Asim Malik

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Is Coronavirus disease (COVID-19) case fatality ratio underestimated?

The number of cases of coronavirus disease (COVID-19) is increasing rapidly and case fatality rat... more The number of cases of coronavirus disease (COVID-19) is increasing rapidly and case fatality ratio (CFR) is estimated to be around 2 to 3%. However, the epidemic is still ongoing and the outcome of many sick cases of COVID-19, particularly the outcome of severe cases, is not yet available, which may lead to underestimation of CFR. This was observed during the initial phase of severe acute respiratory syndrome coronavirus (SARS-CoV) outbreak as well, where CFR increased with the passage of time. We estimated the CFR of COVID-19 by extrapolating the data using SARS as an analogy. According to our estimates, the actual CFR of COVID-19 may be around 4.4 to 4.8%. However, these results should be interpreted with cautions as we did not adjust for many confounding factors. Various epidemiological and modelling techniques can be used to estimate CFR of COVID-19 during the epidemic. Precise estimates of CFR will be available after the end of the epidemic when the outcome of all cases will b...

Charged particle induced reaction cross section data for production of the emerging medically important positron emitter 64Cu: A comprehensive evaluation

Radiochimica Acta, 2009

The radionuclide 64Cu (T 1/2=12.7 h) is an important non-standard positron emitter, suitable for ... more The radionuclide 64Cu (T 1/2=12.7 h) is an important non-standard positron emitter, suitable for combining PET imaging and targeted therapy. Its production in no-carrier-added form is done via charged particle induced reactions, and considerable amount of cross section data are available in the literature. We evaluated seven reactions, namely 64Ni(p, n) 64Cu, 64Ni(d, 2n) 64Cu, 68Zn(p, αn) 64Cu, 66Zn(p, 2n) 64Cu, 64Zn(d, 2p) 64Cu, 66Zn(p, α) 64Cu and natZn(d, x) 64Cu. Data analysis was generally limited up to about 25 MeV and the consistency check of experimental data was carried out using the nuclear model codes STAPRE, EMPIRE and TALYS. In a few cases experimental data were available up to 100 MeV; the consistency check in the high energy region was done only using the code TALYS. A statistical procedure (supported by nuclear model calculations) was then used to fit the data. The derived recommended sets of data, together with 95% confidence limits, are reported. The integral yield...

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Evaluation of charged particle induced reaction cross section data for production of the important therapeutic radionuclide186Re

Radiochimica Acta, 2010

186Re is an important radionuclide having a half-life of 3.72 d that is suitable for radioimmunot... more 186Re is an important radionuclide having a half-life of 3.72 d that is suitable for radioimmunotherapy. Its production in no-carrier-added form is doneviacharged particle induced reactions and the data are available in EXFOR library. We evaluated two charged particle induced reactions, namely186W(p,n)186Re and186W(d,2n)186Re. In the first case, analysis was done up to about 70 MeV but in the latter only up to about 50 MeV. A statistical procedure supported by nuclear model calculations using the codes STAPRE, EMPIRE and TALYS was used to validate and fit the data. The recommended sets of data derived together with 95% confidence limits are reported. The application of those data, particularly in the calculation of integral yields is discussed. The186W(p,n)186Re reaction on highly enriched186W is presently the method of choice for production of no-carrier-added186Re and, taking into account the radionuclidic purity, the maximum recommended proton energy is 18 MeV. The formation of t...

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Evaluations of Charged Particle Data for Production of the Therapeutic Radionuclides 103Pd, 186Re and 67Cu

Journal of the Korean Physical Society, 2011

ABSTRACT The charged particle data for the production of three important radionuclides, namely Pd... more ABSTRACT The charged particle data for the production of three important radionuclides, namely Pd-103 (T-1/2 = 16.99 d), Re-186 (T-1/2 = 3.7 d) and Cu-67 (T-1/2 = 61.9 h) were evaluated. A statistical procedure supported by nuclear model calculations employing the codes STAPRE, EMPIRE 2.19 and TALYS was used to validate and fit the experimental data. The recommended sets of data, derived together with 95% confidence limits, should be useful for optimization of the production routes of the three radionuclides at cyclotrons.

A comprehensive evaluation of charged-particle data for production of the therapeutic radionuclide 103Pd

Applied Radiation and Isotopes, 2009

103 Pd is an important radionuclide having a half-life of 16.99 d, which is suitable for internal... more 103 Pd is an important radionuclide having a half-life of 16.99 d, which is suitable for internal radiation therapy, especially used for the treatment of prostate cancer. Its production in no-carrier-added form is done via charged-particle-induced reactions and the data are available in EXFOR library. We evaluated six charged-particle-induced reactions, namely nat Ag(p,x) 103 Pd, 103 Rh(p,n) 103 Pd, 103 Rh(d,2n) 103 Pd, 100 Ru(a,n) 103 Pd, 101 Ru(a,2n) 103 Pd, and 102 Ru(3 He,2n) 103 Pd process. In the first case, analysis was done up to about 100 MeV but in other cases only up to about 25 or 40 MeV. Furthermore, an evaluation of the data for the nat Ag(p,x) 103 Ag process was also done since it may serve as a typical example for the 103 Ag-103 Pd precursor system. A statistical procedure supported by nuclear model calculations using the codes STAPRE, EMPIRE 2.19, and TALYS was used to validate and fit the experimental data. The recommended sets of data derived together with confidence limits are reported. The application of those data, particularly in the calculation of integral yields, is discussed. A comparison of the investigated routes from the viewpoint of practical applicability to the production of 103 Pd is given. Presently the 103 Rh(p,n) 103 Pd reaction is the method of choice.

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Evaluation of excitation functions of 3He- and α-particle induced reactions on antimony isotopes with special relevance to the production of iodine-124

Applied Radiation and Isotopes, 2011

Cross section data were evaluated for the production of the medically important positron emitter ... more Cross section data were evaluated for the production of the medically important positron emitter 124 I (T 1/2 ¼ 4.18 d) via 3 He-and a-particle induced reactions on Sb isotopes. The consistency in the measured data available in the literature was checked against the cross section calculations of three nuclear model codes (i.e. STAPRE, EMPIRE and TALYS). The recommended excitation functions obtained by a statistical procedure were used to derive the integral yields. An assessment of the 124 I yields and associated radioisotopic impurities suggests that the 123 Sb(a,3n) 124 I process over the energy range of E a ¼ 45-32 MeV could be of potential interest for the production of 124 I.

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Evaluation of excitation functions of proton, 3He- and α-particle induced reactions for production of the medically interesting positron-emitter bromine-76

Applied Radiation and Isotopes, 2011

Cross section data for production of the medically interesting radionuclide ⁷⁶Br (T(½)=16.2 h) vi... more Cross section data for production of the medically interesting radionuclide ⁷⁶Br (T(½)=16.2 h) via the proton induced reactions on ⁷⁶Se, ⁷⁷Se, ⁷⁸Se and ⁷⁹Br, and ³He- and α-particle induced reactions on ⁷⁵As were evaluated. The nuclear model codes STAPRE, EMPIRE and TALYS were used to check the consistency in the experimental data and a statistical procedure was applied to derive the recommended excitation functions. A comparison of various production routes of ⁷⁶Br (and of ⁷⁵Br) is presented.

Evaluation of excitation functions of proton and deuteron induced reactions on enriched tellurium isotopes with special relevance to the production of iodine-124

Applied Radiation and Isotopes, 2010

Cross-section data for the production of medically important radionuclide 124 I via five proton a... more Cross-section data for the production of medically important radionuclide 124 I via five proton and deuteron induced reactions on enriched tellurium isotopes were evaluated. The nuclear model codes, STAPRE, EMPIRE and TALYS, were used for consistency checks of the experimental data. Recommended excitation functions were derived using a well-defined statistical procedure. Therefrom integral yields were calculated. The various production routes of 124 I were compared. Presently the 124 Te(p,n) 124 I reaction is the method of choice; however, the 125 Te(p,2n) 124 I reaction also appears to have great potential.

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007 Rebalancing Wound Biochemistry Improves Healing: A Clinical Study Examining Effect of Promogran

Wound Repair and Regeneration, 2004

Biocompatible matrices, such as bovine collagen, have demonstrated usefulness in delivering gene ... more Biocompatible matrices, such as bovine collagen, have demonstrated usefulness in delivering gene therapy vectors that express growth factors to local environments for tissue repair. Unlike animal derived matrices, we have developed a new synthetic matrix consisting of a linear cyclodextrin-polyethyleneglycol co-polymer that is non-covalently cross-linked with di-adamantane-polyethyleneglycol via inclusion complex formation between adamantane and cyclodextrin (CD-Ada). We performed both in vitro and in vivo experiments for biocompatibility and localized transgene expression using a recombinant adenovirus (rAd) vector containing either the reporter gene, GFP, or the therapeutic gene, PDGF-B. In vitro results demonstrated cell migration, adenoviral transduction, and gene expression with no visible signs of toxicity in human skin fibroblasts. Qualitative gene expression from the CD-Ada containing rAd was delayed by approximately two days when compared to collagen, but the level of expression was greater over a longer period of time. In vivo experiments demonstrated gene expression after local delivery to mouse skin using rAd-GFP in CD-Ada. Again, the expression was slightly delayed but duration of expression was comparable to collagen. Expression studies using rAd-PDGF-B, were performed in the rat polyvinyl alcohol sponge model and showed comparable quantitative DNA and RNA levels between CD-Ada and collagen (DNA: 4.1 • 10 10 and 4.5 • 10 10 MEQ of PDGF-B/assayed sponge, respectively; RNA: 7.0 • 10 8 and 3.2 • 10 8 MEQ of PDGF-B/assayed sponge, respectively). Additionally, we explored the use of plasmid DNA with the CD-Ada matrix and observed PDGF-B expression in vivo. Our results show that this new delivery system provides a safe, efficient, and adaptable medium for both viral and non-viral gene delivery.

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Combining Optical Coherence Tomography (OCT) with an Operating Microscope

Springer Proceedings in Physics

Optical coherence tomography (OCT) is an emerging biomedical imaging technology which gives high-... more Optical coherence tomography (OCT) is an emerging biomedical imaging technology which gives high-resolution sectional images of light scattering tissue down to a depth of a few millimeter. The objective of this work is to combine OCT with an operation microscope. A spectral domain OCT was adapted via a specially designed scanning optics to the camera port of an operation microscope. This enables a non-contact on-line OCT during different medical applications. Hidden tissue structures were visualized with a resolution below 30 µm. As a first example for an application in otolaryngology we demonstrated that the OCT operation microscope is basically able to reveal parts of the cochlear morphology without opening its enveloping membranes. Thus it may serve as a helpful guide for the surgeon to exactly localize the scala tympani before opening the fluid-filled inner ear for inserting the electrode array of cochlear implants.

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