A
bstract
We consider the most general Kaluza-Klein (KK) compactification on
S
1
/
ℤ
2
of a five dimensional (5
D
) graviton-dilaton system, with a non-vanishing dilaton background varying linearly ...along the fifth dimension. We show that this background produces a Higgs mechanism for the KK vector coming from the 5
D
metric, which becomes massive by absorbing the string frame radion. The
N
= 2 minimal supersymmetric extension of this model, recently built as the holographic dual of Little String Theory, is then reinvestigated. An analogous mechanism can be considered for the 4
D
vector coming from the (universal) 5
D
Kalb-Ramond two-form. Packaging the two massive vectors into a spin-3
/
2 massive multiplet, it is shown that the massless spectrum arranges into a
N
= 1,
D
= 4 supersymmetric theory. This projection is compatible with an orbifold which preserves half of the original supersymmetries already preserved by the background. The description of the partial breaking
N
= 2 →
N
= 1 in this framework, with only vector multiplets and no hypermultiplets, remains an interesting open question which deserves further investigation.
Plant immune receptors are often difficult to express heterologously, hindering study of direct interactions between these receptors and their targets with traditional biochemical approaches. The ...cell-free method ribosome display (RD) enables expression of such recalcitrant proteins by keeping each nascent polypeptide chain tethered to its ribosome, which can enhance protein folding by virtue of its size and solubility. Moreover, in contrast to an in planta readout of receptor activity such as a hypersensitive response that conflates binding and signaling, RD enables direct probing of the interaction between plant immune receptors and their targets. Here, we demonstrate the utility of this approach using tomato recognition of Trichoderma viride ethylene-inducing xylanase (EIX) as a case study. Leveraging the modular nature of the tomato LeEIX2 and LeEIX1 leucine-rich repeat (LRR) receptors, we applied an entropy-informed algorithm to maximize the information content in our receptor segmentation RD experiments to identify segments implicated in EIX binding. Unexpectedly, two distinct EIX-binding hotspots were discovered on LeEIX2 and both hotspots are shared with decoy LeEIX1, suggesting that their contrasting receptor functions are not due to differential modes of ligand binding. Given that most plant immune receptors are thought to engage targets via their LRR sequences, this approach should be of broad utility in rapidly identifying their binding hotspots.
•Advances in cell-free evolution allow for more sophisticated protein engineering.•New display formats enable evolution of multimeric and integral membrane proteins.•Incorporation of unnatural amino ...acids expands chemical repertoire in vitro.•Technical enhancements improve method accessibility, efficiency, and robustness.
Although cell-free directed evolution methods have been used to engineer proteins for nearly two decades, selections on more complex phenotypes have largely remained in the domain of cell-based engineering approaches. Here, we review recent conceptual advances that now enable in vitro display of multimeric proteins, integral membrane proteins, and proteins with an expanded amino acid repertoire. Additionally, we discuss methodological improvements that have enhanced the accessibility, efficiency, and robustness of cell-free approaches. Coupling these advances with the in vitro advantages of creating exceptionally large libraries and precisely controlling all experimental conditions, cell-free directed evolution is poised to contribute significantly to our understanding and engineering of more complex protein phenotypes.
Sea lamprey immunization can yield leucine-rich repeat (LRR) protein binders analogous to globular antibodies developed from mammals. A novel minimal LRR was discovered through lamprey immunization ...with human immunoglobulin G Fc domain (IgG Fc). Initial attempts to solubly express this LRR protein, VLRB.IgGFc, in
Escherichia coli
proved challenging, so it was analyzed using the cell-free method ribosome display. In ribosome display, VLRB.IgGFc was found to bind specifically to the Fc domain of IgG, with little observed cross-reactivity to IgA or IgM. The minimal repeat protein architecture of VLRB.IgGFc may facilitate modular LRR extensions to incorporate additional or augmented functionality within a continuous, structurally defined scaffold. We exploited this modularity to design a chimera of a well-characterized, soluble LRR repebody and the initially insoluble VLRB.IgGFc to produce soluble Repe-VLRB.IgGFc. The minimal IgG Fc–binding module, Repe-VLRB.IgGFc, and future-engineered variants thereof should be useful additions to the biotechnological toolbox for detecting, purifying, or targeting IgGs. More generally, this two-step approach of minimal LRR binder discovery via sea lamprey immunization followed by modular augmentation of functionality may be of general utility in protein engineering.
Context:
Although adrenal incidentalomas (AIs) are associated with a high prevalence of cardiovascular risk (CVR) factors, it is not clear whether patients with nonfunctioning AI (NFAI) have ...increased CVR.
Objective:
Our objective was to investigate CVR in patients with NFAI.
Design and Setting:
This case-control study was performed in a tertiary general hospital.
Subjects:
Subjects included 60 normotensive euglycemic patients with AI and 32 healthy controls (C) with normal adrenal imaging.
Main Outcome Measures:
All participants underwent adrenal imaging, biochemical and hormonal evaluation, and the following investigations: 1) measurement of carotid intima-media thickness (IMT) and flow-mediated dilatation, 2) 2-hour 75-gram oral glucose tolerance test and calculation of insulin resistance indices (homeostasis model assessment, quantitative insulin sensitivity check, and Matsuda indices), 3) iv ACTH stimulation test, 4) low-dose dexamethasone suppression test, and 5) NaCl (0.9%) post-dexamethasone saline infusion test.
Results:
Based on cutoffs obtained from controls, autonomous cortisol secretion was documented in 26 patients (cortisol-secreting AI CSAI group), whereas 34 exhibited adequate cortisol and aldosterone suppression (NFAI group). IMT measurements were higher and flow-mediated vasodilatation was lower in the CSAI group compared with both NFAI and C and in the NFAI group compared with C. The homeostasis model assessment index was higher and quantitative insulin sensitivity check index and Matsuda indices were lower in the CSAI and NFAI groups compared with C as well as in CSAI compared with the NFAI group. The area under the curve for cortisol after ACTH stimulation was higher in the CSAI group compared with the NFAI group and C and in the NFAI group compared with C. In the CSAI group, IMT correlated with cortisol, urinary free cortisol, and cortisol after a low-dose dexamethasone suppression test, whereas in the NFAI group, IMT correlated with area under the curve for cortisol after ACTH stimulation and urinary free cortisol.
Conclusions:
Patients with CSAI without hypertension, diabetes, and/or dyslipidemia exhibit adverse metabolic and CVR factors. In addition, NFAIs are apparently associated with increased insulin resistance and endothelial dysfunction that correlate with subtle but not autonomous cortisol excess.
GRBNeT is a Gamma Ray Burst Neutrino Telescope made of autonomously operated arrays of deep-sea light detectors, anchored to the sea-bed without any cabled connection to the shore. This paper ...presents the digital and analog electronics that we have designed and developed for the GRBNeT prototype. We describe the requirements for these electronics and present their design and functionality. We present low-power analog electronics for the PMTs utilized in the GRBNeT prototype and the FPGA based digital system for data selection and storage. We conclude with preliminary performance measurements of the electronics systems for the GRBNeT prototype.
ABSTRACTBiocompatible stent coatings may alleviate problems of increased (sub)acute thrombosis after stent implantation. Hyaluronic acid (HA), a ubiquitous, nonsulfated glycosaminoglycan, inhibits ...platelet adhesion and aggregation and prolongs bleeding when administered systemically. However, the effects of immobilized HA for reducing stent platelet deposition in vivo are unknown. We therefore quantified the antithrombotic effects of coating stainless steel stents and tubes with HA using an established baboon thrombosis model under physiologically relevant blood flow conditions. HA-coated and uncoated (control) stents (3.5 mm in diameter, n=32) and stainless steel tubes (4.0 mm in diameter, n=18) were deployed into exteriorized arteriovenous shunts of conscious, nonanticoagulated baboons. Accumulation of In-radiolabeled platelets was quantified by continuous gamma-camera imaging during a 2-hour blood exposure period. HA coating resulted in a significant reduction in platelet deposition in long (4 cm) tubes (0.24±0.15×10 versus 6.12±0.49×10 platelets;P <0.03), short (2 cm) stainless steel tubes (0.18±0.06×10 versus 3.03±0.56×10 platelets;P <0.008), and stents (0.82±0.20×10 versus 1.83±0.23×10 platelets;P <0.02) compared with uncoated control devices. Thus, HA coating reduces platelet thrombus formation on stainless steel stents and tubes in primate thrombosis models. These results indicate that immobilized HA may represent an attractive strategy for improving the thromboresistance of endovascular devices.
GRBNeT is a project aiming at the detection of ultra–high energy neutrinos, for example neutrinos originating from Gamma Ray Bursts. The goal is to design, construct and deploy a prototype unit of an ...autonomous (data/energy–wise) neutrino detector. Being autonomous is crucial since for the detection of ultra–high energy neutrinos a very large volume of water is required. Large scale facilities such as IceCube and KM3NeT are designed to be more sensitive to galactic and diffuse flux neutrinos rather than extragalactic ultra–high energy neutrinos. However, their sensitivity to such neutrinos could be increased by placing around and at larger distances detectors such as the one of the GRBNeT project. This extension would increase the instrumented volume of neutrino telescopes to several cubic kilometres. In addition to that, as no cable connection to the shore is required, GRBNeT detection units cost significantly less than regular detection units and can become a cost effective extension of large scale facilities. For the GRBNeT prototype unit ultra low power electronics have been developed. The response to high energy neutrinos from GRBs and to the atmospheric muon background has been simulated.
High energy neutrino astronomy is emerging as one of the most exciting options for studying astrophysical processes. To establish neutrino detectability from specific sources, neutrino telescopes of
...km
3
scale are needed. In order to complement the IceCube detector currently under construction in the South Pole, a corresponding Northern Hemisphere detector is needed. The three neutrino telescope projects in the Mediterranean, ANTARES, NEMO and NESTOR have joined forces in order to develop, prepare, construct and operate such a research facility, KM3NeT. To this end, the EU is funding a 3-year design study. In the present paper, the status of the design study is presented and options for the various technical problems are discussed.
•Project resources leveling and scheduling under time and cost constraints.•Prioritization rules examination as decision making problem.•Standard optimization techniques and Multi-Attribute Decision ...Models combination.•Project duration and resources moments compensation to select the most suitable schedule.
Project scheduling is one of the most vital processes in Project Management. It is a widely discussed topic in academic and practical circles due to its importance and complexity. Manpower, machines, materials and equipment are used for the execution of project activities, but these mostly have limited availability, which can constrain project scheduling procedures. Project resources might exceed or fall short of the resource demand in a project's time horizon. These considerations present issues to project managers who must try to properly allocate among these demands in order to achieve a near optimal utilization during a project's lifetime. Resource leveling is among the greatest challenges faced by project managers as the success of a project largely depends on it. This is because peaks and valleys in the resource usage histogram are responsible for cost overruns due to the necessary recruitment, dismissal and training of the personnel Moreover, issues may arise regarding the efficient management of available resources given that large peaks correspond to fluctuations in resource allocation during a project's life cycle or construction period. To address these issues, resource leveling provides procedures and frameworks that ensure the efficient management of resources to obtain smooth resource usage profiles. These procedures attempt to identify activities that should be delayed to resolve resource over-allocations under time and cost constraints. Given the existence of a variety of available rules that could be followed by project managers to prioritize activities, the paper at hand examines the implementation of five Multi-Attribute Decision Making models and how they perform in the scheduling of a solar park construction project. Namely these models are the Weighted Sum Method, Analytic Hierarchy Process, PROMETHEE, TOPSIS, Ordered Weighted Average (OWA) and Hybrid Weighted Average (HWA). Finally, the derived results are discussed in comparison with those obtained by the standard resource leveling procedures of MS-Project.
PDF
