A one-to-one conformal time-to-frequency mapping provides real-time spectral decoding of the signal under test without additional digital signal processing. The idea is validated by several experimental results with single-tone and two-tone input signals in a compact, low-power, silicon PIC. The proposed real-time temporal analog frequency decoder may be very intriguing for high-speed, low-latency wireless applications, such as autonomous driving and 6G.

Synthesis and Evaluation of Compound Targeting α7 and ß2 Subunits in Nicotinic Acetylcholinergic Receptor.

Nicotinic acetylcholine receptors (nAChRs) are involved in various central nervous system functions and have also been implicated in several neurodegenerative disorders. The heteromeric α4ß2* and homomeric α7 are two major nAChR subtypes which have been studied in the brain using positron emission tomography (PET). Our comparative autoradiographic studies of the two receptor types in the mouse and rat brains show major differences in the thalamus (α4ß2* >> α7), hippocampus (α7 >> α4ß2*), and subiculum (α4ß2* >> α7). A relatively newer heteromeric α7ß2 nAChR subtype has been identified in the brain which may have a greater role in neurodegeneration. We report the development of KS7 (3-(2-(S)-azetidinylmethoxy)-5-(1,4-diaza-bicyclo[3.2.2]nonane)pyridine) which incorporates structural features of Nifzetidine (high affinity for α4ß2* nAChR) and ASEM (high affinity for α7 nAChR) in an effort to target α7 and ß2 subunits in α7ß2 nAChR. KS7 exhibited higher affinities (IC50 = 50 to 172 nM) for [3H]cytisine radiolabeled sites and weaker affinities (IC50 = 10 µM) for [125I]-α-bungarotoxin radiolabeled rat brain sites in several brain regions. The weaker affinity of KS7 to α7 nAChR may suggest lack of binding at the α7 subunit of α7ß2 nAChR. A radiolabeled derivative of KS7 may be required to identify any specific binding to brain regions suggested to contain α7ß2 nAChR.

Reconfigurable and real-time high-bandwidth Nyquist signal detection with low-bandwidth in silicon photonics.

We demonstrate for the first time, to the best of our knowledge, reconfigurable and real-time orthogonal time-domain detection of a high-bandwidth Nyquist signal with a low-bandwidth silicon photonics Mach-Zehnder modulator based receiver. As the Nyquist signal has a rectangular bandwidth, it can be multiplexed in the wavelength domain without any guardband as a part of a Nyquist-WDM superchannel. These superchannels can be additionally multiplexed in space and polarization. Thus, the presented demonstration can open a new possibility for the detection of multidimensional parallel data signals with silicon photonics. No external pulse source is needed for the receiver, and frequency-time coherence is used to sample the incoming Nyquist signal with orthogonal sinc-shaped Nyquist pulse sequences. All parameters are completely tunable in the electrical domain. The feasibility of the scheme is demonstrated through a proof-of-concept experiment over the entire C-band (1530 nm-1560 nm), employing a 24 Gbaud Nyquist QPSK signal due to experimental constraints on the transmitter side electronics. However, the silicon Mach-Zehnder modulator with a 3-dB bandwidth of only 16 GHz can process Nyquist signals of 90 GHz optical bandwidth, suggesting a possibility to detect symbol rates up to 90 GBd in an integrated Nyquist receiver.

Agnostic sampling transceiver.

Increasing demands for data centers, backbone, access, and wireless networks require inventive concepts to transmit and distribute digital or analog signal waveforms. We present a new, extremely simple transceiver concept, fundamentally different from conventional approaches. It does not rely on high-speed electronics and enables transmission of various time multiplexed analog waveforms or digital data signals with the maximum possible symbol rate in the same rectangular optical spectral band B. The aggregate symbol rate of N signal channels corresponds to B or twice the used modulator's electro-optical bandwidth. By a modification of the system, it can be increased to three times the modulator bandwidth. The rectangular spectra can be further multiplexed into wavelength-superchannels without guardbands. To time demultiplex single signal channel, just another intensity modulator and a detector with an electrical bandwidth corresponding to the channel's baseband width (B/(2N)) is required. No optical filter, high-speed signal processing, or unconventional photonic devices are needed; thus, it has the potential to be easily integrated into any platform and provides an economical and energy-efficient solution for future communication networks and microwave photonic links.

Genome-wide discovery of SNPs in candidate genes related to production and fertility traits in Sahiwal cattle.

The present study was carried out to identify genome-wide genetic markers and variants in candidate genes for production and reproduction traits in Sahiwal cattle using a cost-effective reduced representation sequencing method. A total of 258,231 genome-wide SNPs were identified in Sahiwal cattle with reference to Bos indicus genome, of which 150,231 were novel SNPs. Among the high-confidence SNPs identified, 91.86% and 27.30% were genotyped in 50% and 100% of the samples. Mapping of the identified SNPs revealed 525 SNPs in candidate genes related to production traits while 333 SNPs were mapped to candidate genes related to reproduction traits. The SNPs identified in this study will facilitate further insights on tropical adaptation, domestication history and population structure of indigenous cattle. The variants in candidate genes identified in this study will serve as useful genetic tools, in the quest for phenotype modifying nucleotide change and help in designing appropriate genetic improvement programs.

Integrated source-free all optical sampling with a sampling rate of up to three times the RF bandwidth of silicon photonic MZM.

Source-free all optical sampling, based on the convolution of the signal spectrum with a frequency comb in an electronic-photonic, co-integrated silicon device will be presented for the first time, to the best of our knowledge. The method has the potential to achieve very high precision, requires only low power and can be fully tunable in the electrical domain. Sampling rates of three and four times the RF bandwidths of the photonics and electronics can be achieved. Thus, the presented method might lead to low-footprint, fully-integrated, precise, electrically tunable, photonic ADCs with very high-analog bandwidths for the digital infrastructure of tomorrow.

Mid upper-arm circumference is an effective tool to identify infants and young children with severe acute malnutrition in India.

OBJECTIVE: To assess the appropriateness of current mid upper-arm circumference (MUAC) cut-offs to identify children with severe acute malnutrition in India. DESIGN: The analysis concerned 6307 children admitted to nutrition rehabilitation centres (2009-2011) where they received therapeutic care as per guidelines by WHO and the Indian Academy of Pediatrics. SETTING: States of Jharkhand, Madhya Pradesh and Uttar Pradesh, India. SUBJECTS: Children aged 6-59 months with bilateral pitting oedema or weight-for-height Z-score (WHZ)<-3 or MUAC<115 mm at admission. RESULTS: Children aged 6-23 months represented ~80 % of the admissions. Among them, the proportion with WHZ<-3 was similar to that with MUAC<115 mm (85·7 % v. 81·8 %); the proportion with MUAC<115 mm whose WHZ was <-3 was 82·6 %; and the proportion with WHZ<-3 whose MUAC<115 mm was 78·8 %. MUAC<115 mm was as effective as WHZ<-3 in identifying 6-59-month-old children with medical complications (32·2 % v. 31·6 %, respectively), the most important risk factor of death among oedema-free children. Furthermore, death rates in children with MUAC<115 mm were higher than in children with WHZ<-3 (0·61 % v. 0·58 %, respectively) and 91 % of the deaths among oedema-free children were deaths of children with MUAC<115 mm. CONCLUSIONS: In populations similar to those included in our analysis, MUAC<115 mm appears to be an appropriate criterion to identify children with severe acute malnutrition who are at a greater risk of medical complications and death, particularly among children 6-23 months old.

Providing care for children with severe acute malnutrition in India: new evidence from Jharkhand.

OBJECTIVE: To assess the effectiveness of facility-based care for children with severe acute malnutrition (SAM) in malnutrition treatment centres (MTC). DESIGN: Early detection and treatment of SAM using locally adapted protocols; assessment of programme outcomes, including survival, default, discharge and recovery rates. SETTING: All forty-eight MTC in Jharkhand, India. SUBJECTS: Children (n 3595) with SAM admitted to MTC (1 July 2009-30 June 2011). RESULTS: Of children admitted, 55·0% were girls, 77·7% were 6-23 months old and 68·6% belonged to scheduled tribes or castes; 34·4% had oedema or medical complications. Of the 3418 programme exits, the proportion of children who died was 0·6% (n 20), the proportion of children who defaulted was 18·4% (n 628) and the proportion of children discharged was 81·0% (n 2770). Children's average weight gain was 9·6 (sd 8·4) g/kg body weight per d and their average length of stay was 16·0 (sd 5·7) d. Among the 2770 children who were discharged from the programme, 39·4% (n 1090) gained 15 % or more of their initial weight while 60·6% (n 1680) gained less than 15 % of their initial weight. CONCLUSIONS: MTC provide live-saving care for children with SAM as demonstrated by high survival rates. However, the protocols and therapeutic foods currently used need to improve to ensure the recovery of all discharged children. MTC should be reserved for children with complicated SAM; children with uncomplicated SAM should be admitted to a community-based programme for the management of SAM, at a lesser risk to children and a lesser cost to families and the health system.

Graphene oxide-coated Ag-TiO2 hybrid nanocomposites for superior photocatalytic activity.

Graphene oxide (GO) has now emerged as one of the most promising materials in different areas such as photocatalysis, adsorption, and energy storage due to its high surface area, unique layered structure, etc. Among various types of precursors, anthracite coal has attracted a lot of attention nowadays as it affords GO a high concentration of sp2 carbons resulting in high conductivity and superior absorbance in the visible region. In this report, we have prepared GO-TiO2 nanocomposites as it is supposed to possess high photocatalytic activity owing to facile electron transmission from the conduction band of TiO2 to the GO surface resulting in a much lower degree of electron-hole pair recombination. To boost the photocatalytic activity further, TiO2 was coated with Ag nanoparticles as well. These hybrid structures were characterized by different analytical techniques, for example, XRD, HR-TEM, SEM, and Raman spectroscopy. The XRD pattern of these composites consists of characteristic peaks corresponding to GO, TiO2, and Ag. The HR-TEM studies confirm the presence of GO layers, cube-shaped TiO2, and spherical Ag nanoparticles. Phenol and 4-nitrophenol have been used as model pollutants to evaluate the photooxidation efficiencies under both UV and visible light irradiation. Under UV irradiation, the GO/Ag-TiO2 ternary nanocomposite shows better photooxidation efficiency (62%) compared to Ag-TiO2 (38%), GO-TiO2 (9%), GO (17%), and TiO2 (8%) toward phenol degradation. The GO/Ag-TiO2 is also having the highest photocatalytic activity toward the removal of phenol under visible light irradiation (34%). The ternary heterostructure (85%) also possesses superior photooxidation activity compared to Ag-TiO2 (44%) and GO-TiO2 (71%) toward the degradation of p-nitrophenol under UV light radiation for 60 min. The above observation reveals that the cooperative effect of Ag, TiO2, and GO is playing a crucial role to result in the high photooxidation activity of the GO/Ag-TiO2 hetero-nanocomposites.

Comprehensive device simulation of 23.36% efficient two-terminal perovskite-PbS CQD tandem solar cell for low-cost applications.

The major losses that limit the efficiency of a single-junction solar cell are thermalization loss and transmission loss. Thus, to efficiently utilize the full solar spectrum and to mitigate these losses, tandem solar cells (TSC) have significantly impacted the photovoltaic (PV) landscape. In this context, the research on perovskite/silicon tandems is currently dominating the research community. The stability improvements of perovskite materials and mature fabrication techniques of silicon have underpinned the rapid progress of perovskite/silicon TSC. However, the low absorption coefficient and high module cost of the silicon are the tailbacks for the mass production of perovskite/silicon TSCs. Therefore, PV technology demands to explore some new materials other than Si to be used as absorber layer in the bottom cell. Thus, here in this work, to mitigate the aforementioned losses and to reduce cost, a 23.36% efficient two-terminal perovskite-PbS CQD monolithic tandem solar cell has been designed through comprehensive device simulations. Before analyzing the performance of the proposed TSC, the performance of perovskite top cells has been optimized in terms of variation in optical properties, thickness, and interface defect density under standalone conditions. Thereafter, filtered spectrum and associated integrated filtered power by the top cell at different perovskite thickness from 50 to 500 nm is obtained to conceive the presence of the top cell above the bottom cell with different perovskite thickness. The current matching by concurrently varying the thickness of both the top and bottom subcell has also been done to obtain the maximum deliverable tandem JSC for the device under consideration. The top/bottom subcell with current matched JSC of 16.68 mA cm-2/16.62 mA cm-2 showed the conversion efficiency of 14.60%/9.07% under tandem configuration with an optimized thickness of 143 nm/470 nm, where the top cell is simulated under AM1.5G spectrum, and bottom cell is exposed to the spectrum filtered by 143 nm thick top cell. Further, the voltages at equal current points are added together to generate tandem J-V characteristics. This work concludes a 23.36% efficient perovskite-PbS CQD tandem design with 1.79 V (VOC), 16.67 mA cm-2 (JSC) and 78.3% (FF). The perovskite-PbS CQD tandem device proposed in this work may pave the way for the development of high-efficiency tandem solar cells for low-cost applications.

Development of zirconium-89 PET for in vivo imaging of alpha-klotho.

Alpha-klotho is a single-pass membrane protein primarily expressed by the kidneys. Klotho deficiency in chronic kidney disease contributes to an accelerated aging phenotype. We report here development of [89Zr]DFO-anti-klotho positron emission tomography (PET) imaging as a novel non-invasive method for assessing whole-body alpha-klotho distribution. Rat monoclonal anti-mouse klotho antibody was reacted with SCN-Bn-deferoxamine (DFO) and was radiolabeled using Zirconium-89. In vitro testing of [89Zr]DFO-anti-mKlotho was done in a distal convoluted tubule kidney cell line and with 40-micron whole kidney sections from C57BL/6J mice. Competitive binding was assessed in co-incubation studies with unlabeled anti-mKlotho antibody. For in vivo testing, C57BL/6J mice were injected retro-orbitally with [89Zr]DFO-anti-mKlotho and were scanned using Inveon PET/CT. Autoradiographs of kidney sections were obtained post-imaging on select animals. Radiochemical yield of [89Zr]DFO-anti-mKlotho was >70% and radiochemical purity was confirmed by iTLC. Specific binding in the kidney cell line was reduced by 60% in the presence of unlabeled anti-mKlotho. In the PET/CT scans, initial uptake of [89Zr]DFO-anti-mKlotho was observed in the intestines and liver. Selective retention of radioactivity was observed in the kidneys in the subsequent 24, 48, and 72 hrs scans with cortical binding of [89Zr]DFO-anti-mKlotho clearly visualized. Sites of lower alpha-klotho expression were not visualized. In summary, we have successfully synthesized [89Zr]DFO-anti-mKlotho and our initial in vitro and in vivo studies in mice demonstrate selective binding in the kidney cortex, which is known to express high levels of alpha-klotho. PET imaging promises to be a novel tool for in vivo evaluation of alpha-klotho distribution.

Genomic divergence reveals unique populations among Indian Yaks.

The present study focused upon identification of genome-wide SNPs through the reduced representation approach and to study the genomic divergence of the Indian yak populations. A total of 80 samples belonging to Arunachali yak (N = 20), Himachali yak (N = 20), Ladakhi yak (N = 20) and Sikkimi yak (N = 20) of India were used in the study. The results of the study revealed a total of 579575 high quality SNPs along with 50319 INDELs in the Indian yaks. The observed heterozygosity was found to be high in Himachali yak, followed by Arunachali yak, Ladakhi yak and Sikkimi yaks. The Sikkimi yaks was found to be genetically distant, followed by Ladakhi yaks which was observed to have some few individuals from Arunachali and Himachali yaks. Arunachali and Himachali yaks are found to get clustered together and are genetically similar. The study provides evidence about the genomic diversity in the Indian yak populations and information generated in the present study may help to formulate a suitable breeding plan for endangered Indian yaks. Moreover, the unique yak populations identified in the study will further help to focus attention for future characterization and prioritization of the animals for conservation purposes through the ddRAD approach.

Integrated program achieves good survival but moderate recovery rates among children with severe acute malnutrition in India.

BACKGROUND: At any point in time, an average 8 million Indian children suffer from severe acute malnutrition (SAM). OBJECTIVE: This article assesses the effectiveness of an integrated model for the management of SAM (IM-SAM) in India comprising facility- and community-based care and using locally adapted protocols. DESIGN: Children (n = 2740) were randomly sampled from the 44,017 children aged 6-59 mo admitted to 199 Nutrition Rehabilitation Centers in the state of Madhya Pradesh (1 January to 31 December 2010). RESULTS: On admission, 2.2% of children had edema, 23.4% had medical complications, 56% were girls, 79% were in the age group 6-23 mo, and 64% belonged to scheduled tribe or scheduled caste families. Fifty-six children (2.0%) with severe congenital or pathological conditions were transferred to the district hospital. Of the 2684 program exits, 10 children (0.4%) died, 860 (32.0%) did not complete treatment (defaulted), and 1814 (67.6%) were discharged after a mean (±SD) stay of 75.8 ± 9.4 d. The mean weight gain among discharged children was 2.7 ± 1.9 g · kg body wt(-1) · d(-1); on discharge, 1179 (65%) of the children had recovered (weight gain ≥15% of initial weight). CONCLUSIONS: The survival rates in the IM-SAM program were very high. However, the moderate recovery rates documented seem to indicate that the protocols currently in use need to be improved. This trial was registered at clinicaltrials.gov as NCT01917734.