Dietary supplements containing bitter orange unripe fruit extract/
p-synephrine are consumed worldwide for lose weight. This study were conducted to determine the concentration of
p-synephrine in ...unripe fruits and leaves from
Citrus aurantium Lin,
C. sinensis Osbeck,
C. deliciosa Ten,
C. limon Burm and
C. limonia Osbeck, collected in Southern Brazil, and to evaluate the acute toxicity of
C. aurantium extract and
p-synephrine. A high performance liquid chromatographic method with diode array detector (HPLC-DAD) was optimized and validated for determination of
p-synephrine. The results indicate that all of analyzed samples present
p-synephrine in amounts that range from 0.012% to 0.099% in the unripe fruits and 0.029 to 0.438% in the leaves. Acute oral administration of
C. aurantium extracts (2.5%
p-synephrine, 300–5000
mg/kg) in mice produced reduction of locomotor activity,
p-synephrine (150–2000
mg/kg) produced piloerection, gasping, salivation, exophtalmia and reduction in locomotor activity, which was confirmed in spontaneous locomotor activity test. All the effects were reversible and persisted for 3–4
h. The toxic effects observed seem to be related with adrenergic stimulation and should alert for possible side effects of
p-synephrine and
C. aurantium.
The improved radiation hardness of p-type Si detectors is hindered by the radiation-induced acceptor removal process, which is not fully understood yet. Through atomistic modeling of displacement ...damage and dopant interactions, we analyze the acceptor removal under neutron irradiation, providing physical insight into its microscopic origin. Our results show that the fast decay of the effective dopant concentration (Neff) at low irradiation fluences is due to B deactivation caused by Si self-interstitials. The intriguing increase of the acceptor removal parameter with the initial dopant concentration (Neff,0) is explained by the limited number of mobile Si self-interstitials that survive annihilation and clustering processes. The sublinear dependence of the removal parameter on Neff,0 is associated to the inhomogeneity of damage for low Neff,0 and the formation of B-interstitial clusters with several B atoms for high Neff,0. The presence of O and C modifies B deactivation mechanisms due to the key role of BiO defects and the trapping of vacancies and Si self-interstitials, but for the impurity concentrations analyzed in this work (O >> C) it has little effect on the overall amount of removed acceptors. At high irradiation fluences, the reported increase of Neff is attributed to the formation of defect-related deep acceptors. From the analysis of the defect concentrations resulting from neutron irradiation and the occupancy of small clusters with acceptor levels reported in literature, we point out the tetra-vacancy cluster as one of the main contributors to Neff with negative space charge.
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Front-end process modeling in silicon Pelaz, L.; Marqués, L. A.; Aboy, M. ...
The European physical journal. B, Condensed matter physics,
12/2009, Letnik:
72, Številka:
3
Journal Article
Recenzirano
Front-end processing mostly deals with technologies associated to junction formation in semiconductor devices. Ion implantation and thermal anneal models are key to predict active dopant placement ...and activation. We review the main models involved in process simulation, including ion implantation, evolution of point and extended defects, amorphization and regrowth mechanisms, and dopant-defect interactions. Hierarchical simulation schemes, going from fundamental calculations to simplified models, are emphasized in this Colloquium. Although continuum modeling is the mainstream in the semiconductor industry, atomistic techniques are starting to play an important role in process simulation for devices with nanometer size features. We illustrate in some examples the use of atomistic modeling techniques to gain insight and provide clues for process optimization.
Abstract
Background
In the last decade, direct oral anticoagulants (DOACs) were incorporated as an alternative for anticoagulation in patients with venous thromboembolism. Although they have a better ...pharmacologic profile than vitamin K antagonists (VKAs), the use of these drugs is not massive.
Purpose
Assess the rate of use of DOACs in acute pulmonary embolism (PE) patients (P) in Argentina and analyze the determinants of their use.
Methods
Based on a registry of 684 P admitted for acute PE in 75 academic centers between October 2016 and November 2017, we performed an analysis of DOACs prescription at discharge. A conventional statistical analysis was performed, to assess the differences between the P that received DOACs or other anticoagulants using univariate and multivariate models.
Results
579 of 601 P who survived were discharged with anticoagulant treatment: 348 (60%) received VKA; 108 (19%) received DOACs (49% Rivaroxaban, 34% Apixaban, 17% Dabigatran) and 123 (21%) received low molecular weight heparins.
Patients who received DOACs had lower severity of PE and less risk of bleeding. The main baseline characteristics are described in table 1. Also, those patients who received DOACs at discharge had fewer in-hospital complications (heart failure, infections or bleeding; all p<0.05).
In the multivariate analysis, health insurance (OR 7.45, 95% CI: 1.74–31.9, p<0.01) was an independent predictor of DOACs prescription at discharge. The history of previous heart failure (OR 0.19, 95% CI: 0.04–0.84, p=0.03) or oncologic disease (OR 0.49; 95% CI: 0.27–0.89; p=0.02) were inversely and independent predictors for DOACs prescription.
Variable
DOACs
Other anticoagulants
P
OR
CI (95%)
Male sex
51 (47.2%)
196 (41.6%)
0.29
–
–
Age
64.3±17.6
63.3±16.6
0.61
–
–
Health insurance
106 (98.1%)
402 (85.4%)
0.01
9.1
(2.2–37.7)
CKD without dialysis
2 (1.9%)
34 (7.3%)
0.06
0.24
(0.06–1.03)
Heart failure
2 (1.9%)
55 (11.7%)
0.01
0.14
(0.03–0.59)
Oncology disease
16 (14.8%)
127 (27%)
0.01
0.47
(0.27–0.83)
Previous anticoagulation
3 (2.8%)
44 (9.3%)
0.03
0.28
(0.08–0.91)
sPESI
1±1.12
1.28±1.11
0.02
0.78
(0.64–0.96)
RIETE
1.71±1.17
2.05±1.33
0.02
0.81
(0.68–0.97)
CKD: Chronic kidney disease; TIA: Transient ischemic attack.
Conclusions
The rate of use of DOACs in survivors of an acute PE in Argentina was 19%, and this P present lower clinical risk, fewer co-morbidities and greater access to health coverage.
Ion implantation is a very well established technique to introduce dopants in semiconductors. This technique has been traditionally used for junction formation in integrated circuit processing, and ...recently also in solar cells fabrication. In any case, ion implantation causes damage in the silicon lattice that has adverse effects on the performance of devices and the efficiency of solar cells. Alternatively, damage may also have beneficial applications as some studies suggest that small defects may be optically active. Therefore it is important an accurate characterization of defect structures formed upon irradiation. Furthermore, the technological evolution of electronic devices towards the nanometer scale has driven the need for the formation of ultra-shallow and low-resistive junctions. Ion implantation and thermal anneal models are required to predict dopants placement and electrical activation. In this article, we review the main models involved in process simulation, including ion implantation, evolution of point and extended defects and dopant-defect interactions. We identify different regimes at which each type of defect is more relevant and its inclusion in the models becomes crucial. We illustrate in some examples the use of atomistic modeling techniques to gain insight into the physics involved in the processes as well as the relevance of the accuracy of models.
Laser thermal annealing of pre-amorphized silicon can be used to achieve sharp junctions with enhanced dopant activation. The changes in the properties of silicon as a consequence of the phase ...transition form amorphous to liquid caused by the laser annealing could influence the subsequent recrystallization and the activation of the dopants. In this work we have used the molecular dynamics simulation technique to study the physics of the amorphous-to-liquid transition in silicon. The changes in density, internal energy, structure and diffusion behavior are obtained from the simulations and analyzed. We have observed that for temperatures between the amorphous and crystal melting points there exists an intermediate phase which shares some of the properties of the amorphous and liquid silicon.
Abstract
Introduction
Cardiac resynchronization therapy (CRT) has emerged as an important treatment for patients with heart failure and reduced ejection fraction (EF) despite optimal pharmacological ...therapy. Some studies showed non-responders rate near 30%. Nowaday there is no gold standard method for selection, evaluation and follow up on this group of patients. Multiple techniques used and operator dependence made echocardiogram failed. Synchromax 2 is a device designed to evaluate non-invasive electrical synchrony. It is fast, reproducible and non-operator dependent. Synchromax was evaluated and correlated with other techniques in previous studies.
Objective
Evaluate CRT response rate guided by electrical synchrony during the device implantation and follow up.
Material and methods
43 patients were evaluated in an institution in Buenos Aires. A ICD-CRT was implanted in all patients due dilated cardiomyopathy, low EF (less than 35%) and left bundle branch block (LBBB). Non-invasive electrical synchrony evaluation (Synchromax 2) was performed in all patients in baseline condition, during device implantation and the follow up. Synchrony index and curves were analyzed. Curve type 4 and index between 0,4 and 0,7 were considered synchronous. Curve type 6 and 10 and index more than 0.7 were considered disynchronous. Interventricular intervals were modified to achieve the best curve and synchrony index. Super responders were considered when EF increased >50%. Baseline and 6 month after implantation echocardiogram were performed.
Results
Mean age 64 years. 39% females. Non-coronary dilated cardiomyopathy was main aetiology (63,1%). EF baseline average was 27%. A baseline index more than 0,7 was in 73,3% of the patients. Curve 6 was the most frequent (55,2%). Follow up average EF was 39% (increased 12%), the super responders rate was 18,6% (8 patients). Type 4 curve and index between 0,4 and 0,7 were achieved in 28 cases (65,1%). EF increased from 23% (baseline) to 42% (follow up). Average 19%. Type 4 curve was not achieved in 15 patients (34,9%). In this group, EF increased from 29% (baseline) to 34% (follow up). Average 5%.
Conclusion
Electrical synchrony evaluation using Synchromax 2 during ICD-CRT device implantation improves responders rate. When synchronous type 4 curve is achieved EF improves significantly. If type 4 curve is not found results will be unsuccessfully. Synchromax is fast, simple and non-operator dependent.
Funding Acknowledgement
Type of funding source: None
Abstract
Introduction
Para-hisian stimulation produces a physiological cardiac activation through normal conduction system. Frequently it is used in patients with no electrical conduction disorders. ...We developed an implant technique guided by non-invasive electrical synchrony using conventional screw-in leads. Non-selective para-hisian stimulation can normalize electrical conduction disorders. Synchromax is a novel device used to evaluate non-invasive cardiac electrical synchrony. It is easy to understand, fast to obtain, non-invasive and reproducible. Synchromax was analyzed in previous studies and correlated with other methods.
Objective
Evaluate usefulness and safety of non-selective para-hisian stimulation guided by non-invasive cardiac electrical synchrony method using conventional screw-in leads to normalize electrical conduction disorders.
Materials and methods
421 patients with para-hisian stimulation were analyzed retrospectively. 139 patients had different intraventricular and auriculo-ventricular electrical disorders. Non-selective para-hisian stimulation guided by no-invasive electrical synchrony method (Synchromax) was performed in all cases. Synchrony index and curves were analyzed according curves chart. Type 2 curve and index between 0,1 and 0,4 were considered synchronous. Type 8 curve and index more than 0.7 were considered dyssynchronous.
Results
Mean age 71 years (±7 years). 65,4% males. 30,9% had 2° and 3° grade AV block associated. Patients were divided in 5 groups:
1-Right bundle branch block (RBBB): 43 patients
2-Left bundle branch block (LBBB): 33 patients
3-Brugada Syndrome: 8 patients
4-Left anterior hemi-block (LAHB) 30 patients.
5-RBBB associated with LAHB: 25 patients.
QRS normalization was achieved in 87% of the cases using non-selective para-hisian stimulation guided by Synchromax with conventional screw in leads. A ventricular approach was performed during implantation. Electrical synchrony was not solved in 13% of patients mostly in LBBB and RBBB associated with LAHB. Two dislodgments were evidenced.
Conclusions
Non-selective para-hisian stimulation guided by Synchromax method using conventional screw in leads solved most of intraventricular electrical disorders. It is also safe to use in patients with auriculo-ventricular electrical disorder.
Funding Acknowledgement
Type of funding source: None
Abstract
Introduction
Right ventricular apex stimulation solves electrical disorder but electrical disynchrony can be generated. Left bundle branch block results in heart failure and device upgrade ...is needed in some cases. Para-hisian stimulation generates a physiological cardiac activation through normal conduction system. Sheaths and special leads are used with current techniques. We developed an implantation technique guided by non-invasive electric synchrony using conventional screw-in leads. Synchromax is a novel device used to evaluate non-invasive cardiac electrical synchrony. It is easy to understand, fast to obtain, non-invasive and reproducible. Synchromax was analyzed in previous studies and correlated with other methods.
Objective
Usefulness and safety of non-invasive cardiac electrical synchrony method using conventional screw-in leads to guide para-hisian device implantation.
Materials and methods
421 patients were evaluated. All patients had indication of ventricular stimulation (pacemaker and ICD). Non-invasive electrical synchrony was performed with Synchromax study during the device implantations in all patients. Synchrony index and curves were analyzed. Type 2 curve and index between 0,1 and 0,4 were considered synchronous. Type 8 curve and index more than 0.7 were considered dyssynchronous. Attempt numbers, thresholds, fluoroscopy time and dislodgments were analyzed.
Results
Mean age 69 years (±8 years). 67,9% males. 421 devices were implanted (334 pacemakes and 87 ICDs). Sick sinus syndrome was the main pacemaker aetiology and dilated cardiomyopathy was in patients with ICD. Conventional screw-in leads were used in all cases. An implant technique was designed. A J-shaped curve with a small perpendicular curve at the tip is performed in the stylet. On average 1,9 attempts were made. Thresholds average 1,2 mV. High thresholds in 4 patients with selective parahisian stimulation. 7 dislodgments was evidenced (1,6%). Fluoroscopy time average 8,4 min. Type 2 curve and index under 0,4 was obtained in 94,5% of cases.
Conclusions
Para-hisian pacemaker implantation guided by Synchromax method using conventional screw-in leads is safe and useful achieving a physiological stimulation. Few attempts were needed with this new technique. Thresholds were similar to those used in conventional technique.
Funding Acknowledgement
Type of funding source: None
Metacognitive strategies are vital in enhancing students’ writing competence, but local studies correlating them are limited. Thus, this descriptive-comparative and correlational study examined the ...use of the metacognitive strategies and the writing competence of 303 Grade 11 students of a public high school. Data gathered using a researcher-made survey questionnaire and a test led to the recommendation for the Division of Negros Occidental to adopt the proposed syllabus for English for Academic and Professional Purposes.
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