Publications by authors named "Kashif Riaz"

12 Publications

  • Page 1 of 1

Single-layered meta-reflectarray for polarization retention and spin-encrypted phase-encoding.

Opt Express 2021 Feb;29(3):3230-3242

Broadband communication with high data rates is a dire need for state-of-the-art wireless technologies. For achieving efficient wireless communication (particularly in an indoor environment), the electromagnetic (EM) waves should maintain their state of polarization despite encountering multiple reflections. Metasurfaces provide a unique platform to design subwavelength-featured meta-reflectarrays which enable the desired retention of the polarization state of an EM wave upon reflection. We present a single-layered broadband meta-reflectarray, simultaneously breaking n-fold (n > 2) rotational and mirror symmetry, which exhibits an unprecedented control over the phase, amplitude, and polarization of a reflected EM wave. This unique control enables the retention of polarization state and recording of spin-encrypted information for the reflected EM waves. Such novel multifunctional meta-reflectarray can be crucial to building an indoor setup for high data rate wireless communications. Meanwhile, the meta-array's ability to encode phase information provides an extra degree of freedom to structure and control (via incident spin) the reflected EM beam in the desired way. For the proof of concept, we have experimentally demonstrated a spin-encrypted holographic display which reconstructs the recorded holographic image at an image plane for the left circularly polarized (LCP) illumination and exhibits circular dichroism for the right circularly polarized (RCP) incident waves. The proposed meta-array can find applications in 5G indoor wireless communication, chiral sensing, spin-selective imaging, holography, and encryption.
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http://dx.doi.org/10.1364/OE.415562DOI Listing
February 2021

Complete Genome Sequence of the Type Strain Pectobacterium punjabense SS95, Isolated from a Potato Plant with Blackleg Symptoms.

Microbiol Resour Announc 2020 Aug 6;9(32). Epub 2020 Aug 6.

Institute for Integrative Biology of the Cell (I2BC), CEA CNRS University Paris-Saclay, Gif-sur-Yvette, France

is a newly described species causing blackleg disease in potato plants. Therefore, by the combination of long (Oxford Nanopore Technologies, MinION) and short (Illumina MiSeq) reads, we sequenced the complete genome of SS95, which contains a circular chromosome of 4.793 Mb with a GC content of 50.7%.
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http://dx.doi.org/10.1128/MRA.00420-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409842PMC
August 2020

Engineering multimodal dielectric resonance of TiO based nanostructures for high-performance refractive index sensing applications.

Opt Express 2020 Aug;28(16):23509-23522

Optical metasurface based refractive index (RI) sensors find applications in chemical, environmental, biomedical, and food processing industries. The existing RI sensors based on metals suffer from the plasmonic loss in the optical regime; in contrast, those based on Fano-type resonances generated by dielectric materials are either polarization-sensitive or are based on complex geometrical structures prone to fabrication imperfections that can lead to severe performance degradation. Here, we demonstrate that careful engineering of resonance modes in dielectric metasurfaces based on simple symmetric meta-atoms can overcome these limitations. More specifically, we have designed low-loss high-performance RI sensors using all-dielectric metasurfaces composed of TiO based nanostructures of three different shapes (i.e., cylindrical, square and elliptical) operating at near-infrared (NIR) wavelengths, which are robust against the perturbations of geometric parameters. In terms of physics, this work reports sensor structures achieving sharp resonant dips of high Q-factor in the transmission spectra corresponding to multiple dielectric resonance modes (i.e., electric quadrupole, magnetic dipole, and electric dipole) with superior performance as compared to the state-of-the-art. Four absolute liquids (water, ethanol, pentanol, and carbon tetrachloride) with a refractive index ranging from 1.333 to 1.453 are used to numerically validate the performance, and a maximum sensitivity of 798 nm/RIU with FOM up to 732 has been achieved.
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http://dx.doi.org/10.1364/OE.397431DOI Listing
August 2020

Species Diversity of and Causing Potato Blackleg Disease in Pakistan.

Plant Dis 2020 May 8;104(5):1492-1499. Epub 2020 Mar 8.

Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.

Potato blackleg is caused by a diverse species of pectinolytic bacteria. In Pakistan, approximately 90% of the pathogens involved belong to Survey (2014 to 2017), sampling, and isolation from different potato growing areas of Punjab, Pakistan depicted an overall disease incidence of approximately 15%. Thirty-six pectinolytic strains confirmed through biochemical and pathogenicity testing were characterized via gene to identify them at the species level. To further validate the identification, one strain from each species SS26 (), SS28 (), SS70 (), SS90 (), SS95 (), and SS96 () were selected for draft genome sequencing and multilocus sequence analysis of 13 housekeeping genes (, , , , , , , , , , , , and ). Phylogenetic analysis revealed considerable genetic diversity in the genus . DNA-DNA hybridization and average nucleotide identity values of the strains selected for genome sequencing were determined with other reference and strains. Moreover, all six representative strains were also phenotypically characterized on the basis of metabolism of different carbon sources. Overall, on the basis of genotypic and phenotypic characteristics, these 36 isolates were grouped into six species: , , , , , and .
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http://dx.doi.org/10.1094/PDIS-08-19-1743-REDOI Listing
May 2020

Pectobacterium punjabense sp. nov., isolated from blackleg symptoms of potato plants in Pakistan.

Int J Syst Evol Microbiol 2018 Nov 21;68(11):3551-3556. Epub 2018 Sep 21.

2​Institute for Integrative Biology of the Cell (I2BC), CEA CNRS Univ. Paris-Sud, University Paris-Saclay, 91198 Gif-sur-Yvette, France.

Pectobacterium isolates SS95, SS54 and SS56 were collected from a potato field in the Chiniot district in the plains of the Punjab province, Pakistan. Sequencing of the gapA barcode revealed that these strains belong to a novel phylogenetic group separated from P.ectobacterium wasabiae and Pectobacterium parmentieri species. Furthermore, multilocus sequence analyses of 13 housekeeping genes (fusA, rpoD, acnA, purA, gyrB, recA, mdh, mtlD, groEL, secY, glyA, gapA and rplB) clearly distinguished the type strain, SS95, from its closest relatives, i.e. P. parmentieri RNS 08-42-1A and P. wasabiae CFBP3304, as well as from all the other known Pectobacteriumspecies. In silico DNA-DNA hybridization (<44.1 %) and average nucleotide identity (<90.75 %) values of strain SS95 compared with other Pectobacterium type strains supported the delineation of a new species. Genomic and phenotypic comparisons permitted the identification of additional traits that distinguished the Pakistani isolates from all other known Pectobacterium type strains. The name Pectobacterium punjabense sp. nov. is proposed for this taxon with the type strain SS95 (=CFBP 8604=LMG 30622).
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http://dx.doi.org/10.1099/ijsem.0.003029DOI Listing
November 2018

Pulmonary delivery of triptolide-loaded liposomes decorated with anti-carbonic anhydrase IX antibody for lung cancer therapy.

Sci Rep 2017 04 20;7(1):1097. Epub 2017 Apr 20.

School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Hong Kong, China.

Antibody-decorated liposomes can facilitate the precise delivery of chemotherapeutic drugs to the lung by targeting a recognition factor present on the surface of lung tumor cells. Carbonic anhydrase IX (CA IX) is an enzyme expressed on the surface of lung cancer cells with a restricted expression in normal lungs. Here, we explored the utility of anti-carbonic anhydrase IX (CA IX) antibody, conjugated to the surface of triptolide (TPL)-loaded liposomes (CA IX-TPL-Lips), to promote the therapeutic effects for lung cancer via pulmonary administration. It was found that the CA IX-TPL-Lips significantly improved the cellular uptake efficiency in both CA IX-positive human non-small cell lung cancer cells (A549) and A549 tumor spheroids, resulting in the efficient cell killing compared with free TPL and non-targeted TPL-Lips. In vivo, CA IX-Lips via pulmonary delivery showed specificity and a sustained release property resided up to 96 h in the lung, both of which improved the efficiency of TPL formulations in restraining tumor growth and significantly prolonged the lifespan of mice with orthotopic lung tumors. The results suggest that CA IX-decorated liposomes can potentially be used as an effective therapeutic strategy for lung cancer.
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http://dx.doi.org/10.1038/s41598-017-00957-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5430522PMC
April 2017

A novel combination of four flavonoids derived from Astragali Radix relieves the symptoms of cyclophosphamide-induced anemic rats.

FEBS Open Bio 2017 03 28;7(3):318-323. Epub 2017 Jan 28.

Division of Life Science and Center for Chinese Medicine The Hong Kong University of Science and Technology China; HKUST Shenzhen Research Institute Nanshan Shenzhen Guangdong Province China.

By using a feedback system control scheme, the best combination of formononetin, ononin, calycosin, and calycosin-7--β-d-glucoside derived from Astragali Radix was shown to activate a hypoxia response element, a regulator for erythropoietin (EPO) transcription, in kidney fibroblast. In cyclophosphamide-induced anemic rats, the treatment of combined flavonoids, or EPO, improved the levels of red blood cells, white blood cells, hemoglobin, and hematocrit. In addition, the altered levels of antioxidant capacity, super oxidase dismutase, and malondialdehyde, triggered in anemic rats, were restored to control levels by the treatment of flavonoids. Here, we proposed a possible therapy by using the common flavonoids in treating anemia.
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http://dx.doi.org/10.1002/2211-5463.12146DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5337903PMC
March 2017

Innovative solution to sharp waste management in a tertiary care hospital in Karachi, Pakistan.

Infect Control Hosp Epidemiol 2013 Dec 28;34(12):1297-305. Epub 2013 Oct 28.

Health Foundation, Karachi, Pakistan.

Background: Prevalence of hepatitis B and C in Pakistan is 2.5% and 4.5%, respectively. Major cause of these infections is reuse of syringes.

Objective: To determine a cost-effective, innovative solution to prevent syringe reuse and break the transmission cycle of blood-borne infections. STUDY DESIGN, SETTINGS, AND DURATION: Analytical study in a tertiary care hospital, Jinnah Postgraduate Medical Centre, Karachi, Pakistan, July 2011 to June 2012.

Methods: Healthcare workers from 30 wards included in the study were trained on injection safety, use of needle remover and needle pit, and management of needlestick injuries. Each ward was provided with 2 needle-removing devices, and a pit was constructed for disposal of needles. Usage of the device in wards and pit use were monitored regularly.

Results: In 28 (93.3%) wards, sharp containers were accessible by public and were slack. Syringes were recapped using both hands in 27 (90%) cases; needlestick injury was reported by 30% of paramedics, while 25 (83.3%) of the interviewed staff had not received any formal training in injection safety. Vigilant monitoring and information sharing led to healthcare workers in 28 (96.5%) wards using the device. Needle containers were emptied in 27 (93.1%) wards, and needle pits were used in 26 (96.3%) wards. Needlestick injury was nil in follow-up.

Conclusions: Needle removers permanently disable syringes. The needle pit served as a cost-effective, innovative method for disposal of needles. The intervention resulted in reducing the risk of needlestick injury.
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http://dx.doi.org/10.1086/673978DOI Listing
December 2013

Synthesis, characterization, in vitro antimicrobial, and U2OS tumoricidal activities of different coumarin derivatives.

Chem Cent J 2013 Apr 15;7(1):68. Epub 2013 Apr 15.

Institute of Chemical Sciences, University of Peshawar 25120, Peshawar, Pakistan.

Background: Coumarin and its derivatives are biologically very active. It was found that the enhanced activities are dependent on the coumarin nucleus. Biological significance of these compounds include anti-bacterial, anti-thrombotic and vasodilatory, anti-mutagenic, lipoxygenase and cyclooxygenase inhibition, scavenging of reactive oxygen species, and anti-tumourigenic. Our interest in medicinal chemistry of dicoumarol compounds have been developed by keeping in view the importance of coumarins along with its derivatives in medicinal chemistry. All the synthesized compounds were fully characterized by spectroscopic and analytical techniques and were screened for antimicrobial and U2OS bone cancer activities.

Results: 4-hydroxycoumarin was derivatized by condensing with different aldehydes yielding the dicoumarol and translactonized products. Elemental analyses, ESI(+,-) MS, 1H and 13C{1H}-NMR, infrared spectroscopy and conductance studies were used to characterize the synthesized compounds which revealed the dicoumarol and dichromone structures for the compounds. The compounds were screened against U2OS cancerous cells and pathogenic micro organisms. The compounds with intermolecular H-bonding were found more active revealing a possible relationship among hydrogen bonding, cytotoxicity and antimicrobial activities.

Conclusion: Coumarin based drugs can be designed for the possible treatment of U2OS leukemia.
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http://dx.doi.org/10.1186/1752-153X-7-68DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3668295PMC
April 2013

High factor XI, recurrent pregnancy loss, enoxaparin.

Fertil Steril 2010 Dec 17;94(7):2828-31. Epub 2010 Jun 17.

Cholesterol Center, Jewish Hospital, Cincinnati, Ohio 45229, USA.

Of the 149 women with 0 pregnancy losses, 7 (5%) had factor XI level ≥150% versus 5 of 31 (16%) women with recurrent pregnancy loss. Three of the 5 women with high factor XI and recurrent pregnancy loss, with 19 previous pregnancy losses and 0 live births, were given enoxaparin during 5 subsequent pregnancies, and had 6 term live births and 1 miscarriage.
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http://dx.doi.org/10.1016/j.fertnstert.2009.12.084DOI Listing
December 2010

Determination of risk factors for hepatitis B and C in male patients suffering from chronic hepatitis.

BMC Res Notes 2009 Oct 23;2:212. Epub 2009 Oct 23.

Medilink and Orthopeadic and Medical Institute (OMI) Hospital Karachi, Karachi, Pakistan.

Background: Hepatitis B and C is common in Pakistan and various risk factors are attributable to its spread.One thousand and fifty consecutive male cases suffering from chronic liver disease (327 HBV and 723 HCV) were selected from the OPD of public sector hospital and a private clinic dealing exclusively with the liver patients. To compare the results 723 age and gender matched controls were selected from the blood transfusion services of the public sector hospital. A standard questionnaire was filled for all patients and controls which included the information on possible risk factors.

Findings: Family history of liver disease was significantly higher (43% and 34%) in HBV and HCV positive cases as compared to 5% in controls [odds ratio 15.6; 95% Confidence Interval CI: 10.1 - 24.1, 10.9; 95% Confidence Interval CI: 7.3 - 16.4] and same trend was seen for death due to liver disease in the family. Majority 74% hepatitis B positive cases had their shaves done at communal barbers but this practice was equally prevalent amongst controls (68%), thus negating it as a possible risk factor, but there is a significant risk with p < 0.05 associated with HCV in male that get their shave in barber. Very strong association of the disease was found with history of dental treatment (38% HCV 36% HBV and 21% controls) [Odd ratio 2.3; 95% CI: 1.8-3.0, Odd ratio 2.1; 95% CI: 1.5-2.8], surgery (23% HCV cases,14% HBV cases and 12% controls), history of blood transfusion was significantly higher in HCV (6%) as compared to controls (2.1%) [Odd ratio 2.9; 95% CI: 1.5-5.5]. History of taking injections for various ailments by the general practitioners (over 90% patients in both hepatitis B and C cases) was significantly higher as compared to 75% in controls [Odds ratio 3.8, 6.9; 95% CI: 2.4-6.1, 4.5-10.4] but hospitalization was not significant in HBV and HCV cases.

Conclusion: Injections, surgery and dental treatment appear as major risk factors for the transmission of hepatitis B and C in the community. Massive health care awareness drives need to be done for both health care providers and the public to reduce this menace.
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http://dx.doi.org/10.1186/1756-0500-2-212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2772845PMC
October 2009

A metagenomic analysis of soil bacteria extends the diversity of quorum-quenching lactonases.

Environ Microbiol 2008 Mar 7;10(3):560-70. Epub 2008 Jan 7.

Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, UPR2355, Gif-sur-Yvette, France.

A metagenomic library of 10,121 clones, generated from bacteria inhabiting a pasture soil from France, was screened for the presence of fosmids conferring either N-acylhomoserine lactone (NAHL) synthesis or NAHL degradation ability upon their Escherichia coli host. No clone producing NAHLs was identified whereas one, containing a 31 972 bp insert in fosmid p2H8, allowed NAHL degradation. This led to the cloning and identification of a gene, qlcA, encoding an NAHL-lactonase activity, as judged by lactone-ring closure and HPLC/MS analyses of NAHL degradation products. The qlcA gene efficiently quenched quorum-sensing regulated pathogenic functions when expressed in Pectobacterium carotovorum. The QlcA peptide belongs to the family of zinc-dependent metallohydrolases and appears to be distantly related to other NAHL-lactonases discovered in Agrobacterium, Bacillus, Photorhabdus and Rhizobium. In-silico analysis of the metagenomic insert revealed the occurrence of 20 orf, with a constant GC% and codon usage, suggesting a unique bacterial origin. Nine out of these 20 orf were homologous to genes encoding biosynthesis of arginine; they were clustered with an unusual succession argFJADBCRGH. The fosmid p2H8 is able to complement the argA, argB and argC mutants in E. coli. Phylogenetic analysis showed that 9 orf out of 20 were related to sequences from members of the Acidobacteria, supporting the hypothesis that the analysed insert might be originated from an organism related to this phylum.
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http://dx.doi.org/10.1111/j.1462-2920.2007.01475.xDOI Listing
March 2008