Optimization of the Synthesis and Conjugation of the Methyl Rhamnan Tip of Pseudomonas aeruginosa A-Band Polysaccharide and Immunogenicity Evaluation for the Continued Development of a Potential Glycoconjugate Vaccine.

Pseudomonas aeruginosa is an antimicrobial-resistant bacterium that has no vaccine approved for human use. Additionally, it has been identified by the World Health Organization as a priority pathogen for novel vaccines and therapeutic development. We previously developed a synthetic mimic of the A-band polysaccharide tip that showed promise in terms of immunogenicity for use as a glycoconjugate vaccine. In this current manuscript, we improve upon the previous work to continue the development of this glycoconjugate vaccine. Herein, we report a higher-yielding synthesis of mimics containing a handle and a spacer that improved conjugation efficiency, resulting in better carbohydrate-to-protein ratios and also good immunogenicity of these conjugates in mice and rabbits. The data suggested that perhaps only a tetrasaccharide was required to induce an immune response capable of recognizing whole cells of P. aeruginosa.

Recovery and post-operative analgesic efficacy from fentanyl- versus dexmedetomidine-based anesthesia in head and neck cancer surgery: A prospective comparative trial.

Background: Opioids such as fentanyl are being used frequently in the management of postoperative period, whereas non-opioid drugs such as dexmedetomidine are now commonly being used as adjuvants during the perioperative period to hasten the fast recovery and better outcome in the post-operative period because of their anesthetic and analgesic property. The recovery profile was measured by the emergence of anesthesia and pain characteristics. We aimed to evaluate and compare the efficacy of dexmedetomidine and fentanyl in the surgery of head and neck cancer patients. Methods: Prospective double-blind study on 60 patients with the American Society Anesthesiologists (ASA) grade I and II were randomly divided into two groups. Group DM received a loading dose of dexmedetomidine 1 µg/kg over 10 min followed by a maintenance dose of 0.5 µg/kg/h and Group FM received a loading dose of fentanyl 2 µg/kg/h for over 10 min followed by 1 µg/kg/h maintenance dose. Data were analyzed using a Chi-square test or Student's 't' test. Results: The group DM was hemodynamic stable as compared to group FM. The perturbation during extubation emergence was significantly lower in group DM as compared to that in group FM. A total of four patients were severely agitated in group FM, whereas it was absent in group DM. Severe agitation was significantly different between Group FM and Group DM. The visual analog scale (VAS) was lower among patients of Group DM as compared to Group FM at all times except at 4 h. Conclusions: The infusion of dexmedetomidine was better in controlling emergence agitation, postoperative pain, and achieving peri-operative hemodynamic stability as compared to fentanyl.

Synthesis and Immunogenicity of a Methyl Rhamnan Pentasaccharide Conjugate from Pseudomonas aeruginosa A-Band Polysaccharide.

Pseudomonas aeruginosa was added to the World Health Organization's priority pathogen list for research and development of new antibiotics in 2017. Alongside the development of new antibiotics to fight antimicrobial-resistant P. aeruginosa, vaccines would be an appealing addition to the toolbox health professionals have against this bacteria, which causes life-threatening respiratory infections. Recently, the structure of a novel immunogenic terminal carbohydrate moiety on the cell surface of P. aeruginosa was elucidated, consisting of a 3-O-methyl (1→4)-α-d-rhamnan pentasaccharide. As isolating this oligosaccharide from P. aeruginosa in sufficient amounts for producing a conjugate vaccine is challenging, herein we describe the synthesis of 3-O-methyl d-rhamnose oligosaccharide. We also report the conjugation of the synthetic pentasaccharide to human serum albumin and its resulting immunogenicity.

A Fast Approximate Method for Predicting the Behavior of Auditory Nerve Fibers and the Evoked Compound Action Potential (ECAP) Signal.

BACKGROUND: The goal of the current research is to develop a model based on computer simulations which describes both the behavior of the auditory nerve fibers and the cochlear implant system as a rehabilitation device. METHODS: The approximate method was proposed as a low error and fast tool for predicting the behavior of auditory nerve fibers as well as the evoked compound action potential (ECAP) signal. In accurate methods every fiber is simulated; whereas, in approximate method information related to the response of every fiber and its characteristics such as the activation threshold of cochlear fibers are saved and interpolated to predict the behavior of a set of nerve fibers. RESULTS: The approximate model can predict and analyze different stimulation techniques. Although precision is reduced to <1.66% of the accurate method, the required execution time for simulation is reduced by more than 98%. CONCLUSION: The amplitudes of the ECAP signal and the growth function were investigated by changing the parameters of the approximate model including geometrical parameters, electrical, and temporal parameters. In practice, an audiologist can tune the stimulation parameters to reach an effective restoration of the acoustic signal.

d-Glycero-ß-d-mannoheptose Phosphate 7-O-Modifications.

Pathogen-associated molecular patterns activate the immune system via pattern recognition receptors. Recently, newly discovered pathogen-associated molecular patterns, d-glycero-ß-d-mannoheptose phosphate and d-glycero-ß-d-mannoheptose 1,7-biphosphate, were shown to induce a TRAF-interacting protein with a forkhead-associated domain-dependent immune response in human embryonic kidney cells and colonic epithelial cells. Concurrently, ADP-heptose was shown to bind α-kinase 1 and activate TIFA via phosphorylation leading to an immune cascade to ultimately activate NF-κB. These pathogen-associated molecular patterns have raised interest in the pharmaceutical industry for their potential use as immunomodulators. However, little is understood about the host cell uptake of d-glycero-ß-d-mannoheptose phosphate, d-glycero-ß-d-mannoheptose 1,7-biphosphate, and ADP-heptose in vivo and derivatives of these molecules are needed to interrogate this. In this regard, herein we describe 7-O-modifications of d-glycero-ß-d-mannoheptose phosphate to produce molecular probes toward the development of a useful toolbox for biologists. A convergent strategy that involves introduction of a substituent at O-7 before alkene oxidation was investigated and proved successful in the generation of a range of molecular probes.

An EEG channel selection method for motor imagery based brain-computer interface and neurofeedback using Granger causality.

Motor imagery (MI) brain-computer interface (BCI) and neurofeedback (NF) with electroencephalogram (EEG) signals are commonly used for motor function improvement in healthy subjects and to restore neurological functions in stroke patients. Generally, in order to decrease noisy and redundant information in unrelated EEG channels, channel selection methods are used which provide feasible BCI and NF implementations with better performances. Our assumption is that there are causal interactions between the channels of EEG signal in MI tasks that are repeated in different trials of a BCI and NF experiment. Therefore, a novel method for EEG channel selection is proposed which is based on Granger causality (GC) analysis. Additionally, the machine-learning approach is used to cluster independent component analysis (ICA) components of the EEG signal into artifact and normal EEG clusters. After channel selection, using the common spatial pattern (CSP) and regularized CSP (RCSP), features are extracted and with the k-nearest neighbor (k-NN), support vector machine (SVM) and linear discriminant analysis (LDA) classifiers, MI tasks are classified into left and right hand MI. The goal of this study is to achieve a method resulting in lower EEG channels with higher classification performance in MI-based BCI and NF by causal constraint. The proposed method based on GC, with only eight selected channels, results in 93.03% accuracy, 92.93% sensitivity, and 93.12% specificity, with RCSP feature extractor and best classifier for each subject, after being applied on Physionet MI dataset, which is increased by 3.95%, 3.73%, and 4.13%, in comparison with correlation-based channel selection method.

Assessment of stability of sulphated lactosyl archaeol archaeosomes for use as a vaccine adjuvant.

Archaeosomes, composed of sulphated lactosyl archaeol (SLA) glycolipids, have been proven to be an effective vaccine adjuvant in multiple preclinical models of infectious disease or cancer. In addition to efficacy, the stability of vaccine components including the adjuvant is an important parameter to consider when developing novel vaccine formulations. To properly evaluate the potential of SLA glycolipids to be used as vaccine adjuvants in a clinical setting, a comprehensive evaluation of their stability is required. Herein, we evaluated the long term stability of preformed empty SLA archaeosomes prior to admixing with antigen at 4 °C or 37 °C for up to 6 months. In addition, the stability of adjuvant and antigen was evaluated for up to 1 month following admixing. Multiple analytical parameters evaluating the molecular integrity of SLA and the liposomal profile were assessed. Following incubation at 4 °C or 37 °C, the SLA glycolipid did not show any pattern of degradation as determined by mass spectroscopy, nuclear magnetic resonance (NMR) and thin layer chromatography (TLC). In addition, SLA archaeosome vesicle characteristics, such as size, zeta potential, membrane fluidity and vesicular morphology, were largely consistent throughout the course of the study. Importantly, following storage for 6 months at both 4 °C and 37 °C, the adjuvant properties of empty SLA archaeosomes were unchanged, and following admixing with antigen, the immunogenicity of the vaccine formulations was also unchanged when stored at both 4 °C and 37 °C for up to 1 month. Overall this indicates that SLA archaeosomes are highly stable adjuvants that retain their activity over an extended period of time even when stored at high temperatures.

Epidemiology of surgically treated patient in road traffic accident with lower extremity vascular injury from a single centre in Kelantan.

INTRODUCTION: Lower extremity vascular injury can result in either temporary or permanent disability. METHODS: This is a clinical audit involving all patients admitted to our institution from January 2008 to June 2018 of those who had undergone revascularization surgery for lower limb trauma. RESULTS: Fifty-nine patients were in this study with a mean age of 28.1 years. Most of the patients were motorcyclist involved in road traffic accidents with cars (n=30, 50.8%). The popliteal artery was most commonly seen injury (n=41, 69.5%). The mean duration of ischaemia was 14.1 hours. The limb salvage rate was 89.8%. CONCLUSION: Lower extremity vascular injury caused by RTA treated in our institution predominantly involved young patients aged between 18-30 years associated with long bone fractures causing contusion and thrombosis of the popliteal artery.

Prognostic Value of Cardiac Biomarkers Assessment in Combination with Myocardial 2D Strain Echocardiography for Early Detection of Anthracycline-Related Cardiac Toxicity.

BACKGROUND: Anthracyclines, a widely used chemotherapy agent with a definite survival improvement, can result in cardiac toxicity presenting with HF (heart failure). OBJECTIVE: We aim to assess the predictive value of cardiac biomarkers assessment in combination with myocardial two-dimensional strain echocardiography for early detection of cardiac toxicity in patients who underwent Anthracycline-based chemotherapy. METHODS: Fifty-two consecutive adult patients scheduled to undergo the first course of Anthracycline-based chemotherapy were subjected to the study. All the patients underwent highly sensitive 2D echocardiographic evaluation before the treatment, 4 and 12 weeks after completion of first-course chemotherapy. Longitudinal and segmental strains were measured. Serum levels of High-sensitive cardiac troponin I (hscTn-I) and N-terminal-pro-BNP (NT-proBNP) were also assessed before the initiation and 3 weeks after completion of first-course chemotherapy. RESULTS: Fifteen patients (28.8%) revealed a decrease in LVEF (Left Ventricular Ejection Fraction) throughout the evaluations, while just 5 patients met the criteria of cardiac toxicity (9.6%). AUC for Global Longitudinal Strain (GLS) ROC curve at 4 weeks of follow-up was calculated to be 0.968. Inferoseptal Systolic Longitudinal Strain (SLS) had the highest AUC value (AUC: 0.934) among different wall SLS. LVESD (Left Ventricular End-Systolic Diameter) at first and second evaluation could predict the risk of cardiac toxicity among LVESD, LVEDD (Left Ventricular End Diastolic Diameter) and LVEDV (Left Ventricular End-Diastolic Volume). Among cardiac biomarkers, hscTnI had higher sensitivity, while NT-proBNP had higher specificity for cardiac toxicity. CONCLUSION: This study has shown that hs-cTnI with good sensitivity can predict cardiac toxicity in Anthracycline-based chemotherapy receiver. The use of strain with speckle echocardiography method has a prognostic value; however, both longitudinal and segmental strain should be assessed. Lateral and inferoseptal SLS (Segmental Longitudinal Strain) are specific markers of cardiac toxicity in the course of anthracycline-related cardiac toxicity.

Non-Hermitian ring laser gyroscopes with enhanced Sagnac sensitivity.

Gyroscopes are essential to many diverse applications associated with navigation, positioning and inertial sensing1. In general, most optical gyroscopes rely on the Sagnac effect-a relativistically induced phase shift that scales linearly with the rotational velocity2,3. In ring laser gyroscopes (RLGs), this shift manifests as a resonance splitting in the emission spectrum, which can be detected as a beat frequency4. The need for ever more precise RLGs has fuelled research activities aimed at boosting the sensitivity of RLGs beyond the limits dictated by geometrical constraints, including attempts to use either dispersive or nonlinear effects5-8. Here we establish and experimentally demonstrate a method using non-Hermitian singularities, or exceptional points, to enhance the Sagnac scale factor9-13. By exploiting the increased rotational sensitivity of RLGs in the vicinity of an exceptional point, we enhance the resonance splitting by up to a factor of 20. Our results pave the way towards the next generation of ultrasensitive and compact RLGs and provide a practical approach for the development of other classes of integrated sensor.

Archaeal glycolipid adjuvanted vaccines induce strong influenza-specific immune responses through direct immunization in young and aged mice or through passive maternal immunization.

Vaccine induced responses are often weaker in those individuals most susceptible to infection, namely the very young and the elderly, highlighting the need for safe and effective vaccine adjuvants. Herein we evaluated different archaeosome formulations as an adjuvant to the H1N1 influenza hemagglutinin protein and compared immune responses (anti-HA IgG and hemagglutination inhibition assay titers) as well as protection to an influenza A virus (strainA/PuertoRico/8/1934H1N1)homologous challenge to those generated using a squalene-based oil-in-water nano-emulsion, AddaVax™ in a murine model. The impact of age (young adult vs aged) on vaccine induced immune responses as well as the protection in pups due to the transfer of maternal antibodies was measured. Overall, we show that archaeal lipid based adjuvants can induce potent anti-HA responses in young and aged mice that can also be passed from vaccinated mothers to pups. Furthermore, young and aged mice immunized with archaeal lipid adjuvants as well as pups from immunized mothers were protected from challenge with influenza. In addition, we show that a simple admixed archaeosome formulation composed of a single sulfated glycolipid namely sulfated lactosylarchaeol (SLA; 6'-sulfate-ß-D-Galp-(1,4)-ß-D-Glcp-(1,1)-archaeol) can give equal or better protection compared to AddaVax™ or the traditional antigen-encapsulated archaeosome formulations.

A comparison of the immune responses induced by antigens in three different archaeosome-based vaccine formulations.

Archaeosomes are liposomes composed of natural or synthetic archaeal lipids that can be used as adjuvants to induce strong long-lasting humoral and cell-mediated immune responses against entrapped antigen. However, the entrapment efficiency of antigen within archaeosomes constituted using standard liposome forming methodology is often only 5-40%. In this study, we evaluated different formulation methods using a simple semi-synthetic archaeal lipid (SLA, sulfated lactosyl archaeol) and two different antigens, ovalbumin (OVA) and hepatitis B surface antigen (HBsAg). Antigen was entrapped within archaeosomes using the conventional thin film hydration-rehydration method with or without removal of non-entrapped antigen, or pre-formed empty archaeosomes were simply admixed with an antigen solution. Physicochemical characteristics were determined (size distribution, zeta potential, vesicle morphology and lamellarity), as well as location of antigen relative to bilayer using cryogenic transmission electron microscopy (TEM). We demonstrate that antigen (OVA or HBsAg) formulated with SLA lipid adjuvants using all the different methodologies resulted in a strong antigen-specific immune response. Nevertheless, the advantage of using a drug substance process that comprises of simply admixing antigen with pre-formed empty archaeosomes, represents a simple, efficient and antigenic dose-sparing formulation for adjuvanting and delivering vaccine antigens.

Supersymmetric laser arrays.

Scaling up the radiance of coupled laser arrays has been a long-standing challenge in photonics. In this study, we demonstrate that notions from supersymmetry-a theoretical framework developed in high-energy physics-can be strategically used in optics to address this problem. In this regard, a supersymmetric laser array is realized that is capable of emitting exclusively in its fundamental transverse mode in a stable manner. Our results not only pave the way toward devising new schemes for scaling up radiance in integrated lasers, but also, on a more fundamental level, could shed light on the intriguing synergy between non-Hermiticity and supersymmetry.

Sulfated archaeol glycolipids: Comparison with other immunological adjuvants in mice.

Archaeosomes are liposomes traditionally comprised of total polar lipids (TPL) or semi-synthetic glycerolipids of ether-linked isoprenoid phytanyl cores with varied glyco- and amino-head groups. As adjuvants, they induce robust, long-lasting humoral and cell-mediated immune responses and enhance protection in murine models of infectious disease and cancer. Traditional total polar lipid (TPL) archaeosome formulations are relatively complex and first generation semi-synthetic archaeosomes involve many synthetic steps to arrive at the final desired glycolipid composition. We have developed a novel archaeosome formulation comprising a sulfated disaccharide group covalently linked to the free sn-1 hydroxyl backbone of an archaeal core lipid (sulfated S-lactosylarchaeol, SLA) that can be more readily synthesized yet retains strong immunostimulatory activity for induction of cell-mediated immunity following systemic immunization. Herein, we have evaluated the immunostimulatory effects of SLA archaeosomes when used as adjuvant with ovalbumin (OVA) and hepatitis B surface antigen (HBsAg) and compared this to various other adjuvants including TLR3/4/9 agonists, oil-in-water and water-in-oil emulsions and aluminum hydroxide. Overall, we found that semi-synthetic sulfated glycolipid archaeosomes induce strong Ag-specific IgG titers and CD8 T cells to both antigens. In addition, they induce the expression of a number of cytokines/chemokines including IL-6, G-CSF, KC & MIP-2. SLA archaeosome formulations demonstrated strong adjuvant activity, superior to many of the other tested adjuvants.

Unidirectional light emission in PT-symmetric microring lasers.

The synergetic use of gain and loss in parity-time symmetric coupled resonators has been shown to lead to single-mode lasing operation. However, at the corresponding resonance frequency, an ideal ring resonator tends to support two degenerate eigenmodes, traveling along the cavity in opposite directions. Here, we show a unidirectional single-moded parity-time symmetric laser by incorporating active S-bend structures with opposite chirality in the respective ring resonators. Such chiral elements break the rotation symmetry of the ring cavities by providing an asymmetric coupling between the clockwise (CW) and the counterclockwise (CCW) traveling modes, hence creating a new type of exceptional point. This property, consequently, leads to the suppression of one of the counter-propagating modes. In this paper, we first measure the extinction ratio between the CW and CCW modes in a single ring resonator in the presence of an S-bend waveguide. We then experimentally investigate the unidirectional emission in PT-symmetric systems below and above the exceptional point. Finally, unidirectional emission will be shown in systems of two S-bend ring resonators coupled through a link structure.

On the Ability of Formaldehyde to Act as a Tethering Catalyst in Water.

The low concentration issue is a fundamental challenge when it comes to prebiotic chemistry, as macromolecular systems need to be assembled via intermolecular reactions, and this is inherently difficult in dilute solutions. This is especially true when the reactions are challenging, and reactions that proceeded more rapidly could have dictated chemical evolution. Herein we establish that formaldehyde is capable of catalyzing, via temporary intramolecularity, a challenging reaction in water at low concentrations, thus providing an alternative to other approaches that can either lead to higher concentrations or higher effective molarities.

Interaction of Individual Structural Domains of hnRNP LL with the BCL2 Promoter i-Motif DNA.

The recently discovered role of the BCL2 (B-cell lymphoma 2 gene) promoter i-motif DNA in modulation of gene expression via interaction with the ribonucleoprotein hnRNP L-like (hnRNP LL) has prompted a more detailed study of the nature of this protein-DNA interaction. The RNA recognition motifs (RRMs) of hnRNP LL were expressed individually, and both RRM1 and RRM2 were found to bind efficiently to the BCL2 i-motif DNA, as well as being critical for transcriptional activation, whereas RRM3-4 bound only weakly to this DNA. Binding was followed by unfolding of the DNA as monitored by changes in the CD spectrum. Mutational analysis of the i-motif DNA revealed that binding involved primarily the lateral loops of the i-motif. The kinetics of binding of the DNA with RRM1 was explored by recording CD spectra at predetermined times following admixture of the protein and DNA. The change in molar ellipticity was readily apparent after 30 s and largely complete within 1 min. A more detailed view of protein-DNA interaction was obtained by introducing the fluorescence donor 6-CNTrp in RRM1 at position 137, and the acceptor 4-aminobenzo[g]quinazoline-2-one (Cf) in lieu of cytidine22 in the i-motif DNA. The course of binding of the two species was monitored by FRET, which reflected a steady increase in energy transfer over a period of several minutes. The FRET signal could be diminished by the further addition of (unlabeled) RRM2, no doubt reflecting competition for binding to the i-motif DNA. These experiments using the individual RRM domains from hnRNP LL confirm the role of this transcription factor in activation of BCL2 transcription via the i-motif in the promoter element.

Low-Complexity Discriminative Feature Selection From EEG Before and After Short-Term Memory Task.

A reliable and unobtrusive quantification of changes in cortical activity during short-term memory task can be used to evaluate the efficacy of interfaces and to provide real-time user-state information. In this article, we investigate changes in electroencephalogram signals in short-term memory with respect to the baseline activity. The electroencephalogram signals have been analyzed using 9 linear and nonlinear/dynamic measures. We applied statistical Wilcoxon examination and Davis-Bouldian criterion to select optimal discriminative features. The results show that among the features, the permutation entropy significantly increased in frontal lobe and the occipital second lower alpha band activity decreased during memory task. These 2 features reflect the same mental task; however, their correlation with memory task varies in different intervals. In conclusion, it is suggested that the combination of the 2 features would improve the performance of memory based neurofeedback systems.

Cyanotryptophans as Novel Fluorescent Probes for Studying Protein Conformational Changes and DNA-Protein Interaction.

Described herein are the syntheses and photophysical characterization of three novel cyanotryptophans, and their efficient incorporation into proteins as fluorescent probes. Photophysical characteristics indicated that each was significantly brighter and red-shifted in fluorescence emission relative to tryptophan. Each analogue was used to activate a suppressor tRNA transcript and was incorporated with good efficiency into two different positions (Trp22 and Trp74) of Escherichia coli dihydrofolate reductase (ecDHFR). The Trp analogues could be monitored selectively in the presence of multiple native Trp residues in DHFR. 6-CNTrp (A) formed an efficient Förster resonance energy transfer (FRET) pair with l-(7-hydroxycoumarin-4-yl)ethylglycine (HCO, D) at position 17. Further, 6-CNTrp (A) was incorporated into two DNA binding proteins, including the Klenow fragment of DNA polymerase I and an RNA recognition motif (RRM2) of heterogeneous nuclear ribonucleoprotein L-like (hnRNP LL). Using these proteins, we demonstrated the use of FRET involving A as a fluorescence donor and benzo[g]quinazoline-2,4-(1H,3H)-dione 2'-deoxyriboside (Tf) or 4-aminobenzo[g]quinazoline-2-one 2'-deoxyriboside (Cf) as fluorescent acceptors to study the binding interaction of the Klenow fragment with duplex DNA oligomers (labeled with Tf), or the domain-specific association between hnRNP LL and the BCL2 i-motif DNA (labeled with Cf). Thus, the non-natural amino acid could be used as a FRET partner for studying protein-nucleic acid interactions. Together, these findings demonstrate the potential utility of 6-CNTrp (A) as a fluorescence donor for the study of protein conformational events.