Aliaa Shallan - Academia.edu (original) (raw)

Papers by Aliaa Shallan

The Canadian Journal of Chemical Engineering, 2022

Encyclopedia of Forensic Sciences, 2013

Capillary electrophoresis is one of the most powerful liquid phase separation techniques. It is r... more Capillary electrophoresis is one of the most powerful liquid phase separation techniques. It is renowned for its speed, resolution, simplicity, and the small sample and reagent requirements. It is exceptionally versatile, and a number of different and complementary separation mechanisms can be employed simply by changing the composition of the liquid inside the capillary. Here, the fundamental concepts of electrophoresis when implemented in capillaries and microchips are introduced.

ELECTROPHORESIS, 2009

Trophy quality in hunted ungulates in northeastern Slovakia (Cetartiodactyla). Based on the data ... more Trophy quality in hunted ungulates in northeastern Slovakia (Cetartiodactyla). Based on the data from trophy hunting statistics (1997-2019), this paper describes changes in the potential economic trophy value evaluation of hunted ungulates (PETV) by comparison of two groups of areas, (1) the hunting grounds with wolf protection (since 2014), and (2) the hunting grounds without wolf protection. In both groups of areas in the long-term aspect (1997-2019), the value of PETV had an increasing trend in the roe deer, wild boar, and red deer. Since 2014, in the areas with wolf protection the average value of PETV was at the level of 249 €/year/km 2 (SD 69 €/year/km 2) and in the areas without wolf protection, it was 185 €/ year/km 2 (SD 8 €/year/km 2). Since 2014, in the areas with wolf protection, the mortality did not affect the PETV trend, but in the red deer a significant fluctuation in PETV values was observed compared to the previous period. Since 2014, in the areas with wolf protection, a qualitative increase in the value of hunted red deer trophies was registered, in almost all C.I.C. categories above 170 points. Key words. Ungulates, red deer, roe deer, wild boar, hunting, wolf protection. ÚVOD V Slovenskej republike zákon o poľovníctve nerieši výslovne právny status, resp. vlastníctvo voľne žijúcej zveri (Bubelíny 2014). Avšak zákon o poľovníctve stanovuje, že ulovená, usmrtená, uhynutá zver, alebo jej časti nachádzajúce sa v poľovnom revíri, patria užívateľovi poľovného revíru (Anonymus 2009b), ktorý ma nájomnú zmluvu s vlastníkom (Anonymus 1992). Užívateľovi poľovného revíru zákon o poľovníctve (Anonymus 2009b) stanovuje povinnosti týkajúce sa starostlivosti o zver a zodpovednosť za dodržiavanie právnych predpisov týkajúcich sa poľovníctva. V zmysle nájomnej zmluvy patrí vlastníkovi poľovných pozemkov primeraná náhrada (Anonymus 1992), ktorá sa v súčasnosti vypočítava podľa sadzobníka na výpočet náhrad za poľovné pozemky pre hlavné druhy lovnej zveri (Anonymus 2009b) na základe bonity územia (Anonymus 2009c). Najefektívnejšu formu zhodnotenia produkcie poľovných pozemkov predstavuje organizovanie poľovníckej turistiky a poplatkového lovu (Lehocký & Kuric 2007, Rivrud et al. 2013). Poplatkový lov je popri organizačných poplatkoch (Anonymus 2017, 2018a, b, 2019a, b, c) zameraný aj na kvalitatívne zhodnotenie chovu úlovkami. Zákon o poľovníctve (Anonymus 2009b) pod odbornou starostlivosťou o chov definuje aj dosiahnutie kvality trofejí. Kvalita sa zisťuje na chovateľských prehliadkach a hodnotí bodmi Mezinárodnej rady pre poľovníctvo

Chemical Communications, 2013

Control of the dielectric breakdown of PDMS was achieved by limiting the current during the break... more Control of the dielectric breakdown of PDMS was achieved by limiting the current during the breakdown process. This enabled tuning of the nanochannel pore size and hence their permeability for molecules of different molecular weights. This method enabled the analysis of the drug quinine from whole blood in 3 min using a simple, disposable microfluidic device.

Scientific Reports

A green spectrofluorimetric method was introduced for the determination of selected genotoxic imp... more A green spectrofluorimetric method was introduced for the determination of selected genotoxic impurities; 2-aminopyridine and 3-aminopyridine in different pharmaceutical raw materials and dosage forms. The method relied on the native fluorescence of these impurities in acidic medium. The experimental conditions were carefully studied and optimized, and the method was validated according to International Council on Harmonisation (ICH) guidelines. The linear range for both analytes was 2.50–100 ng/mL with good determination coefficients of 0.9995 and 0.9992 and detection limits of 0.62 ng/mL and 0.74 ng/mL for 2-aminopyridine and 3-aminopyridine, respectively. The method was successfully applied for determination of 2-aminopyridine and 3-aminopyridine in four active pharmaceutical ingredients and nine dosage forms with satisfactory percentage recoveries and without interference from co-formulated excipients. Analytical performance of the proposed method was comparable to that of the r...

Molecules

Breast cancer is one of the most prevalent cancers worldwide usually treated with Tamoxifen. Tamo... more Breast cancer is one of the most prevalent cancers worldwide usually treated with Tamoxifen. Tamoxifen resistance development is the most challenging issue in an initially responsive breast tumor, and mechanisms of resistance are still under investigation. The objective of this study is to develop and validate a selective, sensitive, and simultaneous high performance liquid chromatography–tandem mass spectrometry method to explore the changes in substrates and metabolites in supernatant media of developed Tamoxifen resistance MCF-7 cells. We focus on the determination of lactate, pyruvate, and L-glutamine which enables the tracking of changes in metabolic pathways as a result of the resistance process. Chromatographic separation was achieved within 3.5 min. using a HILIC column (4.6 × 100 mm, 3.5 µm particle size) and mobile phase of 0.05 M acetic acid–ammonium acetate buffer solution pH 3.0: Acetonitrile (40:60 v/v). The linear range was 0.11–2.25, 0.012–0.227, and 0.02–0.20 mM for...

Angewandte Chemie, 2020

High solids content complicates in situ analysis of chemical processing, biological suspensions, ... more High solids content complicates in situ analysis of chemical processing, biological suspensions, and environmental streams. In most cases, analytical methods require at least one pre-treatment step of a small volume of sample before a particle-free fluid can be analyzed. We have developed a continuous in situ sampler that can "sip" particle-free solution from a turbulent high solids content stream (a slurry). An open microfluidic chip with an extended slit opening shields the internal laminar flow from the turbulence outside. Unlike other open chips, our chip does not require close proximity to a solid surface and operates in turbulent environments for hours without maintenance. Two applications are demonstrated: monitoring iron (III) in a stirred slurry of mixed ore particles at high solids loading (4%wt) and paracetamol tablet dissolution profiles for two different formulations.

Eurasian Journal of Analytical Chemistry, 2008

A method for the separation and determination of inorganic anions using a reversed phase column p... more A method for the separation and determination of inorganic anions using a reversed phase column permanently coated with n -cetylpyridinium chloride is described. A 1 mM sodium salicylate solution in 5% (v/v) methanol was used as the mobile phase. The separation of some inorganic anions (monofluorophosphate (MFP), phosphate and iodide) was carried out in about 10 minutes. Detection was made using indirect UV detection at 290 nm. Satisfactory reproducibility of the results was obtained even after a four months period of continual use of the column. Through the evaluation of the analytical parameters, the method was linear (r = 0.999) at concentrations ranging from 10.0 to 100.0 μg mL -1 .

Analytical Chemistry is published by the American Chemical Society. 1155 SixteenthStreet N.W., Wa... more Analytical Chemistry is published by the American Chemical Society. 1155 SixteenthStreet N.W., Washington, DC 20036Published by American Chemical Society. Copyright © American Chemical Society.However, no copyright claim is made to original U.S. Government works, or worksproduced by employees of any Commonwealth realm Crown government in the courseof their duties.

We present a new method for on-chip sample pretreatment based on size and charge exclusion in nan... more We present a new method for on-chip sample pretreatment based on size and charge exclusion in nanochannels formed by simple electric breakdown of poly(dimethylsiloxane) (PDMS). In contrast to previously published methods, control over pore size was achieved by setting a current limit during the breakdown step, allowing selective transport through the nanopores of different size molecules. Finally, we demonstrate the application of this method for the direct analysis of quinine in whole blood samples at clinically relevant concentrations.

The introduction of the “microscale total analysis system (μTAS)” concept in the late 80’s trigge... more The introduction of the “microscale total analysis system (μTAS)” concept in the late 80’s triggered the evolution of microfluidic devices that cover a vast range of applications. Automation, integration of multiple processes, and near zero dead volume for separation techniques are some benefits. Closing the gap between research and commercialization in a resource-limited environment is the main aim of this research. This project feeds into two main streams. The first is to integrate on-chip sample preparation for biological applications, like therapeutic drug monitoring (TDM) and diagnostics, using nanojunctions created by controlled dielectric breakdown (Chapters One - Five). The second part focuses on fast prototyping of microfluidic devices with multiple integrated functionalities using a consumer-based 3D-printer (Chapters Six & Seven). These two approaches were tailored to solve specific problems inherent to each sample type and application. Chapter One starts with a general i...

A new device seamlessly integrating various electrokinetic processes enables the analysis of shor... more A new device seamlessly integrating various electrokinetic processes enables the analysis of short ssDNA (20 bases) directly from whole blood. An electrokinetic trap was integrated to achieve extraction, concentration, and desalting of ssDNA in 200 s followed by a 90 s electrophoretic separation. The trap consists of two sequentially coupled nanojunctions with different pore size and exhibits selective ion transport properties. Depletion forces near the nanojunctions and the apparent electromigration were tuned to enable the trapping and subsequent analysis of fluorescein labeled-ssDNA. The quantitation limit (S/N ratio = 10) was 12.5 nM using 40 μL of spiked whole blood.

A new device integrating diverse electrokinetic steps is presented to extract and enrich analytes... more A new device integrating diverse electrokinetic steps is presented to extract and enrich analytes directly from blood followed by electrophoretic separation. Two sequentially coupled nanojunctions with different pore size formed a trap with selective ion transport properties. The balance between depletion forces near the nanojunctions and/or apparent electromigration can be tuned for analysis of proteins, DNA, or pharmaceuticals. Here, we demonstrate the analysis of ampicillin from blood within 5 min. The obtained linear range of 2.5-20 μg/mL covers the therapeutically relevant concentration for treating sepsis.

Microfluidic devices emerged in the early 1980s, establishing the feasibility of concepts such as... more Microfluidic devices emerged in the early 1980s, establishing the feasibility of concepts such as "Lab-on-a-chip" and "Micro Total Analysis System" because on such a small scale, fluids behave differently allowing multiple analytical processes to be integrated into one platform. The idea of constructing portable analytical devices that are accurate, sensitive, cheap, and easy to handle was, and still is, very promising, especially in the area of therapeutic drug monitoring and personalized medicine. While there is a tendency to think that the use of portable microfluidic devices for therapeutic drug monitoring is quite new, this is in fact incorrect and there are a few devices that have been used for many years. Measuring blood glucose levels is perhaps the oldest and well known example, and this has changed the way in which people with diabetes have been able to live their life. Other commercialized examples include measuring glucose and -hydroxybutyrate and al...

Chemical Engineering and Processing - Process Intensification