The Scimitar Precooled Mach 5 Engine

Accepted versio

Effect of temporary cements on the shear bond strength of luting cements

OBJECTIVE: The purpose of this study was to evaluate, by shear bond strength (SBS) testing, the influence of different types of temporary cements on the final cementation using conventional and self-etching resin-based luting cements. Material and Methods: Forty human teeth divided in two halves were assigned to 8 groups (n=10): I and V (no temporary cementation); II and VI: Ca(OH)2-based cement; III and VII: zinc oxide (ZO)-based cement; IV and VIII: ZO-eugenol (ZOE)-based cement. Final cementation was done with RelyX ARC cement (groups I to IV) and RelyX Unicem cement (groups V to VIII). Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. RESULTS: Means were (MPa): I - 3.80 (&plusmn;1.481); II - 5.24 (&plusmn;2.297); III - 6.98 (&plusmn;1.885); IV - 6.54 (&plusmn;1.459); V - 5.22 (&plusmn;2.465); VI - 4.48 (&plusmn;1.705); VII - 6.29 (&plusmn;2.280); VIII - 2.47 (&plusmn;2.076). Comparison of the groups that had the same temporary cementation (Groups II and VI; III and VII; IV and VIII) showed statistically significant difference (p<0.001) only between Groups IV and VIII, in which ZOE-based cements were used. The use of either Ca(OH)2-based (Groups II and VI) or ZO-based (Groups III and VII) cements showed no statistically significant difference (p>0.05) for the different luting cements (RelyX TM ARC and RelyX TM Unicem). The groups that had no temporary cementation (Groups I and V) did not differ significantly from each other either (p>0.05). CONCLUSION: When temporary cementation was done with ZO- or ZOE-based cements and final cementation was done with RelyX ARC, there was an increase in the SBS compared to the control. In the groups cemented with RelyX Unicem, however, the use of a ZOE-based temporary cement affected negatively the SBS of the luting agent used for final cementation

Učinak topljivosti na kinetiku oslobađanja vodotopljivih i vodonetopljivih lijekova iz matriksnog sustava na bazi HPMC

The purpose of the present research work was to observe the effects of drug solubility on the release kinetics of water soluble verapamil hydrochloride and insoluble aceclofenac from polymer based matrix formulations. Matrix formulations were prepared by the direct compression method. The formulations were evaluated for various physical parameters. Along with the dynamics of water uptake and erosion, SEM and in vitro drug release of tablets were studied. Applying an exponential equation, it was found that the kinetics of soluble drug release followed anomalous non-Fickian diffusion transport whereas insoluble drug showed zero-order release. SEM study showed pore formation on the tablet surface that differed depending on drug solubility. t-Test pointed to a significant difference in the amount of both drugs released due to their difference in solubility. Solubility of the drug affects the kinetics and the mechanism of drug release.Cilj rada bio je praćenje učinka topljivosti na kinetiku oslobađanja vodotopljivog verapamil hidroklorida i netopljivog lijeka aceklofenaka iz matriksnih sustava na bazi hidrofilnog polimera. Matriksni sustavi pripravljeni su izravnom metodom kompresije. Uz ispitivanje uobičajenih fizikalnih svojstava, ispitivana je i dinamika primanja vode, te erozija, SEM i in vitro oslobađanje ljekovite tvari iz tableta. Primjenom eksponencijalne jednadžbe utvrđeno je da mehanizam oslobađanja topljivih lijekova slijedi anomalni ne-Fickov difuzijski transport, dok netopljivi lijekovi slijede kinetiku nultog reda. SEM ispitivanja pokazala su pore na površini matriksa ovisne o topljivosti ljekovite tvari. T-test ukazuje da količina oslobođenog lijeka značajno ovisi o njegovoj topljivosti. Topljivost lijeka ima značajan učinak na kinetiku i mehanizam oslobađanja

Re A (A Child) and the United Kingdom Code of Practice for the Diagnosis and Confirmation of Death: Should a Secular Construct of Death Override Religious Values in a Pluralistic Society?

The determination of death by neurological criteria remains controversial scientifically, culturally, and legally, worldwide. In the United Kingdom, although the determination of death by neurological criteria is not legally codified, the Code of Practice of the Academy of Medical Royal Colleges is customarily used for neurological (brainstem) death determination and treatment withdrawal. Unlike some states in the US, however, there are no provisions under the law requiring accommodation of and respect for residents’ religious rights and commitments when secular conceptions of death based on medical codes and practices conflict with a traditional concept well-grounded in religious and cultural values and practices. In this article, we analyse the medical, ethical, and legal issues that were generated by the recent judgement of the High Court of England and Wales in Re: A (A Child) [2015] EWHC 443 (Fam). Mechanical ventilation was withdrawn in this case despite parental religious objection to a determination of death based on the code of practice. We outline contemporary evidence that has refuted the reliability of tests of brainstem function to ascertain the two conjunctive clinical criteria for the determination of death that are stipulated in the code of practice: irreversible loss of capacity for consciousness and somatic integration of bodily biological functions

Comparative analysis of co-processed starches prepared by three different methods

Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient

Comparative analysis of co-processed starches prepared by three different methods

Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient

Powder Compaction: Compression Properties of Cellulose Ethers

Effective development of matrix tablets requires a comprehensive understanding of different raw material attributes and their impact on process parameters. Cellulose ethers (CE) are the most commonly used pharmaceutical excipients in the fabrication of hydrophilic matrices. The innate good compression and binding properties of CE enable matrices to be prepared using economical direct compression (DC) techniques. However, DC is sensitive to raw material attributes, thus, impacting the compaction process. This article critically reviews prior knowledge on the mechanism of powder compaction and the compression properties of cellulose ethers, giving timely insight into new developments in this field

Systematic 13F hedge fund alpha

Institutions holding greater than $100 million in securities are required to disclose their holdings in US listed stocks to the Securities and Exchange Commission (SEC) no later than 45 days after the quarter-end, in a form known as 13F. We show that the "best ideas" of hedge funds produce economically meaningful and statistically significant risk-adjusted returns that outperform the S&P500, following tests identified in Cohen, Polk, and Silli (2010). We construct alternative measures that are more suitable for hedge funds, rather than mutual funds: conviction and consensus. We find that to systematically identify hedge fund alpha in the 13F filings, one must select the right group of managers that have longer-term views on stock picks. We construct a trading strategy that combines conviction and consensus of such managers that outperforms the S&P500 by 3.80% on average and delivers a Sharpe ratio of 0.75 over the period Q1 2004 to Q2 2019