Optical sensors have proven to be a useful method in identifying explosive devices by recognizing vapors of explosive compounds that become airborne and emanate from the device. To detect high ...explosive compounds such as TNT, a molecularly imprinted polymer (MIP) sensing mechanism was developed. This mechanism consists of MIP microparticles prepared using methacrylic acid as the functional monomer. The MIP microparticles are then combined with fluorescent quantum dots via a simple cross-linking procedure. The result is a highly robust optical sensing scheme that is capable of functioning in an array of environmental conditions. To study the sensing mechanisms’s ability to detect nitroaromatic analytes, the fluorescent-labeled MIP particles were tested for their performance in detecting aqueous 2,4-dinitrotoluene (DNT), a nitroaromatic molecule very similar to TNT, as well as TNT itself. These preliminary data indicate that the system is capable of detecting nitroaromatic compounds in solution with high sensitivity, achieving lower limits of detection of 30.1 and 40.7 μM for DNT and TNT, respectively. The detection mechanism also acted rapidly, with response times as low as 1 min for TNT. Due to the results of this study, it can be concluded that the fluorescent-labeled MIP system is a feasible method for detecting high explosives, with the potential for future use in detecting vapors from explosive devices.
A methodology for computation of flow around circular cylinders is developed and tested using prominent commercial and open-source solvers; ANSYS® CFX-13.0 and OpenFOAM® 1.7.1 respectively. A range ...of diameters and flow conditions are accounted for by generating solutions for flows at Reynolds numbers ranging from 40 to 106. To maintain practical solve times a 2D Unsteady Reynolds-Averaged Navier–Stokes (URANS) approach is taken. Furthermore, to maximise accuracy a tightly controlled meshing methodology, suitable adaptive timestepping, and appropriate turbulence modelling, are assembled. The resulting data is presented for lift and drag forces, Strouhal frequency, time accuracy and boundary layer correlation. Despite closely matching case definitions, significant differences are found in the results between solvers; OpenFOAM displays high correlation with experimental data at low to sub-critical values, whereas ANSYS proves to be more effective in the high sub-critical and critical regions. This variance demonstrates the sensitivity of the case to solver specific mathematical constraints and that for practical engineering a parameter study is essential. By removing many common variances associated with grid and transient components of URANS computations the developed methodology can be used as a benchmark case for further codes solving cylindrical structures.
•Flow around a circular cylinder is modelled for a wide range of Reynolds numbers.•Methodology to achieve low y+ and capture the boundary layer is presented.•Comparisons are made between commercial and open-source solvers.•Low Reynolds number cases show high quantitative agreement with experiments.•OpenFoam is shown to be suitable for quantitative engineering up to Re of 104.
The complex relationships between infectious organisms and their hosts often reflect the continuing struggle of the pathogen to proliferate and spread to new hosts, and the need of the infected ...individual to control and potentially eradicate the infecting population. This has led, in the case of mammals and the pathogens that infect them, to an 'arms race', in which the highly adapted mammalian immune system has evolved to control the proliferation of infectious organisms and the pathogens have developed correspondingly complex genetic systems to evade this immune response. We review how bacterial, protozoan and fungal pathogens from distant evolutionary lineages have evolved surprisingly similar mechanisms of antigenic variation to avoid eradication by the host immune system and can therefore maintain persistent infections and ensure their transmission to new hosts.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Proprotein convertase subtilisin-like/kexin type 9 (PCSK9) is a key regulator of plasma LDL-cholesterol (LDL-C) and a clinically validated target for the treatment of hypercholesterolemia and ...coronary artery disease. In this paper, we describe a series of novel cyclic peptides derived from an mRNA display screen which inhibit the protein–protein interaction between PCSK9 and LDLR. Using a structure-based drug design approach, we were able to modify our original screening lead 2 to optimize the potency and metabolic stability and minimize the molecular weight to provide novel bicyclic next-generation PCSK9 inhibitor peptides such as 78. These next-generation peptides serve as a critical foundation for continued exploration of potential oral, once-a-day PCSK9 therapeutics for the treatment of cardiovascular disease.
ABSTRACT
Purpose
The aim of this study was to evaluate the oral exposure predictions obtained early in drug discovery with a generic GastroPlus Advanced Compartmental And Transit (ACAT) model based ...on the
in vivo
intravenous blood concentration-time profile,
in silico
properties (lipophilicity, pKa) and
in vitro
high-throughput absorption-distribution-metabolism-excretion (ADME) data (as determined by PAMPA, solubility, liver microsomal stability assays).
Methods
The model was applied to a total of 623 discovery molecules and their oral exposure was predicted in rats and/or dogs. The predictions of C
max
, AUC
last
and T
max
were compared against the observations.
Results
The generic model proved to make predictions of oral C
max
, AUC
last
and T
max
within 3-fold of the observations for rats in respectively 65%, 68% and 57% of the 537 cases. For dogs, it was respectively 77%, 79% and 85% of the 124 cases. Statistically, the model was most successful at predicting oral exposure of Biopharmaceutical Classification System (BCS) class 1 compounds compared to classes 2 and 3, and was worst at predicting class 4 compounds oral exposure.
Conclusion
The generic GastroPlus ACAT model provided reasonable predictions especially for BCS class 1 compounds. For compounds of other classes, the model may be refined by obtaining more information on solubility and permeability in secondary assays. This increases confidence that such a model can be used in discovery projects to understand the parameters limiting absorption and extrapolate predictions across species. Also, when predictions disagree with the observations, the model can be updated to test hypotheses and understand oral absorption.
Plantar taping has been used in clinical settings as a short-term conservative treatment for plantar heel pain and related pathologies. The rise of at-home taping methods may offer patients more ...independence, but effectiveness has not been established. The purpose of this study was to evaluate the effects of plantar taping on foot mechanics during gait. We hypothesized that material compliance would drive mechanical effectiveness, with longitudinally inelastic tape reducing medial longitudinal arch (MLA) motion and anterior/posterior (A/P) plantar tissue spreading forces, and laterally inelastic tape reducing medial/lateral (M/L) tissue spreading. We also hypothesized that these effects would be influenced by foot structure. Fifteen healthy participants were tested in a randomized cross-over study design. Barefoot (BF) plus four taping methods were evaluated, including two inelastic tapes (Low-Dye, LD, and FasciaDerm, FD) along with longitudinally elastic kinesiology tape (KT) and a novel laterally elastic kinesiology tape (FAST, FS). Participants' arch height and flexibility were measured followed by instrumented gait analysis with a multi-segment foot model. Ankle eversion and MLA drop/rise were calculated from rearfoot and forefoot reference frames, while plantar tissue spreading was calculated from shear stresses. ANOVAs with Holm pairwise tests evaluated tape effects while correlations connected arch structure and taping effectiveness (α = 0.05). The three longitudinally inelastic tapes (LD, FD, FS) reduced MLA drop by 11-15% compared with KT and BF. In late stance, these tapes also inhibited MLA rise (LD by 29%, FD and FS by 10-15%). FS and FD reduced A/P spreading forces, while FD reduced M/L spreading forces compared with all other conditions. Arch height had a moderately strong correlation (r = -0.67) with the difference in MLA drop between BF and FS. At-home plantar taping can affect the mechanical function of the foot, but tape elasticity direction matters. Longitudinally elastic kinesiology tape has little effect on mechanics, while inelastic tapes control MLA drop but also restrict MLA rise in late stance. Lateral elasticity does not limit tissue spreading and may increase comfort without sacrificing MLA control. At-home taping has the potential to broaden conservative treatment of plantar heel pain, flat foot deformity, and related pathologies, but additional studies are needed to connect mechanics with symptom relief.
► Detection of E. coli with antibody/antigen (specific) binding. ► Qualitative and quantitative analysis, both for dose and time response. ► No need for enhancement step. ► Device is reusable. ► ...Faster results.
A gold interdigitated microelectrode (IME) impedance biosensor was fabricated for the detection of viable Escherichia coli O157:H7. This sensor was fabricated using lithography techniques. The surface of the electrode was immobilized with anti-E. coli IgG antibodies. This approach is different from other studies where the change in impedance is measured in terms of growth of bacteria on the electrode, rather then the antibody/antigen bonding. The impedance values were recorded for frequency ranges between 100Hz and 10MHz. The working range of the dose response for this device was found to be between 2.5×104CFUml−1 and 2.5×107CFUml−1. The time response studies indicated that antibody/antigen binding is not a function of time, but can decrease if excess times are allowed for binding. It was observed that the impedance values for 60min antibody/antigen binding were higher than the impedance values for 120min binding time. The main advantages of the reported device are that, it provides for both qualitative and quantitative detection in 3h while other impedance sensors reported earlier may take up to 24h for detection. If enrichment steps are required then it may take 3–4 days to infer the results. This sensor can be used to detect different types of bacteria by immobilizing the antigen specific antibody. Most of the sensors are not reusable since they either use enzymes or enrichment steps for detection but this device can be reused, following a cleaning protocol which is easy to follow. Each device was used at least five times. The simplicity of this sensor and the ease of fabrication make this sensor a useful alternate to the microfluidics and enzyme based impedance sensors, which are relatively more difficult to fabricate, need programmable fluidic injection pumps to push the sample through the channel, suffer from limitation of coagulation and are difficult to clean.
The protein arginine deiminases (PADs) are a family of enzymes that catalyze the post-translational hydrolytic deimination of arginine residues. Four different enzymologically active PAD subtypes ...have been characterized and exhibit tissue-specific expression and association with a number of different diseases. In this Article we describe the development of an approach for the reliable discovery of low molecular weight, nonpeptidic fragment substrates of the PADs that then can be optimized and converted to mechanism-based irreversible PAD inhibitors. The approach is demonstrated by the development of potent and selective inhibitors of PAD3, a PAD subtype implicated in the neurodegenerative response to spinal cord injury. Multiple structurally distinct inhibitors were identified with the most potent inhibitors having >10,000 min–1 M–1 k inact/K I values and ≥10-fold selectivity for PAD3 over PADs 1, 2, and 4.
Summary
Background Acne affects 83–95% of 16‐year‐olds of both sexes, and many seek help from a clinician. Emerging problems with conventional acne treatments, specifically antibiotic resistance of ...Propionibacterium acnes and fears over the safety and tolerance of oral isotretinoin, create a demand for novel treatment modalities in acne.
Objectives To study the efficacy of aminolaevulinic acid‐photodynamic therapy (ALA‐PDT) in the treatment of acne and to identify the mode of action, looking specifically at the effects on surface numbers of P. acnes and on sebum excretion.
Methods Ten patients (nine men and one woman, age range 16–40 years) with mild to moderate acne on their backs were recruited. Each patient's back was marked with four 30‐cm2 areas of equal acne severity. Each site was then randomly allocated to either ALA‐PDT treatment, light alone, ALA alone or an untreated control site. At baseline, numbers of inflammatory and noninflammatory acne lesions were counted, sebum excretion measured by Sebutapes (CuDerm, Dallas, TX, U.S.A.) and surface P. acnes swabs performed. ALA cream (20% in Unguentum Merck) was applied under occlusion to the ALA‐PDT and ALA alone sites for 3 h. Red light from a diode laser was then delivered to the ALA‐PDT and light alone sites (635 nm, 25 mW cm−2, 15 J cm−2). Each patient was treated weekly for 3 weeks. At each visit acne lesion counts were performed and 3 weeks following the last treatment sebum excretion rates and P. acnes swabs were repeated.
Results There was a statistically significant reduction in inflammatory acne lesion counts from baseline after the second treatment at the ALA‐PDT site but not at any of the other sites. No statistically significant reduction in P. acnes numbers or sebum excretion was demonstrated at any sites including the ALA‐PDT site.
Conclusions ALA‐PDT is capable of clinically improving acne. An alternative mode of action for ALA‐PDT other than direct damage to sebaceous glands or photodynamic killing of P. acnes is suggested from the results of this study.
A method combining immunomagnetic separation and fluorescent sensing was developed to detect Escherichia coli (E. coli) O104:H4. The antibody specific to E. coli O104:H4 was immobilized on protein ...A-coated magnetic beads. This protein-A–anti E. coli O104:H4 complex was used to bind Fluorescein IsoThioCyanate (FITC) labeled E. coli O104:H4 antigen (whole cell) on it. The goal was to achieve a fluorescently detectable protein-A–anti E. coli O104:H4–E. coli O104:H4 complex on the magnetic beads. Fluorescent microscopy was used to image the magnetic beads. The resulting fluorescence on the beads was due to the FITC labeled antigen binding on the protein-A–anti E. coli O104:H4 immobilized magnetic beads. This visually proves the antigen–antibody binding. The fluorescent imaging results were obtained in 2h if the minimum available bacteria in the sample were at least 105CFU/ml. If no fluorescence was observed on the magnetic beads during fluorescent imaging, it indicates the bacterial concentration in the sample to be too low for it to have bound to the magnetic beads and hence no detection was possible. To detect bacterial concentration less than 105CFU/ml in the sample, an additional step was required for detection. The magnetic bead complex was added to the LST-MUG (lauryl sulfate tryptose-4-methylumbelliferyl-β-d-glucuronide), a signaling reporter. The E. coli O104:H4 grows in LST-MUG and releases β-glucuronidase enzyme. This enzyme cleaves the MUG substrate that produces 4-methylumbelliferone, a highly fluorescent species. This fluorescence was detected using a spectrofluorometer. The emission peak in the fluorescent spectrum was found to be at 450nm. The lower and upper detection range for this LST-MUG assay was found to be 2.05×105–4.09×108CFU/ml. The results for the LST-MUG assay for concentrations below 105CFU/ml were ascertained in 8h. The advantages of this technique include the specific detection of bacteria without an enrichment step and allowing the procedure to be completed in hours rather than days.
•Specific detection of E. coli O104:H4 using fluorescent imaging in 2h•Quantitative analysis in 8h•This platform could be used for “specific” detection of “any” bacteria.•Interpreting relationship between fluorescence and bacterial concentration (CFU/ml)
PDF
