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1.
Nature ; 629(8012): 573-578, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38750231

RESUMEN

A key challenge in realizing practical quantum networks for long-distance quantum communication involves robust entanglement between quantum memory nodes connected by fibre optical infrastructure1-3. Here we demonstrate a two-node quantum network composed of multi-qubit registers based on silicon-vacancy (SiV) centres in nanophotonic diamond cavities integrated with a telecommunication fibre network. Remote entanglement is generated by the cavity-enhanced interactions between the electron spin qubits of the SiVs and optical photons. Serial, heralded spin-photon entangling gate operations with time-bin qubits are used for robust entanglement of separated nodes. Long-lived nuclear spin qubits are used to provide second-long entanglement storage and integrated error detection. By integrating efficient bidirectional quantum frequency conversion of photonic communication qubits to telecommunication frequencies (1,350 nm), we demonstrate the entanglement of two nuclear spin memories through 40 km spools of low-loss fibre and a 35-km long fibre loop deployed in the Boston area urban environment, representing an enabling step towards practical quantum repeaters and large-scale quantum networks.

2.
Nature ; 580(7801): 60-64, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32238931

RESUMEN

The ability to communicate quantum information over long distances is of central importance in quantum science and engineering1. Although some applications of quantum communication such as secure quantum key distribution2,3 are already being successfully deployed4-7, their range is currently limited by photon losses and cannot be extended using straightforward measure-and-repeat strategies without compromising unconditional security8. Alternatively, quantum repeaters9, which utilize intermediate quantum memory nodes and error correction techniques, can extend the range of quantum channels. However, their implementation remains an outstanding challenge10-16, requiring a combination of efficient and high-fidelity quantum memories, gate operations, and measurements. Here we use a single solid-state spin memory integrated in a nanophotonic diamond resonator17-19 to implement asynchronous photonic Bell-state measurements, which are a key component of quantum repeaters. In a proof-of-principle experiment, we demonstrate high-fidelity operation that effectively enables quantum communication at a rate that surpasses the ideal loss-equivalent direct-transmission method while operating at megahertz clock speeds. These results represent a crucial step towards practical quantum repeaters and large-scale quantum networks20,21.

3.
Indian J Clin Biochem ; 39(1): 110-117, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38223014

RESUMEN

Owing to limited usefulness of Rheumatoid Factor and anti-CCP in rheumatoid arthritis, there is a need to identify a more sensitive and specific biomarker to detect rheumatoid arthritis (RA), particularly seronegative RA cases. Tenascin-C is an extracellular matrix glycoprotein, which has been implicated in the pathophysiology of RA. The objective of our study was to evaluate the diagnostic utility of serum Tenascin-C in seropositive and seronegative rheumatoid arthritis patients. We conducted a cross-sectional case control study. Sixty patients who fulfilled the ACR 2010 criteria for rheumatoid arthritis were included in the study. Thirty patients were found to be positive for RF and/or anti-CCP and 30 were negative for both RF and anti-CCP. Thirty age and gender-matched healthy subjects were taken as controls. Serum Tenascin-C was measured by quantitative sandwich enzyme immunoassay technique. The mean serum concentration of Tenascin-C in controls, seronegative and seropositive cases was 0.66 ng/ml, 20.54 ng/ml and 23.42 ng/ml, respectively. Tenascin-C levels were significantly higher in RA cases compared to controls (p < 0.0001). There was no significant difference in Tenascin-C between seropositive and seronegative cases (p = 0.603). ROC curve analysis showed a sensitivity of 96.6% and specificity of 100% with AUC of 0.98 at 2.21 ng/ml as cut-off value for diagnosing RA. Tenascin-C is elevated in both seronegative and seropositive RA, which indicates that it can be used as a sensitive marker for RA. The addition of Tenascin-C to the existing RF and anti-CCP may help in identifying a large number of patients with RA, particularly seronegative rheumatoid arthritis cases.

4.
J Indian Assoc Pediatr Surg ; 28(4): 319-324, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37635895

RESUMEN

Aim: Enhanced recovery after surgery (ERAS) are multimodal perioperative pathways that have shown improved outcomes. ERAS after colostomy reversal has shown promising results in adults and few pediatric studies. We report our experience using ERAS for a colostomy reversal. Materials and Methods: A retrospective analysis of children in whom ERAS was used during colostomy reversal between May 2016 and 2019 was carried out. ERAS protocol in our study included avoiding mechanical bowel preparation (MBP), oral liquid diet upto 3 h preoperatively, usage of regional anesthesia, minimal handling of bowel intraoperatively, using nonopioid analgesics for pain relief, early initiation of feeding on the first postoperative day, early discharge once full feeds are established. Outcomes analyzed are the duration of hospital stay and complications, including readmissions. Requirement for opioids and anti-emetics are noted. The outcomes are compared with traditional care pathways (TCP), which use MBP, overnight fasting, opioid analgesia, and delayed feeding. A total of 48 are included in the study, with 13 cases using ERAS and TCP in 35 cases. Statistical Analysis Used: Nonparametric Mann-Whitney U-test was used. Results: In the ERAS group, the mean length of hospital stay (LOS) postoperatively was 3.7 days (2-5 days) as opposed to 7.2 days (5-11 days) in TCP. There was only one child with complications in the ERAS group, while 9 cases in TCP had complications, though none of them required operative intervention. There was the requirement of anti-emetic in only one child in the ERAS group. Conclusion: ERAS for colostomy reversal is feasible in the pediatric population. For successful implementation, all personnel involved in the care of the child need to be educated about the protocol. It reduces LOS and complications.

5.
Phys Rev Lett ; 128(21): 213602, 2022 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-35687460

RESUMEN

Solid-state quantum emitters are promising candidates for the realization of quantum networks, owing to their long-lived spin memories, high-fidelity local operations, and optical connectivity for long-range entanglement. However, due to differences in local environment, solid-state emitters typically feature a range of distinct transition frequencies, which makes it challenging to create optically mediated entanglement between arbitrary emitter pairs. We propose and demonstrate an efficient method for entangling emitters with optical transitions separated by many linewidths. In our approach, electro-optic modulators enable a single photon to herald a parity measurement on a pair of spin qubits. We experimentally demonstrate the protocol using two silicon-vacancy centers in a diamond nanophotonic cavity, with optical transitions separated by 7.4 GHz. Working with distinguishable emitters allows for individual qubit addressing and readout, enabling parallel control and entanglement of both colocated and spatially separated emitters, a key step toward scaling up quantum information processing systems.

6.
Phys Rev Lett ; 129(5): 053603, 2022 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-35960557

RESUMEN

An efficient, scalable source of shaped single photons that can be directly integrated with optical fiber networks and quantum memories is at the heart of many protocols in quantum information science. We demonstrate a deterministic source of arbitrarily temporally shaped single-photon pulses with high efficiency [detection efficiency=14.9%] and purity [g^{(2)}(0)=0.0168] and streams of up to 11 consecutively detected single photons using a silicon-vacancy center in a highly directional fiber-integrated diamond nanophotonic cavity. Combined with previously demonstrated spin-photon entangling gates, this system enables on-demand generation of streams of correlated photons such as cluster states and could be used as a resource for robust transmission and processing of quantum information.

7.
Indian J Clin Biochem ; 35(1): 121-126, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32071505

RESUMEN

The rationale of the current study was to assess the prevalence of 25-hydroxyvitamin D (25-OHD) deficiency and hyperparathyroidism in South Indian population and to explore interrelationships of 25-OHD, Ca, P towards parathyroid hormone (PTH) production using adaptive neuro-fuzzy inference system (ANFIS). A total of 407 subjects (228 men 179 women) with the mean age 56.8 ± 14.1 were tested for these parameters. In view of the skewed distribution of biochemical variables, data segregation was performed in tertiles and this data was trained to generate fuzzy interference system based on subclusters. The optimized model had 358 nodes and followed 44 fuzzy rules for prediction. This ANFIS model demonstrates that the deficiency of 25-OHD and Calcium triggers PTH production. PTH elevation is significant when Phosphorus is in the highest tertile. The associations observed by this model were consistent with the Kendall-Tau correlation matrix, which revealed inverse associations of Ca with P; and Ca with PTH and positive associations of P with PTH, and Ca with 25-OHD. Furthermore, the association statistics of the machine learning algorithm were also consistent, which suggested that depletion of Ca below 8.245 mg/dl was shown to elevate PTH levels greater than 167 pg/ml when P > 4.66. Subnormal depletion in 25-OHD (9.3-16.2 ng/ml) is associated with subnormal elevation in PTH (47-73.6 pg/ml). To conclude, ANFIS and machine learning algorithm are in agreement with each other in stating that 25-OHD deficiency triggers lower calcium levels, lower calcium and higher phosphorus trigger PTH production.

8.
Phys Rev Lett ; 123(18): 183602, 2019 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-31763904

RESUMEN

Quantum networks require functional nodes consisting of stationary registers with the capability of high-fidelity quantum processing and storage, which efficiently interface with photons propagating in an optical fiber. We report a significant step towards realization of such nodes using a diamond nanocavity with an embedded silicon-vacancy (SiV) color center and a proximal nuclear spin. Specifically, we show that efficient SiV-cavity coupling (with cooperativity C>30) provides a nearly deterministic interface between photons and the electron spin memory, featuring coherence times exceeding 1 ms. Employing coherent microwave control, we demonstrate heralded single photon storage in the long-lived spin memory as well as a universal control over a cavity-coupled two-qubit register consisting of a SiV and a proximal ^{13}C nuclear spin with nearly second-long coherence time, laying the groundwork for implementing quantum repeaters.

9.
Phys Rev Lett ; 119(22): 223602, 2017 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-29286819

RESUMEN

The negatively charged silicon-vacancy (SiV^{-}) color center in diamond has recently emerged as a promising system for quantum photonics. Its symmetry-protected optical transitions enable the creation of indistinguishable emitter arrays and deterministic coupling to nanophotonic devices. Despite this, the longest coherence time associated with its electronic spin achieved to date (∼250 ns) has been limited by coupling to acoustic phonons. We demonstrate coherent control and suppression of phonon-induced dephasing of the SiV^{-} electronic spin coherence by 5 orders of magnitude by operating at temperatures below 500 mK. By aligning the magnetic field along the SiV^{-} symmetry axis, we demonstrate spin-conserving optical transitions and single-shot readout of the SiV^{-} spin with 89% fidelity. Coherent control of the SiV^{-} spin with microwave fields is used to demonstrate a spin coherence time T_{2} of 13 ms and a spin relaxation time T_{1} exceeding 1 s at 100 mK. These results establish the SiV^{-} as a promising solid-state candidate for the realization of quantum networks.

10.
Phys Rev Lett ; 118(22): 223603, 2017 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-28621982

RESUMEN

We demonstrate a quantum nanophotonics platform based on germanium-vacancy (GeV) color centers in fiber-coupled diamond nanophotonic waveguides. We show that GeV optical transitions have a high quantum efficiency and are nearly lifetime broadened in such nanophotonic structures. These properties yield an efficient interface between waveguide photons and a single GeV center without the use of a cavity or slow-light waveguide. As a result, a single GeV center reduces waveguide transmission by 18±1% on resonance in a single pass. We use a nanophotonic interferometer to perform homodyne detection of GeV resonance fluorescence. By probing the photon statistics of the output field, we demonstrate that the GeV-waveguide system is nonlinear at the single-photon level.

11.
Eur J Neurol ; 22(5): 796-805, e53-4, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25623591

RESUMEN

BACKGROUND AND PURPOSE: Writer's cramp (WC) is a focal task-specific dystonia of the hand which is increasingly being accepted as a network disorder. Non-invasive cortical stimulation using repetitive transcranial magnetic stimulation (rTMS) has produced therapeutic benefits in some of these patients. This study aimed to visualize the motor network abnormalities in WC and also its rTMS induced modulations using resting state functional magnetic resonance imaging (rsfMRI). METHODS: Nineteen patients with right-sided WC and 20 matched healthy controls (HCs) were prospectively evaluated. All patients underwent a single session of rTMS and rsfMRI was acquired before (R1) and after (R2) rTMS. Seed-based functional connectivity analysis of several regions in the motor network was performed for HCs, R1 and R2 using SPM8 software. Thresholded (P < 0.05, false discovery rate corrected) group level mean correlation maps were used to derive significantly connected region of interest pairs. RESULTS: Writer's cramp showed a significant reduction in resting state functional connectivity in comparison with HCs involving the left cerebellum, thalamus, globus pallidus, putamen, bilateral supplementary motor area, right medial prefrontal lobe and right post central gyrus. After rTMS there was a significant increase in the contralateral resting state functional connectivity through the left thalamus-right globus pallidus-right thalamus-right prefrontal lobe network loop. CONCLUSIONS: It is concluded that WC is a network disorder with widespread dysfunction much larger than clinically evident and changes induced by rTMS probably act through subcortical and trans-hemispheric unaffected connections. Longitudinal studies with therapeutic rTMS will be required to ascertain whether such information could be used to select patients prior to rTMS therapy.


Asunto(s)
Encéfalo/fisiopatología , Conectoma/métodos , Trastornos Distónicos/terapia , Mano/fisiopatología , Red Nerviosa/fisiopatología , Estimulación Magnética Transcraneal/métodos , Adulto , Trastornos Distónicos/fisiopatología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Resultado del Tratamiento , Adulto Joven
13.
J Orthod ; 41(1): 51-2, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24671289

RESUMEN

Temporary pontics are a popular strategy to hide tooth extraction sites ('black holes') during course of the orthodontic treatment, especially with lingual appliances. Here, we describe a technique for using the patient's extracted premolar as a temporary pontic.


Asunto(s)
Diente Premolar , Coronas , Dentadura Parcial Fija con Resina Consolidada , Humanos , Cierre del Espacio Ortodóncico/instrumentación , Extracción Dental
14.
Indian J Clin Biochem ; 29(2): 232-7, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24757308

RESUMEN

Decompensation followed by death is the most serious outcome in patients suffering from cirrhosis of the liver. Alteration of trace elements may play a vital role in the process of decompensation. To examine the change in status of trace elements during the decompensation process, we analysed the zinc, copper, iron, magnesium, bilirubin and albumin levels in the serum of compensated (n = 34) and decompensated (n = 31) liver cirrhosis patients and compared them with healthy control group (n = 36) by post hoc ANOVA. We observed significant alteration in the selected micronutrients in the diseased group relative to healthy controls (P < 0.05). Moreover, mean serum zinc and iron levels were significantly lower with a higher level of serum copper in decompensated cirrhosis group than in compensated group (P < 0.05). However, no significant decrease of serum magnesium was found between the two diseased groups. Our findings imply that the trace elements like zinc, copper and iron might exert important contributory roles in decompensation process in liver cirrhosis and hence, may be utilized as important biomarkers for these patients. Furthermore, we propose that replacements of those micronutrients at an early stage can delay or prevent the severe outcomes like hepatic encephalopathy, gastrointestinal bleeding, severe jaundice or ascites in these patients.

15.
Access Microbiol ; 5(9)2023.
Artículo en Inglés | MEDLINE | ID: mdl-37841101

RESUMEN

Introduction: Melioidosis is an emerging life-threatening infectious disease caused by the Gram-negative Burkholderia pseudomallei found in contaminated soil and surface ground water. It often presents with varied clinical manifestations and has a high mortality if left untreated due to lack of clinical suspicion. Here we report a rare and fatal case of tubo-ovarian abscess presenting as puerperal sepsis due to B. pseudomallei in a young woman. Case report: A 25-year-old female presented for medical consultation at day 43 postpartum complaining of fever on and off for the past 40 days associated with vomiting. On per speculum examination, greenish discharge from the cervix was seen and a right adnexal mass was felt which was cystic in consistency, non-tender and pushing the cervix to the left side. An exploratory laparotomy was carried out and pus was drained from below the rectus sheath, and from the right tubo-ovarian mass. Peripheral blood and the pus samples collected intraoperatively grew B. pseudomallei . The patient died on the fifth post-operative day due to septic shock with disseminated intravascular coagulation secondary to puerperal sepsis. Conclusion: Melioidosis is a fatal but treatable disease when it is promptly diagnosed. In countries such as India, where tuberculosis is highly endemic, underdiagnosis of melioidosis can be common. Clinicians and microbiologists should have a high index of suspicion of melioidosis especially in individuals with underlying illness.

16.
J Environ Biol ; 33(1): 127-32, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23033655

RESUMEN

Hemidactylus flaviviridis Ruppell, 1835 (n= 199) sampled during different seasons from Bareilly (Uttar Pradesh, India) were infected with a sporozoan parasite belonging to the genus Hepatozoon Miller, 1908. Four morphovariants of the parasite, Type I, II, III and IV were identified on their growing pattern. When compared with earlier reported species, the parasite could be characterized taxonomically by its comparatively greater length 17.35 (13.57-21.30) microm and width 7.51 (5.59-10.11) microm, unusual larger size of parasite nuclear length 8.86 (4.75-15.83) microm and width 3.55 (2.14-5.11) microm and cytomorphological differences. These characteristics warrant creation of a new species and was named Hepatozoon lacertilis sp. nov. The morpho-variants, their effect on hostcell and host nuclei are clearly illustrated. The influence of macroenvironmental factor (host sex) on parasitic infectivity indicated that it was 7.14% prevalant in male and 6.25% in female Hemidactylus flaviviridis.


Asunto(s)
Apicomplexa/fisiología , Lagartos/parasitología , Infecciones Protozoarias en Animales/parasitología , Animales , Ecosistema , Femenino , Interacciones Huésped-Parásitos , Masculino , Especificidad de la Especie
17.
Int J Low Extrem Wounds ; : 15347346221076625, 2022 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-35275009

RESUMEN

Diabetic foot ulcer (DFU), if untreated, accounts for lower-limb amputations affecting patients' quality-of-life. Diperoxochloric acid (DPOCL) is known to heal DFU by its antibacterial and fibroblast stimulating activity. This was a phase 3, multicentre, randomized, double-blind, active-controlled, parallel-group study conducted to evaluate the efficacy and safety of topic solution of DPOCL compared with isotonic sodium chloride solution (ISCL). Adult patients with type 1 or 2 diabetes with random blood glucose levels of <250 mg/dL, with ≤ than three full-thickness foot ulcers were enrolled. Primary efficacy endpoint was complete wound closure and secondary was wound surface area. Adverse events were analyzed as safety endpoint. Of 311 enrolled patients, 289 were randomized 1:1 to DPOCL (139) and ISCL (150) treatment (10-weeks [8-Visits]). Percentage of patients with complete wound closure at visit-8, were significantly higher (P = .0156) in DPOCL arm (76% [105/139]) compared to ISCL (62% [93/150]) arm. At end-of-study, mean wound surface area in DPOCL arm (0.639 cm2) was significantly lower (P = .0209) compared to ISCL (0.818 cm2) arm. One death was reported in control arm which was not considered as treatment-related. No important safety finding were observed. Results indicate that, DPOCL can be considered as effective and safe treatment option for DFU compared to ISCL, although future confirmatory studies are warranted.

18.
Science ; 378(6619): 557-560, 2022 11 04.
Artículo en Inglés | MEDLINE | ID: mdl-36378964

RESUMEN

Long-distance quantum communication and networking require quantum memory nodes with efficient optical interfaces and long memory times. We report the realization of an integrated two-qubit network node based on silicon-vacancy centers (SiVs) in diamond nanophotonic cavities. Our qubit register consists of the SiV electron spin acting as a communication qubit and the strongly coupled silicon-29 nuclear spin acting as a memory qubit with a quantum memory time exceeding 2 seconds. By using a highly strained SiV, we realize electron-photon entangling gates at temperatures up to 1.5 kelvin and nucleus-photon entangling gates up to 4.3 kelvin. We also demonstrate efficient error detection in nuclear spin-photon gates by using the electron spin as a flag qubit, making this platform a promising candidate for scalable quantum repeaters.

19.
Bioinformation ; 16(7): 513-524, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32994676

RESUMEN

Controlled drug release in formulation is an important area of research. Formulations using crospovidone as super-disintegrants to achieve immediate release once it reaches the ileo- cecal region is relevant. The Eudragit L30D pH dependent polymer that allows drug release after a lag time of 4-5 hrs to achieve desired drug release from the drug delivery system is critical. Hence, pre-formulation to study drug-polymer interaction is essential. The linear correlation between the predicted and actual values for all the batches of optimization is shown with high correlation coefficient (r-value). Therefore, the designed formulation is promising for ileo-cecal targeted pulsatile drug delivery system in the management of Crohn's disease.

20.
J Lab Physicians ; 12(2): 126-132, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32905127

RESUMEN

Background Heart failure is a complex cardiovascular disease with a variety of etiologies and heterogeneity. The N-terminal pro-B-type natriuretic peptide (NT-proBNP) value has limited usefulness in diagnosing heart failure with preserved ejection fraction (HFpEF). Aim The aim of the present study is to evaluate serum Galectin-3 as a diagnostic biomarker in patients with HFpEF and to compare Galectin-3 with NT-proBNP levels. Materials and Methods A cross-sectional case-control study including 63 cases of heart failure with ejection fraction ≥50% confirmed by echocardiography. NT-proBNP levels in serum were measured by electrochemiluminescence immunoassay and Galectin-3 levels in serum were measured by using an enzyme-linked-immunosorbent serologic assay kit. Results The median levels of serum Galectin-3 and NT-proBNP in patients were significantly higher than those of controls (26.59 vs. 5.27 and 927 vs. 49.3, p < 0.0001). A positive correlation was observed between serum levels of Galection-3 and NT-ProBNP ( r : 0.21, p = 0.048). At cut-off values of 10.1 ng/mL and 160 pg/mL, serum Galectin-3 has 77.78% sensitivity, 95% specificity with an area under the curve (AUC) of 0.93, and serum NT-proBNP has 71.43% sensitivity, 100% specificity with an AUC of 0.87, respectively, for diagnosing HFpEF. The comparison of receiver operating characteristics curves showed that Galectin-3 has better AUC compared with NT-proBNP in diagnosing HFpEF. Serum Galectin-3 showed a positive correlation with NT-proBNP and lipid parameters. Conclusion Galectin-3 with higher sensitivity and AUC can be used as a valuable biomarker for the diagnosis of HFpEF. Simultaneous testing of both Galectin-3 and NT-proBNP can further improve the detection of patients with HFpEF.

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