Fluorescence Enhancement of Single V2 Centers in a 4H-SiC Cavity Antenna.

Solid state quantum emitters are a prime candidate in distributed quantum technologies since they inherently provide a spin-photon interface. An ongoing challenge in the field, however, is the low photon extraction due to the high refractive index of typical host materials. This challenge can be overcome using photonic structures. Here, we report the integration of V2 centers in a cavity-based optical antenna. The structure consists of a silver-coated, 135 nm-thin 4H-SiC membrane functioning as a planar cavity with a broadband resonance yielding a theoretical photon collection enhancement factor of ∼34. The planar geometry allows us to identify over 20 single V2 centers at room temperature with a mean (maximum) count rate enhancement factor of 9 (15). Moreover, we observe 10 V2 centers with a mean absorption line width below 80 MHz at cryogenic temperatures. These results demonstrate a photon collection enhancement that is robust to the lateral emitter position.

High-Fidelity Optical Readout of a Nuclear-Spin Qubit in Silicon Carbide.

Quantum state readout is a key requirement for a successful qubit platform. In this work, we demonstrate a high-fidelity quantum state readout of a V2 center nuclear spin based on a repetitive readout technique. We demonstrate up to 99.5% readout fidelity and 99% for state preparation. Using this efficient readout, we initialize the nuclear spin by measurement and demonstrate its Rabi and Ramsey nutation. Finally, we use the nuclear spin as a long-lived memory for quantum sensing application of a weakly coupled diatomic nuclear-spin bath.

Qudit-Based Spectroscopy for Measurement and Control of Nuclear-Spin Qubits in Silicon Carbide.

Nuclear spins with hyperfine coupling to single electron spins are highly valuable quantum bits. Here we probe and characterize the particularly rich nuclear-spin environment around single silicon vacancy color centers (V2) in 4H-SiC. By using the electron spin-3/2 qudit as a four level sensor, we identify several sets of ^{29}Si and ^{13}C nuclear spins through their hyperfine interaction. We extract the major components of their hyperfine coupling via optical detected nuclear magnetic resonance, and assign them to shells in the crystal via the density function theory simulations. We utilize the ground-state level anticrossing of the electron spin for dynamic nuclear polarization and achieve a nuclear-spin polarization of up to 98±6%. We show that this scheme can be used to detect the nuclear magnetic resonance signal of individual spins and demonstrate their coherent control. Our work provides a detailed set of parameters and first steps for future use of SiC as a multiqubit memory and quantum computing platform.

A state-of-the-art review of the recent advances in exosome isolation and detection methods in viral infection.

Proteins, RNA, DNA, lipids, and carbohydrates are only some of the molecular components found in exosomes released by tumor cells. They play an essential role in healthy and diseased cells as messengers of short- and long-distance intercellular communication. However, since exosomes are released by every kind of cell and may be found in blood and other bodily fluids, they may one day serve as biomarkers for a wide range of disorders. In many pathological conditions, including cancer, inflammation, and infection, they play a role. It has been shown that the biogenesis of exosomes is analogous to that of viruses and that the exosomal cargo plays an essential role in the propagation, dissemination, and infection of several viruses. Bidirectional modulation of the immune response is achieved by the ability of exosomes associated with viruses to facilitate immunological escape and stimulate the body's antiviral immune response. Recently, exosomes have received a lot of interest due to their potential therapeutic use as biomarkers for viral infections such as human immunodeficiency virus (HIV), Hepatitis B virus (HBV), Hepatitis C virus (HCV), Epstein-Barr virus (EBV), and SARS-CoV-2. This article discusses the purification procedures and detection techniques for exosomes and examines the research on exosomes as a biomarker of viral infection.

Fabrication and nanophotonic waveguide integration of silicon carbide colour centres with preserved spin-optical coherence.

Optically addressable spin defects in silicon carbide (SiC) are an emerging platform for quantum information processing compatible with nanofabrication processes and device control used by the semiconductor industry. System scalability towards large-scale quantum networks demands integration into nanophotonic structures with efficient spin-photon interfaces. However, degradation of the spin-optical coherence after integration in nanophotonic structures has hindered the potential of most colour centre platforms. Here, we demonstrate the implantation of silicon vacancy centres (VSi) in SiC without deterioration of their intrinsic spin-optical properties. In particular, we show nearly lifetime-limited photon emission and high spin-coherence times for single defects implanted in bulk as well as in nanophotonic waveguides created by reactive ion etching. Furthermore, we take advantage of the high spin-optical coherences of VSi centres in waveguides to demonstrate controlled operations on nearby nuclear spin qubits, which is a crucial step towards fault-tolerant quantum information distribution based on cavity quantum electrodynamics.

PET waste management in Pakistan through use of PET shreds as additive in backfill soil.

The management of waste plastic bottles is one of the major environmental challenges in the world. Plastic bottles are composed of polyethylene terephthalate (PET), which is non-biodegradable, resulting in environmental problems. Various studies have been carried out on the use of waste PET bottles in the form of custom-made strips as a stabilizer. However, no significant research has been carried out on the use of waste PET bottle shreds already available in the market. These shreds do not require any special technology or arrangement for bulk production. In this study, the shear strength of low plastic silty clay was improved using locally available PET shreds, and their prospective application in the backfill soil was investigated. Standard Proctor tests and direct shear tests were conducted on soil stabilized with three different sizes of plastic shreds (2 mm, 6 mm, and 10 mm) in four different percentages (1%, 3%, 5%, and 10%). Findings revealed that adding PET shreds in 1% content improves the shear strength characteristics. However, the shear strength parameters decrease with further increase in PET shred content. Therefore, PET shreds in 1% content can be added in backfill soil to improve its shear strength. Pakistan needs to construct 0.77 million housing units annually to keep up with its population growth. The statistics of seven major cities of Pakistan show that the PET waste management issue of Pakistan can be resolved by using PET shreds as a backfill additive in only 32% of the new houses required to be constructed.

Designing mRNA- and Peptide-Based Vaccine Construct against Emerging Multidrug-Resistant Citrobacter freundii: A Computational-Based Subtractive Proteomics Approach.

Background and Objectives: Citrobacter freundii (C. freundii) is an emerging and opportunistic Gram-negative bacteria of the human gastrointestinal tract associated with nosocomial and severe respiratory tract infections. It has also been associated with pneumonia, bloodstream, and urinary tract infections. Intrinsic and adaptive virulence characteristics of C. freundii have become a significant source of diarrheal infections and food poisoning among immune-compromised patients and newborns. Impulsive usage of antibiotics and these adaptive virulence characteristics has modulated the C. freundii into multidrug-resistant (MDR) bacteria. Conventional approaches are futile against MDR C. freundii. Materials and Methods: The current study exploits the modern computational-based vaccine design approach to treat infections related to MDR C. freundii. A whole proteome of C. freundii (strain: CWH001) was retrieved to screen pathogenic and nonhomologous proteins. Six proteins were shortlisted for the selection of putative epitopes for vaccine construct. Highly antigenic, nonallergen, and nontoxic eleven B-cell, HTL, and TCL epitopes were selected for mRNA- and peptide-based multi-epitope vaccine construct. Secondary and tertiary structures of the multi-epitope vaccine (MEVC) were designed, refined, and validated. Results: Evaluation of population coverage of MHC-I and MHC-II alleles were 72% and 90%, respectively. Docking MEVC with TLR-3 receptor with the binding affinity of 21.46 (kcal/mol) occurred through the mmGBSA process. Further validations include codon optimization with an enhanced CAI value of 0.95 and GC content of about 51%. Immune stimulation and molecular dynamic simulation ensure the antibody production upon antigen interaction with the host and stability of the MEVC construct, respectively. Conclusions: These interpretations propose a new strategy to combat MDR C. freundii. Further, in vivo and in vitro trials of this vaccine will be valuable in combating MDR pathogens.

Entanglement and control of single nuclear spins in isotopically engineered silicon carbide.

Nuclear spins in the solid state are both a cause of decoherence and a valuable resource for spin qubits. In this work, we demonstrate control of isolated 29Si nuclear spins in silicon carbide (SiC) to create an entangled state between an optically active divacancy spin and a strongly coupled nuclear register. We then show how isotopic engineering of SiC unlocks control of single weakly coupled nuclear spins and present an ab initio method to predict the optimal isotopic fraction that maximizes the number of usable nuclear memories. We bolster these results by reporting high-fidelity electron spin control (F = 99.984(1)%), alongside extended coherence times (Hahn-echo T2 = 2.3 ms, dynamical decoupling T2DD > 14.5 ms), and a >40-fold increase in Ramsey spin dephasing time (T2*) from isotopic purification. Overall, this work underlines the importance of controlling the nuclear environment in solid-state systems and links single photon emitters with nuclear registers in an industrially scalable material.

Coagulation abnormalities in dengue and dengue haemorrhagic fever patients.

OBJECTIVE: The aim of this study was to assess abnormality of coagulation and anticoagulation parameters in dengue fever patients and the impact of these tests on the management of patients. BACKGROUND: Dengue fever is endemic in Pakistan with seasonal rise in cases. Morbidities and mortalities are proportionately reported to be increasing and associated with disseminated intravascular coagulation resulting in haemorrhagic or thrombotic manifestations in patients having deranged coagulation profiles. METHODS/MATERIALS: This observational and descriptive study was conducted on confirmed Dengue patients at the National Institute of Blood Diseases during the years 2013 to 2016. Patients of all age groups were included in this study. Results were analysed by SPSS version 23. RESULTS: A total of 200 patients were selected with the mean age being 28.68 years (±13.28) and male predominance (147/200). The mean platelet count, haemoglobin and haematocrit at base line for bleeders and non-bleeders showed significant results, where platelet count at baseline for bleeders was 24 000, whereas for non-bleeders it was 29 000 and it showed significant correlation with bleeding (P-value .027). Platelets were transfused to 76 (38%) patients. However, none of the specialised haemostasis parameters beside the platelet count correlated with bleeding, requiring platelet transfusions. CONCLUSION: Our study showed a significant association of platelet counts, haemoglobin and haematocrit with bleeding. It can be concluded that coagulation and anticoagulation profiles will not benefit the management of dengue patients and in countries like Pakistan, it will only add to the economic burden on the patients.

Electrical Charge State Manipulation of Single Silicon Vacancies in a Silicon Carbide Quantum Optoelectronic Device.

Color centers with long-lived spins are established platforms for quantum sensing and quantum information applications. Color centers exist in different charge states, each of them with distinct optical and spin properties. Application to quantum technology requires the capability to access and stabilize charge states for each specific task. Here, we investigate charge state manipulation of individual silicon vacancies in silicon carbide, a system which has recently shown a unique combination of long spin coherence time and ultrastable spin-selective optical transitions. In particular, we demonstrate charge state switching through the bias applied to the color center in an integrated silicon carbide optoelectronic device. We show that the electronic environment defined by the doping profile and the distribution of other defects in the device plays a key role for charge state control. Our experimental results and numerical modeling evidence that control of these complex interactions can, under certain conditions, enhance the photon emission rate. These findings open the way for deterministic control over the charge state of spin-active color centers for quantum technology and provide novel techniques for monitoring doping profiles and voltage sensing in microscopic devices.

Emerging Anti-Microbial Resistance in Febrile Neutropenia: Is it high time to evaluate quality control measures?

OBJECTIVE: We performed a prospective analysis at our center to find out the most common organisms causing bacterial infections to establish pattern of antibiotic resistance, in order to combat febrile neutropenia effectively in the terms of outcome as well as cost. METHODS: A hospital based observational study was conducted at National Institute of Blood Diseases and bone marrow transplantation from January 2017 to December 2017. Patients presented with absolute neutrophil count (ANC) of less than 500/ml were enrolled. Data were analyzed by SPSS version 21.0. P value of <0.05 was considered statistically significant. RESULTS: In this study, a total of 242 patients from various hematological disorders were enrolled and 403 bacterial isolates were obtained. The most frequent isolated gram-negative organisms were Escherichia coli, followed by Klebsiella pneumoniae and the most prevalent gram-positive organisms were staphylococcus aureus and Enterococcus species. The antimicrobial susceptibility testing revealed that most of the Staphylococcus aureus isolates were highly resistant to methicillin (p=0.002), whereas Enterococcus species were resistant to vancomycin (p=0.000). CONCLUSION: The choice of empirical antibiotic regimen should be based on local spectrum of bacteria and their regional susceptibility pattern to improve the survival and minimize hospital stay of patients.

Frequency of Alpha Thalassaemia in homozygous Beta Thalassaemia paediatric patients and its clinical impact at a blood disease centre in Karachi, Pakistan.

OBJECTIVE: To find frequency ofalpha Thalsaemia nhomozygous beta Thalsaemia patients, and to se any difernce infrequency and age ofirst ransfusion and mean haemoglobin concentration. METHODS: The single-centred, escriptive cros-sectional study was conducted athe National Instiute of Blod Disease and Bone Marow Transplantaion, Karchi, from June 1,2012, to May 31, 2013. Patients of homozygous beta halsaemia, diagnosed by polymerase chain reaction, wer tested for coinheritance of alpha Thalsaemia nd foetal haemoglobin XMN1 polymorphism using polymerase chain reaction. SPS 17 was used for dat anlysi. RESULTS: Of the 286 patients, 19(41.6%) wer males, and 9(34.6%) showed coinheritance ofalpha thalsaemia. In the coinheritance group, 50(50%) and 1(1%) patients recived 1-20 and 21-40 times transfusions per year espectively, while inthe non-coinheritance group, the coresponding numbers wer 125(67%) and 27(14.%). Overal, 73(25.%) patients had nevr ben transfused, including 38(13.%) patients inthe alpha Thalsaemia group. XMN1 polymorphism was found in 86(41%) ofthe 208 patients who wer tested and anlysed on this count. CONCLUSIONS: Alpha thalsemia was presnt inmore than one-third homozygous beta halsemia patients.

Alpha thalassemia deletions found in suspected cases of beta thalassemia major in Pakistani population.

BACKGROUND & OBJECTIVE: Alpha (α) thalassemia is a hereditary disorder and is caused by deletions or mutations in globin genes. It is present in two clinically significant forms: hemoglobin Bart hydrops fetalis (Hb Bart) syndrome and hemoglobin H (HbH) disease. It is highly prevalent in South-East Asia or Mediterranean countries. The most common deletion reported in alpha thalassemia in Pakistani population was -α3.7 with a frequency of 8.3%, and the rare forms were -α4.2 (0.2%) and αααanti3.7 (0.9%). In our study, diagnosis of severe anemia cases without any α and ß mutations or deletions were made by using extended alpha thalassemia deletions panel. The main objective of this study was to determine the prevalence and to study the spectra of alpha thalassemia gene deletions in beta thalassemia patients with the use of an extended panel including --SEA, --FIL, --MED, --20.5, --THAI in addition to -α3.7, -α4.2 & -αααanti3.7. METHODS: The samples were collected in ethylenediaminetetraacetic acid (EDTA) vacutainers. A total of 156 samples were analyzed for alpha thalassemia mutations. This cohort included 121 samples of beta thalassemia major, nine samples of beta thalassemia minor and 26 without any evidence of beta thalassemia mutations. DNA was extracted with Qiagen extraction kit. The primers for determination of different subsets of alpha thalassemia deletions were included. PCR amplification was performed and result interpreted on agarose gel. RESULTS: Co-inheritance of alpha thalassemia (-α3.7, -α4.2) with homozygous beta thalassemia was detected in 30% cases of studied cohort (37 out of 121). The most common found was -α3.7 deletion (35/37) as single/double deletions or in combination with -αααanti3.7. In undiagnosed cases screened for beta thalassemia major, we found Mediterranean (-αMED) deletion at specifically 875 bp on agarose gel. This is distinctive finding in case of detecting -αMED instead of any other deletion from Pakistan. CONCLUSION: Alpha thalassemia deletions (-α3.7, -α4.2) are the common co-inherited deletions found in beta thalassemia major patients. On the basis of results, we propose an extended alpha thalassemia genetic mutation panel should be used for screening of children presenting with anemia with suspicion of haemoglobinopathy.

Isolated electron spins in silicon carbide with millisecond coherence times.

The elimination of defects from SiC has facilitated its move to the forefront of the optoelectronics and power-electronics industries. Nonetheless, because certain SiC defects have electronic states with sharp optical and spin transitions, they are increasingly recognized as a platform for quantum information and nanoscale sensing. Here, we show that individual electron spins in high-purity monocrystalline 4H-SiC can be isolated and coherently controlled. Bound to neutral divacancy defects, these states exhibit exceptionally long ensemble Hahn-echo spin coherence times, exceeding 1 ms. Coherent control of single spins in a material amenable to advanced growth and microfabrication techniques is an exciting route towards wafer-scale quantum technologies.

Precise Characterization of a Waveguide Fiber Interface in Silicon Carbide.

Spin-active optical emitters in silicon carbide are excellent candidates toward the development of scalable quantum technologies. However, efficient photon collection is challenged by undirected emission patterns from optical dipoles, as well as low total internal reflection angles due to the high refractive index of silicon carbide. Based on recent advances with emitters in silicon carbide waveguides, we now demonstrate a comprehensive study of nanophotonic waveguide-to-fiber interfaces in silicon carbide. We find that across a large range of fabrication parameters, our experimental collection efficiencies remain above 90%. Further, by integrating silicon vacancy color centers into these waveguides, we demonstrate an overall photon count rate of 181 kilo-counts per second, which is an order of magnitude higher compared to standard setups. We also quantify the shift of the ground state spin states due to strain fields, which can be introduced by waveguide fabrication techniques. Finally, we show coherent electron spin manipulation with waveguide-integrated emitters with state-of-the-art coherence times of T 2 ∼ 42 µs. The robustness of our methods is very promising for quantum networks based on multiple orchestrated emitters.

Cytogenetic culture failure and its causes in hematological disorders; a single centre perspective.

OBJECTIVE: To highlight the reasons of culture failure in bone marrow aspirate samples sent for Cytogenetic analysis and to identify the associated parameters causing this impact. METHODOLOGY: This is a retrospective cross-sectional study conducted in the Clinical and Molecular Cytogenetics Laboratory of NIBD Hospital, Karachi, Pakistan. The rates of culture failure are assessed from the year 2017-2020 along with their reasons. Bone Marrow aspirate samples of patients with hematological malignancies were cultured for chromosomal analysis, both at the time of diagnosis or relapse. Statistical analysis was performed using SPSS version 25. RESULTS: A total of 1061 bone marrow aspirate samples were assessed for cytogenetic culture failures from the duration of 2017 to 2020. Ratio of males was predominantly higher i.e. 62.7% than female 37.3% with Mean ± SD age was 36.78 ± 18.94. Frequency of culture failure in the year 2020 was relatively high 20% as compared to the preceding years i.e. 8% in 2017, 6% in 2018, 7% in 2019. However, the patients were diagnosed with the following hematological malignancies; ALL 23%, CML 17.1%, AML 16.5% and AA 12.5%. Among the reasons of culture failure, cytogenetic analysis of patients with on-going chemo resulted in significant culture failures with p-value < 0.001 and the hematological malignancy, Acute Promyelocytic Leukemia, significantly impacted the growth of bone marrow aspirate cultures, with p-value < 0.001. CONCLUSION: Significant findings were associated with causative factors of culture failure including on-going treatment and sample issues of clotted bone marrow as well as with the clinical diagnosis. These evaluations facilitated in overcoming the rise in culture failures. As per our knowledge, no such data, discussing the effects of various parameters such as sample quality, diagnosis, effects of treatment etc., has been documented previously.

Identification of Bacterial Strains and Development of anmRNA-Based Vaccine to Combat Antibiotic Resistance in Staphylococcus aureus via In Vitro and In Silico Approaches.

The emergence of antibiotic-resistant microorganisms is a significant concern in global health. Antibiotic resistance is attributed to various virulent factors and genetic elements. This study investigated the virulence factors of Staphylococcus aureus to create an mRNA-based vaccine that could help prevent antibiotic resistance. Distinct strains of the bacteria were selected for molecular identification of virulence genes, such as spa, fmhA, lukD, and hla-D, which were performed utilizing PCR techniques. DNA extraction from samples of Staphylococcus aureus was conducted using the Cetyl Trimethyl Ammonium Bromide (CTAB) method, which was confirmed and visualized using a gel doc; 16S rRNA was utilized to identify the bacterial strains, and primers of spa, lukD, fmhA, and hla-D genes were employed to identify the specific genes. Sequencing was carried out at Applied Bioscience International (ABI) in Malaysia. Phylogenetic analysis and alignment of the strains were subsequently constructed. We also performed an in silico analysis of the spa, fmhA, lukD, and hla-D genes to generate an antigen-specific vaccine. The virulence genes were translated into proteins, and a chimera was created using various linkers. The mRNA vaccine candidate was produced utilizing 18 epitopes, linkers, and an adjuvant, known as RpfE, to target the immune system. Testing determined that this design covered 90% of the population conservancy. An in silico immunological vaccine simulation was conducted to verify the hypothesis, including validating and predicting secondary and tertiary structures and molecular dynamics simulations to evaluate the vaccine's long-term viability. This vaccine design may be further evaluated through in vivo and in vitro testing to assess its efficacy.

Ultra-narrow inhomogeneous spectral distribution of telecom-wavelength vanadium centres in isotopically-enriched silicon carbide.

Spin-active quantum emitters have emerged as a leading platform for quantum technologies. However, one of their major limitations is the large spread in optical emission frequencies, which typically extends over tens of GHz. Here, we investigate single V4+ vanadium centres in 4H-SiC, which feature telecom-wavelength emission and a coherent S = 1/2 spin state. We perform spectroscopy on single emitters and report the observation of spin-dependent optical transitions, a key requirement for spin-photon interfaces. By engineering the isotopic composition of the SiC matrix, we reduce the inhomogeneous spectral distribution of different emitters down to 100 MHz, significantly smaller than any other single quantum emitter. Additionally, we tailor the dopant concentration to stabilise the telecom-wavelength V4+ charge state, thereby extending its lifetime by at least two orders of magnitude. These results bolster the prospects for single V emitters in SiC as material nodes in scalable telecom quantum networks.

Whole proteome analysis of MDR Klebsiella pneumoniae to identify mRNA and multiple epitope based vaccine targets against emerging nosocomial and lungs associated infections.

Klebsiella pneumonia is a Gram negative facultative anaerobic bacterium involved in various community-acquired pneumonia, nosocomial and lungs associated infections. Frequent usage of several antibiotics and acquired resistance mechanisms has made this bacterium multi-drug resistance (MDR), complicating the treatment of patients. To avoid the spread of this bacterium, there is an urgent need to develop a vaccine based on immuno-informatics approaches that is more efficient than conventional method of vaccine prediction or development. Initially, the complete proteomic sequence of K. pneumonia was picked over for specific and prospective vaccine targets. From the annotation of the whole proteome, eight immunogenic proteins were selected, and these shortlisted proteins were interpreted for CTL, B-cells, and HTL epitopes prediction, to construct mRNA and multi-epitope vaccines. The Antigenicity, allergenicity and toxicity analysis validate the vaccine's design, and its molecular docking was done with immuno-receptor the TLR-3. The docking interaction showed a stronger binding affinity with a minimum energy of -1153.2 kcal/mol and established 23 hydrogen bonds, 3 salt bridges, 1 disulfide bond, and 340 non-binding contacts. Further validation was done using In-silico cloning which shows the highest CAI score of 0.98 with higher GC contents of 72.25% which represents a vaccine construct with a high value of expression in E. coli. Immune Simulation shows that the antibodies (IgM, IgG1, and IgG2) production exceeded 650,000 in 2 to 3 days but the response was completely neutralized in the 5th day. In conclusion, the study provides the effective, safe and stable vaccine construct against Klebsiella pneumonia, which further needs in vitro and in vivo validations.Communicated by Ramaswamy H. Sarma.

A Familial Case of Robertsonian Translocation 13;14: Case Report.

Robertsonian translocations are the most common form of chromosomal abnormalities that specifically involve the acrocentric chromosomes. Robertsonian translocation between chromosomes 13,14 and 14,21 are the most frequently reported. Infertility is common in genetically balanced carriers of these translocations, and their conceptions are more likely to have imbalances. Here we have reported a case of an 18-year-old female presenting with a complaint of primary amenorrhea. Cytogenetic analysis revealed a familial case of maternally inherited Robertsonian translocation (rob(13;14)(q10;q10)) affecting all the siblings. Genetic counseling and genetic testing are recommended especially in familial cases as the carriers are normal but can lead to several genetic disorders in their future generation.