Fast Initiation Research Articles

The perioperative myocardial infarction - an interdisciplinary task

Cardiovascular complications, particularly perioperative myocardial infarction (PMI), are major contributors to mortaliyt after noncardiac surgery. PMI often occurs unnoticed without symptoms or ECG changes. Despite ist silent presentation, PMI is associated with increased mortality. The combination of high associated mortality and diagnostic challenges mandates increased awareness of PMI. Perioperative myocardial infarction may result from plaque rupture (PMI type I) or be caused by a myocardial supply-demand imbalance of oxygen without plaque rupture (PMI type II). Most PMIs occur within the first 3 days after surgery, highlighting the need for clinical monitoring in order to allow fast diagnosis and initiation of appropriate therapy. Measurement of cardiac troponin and 12-lead ECG are the diagnostic cornerstone. Therapy of PMI represents a challenge for physicians and requires a collaboration of surgeons, anesthesiologists and cardiologists.

Faster initiation in the Friedel-Crafts reaction of benzyl fluorides using trifluoroacetic acid as activator

We report that the addition of a catalytic amount of trifluoroacetic acid (TFA) shortens the induction period associated with the 1,1,1,3,3,3-hexafluoroisopropoanol (HFIP)-promoted Friedel-Crafts reaction of benzylic fluorides. This faster initiation is due to TFA’s strong hydrogen-bond donation capability, not its Brønsted acidity. The improved reaction conditions were applied to a set of substrates, demonstrating how they could improve yields and reliability of this transformation.

Continuous dosing of fast initiator during vinyl chloride suspension polymerization: Polymerization rate and PVC properties

ABSTRACTContinuous dosing of a fast initiator during the suspension polymerization of vinyl chloride has been carried out in a pilot‐scale reactor. The kinetics course of this polymerization and the particle features of the resulting grains were discussed and compared to the conventional polymerization with the same conversion and maximum reaction rate. It was found for the system used that a suitable dosage trajectory allows the reaction rate to remain constant during polymerization. This decreases the polymerization time up to 53% compared with the conventional suspension polymerization, while the molecular weight distribution and molecular weight of the final grains remained almost unchanged. SEM micrographs revealed that PVC grains prepared using this polymerization process had irregularly shaped, uneven particle surfaces and larger particle sizes. The grains also featured high porosity with loosely aggregated smaller primary particles that led to low levels of residual unreacted monomer. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44079.

Continuous Dosing of a Fast Initiator during Suspension Polymerization of Vinyl Chloride for Enhanced Productivity: Mathematical Modeling and Experimental Study

An adopted mathematical model was developed to reduce the batch time required for the suspension polymerization of vinyl chloride in order to improve the productivity by continuous dosage of a fast initiator during polymerization reaction. The model was accompanied by a particle swarm optimization (PSO) algorithm, so as to optimize the initiator dosage rate during the process for a certain conversion. A pilot scale reactor was employed to verify the mathematical model predictions. This showed that the model predictions are in very good agreement with the experimental data. A proper initiator dosage trajectory during the course of the reaction was obtained in such a way that the reaction rate over the course of polymerization was constant and corresponded to the maximum rate in the conventional case (non-continuous addition of a mild initiator). The maximum reduction in reaction time relative to conventional polymerization for the predefined conversion was 53%. Analyzing the molecular characteristics of the samples showed that the molecular characteristics of the final poly(vinyl chloride) (PVC) product remained relatively unchanged under an optimum initiator dosage trajectory compared with the conventional process.

Line-based initialization method for mobile augmented reality in aircraft assembly

A fast line-based initialization method for mobile augmented reality in aircraft assembly is proposed in this paper. The challenge of recognition and pose estimation of aircraft structural parts in monocular images on mobile devices is mainly addressed. Rather than local feature points, straight lines are extracted and utilized here since they are more suitable for aircraft structural parts, which usually have a solid color and lack textures to generate invariant descriptors. The geometric relationship between 3D world lines and their projections on the camera image are built to estimate the relative 6-DOF pose including rotation and translation, respectively. The inertial sensors of mobile devices are used to provide partial rotation information directly, and the rest is obtained through a voting process. To shrink the search space and, therefore, improve the speed and robustness of initialization, a color-based ROI mask and a vertical lines extraction method are proposed. To determine the translation, the color mask is first used to roughly approximate the real pose and then a possible-correspondence map of lines is built by parallelism alignment combined with the rotation already obtained. This paper describes the details of our method and also shows its effectiveness with experiments. Moreover, the proposed method is especially suitable for but not limited to the aircraft assembly field.

Deconstructing Planning Ability in Children and Adolescents with Anorexia Nervosa

ABSTRACTWeaknesses in planning by patients with anorexia nervosa (AN) have been noted (e.g., Zakzanis, Campbell, & Polsinelli, 2010) and are generally based on adults. This study explored D-KEFS Tower Test performance to better understand learning styles and strategies used by child and adolescent patients with AN compared to healthy controls. Overall, no significant differences were found in achievement; however, Item 5 predicted performance across harder items. The AN group was significantly faster to move their first disc suggesting patients with AN did not spend as much time planning their strategies for item completion. The findings of this study in conjunction with other studies investigating planning in AN may suggest the existence of subtle differences in learning style and strategy, such as faster initiation times, rather than gross planning differences. Further research is required to better understand the relationship between these subtle differences and clinical presentations.

Shape-appearance-correlated active appearance model

Among the challenges faced by current active shape or appearance models, facial-feature localization in the wild, with occlusion in a novel face image, i.e. in a generic environment, is regarded as one of the most difficult computer-vision tasks. In this paper, we propose an Active Appearance Model (AAM) to tackle the problem of generic environment. Firstly, a fast face-model initialization scheme is proposed, based on the idea that the local appearance of feature points can be accurately approximated with locality constraints. Nearest neighbors, which have similar poses and textures to a test face, are retrieved from a training set for constructing the initial face model. To further improve the fitting of the initial model to the test face, an orthogonal CCA (oCCA) is employed to increase the correlation between shape features and appearance features represented by Principal Component Analysis (PCA). With these two contributions, we propose a novel AAM, namely the shape-appearance-correlated AAM (SAC-AAM), and the optimization is solved by using the recently proposed fast simultaneous inverse compositional (Fast-SIC) algorithm. Experiment results demonstrate a 5–10% improvement on controlled and semi-controlled datasets, and with around 10% improvement on wild face datasets in terms of fitting accuracy compared to other state-of-the-art AAM models.

Fast and high-fidelity optical initialization of spin state of an electron in a semiconductor quantum dot using light-hole-trion states

We theoretically show that under the Faraday geometry fast and high-fidelity optical initialization of electron spin (ES) state in a semiconductor quantum dot (SQD) can be realized by utilizing the light-hole (LH)-trion states. Initialization is completed within the time scale of ten nanoseconds with high fidelity, and the initialization laser pulse can be linearly, right-circularly, or left-circularly polarized. Moreover, we demonstrate that the time required for initialization can be further shortened down to a few hundreds of picoseconds if we introduce a pillar-microcavity to promote the relaxation of a LH-trion state towards the desired ES state through the Purcell effect. We also clarify the role of heavy-hole and light-hole mixing induced transitions on the fidelity of ES state initialization.

The Fast-Evolving phy-2 Gene Modulates Sexual Development in Response to Light in the Model Fungus Neurospora crassa.

ABSTRACTRapid responses to changes in incident light are critical to the guidance of behavior and development in most species. Phytochrome light receptors in particular play key roles in bacterial physiology and plant development, but their functions and regulation are less well understood in fungi. Nevertheless, genome-wide expression measurements provide key information that can guide experiments that reveal how genes respond to environmental signals and clarify their role in development. We performed functional genomic and phenotypic analyses of the two phytochromes in Neurospora crassa, a fungal model adapted to a postfire environment that experiences dramatically variable light conditions. Expression of phy-1 and phy-2 was low in early sexual development and in the case of phy-2 increased in late sexual development. Under light stimulation, strains with the phytochromes deleted exhibited increased expression of sexual development-related genes. Moreover, under red light, the phy-2 knockout strain commenced sexual development early. In the evolution of phytochromes within ascomycetes, at least two duplications have occurred, and the faster-evolving phy-2 gene has frequently been lost. Additionally, the three key cysteine sites that are critical for bacterial and plant phytochrome function are not conserved within fungal phy-2 homologs. Through the action of phytochromes, transitions between asexual and sexual reproduction are modulated by light level and light quality, presumably as an adaptation for fast asexual growth and initiation of sexual reproduction of N. crassa in exposed postfire ecosystems.

Sticky Projections-A Model-Based Approach to Interactive Shader Lamps Tracking.

Shader lamps can augment physical objects with projected virtual replications using a camera-projector system, provided that the physical and virtual object are well registered to each other. Precise registration and tracking has been a cumbersome and intrusive process in the past. In this paper, we present a new method for tracking complex-shaped physical objects interactively. In contrast to previous approaches our system is mobile and makes solely use of the projection of the virtual replication to track the physical object and "stick" the projection to it. Our method consists of two stages, a fast pose initialization based on structured light patterns and a non-intrusive frame-by-frame tracking based on features detected in the projection. During the tracking phase, a radiometrically corrected virtual camera view based on the current pose prediction is rendered and compared to the captured image. Matched features are triangulated providing a sparse set of surface points that is robustly aligned to the virtual model. The alignment transformation serves as an input for the new pose prediction. Detailed experiments including the evaluation of the overlay accuracy show that our approach can accurately and robustly track complex objects at interactive rates.

Secondary System Initialization Protocol Using FFT-based Correlation Matching for Cognitive Radio Ad-hoc Networks

Due to the increasing demand for spectrum resources, cognitive radio networks and dynamic spectrum access draw a lot of research into efficiently utilizing limited spectrum resources. To set up cluster-based CR ad-hoc common channels, conventional methods require a relatively long time to successfully exchange the initialization messages. In this paper, we propose a fast and reliable common channel initialization protocol for CR ad-hoc networks. In the proposed method, the cluster head sequentially broadcasts a system activation signal through its available channels with a predetermined correlation pattern. To detect the cluster head`s broadcasting channels and to join the cluster, each member node implements fast Fourier transform (FFT) and computes autocorrelation of an FFT bin sequence for each available channel of the member node. This is compared to the predetermined reference pattern. The join request and channel decision procedures are also presented in this paper. In a simulation study, the performance of the proposed method is evaluated.

Effect of the bulkiness of indenylidene moieties on the catalytic initiation and efficiency of second-generation ruthenium-based olefin metathesis catalysts

Fast initiation and high efficiency of ruthenium indenylidene catalysts induced by steric repulsion between two ligands (SIMes ligand and bulky indenylidene ligand).

STAT5 activation in B-cell acute lymphoblastic leukemia: damned if you do, damned if you don't.

A significant role of the microenvironment in leukemogenesis is beginning to emerge. The leukemia cell microenvironment consists of not only the stromal and endothelial cell components but also the normal hematopoietic cells. Signal transducer and activator of transcription 5 (STAT5) is a latent transcription factor that is normally transiently activated by phosphorylation in response to microenvironmental signals. In hematopoietic cells, persistently activated STAT5 via aberrant receptor signaling, Janus kinases (JAKs), or intracellular tyrosine kinases is a bona fide driver of leukemogenesis. However, active IL-7/STAT5 signaling also protects the early B-cell genome by suppressing error-prone recombination and vulnerability to transformation. Along these lines, we have reported that lymphocyte development from transplanted STAT5-deficient fetal liver cells was blocked at the pre-pro-B-cell stage but when combined with transgenic Myc and Bcl-2 promoted faster initiation of B-ALL. Furthermore, inflammatory responses may also be involved in leukemia initiation in both pediatric and adult patients which are associated with decreased phosphorylation of STAT5. Likewise, additional targeted agents continue to be developed for precision medicine that prominently suppress signaling pathways. A common theme of all of these perturbations is potential risk for dysregulating hematopoiesis through general transcriptional modulation. Here we discuss the potential for STAT5 inhibition as a double edged sword in certain hematologic disorders, such as early B-cell lymphoblastic leukemias. Considering the rapid pace of understanding of the pre-leukemic decrease in poly-clonality that precedes leukemia, the functional changes associated with microenvironmental influences are thus of potential clinical significance.

An innovative strategy to increase a professional workforce: the fast track initiative for health visitors in England.

Fast tracking is one strategy that organizations use to ameliorate workforce shortfalls by attracting new recruits, and accelerating their skills development and experience. In response to the Government's target of rapidly expanding the number of health visitors in England's National Health Service, the fast track initiative was launched to recruit newly qualified (fast track) as well as experienced (standard entry) nurses and midwives onto health visiting programmes. This paper evaluates the fast track initiative, from the perspective of fast track and standard entry students, practice teachers and health visitor managers. A mixed methods design was used comprising a questionnaire survey (n = 71 students), semi-structured interviews (n = 37 students), telephone interviews (n = 13 managers) and six focus groups (n = 24 practice teachers). Data were collected between April 2012 and July 2013. Descriptive statistics, t-tests and the Pearson Chi-square test were used to analyse the quantitative data. The qualitative data were analysed thematically. Motivations for health visiting as a career choice were similar for fast track and standard entry students, with career progression and interest in health promotion being key motivators. There was consensus that personal qualities and characteristics were more important than experience or qualifications. However, fast track students were significantly less confident about their public health competencies in leadership and management (p < 0.05) and communication (p < 0.02). Practice teachers and managers also reported that fast track students required more intensive supervision particularly at the beginning of the programme. Programme completion including pass rates and academic achievement showed no significant difference by route of entry (p > 0.5). Fast tracking offers a useful recruitment strategy in order to expand the health visitor workforce, but longitudinal research is needed to confirm benefits such as retention and career trajectories.

High-fidelity initialization of long-lived quantum dot hole spin qubits by reduced fine-structure splitting

We demonstrate an on-demand hole spin qubit initialization scheme meeting four key requirements of quantum information processing: fast initialization (1/e ~ 100 ps), high fidelity (F > 99%), long qubit lifetime $(2T_{1}>T_{2}^{*}\simeq10\:\mathrm{ns})$, and compatibility with optical coherent control schemes. This is achieved by rapidly ionizing an exciton in an InGaAs quantum dot with very low fine-structure splitting at zero magnetic field. Furthermore, we show that the hole spin fidelity of an arbitrary quantum dot can be increased by optical Stark effect tuning of the fine-structure splitting close to zero.

Synthesis, characterization, X-ray crystallography analysis and kinetic study of tris(2-(4-trifluoromethylbenzylideneamino)ethyl)amine copper derivatives

A two-component synthetic procedure for a tetradentate, tripodal organo-fluorine derivative; along with copper(I) and copper(II) analogues is presented. Solid state studies show that the (4TFM-TREN) ligand crystallizes in a monoclinic system with P21/c space group, while the [CuI(4TFM-TREN)][PF6] complex crystallizes in a cubic crystal system with P213 space group. Kinetic studies monitoring the addition of carbon tetrachloride to the copper(I) analogue produced an activation rate constant value of 5×10−2M−1s−1. UV–Vis spectroscopy results confirmed the ability of compounds presented here to slow down the activation step of atom transfer radical addition reactions employing fast initiators such as carbon tetrachloride. This work addresses a need to develop novel methods that can be used in activation rate constant value calculations for ideal atom transfer radical addition (ATRA) reactions incorporating active copper catalysts and fast initiators.

Alternating Sulfone Copolymers Depolymerize in Response to Both Chemical and Mechanical Stimuli.

This work describes the depolymerization of poly(vinyl acetate-alt-sulfur dioxide) (PVAS) as initiated by chemical and mechanical stimuli. In recent years, macromolecules that are able to depolymerize in response to specific stimuli have been highly sought because of their ability to amplify signal for sensing and drug delivery. Examples include self-immolative polymers from alkoxyphenol derivatives and polyaldehydes. We show here that alternating copolymers of sulfur dioxide and vinyl acetate are able to undergo similar depolymerization into their monomer components in response to various chemical and mechanical stimuli. Certain vinyl monomers such as vinyl acetate are able to polymerize with sulfur dioxide in a perfectly alternating manner, and the resulting copolymer possesses a low ceiling temperature. We show that this polymer is able to break down into its monomer components when subjected to UV/acetone, various Reactive Oxygen Species (ROS), and ultrasonication. In the case of UV, the acetone reacted via a Norrish reaction to produce free radicals that caused clean monomer production. For ROS, the polymer showed reactivity to both oxidizing and radical-containing ROS. Through kinetic studies, these polymers were shown to proceed via a two-part, first-order kinetic model with a fast initiation phase and a slow depolymerization phase. Finally, the polymers were subjected to probe ultrasonication, and depolymerization occurred as well. Most tellingly, the polymer again showed a fast initiation step and continued to depolymerize even after ultrasonication stopped. This class of polymers shows potential for drug delivery in response to both endogenous chemical and externally-applied mechanical cues.

A Fast Link Initialization Protocol for Beam-Steering based Cellular Backhaul Systems

&lt;p&gt;To deal with the enormous increase of mobile data traffic, new cellular network topologies are necessary. The reduction of cell area and the usage of light-weighted base stations serving only a handful of users, commonly known as the small cell approach, seems to be a suitable solution addressing changes in user expectations and usage scenarios. This paper is an extended version of [1], where current challenges of small cell deployments were presented from a backhaul perspective. A mesh-type backhaul network topology based on beam-steering millimeter-wave systems was proposed as a future-proof solution. In this paper, we focus on a link initialization protocol for beam-steering with highly directive antennas. Special requirements and problems for link setup are analyzed. Based on that, a fast protocol for link initialization is presented and it is evaluated in terms of the resulting initialization speed-up compared to state-of-the-art solutions. Furthermore, a potential approach for extending the fast link initialization protocol to support point-to-multipoint connections is given.&lt;/p&gt;

Enhanced spin capturing polymerization: Numerical investigation of mechanism

ABSTRACTSimulation on the kinetic scheme of enhanced spin capturing polymerizations (ESCP) were performed to reveal the influence of different parameters, e.g., initiation rate, spin capturing and side reactions on the properties (the monomer conversion, degree of polymerization, polydispersity index, and the fraction of “living” chains) of polymer obtained. The kinetic scheme of ESCP was solved numerically as well as the method of statistical moments of molecular weight distribution was applied to get some numerical expressions for analysis. The simulations showed that fast initiation rate can lead to decrease of living fraction and broadening of molecular weight distribution. Whereas high rate of spin capturing makes the polymer chains shorter but increases living character. And side reactions always decrease livingness of the polymer obtained. Finally in the case of absence of side reaction we were able to formulate criteria for formation of polymer with target molecular weight and quota of living chains via ESCP process. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2546–2556

Minimally Invasive Muscle Sparing Posterior-Only Approach for Lumbar Circumferential Decompression and Stabilization to Treat Spine Metastasis—Technical Report

Palliative tumor resection and subsequent stabilization are important for maximizing function and quality of life for patients suffering from spinal metastases. However, traditional operative techniques for spinal metastases with vertebral body destruction involve extensive soft tissue dissection. In the lumbar spine, open 2-staged spine procedures are routinely required with an anterior retroperitoneal approach for corpectomy and cage insertion and posterior decompression and stabilization with pedicle screws and rods. Both stages require extensive soft tissue dissection that results in significant surgical morbidity, long recovery time, and subsequent delay in initiating postoperative chemoradiotherapy, as well as initially hampering patients' overall quality of life. A minimally invasive approach is desirable for achieving spinal stability, pain control, functional recovery, rapid initiation of adjuvant therapies, and overall patient satisfaction, especially in patients whose medical and surgical therapies are aimed at palliation rather than cure. A 59-year-old man with renal cell carcinoma and a known L1 vertebral body metastasis presented with severe progressive low back pain and was found to have a pathologic L1 vertebral body fracture with focal kyphosis. Here, we describe a minimally invasive muscle-sparing, posterior-only approach for L1 transpedicular hemicorpectomy and expandable cage placement, L1 laminectomy, and T11-L3 posterior instrumented stabilization. The surgical corridor was achieved through the Wiltse muscle plane between the multifidus and longissimus muscles so that minimal muscle detachment was required to achieve transpedicular access to the anterior and middle spinal columns. The L1 nerve root was completely skeletonized to allow adequate lumbar hemicorpectomy, tumor resection, and expandable titanium cage insertion. Lastly, percutaneous pedicle screws and rods were inserted from T11 to L3 for stabilization. The patient tolerated the procedure well with no complications and less than 200 mL estimated blood loss. Postoperative computed tomography revealed restoration of intervertebral height and adequate tumor resection with excellent placement of the expandable cage and posterior construct. The patient was discharged on postoperative day 4 and had nearly no back pain 3 weeks after surgery. Adjuvant therapies were started soon after. At the 6-month follow-up, the patient required minimal narcotic pain medication. Computed tomography scan demonstrated stable hardware with no evidence of failure. A minimally invasive muscle-sparing, posterior-only approach is a promising surgical strategy for 360-degree decompression and stabilization for the treatment of lumbar spinal metastases with minimized blood loss, muscle detachment and postoperative pain, and fast postoperative recovery and initiation of adjuvant therapy.