Xe Recovery from Nuclear Power Plants Off-Gas Streams: Molecular Simulations of Gas Permeation through DD3R Zeolite Membrane

Recent experimental work has shown zeolite membrane-based separation as a promising potential technology for Kr/Xe gas mixtures due to its much lower energy requirements in comparison to cryogenic distillation, the conventional separation method for such mixtures. Such a separation is also economically rewarding because Xe is in high demand, as a valuable product for many applications/processes. In this work, we have used Molecular Dynamics (MD) simulations to study the effects of different conditions, i.e., temperature, pressure, and gas feed composition, on Kr/Xe separation performance via DD3R zeolite membranes. We provide a comprehensive study of the permeation of the different gas species, density profiles, and diffusion coefficients. Molecular simulations show that if the feed is changed from pure Kr/Xe to an equimolar mixture, the Kr/Xe separation factor increases, which agrees with experiments. In addition, when Ar is introduced as a sweep gas, the adsorption of both Kr and Xe increases, while the permeation of pure Kr increases. A similar behavior is observed with equimolar mixtures of Kr/Xe with Ar as the sweep gas. High-separation Kr/Xe selectivity is observed at 50 atm and 425 K but with low total permeation rates. Changing pressure and temperature are found to have profound effects on optimizing the separation selectivity and the permeation throughput.

Ballpoint/Rollerball Pens: Writing Performance and Evaluation

Here, a brief history of the development of the ballpoint/rollerball pen and the fountain pen is presented. Their principle of operation is analogous that of multipart microfluidics-type devices, where capillarity–gravity drives the ink, a complex fluid, to flow in the confinement of a micrometer-sized canal or to lubricate a ball rotating in a socket. The differences in the operational writing principles of the fountain pen versus the ballpoint/rollerball pen are discussed. The ballpoint/rollerball pen’s manner of writing was monitored using lens end fiber optics and was digitally recorded. The ball rotation rate per unit length was monitored using a piezoelectric disk oscilloscope technique. The role of ink (a complex fluid) chemistry in the wetting phenomenon is elucidated. We also discuss methods for studying and evaluating ink–film–ball–paper surface wetting. The goal of the proposed research is to optimize and improve the writing performance of the ballpoint/rollerball pen.

Intracoronary Imaging in left main stent percutaneous coronary intervention has a clear survival benefit particularly in more complex patients

Background

Left Main Stem Disease (LMS) is prognostically important coronary artery disease that is managed either with coronary artery bypass surgery (CABG) or percutaneous coronary intervention (PCI). Use of intracoronary imaging (ICI) modalities such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have been shown to improve outcomes with PCI revascularization.

The primary objective of this study was to evaluate the impact of ICI on outcomes following LMS PCI.

Methods

Retrospective observation study of 498 (5.1% of all PCI cases) patients who had undergone LMS PCI at our tertiary primary PCI centre hospital over a 11-year period between July 2010-July 2021. Data was collected from electronic medical records. Follow-up was also obtained through linkage with the Office of National Statistics.

Results

The mean age at the time of enrolment was 70.7±11.5 years. Majority of the patients were male 351 (70.5%). 353 (70.9%) of cases had acute coronary syndrome (ACS) presentation while the remainder were elective procedures. Mean follow-up duration was 3.75±3.06 years. Survival calculated by Kaplan-Meier was 70%. 87 patients (17.5%) deceased during first year of enrolment. 344 (69.1%) patients had ICI, with IVUS in 316 (63.5%) and OCT in 28 (5.6%) patients. IVUS comprised 91.9% of ICI procedures. Protected LMS (OR 0.175, 95% CI: 0.037–0.833, P-value=0.029) and the use of left ventricular mechanical support device (OR 0.324, 95% CI: 0.122–0.859, P-value=0.024) were associated with decreased odds of undergoing an ICI.

Patients undergoing ICI had significantly better survival compared to those without ICI (HR: 0.54, P<0.001). Moreover, OCT showed significantly better survival compared with IVUS (HR: 0.181, P=0.017). Use of ICI was associated with better survival in patients who had Rotablation (HR: 0.455, 95% CI: 0.232–0.892, P=0.022), ACS (HR: 0.523, 95% CI: 0.383–0.714, P<0.001) or comorbidities of diabetes and stroke (HR: 0.551, 95% CI: 0.337–0.807, P=0.002).

Conclusion

ICI in LMS PCI has a significant survival benefit in our dataset. This is especially the case in patients presenting with ACS, those with comorbidities of Diabetes mellitus and stroke and those undergoing rotablation.

Funding Acknowledgement

Type of funding sources: None.

The 11-year outcome of PCI for treatment of left main stem disease

Background

Left Main Stem Disease (LMS) has historically been treated with coronary artery bypass surgery (CABG). However, not all patents with LMS are candidates for CABG due to co-morbidities. There is limited long-term follow-up of patients undergoing PCI in the real world. The primary objective of this study was to investigate the long-term mortality following LMS PCI.

Methods

We conducted a retrospective study of patients who had undergone PCI for LMS disease at our hospital over a 11-year period between July 2010-July 2021. Data was collected from electronic medical records and analyzed using Kaplain-Meier survival analysis. Follow-up was obtained through linkage with the Office of National Statistics.

Results

498 patients underwent LMS PCI (5.1% of the total PCI cases). The overall survival rate was 70%. Median survival following PCI was 1,196 days (IQR = 1,796). The mean age of the patients was 70.7 years; 70.5% were males. 70.9% of patients underwent PCI for Acute Coronary Syndrome (ACS), and 15.3% had STEMI. 33.7% of patients had a history of diabetes, 8% had stroke, 8.2% had COPD, and 8.8% had PVD. 51 patients went into cardiogenic shock, and 25 died prior to discharge.

Survival of the ACS group was significantly lower than the stable group (67% vs 77%, p<0.01); the STEMI group did not significantly differ from rest of the ACS group (62% vs 66%, p=0.87). Survival in those <60 years of age was significantly higher than in those >60 years (80% vs 68%; p<0.01). The presence of one or more co-morbidities was associated with higher survival compared to zero co-morbidities (74% vs 65%, p<0.01). Patients with a history of diabetes had a significantly lower survival rate than those without diabetes (63% vs 73%, p<0.01). Patients with an LV ejection fraction ≤35% had a significantly lower survival than those with an ejection fraction >35% (22% vs 29%, p<0.01); only 259 patients had data on LV function. Patients who developed cardiogenic shock had a significantly lower survival rate than those who did not develop shock (38% vs 70%; p<0.01). When these patients were excluded from the data set, the overall survival rate increased from 70% to 74%. Lastly, a multinomial analysis showed that the only independent predictors of mortality were age (p<0.01) and cardiogenic shock (p<0.01).

Conclusion

Our results show that the real world 10-year mortality rate following LMS PCI is influenced by multiple factors including age, shock, and LV function. The high mortality rate was potentially due to the significant number of acute cases (70.1%) in non-operable patients. While factors such as age and past medical history are considered in the decision-making process regarding CABG vs PCI, we saw that specific subgroups within these factors may have decreased the effectiveness of PCI as a treatment for LMS disease, suggesting that deeper analysis into these risk factors is required when deciding between CABG and PCI for LMS disease management.

Funding Acknowledgement

Type of funding sources: None.

Novel methods to characterise spatial distribution and enantiomeric composition of usnic acids in four Icelandic lichens

Usnic acid is an antibiotic metabolite produced by a wide variety of lichenized fungal lineages. The enantiomers of usnic acid have been shown to display contrasting bioactivities, and hence it is important to determine their spatial distribution, amounts and enantiomeric ratios in lichens to understand their roles in nature and grasp their pharmaceutical potential. The overall aim of the study was to characterise the spatial distribution of the predominant usnic acid enantiomer in lichens by combining spatial imaging and chiral chromatography. Specifically, separation and quantification of usnic acid enantiomers in four common lichens in Iceland was performed using a validated chiral chromatographic method. Molecular dynamics simulation was carried out to rationalize the chiral separation mechanism. Spatial distribution of usnic acid in the lichen thallus cross-sections were analysed using Desorption Electrospray Ionization-Imaging Mass Spectrometry (DESI-IMS) and fluorescence microscopy. DESI-IMS confirmed usnic acid as a cortical compound, and revealed that usnic acid can be more concentrated around the algal vicinity. Fluorescence microscopy complemented DESI-IMS by providing more detailed distribution information. By combining results from spatial imaging and chiral separation, we were able to visualize the distribution of the predominant usnic acid enantiomer in lichen cross-sections: (+)-usnic acid in Cladonia arbuscula and Ramalina siliquosa, and (-)-usnic acid in Alectoria ochroleuca and Flavocetraria nivalis. This study provides an analytical foundation for future environmental and functional studies of usnic acid enantiomers in lichens.

Atomistic Simulations of Biofouling and Molecular Transfer of a Cross-linked Aromatic Polyamide Membrane for Desalination

Reverse osmosis through a polyamide (PA) membrane is an important technique for water desalination and purification. In this study, molecular dynamics simulations were performed to study the biofouling mechanism (i.e., protein adsorption) and nonequilibrium steady-state water transfer of a cross-linked PA membrane. Our results demonstrated that the PA membrane surface's roughness is a key factor of surface's biofouling, as the lysozyme protein adsorbed on the surface's cavity site displays extremely low surface diffusivity, blocking water passage, and decreasing water flux. The adsorbed protein undergoes secondary structural changes, particularly in the pressure-driven flowing conditions, leading to strong protein-surface interactions. Our simulations were able to present water permeation close to the experimental conditions with a pressure difference as low as 5 MPa, while all the electrolytes, which are tightly surrounded by hydration water, were effectively rejected at the membrane surfaces. The analysis of the self-intermediate scattering function demonstrates that the dynamics of water molecules coordinated with hydrogen bonds is faster inside the pores than during the translation across the pores. The pressure difference applied shows a negligible effect on the water structure and content inside the membrane but facilitates the transportation of hydrogen-bonded water molecules through the membrane's sub-nanopores with a reduced coordination number. The linear relationship between the water flux and the pressure difference demonstrates the applicability of continuum hydrodynamic principles and thus the stability of the membrane structure.

FC16-04 - The clinical effectiveness of individual cognitive behaviour therapy for depressed older people in primary care and the use of a talking control (TC)

Objective

To determine the clinical effectiveness of Cognitive Behaviour Therapy (CBT) delivered in primary care for older people with depression and evaluation of a talking control (TC).

Methods

A single-blind, randomized, controlled trial with 4- and 10-month follow-up. 204 people, aged 65 years or more, with a Geriatric Mental State diagnosis of depression were recruited from primary care. The interventions were: treatment as usual (TAU), TAU plus TC, or TAU plus CBT. The TC and CBT were offered over 4 months. The TC was to control for common effects in therapy. The Beck Depression Inventory-II (BDI-II) was the main outcome. Subsidiary measures were the Beck Anxiety Inventory, Social Functioning Questionnaire, and Euroqol. Intention to treat analysis (ITT) and Compliance Average Causal Effect (CACE) analyses was employed. The Cognitive therapy scale (CTS) evaluated common and specific factors in therapy.

Results

A mean of 7 sessions of TC or CBT were delivered. ITT analysis found improvements of −3.07 (95% confidence interval [CI], −5.73 to −0.42) and −3.65 (95% CI, −6.18 to −1.12) in BDI-II scores in favour of CBT vs TAU and TC respectively. CACE analysis found a benefit of 0.4 points (95% CI, 0.01 to 0.72) per therapy session of CBT over TC. Ratings for CBT on the CTS were high (mean [SD], 54.2 [4.1]) and showed no difference for nonspecific, but significant differences for specific factors in therapy.

Conclusion

CBT is an effective treatment for depressed older people. Improvement appears to be associated with specific factors in CBT.

Modeling Enantiomeric Separations as an Interfacial Process Using Amylose Tris(3,5-dimethylphenyl carbamate) (ADMPC) Polymers Coated on Amorphous Silica

Chiral high-performance liquid chromatography (HPLC) is commonly performed to isolate the biologically active enantiomer of a drug from the ineffective or even harmful ones. Understanding the molecular-level recognition that underlies this process is necessary for trimming down the very large number of possible combinations of chiral stationary phases, solvent systems, and other experimental HPLC conditions, a particularly important consideration when only small quantities of the racemate are available. Fully atomistic molecular dynamics (MD) simulation is a useful tool to provide this molecular-level understanding and predict experimental separation factors under a given set of conditions. To predict the chiral separation results for drug enantiomers by amylose tris(3,5-dimethylphenyl carbamate) (ADMPC) chiral stationary phase, we design a model of multiple ADMPC polymer strands coated on an amorphous silica slab. Using various MD techniques, we successfully coat ADMPCs onto the surface without losing the structural character of the backbone in the presence of the solvent system. Not only is this model more representative of the polymer surface on a solid support that is encountered by the enantiomers, but it also provides more opportunities for chiral molecules interacting with ADMPC, provides the possibility for large drug molecules to interact with two polymer strands at the same instant, and provides better agreement with experiment when we use the overall average quantities as the predictive metric. For a better understanding of why some metrics are better predictors than others, we use charts of the distribution of hydrogen-bonding lifetimes for various donor-acceptor pairs that contribute to the interaction events determining the relative retention times for the enantiomers. We also examine the contribution of ring-ring interactions to the molecular recognition process and ultimately to the differential retention of enantiomers. The results are more consistent than previous models and resolve the problematic case of two drugs, thalidomide and valsartan.

Molecular-Level "Observations" of the Behavior of Gold Nanoparticles in Aqueous Solution and Interacting with a Lipid Bilayer Membrane

We use coarse-grained molecular dynamics simulations to "observe" details of interactions between ligand-covered gold nanoparticles and a lipid bilayer model membrane. In molecular dynamics simulations, one puts the individual atoms and groups of atoms of the physical system to be "observed" into a simulation box, specifies the forms of the potential energies of interactions between them (ultimately quantum based), and lets them individually move classically according to Newton's equations of motion, based on the forces arising from the assumed potential energy forms. The atoms that are chemically bonded to each other stay chemically bonded, following known potentials (force fields) that permit internal degrees of freedom (internal rotation, torsion, vibrations), and the interactions between nonbonded atoms are simplified to Lennard-Jones forms (in our case) and coulombic (where electrical charges are present) in which the parameters are previously optimized to reproduce thermodynamic properties or are based on quantum electronic calculations. The system is started out at a reasonable set of coordinates for all atoms or groups of atoms, and then permitted to develop according to the equations of motion, one small step (usually 10 fs time step) at a time, for millions of steps until the system is at a quasi-equilibrium (usually reached after hundreds of nanoseconds). We then let the system play out its motions further for many nanoseconds to observe the behavior, periodically taking snapshots (saving all positions and energies), and post-processing the snapshots to obtain various average descriptions of the system. Alkanethiols of various lengths serve as examples of hydrophobic ligands and methyl-terminated PEG with various numbers of monomer units serve as examples of hydrophilic ligands. Spherical gold particles of various diameters as well as gold nanorods form the core to which ligands are attached. The nanoparticles are characterized at the molecular level, especially the distributions of ligand configurations and their dependence on ligand length, and surface coverage. Self-assembly of the bilayer from an isotropic solution and observation of membrane properties that correspond well to experimental values validate the simulations. The mechanism of permeation of a gold NP coated with either a hydrophobic or a hydrophilic ligand, and its dependence on surface coverage, ligand length, core diameter, and core shape, is investigated. Lipid response such as lipid flip-flops, lipid extraction, and changes in order parameter of the lipid tails are examined in detail. The mechanism of permeation of a PEGylated nanorod is shown to occur by tilting, lying down, rotating, and straightening up. The nature of the information provided by molecular dynamics simulations permits understanding of the detailed behavior of gold nanoparticles interacting with lipid membranes which in turn helps to understand why some known systems work better than others and aids the design of new particles and improvement of methods for preparing existing ones.

The Composition of the Mobile Phase Affects the Dynamic Chiral Recognition of Drug Molecules by the Chiral Stationary Phase

More than half of all pharmaceuticals are chiral compounds. Although the enantiomers of chiral compounds have the same chemical structure, they can exhibit marked differences in physiological activity; therefore, it is important to remove the undesirable enantiomer. Chromatographic separation of chiral enantiomers is one of the best available methods to get enantio-pure substances, but the optimization of the experimental conditions can be very time-consuming. One of the most widely used chiral stationary phases, amylose tris(3,5-dimethylphenyl carbamate) (ADMPC), has been extensively investigated using both experimental and computational methods; however, the dynamic nature of the interaction between enantiomers and ADMPC, as well as the solvent effects on the ADMPC-enantiomer interaction, are currently absent from models of the chiral recognition mechanism. Here we use QM/MM and molecular dynamics (MD) simulations to model the enantiomers of flavanone on ADMPC in either methanol or heptane/2-propanol (IPA) (90/10) to elucidate the chiral recognition mechanism from a new dynamic perspective. In atomistic MD simulations, the 12-mer model of ADMPC is found to hold the 4/3 left-handed helical structure in both methanol and heptane/IPA (90/10); however, the ADMPC polymer is found to have a more extended average structure in heptane/IPA (90/10) than in methanol. This results from the differences in the distribution of solvent molecules close to the backbone of ADMPC leads to changes in the distribution of the (φ, ψ) dihedral angles of the glycoside bond (between adjacent monomers) that define the structure of the polymer. Our simulations have shown that the lifetime of hydrogen bonds formed between ADMPC and flavanone enantiomers in the MD simulations are able to reproduce the elution order observed in experiments for both the methanol and the heptane/IPA solvent systems. Furthermore, the ratios of hydrogen-bonding-lifetime-related properties also capture the solvent effects, in that heptane/IPA (90/10) is found to make the separation between the two enantiomers of flavanone less effective than methanol, which agrees with the experimental separation factors of 0.9 versus 0.4 for R/S, respectively.

Primary versus secondary immune thrombocytopenia in adults; a comparative analysis of clinical and laboratory attributes in newly diagnosed patients in Southern Pakistan

BACKGROUND

Immune thrombocytopenic purpura (ITP) is a hemorrhagic diathesis, characterized by platelets destruction alongside impaired production. Patients from Asian regions often exhibit distinctive characteristics in comparison to the western patients. We accomplished this study to evaluate the prevalence of primary versus secondary ITP along with the comparative analysis between them. The secondary objective was to determine the etiological spectrum of secondary ITP.

METHODS

We illustrate the results of a large cohort of newly diagnosed adults ITP from southern Pakistan. The study extended from January 2009-December 2013. Complete blood counts, HbsAg, Anti-HCV, ANA, stool for Helicobacterpylori were done on all. HIV, TSH, anti-dsDNA, RA factor, APLA and direct coombs test were evaluated in cases where indicated.

RESULTS

A total of 417 patients were included with a mean age of 40.95±14.82 years. Primarily disease was observed in the 3rd decade of life. Male to female ratio was 1:1.5. Mean platelets count was 46.21±27.45x109/l. At diagnosis 43.16% (n=180) patients had hemorrhagic manifestations whilst 56.8% (n=237) were asymptomatic. None of the patient presented with visceral, retropharyngeal or intracranial bleed. The prevalence of secondary ITP was substantially higher (64.8%) as compared to primary ITP (35.2%). Secondary ITP was predominantly seen in HCV reactive patients (24.4%) followed by helicobacter-pylori infection (11%). Nevertheless 16.4% patients had underlying autoimmune disorders. Providentially no study subject was found to be HIV reactive.

CONCLUSIONS

Our study revealed predominance of secondary ITP. However bleeding manifestations and degree of thrombocytopenia were high in primary-ITP. Infectious etiology followed by autoimmune disorders is mainly implicated for secondary ITP in our setting.

Aromatic Polyamide Reverse-Osmosis Membrane: An Atomistic Molecular Dynamics Simulation

Polyamide (PA) membrane-based reverse-osmosis (RO) serves as one of the most important techniques for water desalination and purification. Fundamental understanding of PA RO membranes at the atomistic level is critical to enhance their separation capabilities, leading to significant societal and commercial benefits. In this paper, a fully atomistic molecular dynamics simulation was performed to investigate PA membrane. Our simulated cross-linked membrane exhibits structural properties similar to those reported in experiments. Our results also reveal the presence of small local two-layer slip structures in PA membrane with 70% cross-linking, primarily due to short-range anisotropic interactions among aromatic benzene rings. Inside the inhomogeneous polymeric structure of the membrane, water molecules show heterogeneous diffusivities and converge adjacent to polar groups. Increased diffusion of water molecules is observed through the less cross-linked pathways. The existence of the fast pathways for water permeation has no effect on membrane's salt rejections.

Simulated Permeation and Characterization of PEGylated Gold Nanoparticles in a Lipid Bilayer System

PEGylated gold nanoparticles are considered suitable nanocarriers for use in biomedical applications and targeted drug delivery systems. In our previous investigation with the alkanethiol-functionalized gold nanoparticle, we found that permeation across a protein-free phospholipid membrane resulted in damaging effects of lipid displacement and water and ion leakage. In the present study, we carry out a series of coarse-grained molecular simulations to explore permeation of lipid bilayer systems by a PEGylated gold nanoparticle, especially at the bulk-liquid-lipid interface as well as the interface between the two lipid leaflets. Initially, we examine molecular-level details of a PEGylated gold nanoparticle (constructed from cycled annealing) in water and find a distribution of ligand configurations (from mushroom to brush states) present in nanoparticles with medium to high surface coverage. We also find that the characteristic properties of the PEGylated gold nanoparticle do not change when it is placed in a salt solution. In our permeation studies, we investigate events of water and ion penetration as well as lipid translocation while varying the ligand length, nanoparticle surface coverage, and ion concentration gradient of our system. Results from our studies show the following: (1) The number of water molecules in the interior of the membrane during ligand-coated nanoparticle permeation increases with PEGn-SH surface coverage, ligand length, and permeation velocity but is not sensitive to the ion concentration gradient. (2) Lipid molecules do not leave the membrane; instead they complete trans-bilayer lipid flip-flop with longer ligands and higher surface coverages. (3) The lack of formation of stable water pores prevents ion translocation. (4) The PEGylated nanoparticle causes less damage to the membrane overall due to favorable interactions with the lipid headgroups which may explain why experimentalists observe endocytosis of PEGylated nanocarriers in vivo.

Trends and Analysis of Cancer Incidence for Common Male and Female Cancers in the Population of Punjab Province of Pakistan during 1984 to 2014

BACKGROUND

The Pakistan Atomic Energy Commission Cancer Registry (PAECCR) program has made availability of a common cancer incidence database possible in Pakistan. The cancer incidence data from nuclear medicine and oncology institutes were gathered and presented.

MATERIALS AND METHODS

The cancer incidence data for the last 30 years (1984-2014) are included to describe a data set of male and female patients. The data analysis concerning occurrence, trends of common cancers in male and female patients, stage-wise distribution, and mortality/follow-up cases is also incorporated for the last 10 years (2004-2014).

RESULTS

The total population of provincial capital Lahore is 9,800,000. The total number of cancer cases was 80,390 (males 32,156, females 48,134). The crude incidence rates in PAECCR areas were 580.8/105 during 2010 to 885.4/105 in 2014 (males 354.1/105, females 530.1/105). The cancer incidence rates for head and neck (15.70%), brain tumors (10.5%), and non-Hodgkin lymphoma (NHL, 9.53%) were found to be the highest in male patients, whereas breast cancer (46.7%), ovary tumors (6.80%), and cervix (6.31%) cancer incidence rates were observed to be the most common in female patients. The age range distribution of diagnosed and treated patients in conjunction with the percentage contribution of cancer patients from 15 different cities of Punjab province treated at the Institute of Nuclear Medicine and Oncology, Lahore are also included. Leukemia was found to be the most common cancer for the age group of 1-12 years. It has been identified that the maximum number of diagnosed cases were found in the age range of 51-60 years for males and 41-50 years for female cancer patients.

CONCLUSIONS

Overall cancer incidence of the thirty years demonstrated that head and neck and breast cancers in males and in females respectively are the most common cancers in Punjab province in Pakistan, at rates almost the highest in Asia, requiring especial attention. The incidence of brain, NHL, and prostate cancers among males and ovarian and cervix cancers among females have increased rapidly. These data from a major population of Punjab province should be helpful for implementation of appropriate planning, prevention and cancer control measures and for determination of risk factors within the country.

Similar vertical transmission rates of dengue and chikungunya viruses in a transgenic and a non-transformed Aedes aegypti (L.) laboratory strain

The increase of the burden of dengue and chikungunya and the relative failure of traditional vector control strategies have highlighted the need to develop new control methods. RIDL-SIT, a vector control method based on the release of engineered male mosquitoes, has shown promising results from field trials conducted in the Cayman Islands and Brazil. In large scale use, a small proportion of females might be released along with the males. Such females are potential virus vectors; here we investigate the vertical transmission of dengue and chikungunya of homozygous OX513A females.We provided females of OX513A-My1 and a wild type comparator strain with blood meals artificially infected with dengue serotype 1, 2, 3, 4 or chikungunya viruses. For 14 days post-feeding, eggs laid by females were collected. Larvae and their mothers were first tested by qRT-PCR, then by inoculation on cell cultures to search for infectious viral particles. We found no significant difference between the minimum infection rate of OX513A-My1 and wild type females. We also discussed the potential number of females being released, a fraction of the female wild population. Consequently, we conclude that there are no evidence that OX513A-My females, if released into the environment, would cause more harm than their wild counterparts.

LRIG1 expression during homeostasis and skin wound healing in mice

Leucine-rich repeats and immunoglobulin-like domains (LRIG)-1 belong to the family of proteins known to be expressed in skin. Ablation of LRIG1 in mice results in epidermal hyperplasia and its aberrant expression levels have been reported in pathological conditions such as psoriasis, thus evident of an indispensible role of LRIG1 in maintaining epidermal homeostasis. In order to gain insight into the homeostatic expression of LRIG1 and in various stages of cutaneous wound healing, LRIG1 expression was immunohistochemically analyzed in full thickness skin wounds in mice. The full thickness skin wounds were established on the dorsal back of Balb/c mice (n=6). LRIG1 expression at various post wounding days (1, 2, 3, 6 and 14) was determined through Immunohistochemical analysis (IHC) of the murine skin sections. The injury caused a sharp decline in LRIG1 expression in the basal epidermal cells and appendages surrounding the wound which correlates with the re-epithelialization phase of healing. LRIG1 expression remained down regulated during most of the wound healing stages. LRIG1+ cells were found to re-populate the neo-epidermis on day 14, suggesting an important homeostatic role of LRIG1 in skin.

Surface-functionalized nanoparticle permeation triggers lipid displacement and water and ion leakage

Functionalized nanoparticles (NPs) are considered suitable carriers for targeted drug delivery systems. However, the ion and water leakage induced by permeation of these nanoparticles is a challenge in these drug delivery methods because of cytotoxic effects of some ions. In this study, we have carried out a series of coarse-grained molecular dynamics simulations to investigate the effect of length of ligands on permeation of a nanoparticle across a protein-free phospholipid bilayer membrane. Water and ion penetration as well as incidence of lipid flip-flop events and loss of lipid molecules from the membrane are explored in this study while varying the nanoparticle size, length of ligand, ion concentration gradient, pressure differential across the membrane, and nanoparticle permeation velocity. Some results from our studies include (1) the number of water molecules in the interior of the membrane during ligand-coated nanoparticle permeation increases with nanoparticle size, ligand length, pressure differential, and permeation velocity but is not sensitive to the ion concentration gradient; (2) some lipid molecules leave the membrane by being entangled with ligands of the NP instead of completing the flip-flop that permits them to rejoin the membrane, thereby leading to fewer flip-flop events; and (3) the formation of water columns or water "fingers" provides a mechanism of ion transport across lipid bilayer membranes, but such ion penetration events are less likely for sodium ions than chloride ions and less likely for nanoparticles with longer-ligands.

Preparation of (99m)Tc-labelled methotraxate by a direct labeling technique as a potential diagnostic agent for breast cancer and preliminary clinical results

Methotrexate (MTX) is being used in clinical oncology for the treatment of a wide variety of cancers. The aim of the present study was to label directly MTX with (99m)Tc by using Sn/pyrophosphate as reducing agent and to use this labeled compound as a potential anticancer radiopharmaceutical for breast cancer imaging. We studied the labeling efficiency of the (99m)Tc-MTX compound by paper chromatography and instant thin layer chromatography (ITLC) in acetone and saline and found it to be more than 95%. In vitro stability of labeled MTX in serum was studied up to 5h. Partition coefficient in n-octanol and saline indicated that the labeled radiopharmaceutical was hydrophilic. We then tested (99m)Tc-MTX in 5 breast cancer female patients. Protein bound (99m)Tc-MTX showed rapid clearance from blood. The biodistibution data suggested that (99m)Tc-MTX was cleared by the kidneys and the liver. Patients ' data also showed highly significant uptake of (99m)Tc-MTX in breast cancer. In conclusion, this study indicated that (99m)Tc-MTX may be used as a potential diagnostic agent for breast cancer patients imaging and may show treatment efficiency in case MTX is to be used for treatment.

In house development of (99m)Tc-Rhenium sulfide colloidal nanoparticles for sentinel lymph node detection

In this study, rhenium sulfide colloidal nanoparticles were developed as radiopharmaceutical for sentinel lymph node detection. We directly used rhenium sulfide as a starting material for the preparation of colloidal nanoparticles. UV-visible spectrophotometry was used for characterization of in house developed colloidal particles. The size distribution of radioactive particles was studied by using membrane filtration method. The percentage of radiolabeled colloidal nanoparticles was determined by paper chromatography (PC). The study also includes in vitro stability, protein binding in human blood and bioevaluation in a rabbit model. The results indicate that 77.27 ± 3.26 % particles of size less than 20nm (suitable for lymphoscintigraphy) were radiolabeled. (99m)Tc labeled rhenium sulfide labeling efficacy with the radiometal is 98.5 ± 0.5%, which remains considerably stable beyond 5h at room temperature. Furthermore, it was observed that 70.2 ± 1.3% radiolabeled colloid complex showed binding with the blood protein. Bioevaluation results show the remarkable achievement of our radiopharmaceutical. The in house prepared (99m)Tc labeled rhenium sulfide colloidal nanoparticles reached the sentinel node within 15 min of post injection. These results indicate that (99m)Tc labeled rhenium sulfide colloid nanoparticles kit produced by a novel procedure seems of significant potential as a feasible candidate for further development to be used in clinical practice.

Synthesis, characterization and bioevaluation of technetium-99m labeled N-(2-Hydroxybenzyl)-2-amino-2-deoxy-D-glucose as a tumor imaging agent

N-(2-Hydroxybenzyl)-2-amino-2-deoxy-D-glucose (NHADG) was synthesized by conjugation of salicylaldehyde to glucosamine. The obtained compound was well characterized via different analytical techniques. Labeling of the synthesized compound with technetium-99m ((99m)Tc) in pertechnetate form ((99m)Tc O4-) was carried out via chelation reaction in the presence of stannous chloride dihydrate. Maximum radiochemical yield of (99m)Tc-NHADG complex (99%) was obtained by using 1 mg NHADG, 200 μg SnCl2.2H2O, at pH 9.5 and reaction time of 15 min. The radiochemical purity of the (99m)Tc-NHADG complex was measured by instant thin layer chromatography (ITLC) and paper chromatography (PC), without any notable decomposition at room temperature over a period of 4h. The biological evaluation results show that the (99m)Tc labeled NHADG conjugate is able to specifically target mammary carcinoma in mice models, thus highlighting its potential as an effective (99m)Tc labeled glucose-derived agent for tumor imaging.

Development of 99mTc-5-fluorouracil as a potential tumor diagnostic agent

5-Fluorouracil is a well know drug for chemotherapy of various types of cancer. In the present study, we radiolabeled 5-fluorouracil with (99m)Tc for a diagnostic study of cancer. After successful labeling of the drug we performed an animal study to evaluate the potential of this radiopharmaceutical as a tumor diagnostic agent. The results showed 98.1 ± 1.2% labeling efficacy of 5-fluorouracil with (99m)Tc. The in vitro stability of the radiolabeled drug at room temperature at 4 hr of post-labeling was >96.5 ± 0.4%. The binding of the radiolabeled drug with plasma proteins was 66.6 ± 3%. Partition coefficient results showed that this drug is hydrophilic in nature. Biodistribution study in rabbit models displayed faint uptake in liver. Both kidney and bladder were prominent as excretory route of the labeled drug. Bioevaluation was performed in Swiss Webster mice having naturally developed tumor. Mice were dissected, uptake of drug in various organs was studied and results showed prominent uptake in liver and tumor. Tumor was further investigated by histopathological study.

Nanoparticle permeation induces water penetration, ion transport, and lipid flip-flop

Nanoparticles are generally considered excellent candidates for targeted drug delivery. However, ion leakage and cytotoxicity induced by nanoparticle permeation is a potential problem in such drug delivery schemes because of the toxic effect of many ions. In this study, we have carried out a series of coarse-grained molecular dynamics simulations to investigate the water penetration, ion transport, and lipid molecule flip-flop in a protein-free phospholipid bilayer membrane during nanoparticle permeation. The effect of ion concentration gradient, pressure differential across the membrane, nanoparticle size, and permeation velocity have been examined in this work. Some conclusions from our studies include (1) The number of water molecules in the interior of the membrane during the nanoparticle permeation increases with the nanoparticle size and the pressure differential across the membrane but is unaffected by the nanoparticle permeation velocity or the ion concentration gradient. (2) Ion transport is sensitive to the size of nanoparticle as well as the ion concentration gradient between two sides of the membrane; no anion/cation selectivity is observed for small nanoparticle permeation, while anions are preferentially translocated through the membrane when the size of nanoparticle is large enough. (3) Incidences of lipid molecule flip-flop increases with the size of nanoparticle and ion concentration gradient and decreases with the pressure differential and the nanoparticle permeation velocity.

Genetic differentiation in Pyrenophora teres f. teres populations from Syria and Tunisia as assessed by AFLP markers

To investigate the level of genetic differentiation and diversity among Pyrenophora teres isolate populations originating from different agro-ecological areas of Syria and Tunisia and to determine the potential of AFLP profiling in genotyping Pyrenophora teres f. teres. In this study, AFLP markers have been employed to identify patterns of population structure in 20 Pyrenophora teres f. teres populations from Syria and Tunisia. Ninety-four isolates were studied by the use of a protocol that involved stringent PCR amplification of fragments derived from digestion of genomic DNA with restriction enzymes EcoRI and MesI. Based on 401 amplified polymorphic DNA markers (AFLP), variance analyses indicated that most of the variation was partitioned within rather than between populations. Genotypic diversity (GD) was high for populations from Rihane, local landraces and different agro-ecological zones (GD = 0·75-0·86). There was high genetic differentiation among pathogen populations from different host populations in Syria (Gst  = 0·31, ht = 0·190) and Tunisia (Gst  = 0·39, ht = 0·263), which may be partly explained by the low gene flow around the areas sampled. A phenetic tree revealed three groups with high bootstrap values (55, 68, 76) and reflected the grouping of isolates based on host, or agro-ecological areas. AFLP profiling is an effective method for typing the genetically diverse pathogen Pyrenophora teres f. teres.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study represents a comparative analysis of the genetic diversity in P. teres isolates from two countries spanning two continents and also shows that several distinct P. teres genotypes may be found in a given environment. The implications of these findings for Pyrenophora teres f. teres evolutionary potential and net blotch-resistance breeding in Syria and Tunisia were also discussed.