In this paper, we obtain upper bounds on the minimum distance for turbo codes using fourth degree permutation polynomial (4-PP) interleavers of a specific interleaver length and classical turbo codes of nominal 1/3 coding rate, with two recursive systematic convolutional component codes with generator matrix G = [ 1 , 15 / 13 ] . The interleaver lengths are of the form 16 Ψ or 48 Ψ , where Ψ is a product of different prime numbers greater than three. Some coefficient restrictions are applied when for a prime p i ∣ Ψ , condition 3 ∤ ( p i − 1 ) is fulfilled. Two upper bounds are obtained for different classes of 4-PP coefficients. For a 4-PP f 4 x 4 + f 3 x 3 + f 2 x 2 + f 1 x ( mod 16 k L Ψ ) , k L ∈ { 1 , 3 } , the upper bound of 28 is obtained when the coefficient f 3 of the equivalent 4-permutation polynomials (PPs) fulfills f 3 ∈ { 0 , 4 Ψ } or when f 3 ∈ { 2 Ψ , 6 Ψ } and f 2 ∈ { ( 4 k L − 1 ) · Ψ , ( 8 k L − 1 ) · Ψ } , k L ∈ { 1 , 3 } , for any values of the other coefficients. The upper bound of 36 is obtained when the coefficient f 3 of the equivalent 4-PPs fulfills f 3 ∈ { 2 Ψ , 6 Ψ } and f 2 ∈ { ( 2 k L − 1 ) · Ψ , ( 6 k L − 1 ) · Ψ } , k L ∈ { 1 , 3 } , for any values of the other coefficients. Thus, the task of finding out good 4-PP interleavers of the previous mentioned lengths is highly facilitated by this result because of the small range required for coefficients f 4 , f 3 and f 2 . It was also proven, by means of nonlinearity degree, that for the considered inteleaver lengths, cubic PPs and quadratic PPs with optimum minimum distances lead to better error rate performances compared to 4-PPs with optimum minimum distances.

The objective of this paper is to find an upper bound on the minimum distance for turbo codes with true cubic permutation polynomial (CPP) interleavers for some particular interleaver lengths. The method we have used consists in proofing that, for the considered interleaver lengths, every true CPP has an inverse true CPP. Then we have proved that some interleaver patterns appear for every CPP. We address interleavers of lengths of the form 8p or 24p, with p a prime number so that 3∣(p−1), used in classical 1/3 rate turbo codes with recursive systematic convolutional component codes having generator matrix G=[1,15/13], in octal form. We prove that 27 is an upper bound on the minimum distance for these types of lengths. We also derive the coefficients of the inverse true CPP for a true CPP of the considered lengths. It is known that for these interleaver lengths an upper bound on the minimum distance for quadratic PP (QPP) interleavers is equal to 36, a much higher value compared to 27. Thus, the importance of the result in the paper consists in that, for interleaver lengths mentioned above, CPP interleavers perform weaker compared to QPP interleavers. Consequently, to find better PP interleavers their degree has to be at least five.

This paper addresses turbo codes with component convolutional codes as those in the Long Term Evolution (LTE) standard. We consider the interleaver lengths of the form L=32kLΨ, with kL∈{1,3} and Ψ is a product of prime numbers greater than three. For these interleaver lengths, we have shown that a true cubic permutation polynomial (CPP) f1x+f2x2+f3x3(modL), under the constraint f3=0(modpi) when a prime pi>3 and 3 does not divide (pi−1), always has an inverse true CPP, except when f3=L∕(4kL) and f2∈{L∕16,3L∕16,5L∕16,7L∕16}. For the previously mentioned exception, a true CPP has an inverse true quadratic PP (QPP). For CPP interleavers with true inverse CPPs, we have shown that the minimum distance is upper bounded by the values of 44, 36, and 27, for three different classes of coefficients. Previously, it was shown that for the same interleaver lengths and for QPP interleavers, the upper bound on the minimum distance is equal to 50. Due to the symmetry of the classical turbo codes, the minimum distance is also upper bounded by the value of 50 for CPP interleavers with a QPP inverse. The nonlinearity degrees for all considered CPP interleavers are computed. Several examples of dmin-optimal CPP interleavers and their inverse QPPs are given.

In this study, we attempted to prepare chlorophyll-free young barley leaf extract powders using three different supercritical carbon dioxide (SCCO2) drying processes. The pure SCCO2 drying process for a methanolic extract solution resulted in a ~30% increase in the antioxidant (saponarin and isovitexin) content and a ~75% decrease in the chlorophyll content compared to a solvent evaporation method. The drying process with ethanol-modified SCCO2 increased the antioxidant content considerably and completely removed the chlorophylls. However, this process could not dry an aqueous ethanolic extract solution with a more than 30% water content. The ethanol-modified SCCO2 drying process that employed a periodic flush with pure SCCO2 was found to effectively dry an aqueous ethanolic extract solution with more than 30% water content.

Supercritical fluid extraction (SFE) using cosolvent-modified supercritical carbon dioxide and a two-step separation/purification method was investigated as a way to improve the purity of glabridin, one of the many bioactive components of Glycyrrhiza glabra (licorice). The SFE parameters were optimized using an analytical-scale SFE system in the temperature range 40–80°C and the pressure range 10–50 MPa. The extraction was then scaled up by 100 times using a preparative SFE system under the following set of optimized conditions: 40°C, 30 MPa, and SCCO 2 modified with ethanol equivalent to its 25% (v/v) concentration. The glabridin purity obtained through the scaled-up SFE system was 6.2%, a much higher level than that obtained through organic solvent extraction. The licorice extract obtained by scaling up the SFE system was isolated and purified by applying alcohol precipitation/ filtration and adsorption chromatography with 80% aqueous ethanol to obtain a purer product. It was confirmed that the glabridin purity of the final extract product was increased by up to 37%, without significant loss of glabridin after two separation/purification steps.

We synthesized 3–16 armed methyl-β-cyclodextrin-poly(l-lactide) (MCD-PLLA) polymers, and then blended them with PLLA. The addition of MCD-PLLA with 9 or 12 arms to PLLA dramatically increased the elongation at break (E) and toughness (UT) of PLLA with little affecting its Tg and tensile strength. The highest E and UT were obtained to be 127% and 6.85 GJ/m3, respectively, for PLLA blends containing these MCD-PLLAs. It was confirmed that the MCD-PLLA served as a nucleation agent for PLLA, inducing PLLA chains to form smaller and more uniform-sized crystallites compared with pure PLLA. The homogeneous fragmentation of these small and uniform-sized crystallites during tensile deformation consequently resulted in such a remarkable increase in E and UT. In contrast, the addition of MCD-PLLAs with more than 12 arms to PLLA decreased its E and UT mainly due to preferential crystallization by themselves.

Nanocellulose and microcellulose have been widely investigated as a next-generation core material in various fields due to its excellent properties such as low density, high modulus, heat resistance, and transparency. Depending upon its resources, cellulose shows different structural properties such as degree of crystallinity, crystal size, morphology, and molecular weight. In this study, various micro- and nano-celluloses were prepared from red pine, ramie and cotton using physical and/or chemical processes. By employing high-pressure homogenization as a physical method and sulfuric acid hydrolysis as a chemical method, four different treatments were carried out. From cotton, microfibrillated cellulose with a uniform network structure and nanowisker cellulose were prepared by homogenization and homogenization/hydrolysis/homogenization/hydrolysis, respectively. On the other hand, microwhisker cellulose was obtained from red pine by hydrolysis/homogenization. It was observed that homogenization with β-cyclodextrin, which have the same monomer structure to cellulose, could lead to a significant reduction in the size of micro- and nano-celluloses.

The permutation polynomial (PP) interleavers are ones of the most attractive and popular deterministic interleavers for turbo codes. Quadratic permutation polynomial (QPP) interleavers have been extensively studied since 2005. QPPs of short lengths with optimum minimum distances were given in 2006 by Rosnes and Takeshita. In this paper, we give PPs of degree 3, 4 and 5 with optimum minimum distances and lowest corresponding codeword multiplicities for turbo codes with recursive convolutional component codes from LTE standard and dual trellis termination. Then, we compare these PP interleavers in terms of truncated upper bounds (TUB) of frame error rate (FER) at high SNR for AWGN channel. We have obtained many PPs of degree 3, 4 or 5 with the smallest TUB(FER). A tradeoff between the error rate performance and implementation complexity is highlighted by means of the minimum number of LPPs from the Parallel Linear PP (PLPP) representation of PPs, so that the coefficients of linear terms of the component LPPs of PLPP are equal to one another.

In this letter, partial upper bounds on minimum distance for turbo codes with permutation polynomial (PP) based interleavers over integer rings are derived using the fact that PPs are equivalent to a family of linear permutation polynomials (LPPs). It is shown that upper bounds on minimum distance of turbo codes using higher order PP based interleavers are bounded by a function of the number of equivalent LPPs for PPs. Besides, it is shown that when the constant terms of LPPs are dithered, the resulting dithered LPP interleavers perform better than the quadratic permutation polynomial (QPP) based interleavers used in long term evolution (LTE) standard or than other good QPP or cubic permutation polynomial (CPP) based interleavers given in the literature.

In this study, gemcitabine (Gem)-Poly(L-lactic acid) (PLLA) conjugates were synthesized through an amide linkage reaction. Then, the microparticles of Gem-PLLA/PLLA blends containing gemcitabine were prepared using a supercritical fluid process, called aerosol solvent extraction system (ASES). Gemcitabine-loaded Gem-PLLA/PLLA microparticles obtained from the ASES process showed a spherical shape. The amount of gemcitabine released after 30 day incubation in a phosphate buffer solution of pH 7.4 was about 90% of the total amount of gemcitabine present in the product.

초임계 이산화탄소를 역용매로 이용하는 aerosol solvent extraction system (ASES) 방법을 사용하여 HP-${\beta}$-CD 미립자를 제조하였으며, 공정변수가 입자의 크기와 형태에 미치는 영향을 조사하였다. 또한, 초임계 이산화탄소를 이용하여 이부프로펜과 HP-${\beta}$-CD의 포접복합체를 제조하였으며, ASES 공정에 의해 변형된 HP-${\beta}$-CD의 입자 형상이 포접효율에 미치는 영향에 대해 고찰하였다. ASES 공정으로 제조된 HP-${\beta}$-CD 미립자는 50~200 nm 크기의 나노 입자들이 응집된 입자 형상을 나타내었다. 에탄올 수용액을 HP-${\beta}$-CD의 용매로 사용한 경우 구형의 입자가 제조되었으며, 물의 양이 증가함에 따라 입자의 크기가 증가하였다. 초임계 이산화탄소를 이용해 고체상태에서 이부프로펜/HP-${\beta}$-CD 포접복합체를 제조하는 경우 초임계 ASES 방법에 의한 미세입자화 공정을 통해 포접효율을 향상시킬 수 있는 가능성을 확인하였다. The microparticles of 2-hydroxypropyl-${\beta}$-cyclodextrin (HP-${\beta}$-CD) were prepared using aerosol solvent extraction system (ASES) by employing supercritical carbon dioxide as an antisolvent, The effects of various process parameters such as temperature, pressure, solution concentration and solution flow rate on the formation of HP-${\beta}$-CD microparticles were investigated. The HP-${\beta}$-CD microparticles prepared by the ASES process were observed to consist of agglomerates of nano-sized (50-200 nm) particles. When an aqueous solution of ethanol was used as a solvent for HP-${\beta}$-CD, the HP-${\beta}$-CD particles were found to be spherical in shape and to become larger as the water content increased. It was confirmed that the micronization of HP-${\beta}$-CD using the ASES process could enhance the inclusion efficiency of ibuprofen/HP-${\beta}$-CD complexes significantly.

Permutation polynomial based interleavers over integer rings have recently received attention for their excellent channel coding performance, elegant algebraic properties and simplicity of implementation. In this letter, it is shown that permutation polynomial based interleavers of practical interest is decomposed into linear permutation polynomials. Based on this observation, it is shown that permutation polynomial based interleavers as well as their inverses can be efficiently implemented.

In this study, peptide-loaded microparticles were prepared using an aerosol solvent extraction system (ASES) by employing supercritical carbon dioxide as an antisolvent. The effects of the molecular weight of poly(Llactide) (PLLA), poly(ethylene glycol) (PEG), the block length of methoxy poly(ethylene glycol)- b -poly(L-lactide) (mPEG-PLLA), the blending of PLLA and PEG, and the drug-to-polymer feed ratio on the formation of leuprolide acetate (LA)-loaded microparticles and their release characteristics were investigated. Scanning electron microscope observations showed that the LA-loaded polymer particles had a spherical morphology with a smooth surface. The entrapment efficiency of LA in the ASES-processed microparticles was found to be extremely high (about 99%), whereas the initial release rate of the LA-loaded microparticles was very low for PLLA. The release rate of LA was observed to increase as the PEG block length of mPEG-PLLA and/or the drug content in the microparticles increased. When PLLA was blended with PEG, the release rate of LA from the PLLA/PEG microparticles was significantly faster compared with the corresponding mPEG-PLLA copolymer.

Permutation polynomial based interleavers over integer rings, in particular quadratic permutation polynomials have been widely studied. In this letter, higher degree permutation polynomials for interleavers are considered for interleavers and permutation polynomials superior to quadratic permutation polynomials are found for some lengths.

In this study, we employed hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as an excipient to produce poly(lactic-co-glycolic acid) (PLGA) fine particles by a supercritical fluid process, called aerosol solvent extraction system (ASES), and investigated the effect of HP-beta-CD content on the morphology of the particles. The influence of HP-beta-CD on the drug release characteristics of paclitaxel-loaded PLGA particles was also evaluated. Fine particles were obtained when the HP-beta-CD content in PLGA/HP-beta-CD mixtures was greater than 40% and 30%, respectively, for PLGA(75:25) and PLGA(50:50), whereas a film-like precipitate was obtained for lower HP-beta-CD content. The release rate for paclitaxel loaded PLGA(75:25)/HP-beta-CD particles was found to increase with HP-beta-CD content.

In this study, gemcitabine-loaded methoxy poly(ethylene glycol)-b-poly(L-lactide) (MPEG-PLLA) microparticles with different PEG block lengths were prepared by a W/O/W double emulsion technique. The present study focuses on the investigation of the influence of various preparative parameters such as the ratio of internal water phase and oil phase, polymer concentration, solvent composition of organic phase and salt concentration of external water phase on the morphology and encapsulation efficiency of the microparticles. The microparticles fabricated at high volume ratios of internal water phase to oil phase and at high polymer concentrations showed a relatively high encapsulation efficiency and low porosity. When a dichloromethane/ethyl acetate mixture was used as solvent, both the encapsulation efficiency and drug loading of the microparticles decreased as the level of ethyl acetate increased. The addition of a salt (NaCl) to the external water phase significantly improved the encapsulation efficiency up to 40%, and the microparticles became more spherical with their size and porosity decreased.

In this study, poly (L-lactic acid) (PLLA) microparticles containing gemcitabine hydrochloride were prepared by a supercritical fluid process, called aerosol solvent extraction system (ASES), utilizing supercritical carbon dioxide as antisolvent. The influence of process parameters such as temperature, pressure, $CO_2$ and solution flow rate, solution concentration, and feed ratio of drug to polymer on the morphology and characteristics of the microparticles was studied in detail. The gemcitabine-loaded microparticles exhibited a spherical shape with a smooth surface. The entrapment efficiency of gemcitabine increased with increasing temperature, solution concentration and $CO_2$ flow rate and with decreasing drug/polymer feed ratio. The maximum drug loading obtained from the ASES process was found to be about 11%. The ASES-processed PLLA microparticles containing gemcitabine showed a relatively high initial burst due to the presence of surface pores on the microparticles and the poor affinity between drug and polymer.