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Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swedish research council Expectations of tele-yoga in persons with long-term illness Background Rehabilitation for people with long-term illness, such as various cardiac disease including heart failure or patients with an Internal Cardioverter Defibrillator (ICD), can be a challenge due to the severity of the illness and the ability to participate in group training. Yoga is a mind-body exercise that is feasible and safe, and can lead to long-term positive effects on both physical and mental well-being. Tele-yoga is a new approach of rehabilitation for this group who may have difficulty leaving their home, where participants practice group yoga with a live-streamed yoga-instructor digitally via a tablet from home. Purpose The aim of the study was to explore the expectations of tele-yoga in people with long-term illness before starting a remotely group yoga intervention at home. Methods The study had a qualitative design and is part of a process evaluation in an ongoing randomised controlled trial, where participants in the intervention group receive yoga online in a group, twice a week for 12 weeks. In total 89 participants were interviewed of which 67 participants were diagnosed with heart failure, 22 participants had an ICD or were admitted to intensive care. The interviews took place before the start of a tele-yoga intervention. The average age was 64.8 (±11.6) year, 67% were male. The interview guide included questions about perceptions about yoga and what expectations they had of participating in tele-yoga. Interviews were recorded, transcribed and analysed with qualitative content analysis. Results Participants described expectations of tele-yoga to improve physical function and health, improved breathing, relief from discomfort, ache and pain, increased flexibility and coordination. They also expected improved psychological well-being and performance, get strategies to manage stress, anger, and anxiety and strengthened motivation drive. Some expectations were based on previous experiences. When asked about expectations some thought it was difficult to know what to anticipate but described a general excitement. The participants described that it would be exciting and fun that yoga took place in a group and expected that they could inspire and encourage each other. They also described tele-yoga as a new and exciting technical solution for being physically active in groups, the technology expected to be easy to use and would facilitate the delivery of yoga. Conclusions The expectations for tele-yoga varied, improved physical function and health together with increased mental well-being and performance emerged. Also, expectation that technical solution could facilitate the delivery of yoga, and the group could be supportive. By studying the expectations of participants in tele-yoga, we can more easily understand what influences to participate and how expectations might influence barriers and adherence to the tele-yoga intervention and be related to outcomes.

Gene editing following designer nuclease cleavage in the presence of a DNA donor template can revert mutations in disease-causing genes. For optimal benefit, reversion of the point mutation in HBB leading to sickle cell disease (SCD) would permit precise homology-directed repair (HDR) while concurrently limiting on-target non-homologous end joining (NHEJ)-based HBB disruption. In this study, we directly compared the relative efficiency of co-delivery of a novel CRISPR/Cas9 ribonucleoprotein targeting HBB in association with recombinant adeno-associated virus 6 (rAAV6) versus single-stranded oligodeoxynucleotides (ssODNs) to introduce the sickle mutation (GTC or GTG; encoding E6V) or a silent change (GAA; encoding E6optE) in human CD34+ mobilized peripheral blood stem cells (mPBSCs) derived from healthy donors. In vitro, rAAV6 outperformed ssODN donor template delivery and mediated greater HDR correction, leading to both higher HDR rates and a higher HDR:NHEJ ratio. In contrast, at 12–14 weeks post-transplant into recipient, immunodeficient, NOD, B6, SCID Il2rγ−/− Kit(W41/W41) (NBSGW) mice, a ∼6-fold higher proportion of ssODN-modified cells persisted in vivo compared to recipients of rAAV6-modified mPBSCs. Together, our findings highlight that methodology for donor template delivery markedly impacts long-term persistence of HBB gene-modified mPBSCs, and they suggest that the ssODN platform is likely to be most amenable to direct clinical translation. Keywords: sickle cell disease, gene editing, rAAV6, ssODN, homology-directed repair, Crispr/Cas9, hemoglobin disorders, NHEJ versus HDR, in vivo engraftment, NBSGW41 mice, CD34, hematopoietic stem cells, stem cell cures

Regenerative medicine approaches for massive craniomaxillofacial bone defects face challenges associated with the scale of missing bone, the need for rapid graft-defect integration, and challenges related to inflammation and infection. Mineralized collagen scaffolds have been shown to promote mesenchymal stem cell osteogenesis due to their porous nature and material properties, but are mechanically weak, limiting surgical practicality. Previously, these scaffolds were combined with 3D-printed polycaprolactone mesh to form a scaffold-mesh composite to increase strength and promote bone formation in sub-critical sized porcine ramus defects. Here, we compare the performance of mineralized collagen-polycaprolactone composites to the polycaprolactone mesh in a critical-sized porcine ramus defect model. While there were no differences in overall healing response between groups, our data demonstrated broadly variable metrics of healing regarding new bone infiltration and fibrous tissue formation. Abscesses were present surrounding some implants and polycaprolactone polymer was still present after 9-10 months of implantation. Overall, while there was limited successful healing, with 2 of 22 implants showed substantial levels of bone regeneration, and others demonstrating some form of new bone formation, the results suggest targeted improvements to improve repair of large animal models to more accurately represent craniomaxillofacial bone healing. Notably, strategies to increase osteogenesis throughout the implant, modulate the immune system to support repair, and employ shape-fitting tactics to avoid implant micromotion and resultant fibrosis. Improvements to the mineralized collagen scaffolds involve changes in pore size and shape to increase cell migration and osteogenesis and inclusion or delivery of factors to aid vascular ingrowth and bone regeneration.

Naked DNA has been shown to bind naturally to the sperm, a method called sperm-mediated gene transfer (SMGT). Based on these observations, we examined the efficiency of exogenous DNA binding to sperm using liposomes. In this experiment, we analyzed methods to select frozen-thawed bovine sperm, and evaluated the binding of exogenous DNA to those sperm. To determine the optimal selection method, we used Computer-Assisted Sperm Analysis (CASA). Percoll or Swim-Up were used to select sperm, followed by incubation up to 3 h with the liposome-DNA complexes. The samples were collected after 1 h and after 3 h. We used enhanced green fluorescent protein (eGFP) in combination with the liposomes as a marker for exogenous DNA binding. Five treatments per selection method were analyzed: (1) no incubation, no liposomes and no DNA, (2) incubation with no liposomes and no DNA, (3) incubation with liposomes and no DNA, (4) incubation with liposomes and 1 µg of DNA and (5) incubation with liposomes and 10 µg of DNA. The CASA results for total motility and rapid motility were statistically significant (P

A tissue engineering approach to address craniofacial defects requires a biomaterial that balances macro-scale mechanical stiffness and strength with the micron-scale features that promote cell expansion and tissue biosynthesis. Such criteria are often in opposition, leading to suboptimal mechanical competence or bioactivity. We report the use of a multiscale composite biomaterial that integrates a polycaprolactone (PCL) reinforcement structure with a mineralized collagen-glycosaminoglycan scaffold to circumvent conventional tradeoffs between mechanics and bioactivity. The composite promotes activation of the canonical bone morphogenetic protein 2 (BMP-2) pathway and subsequent mineralization of adipose-derived stem cells in the absence of supplemental BMP-2 or osteogenic media. We subsequently examined new bone infill in the acellular composite, scaffold alone, or PCL support in 10 mm dia. ramus mandibular defects in Yorkshire pigs. We report an analytical approach to quantify radial, angular, and depth bone infill from micro-computed tomography data. The collagen-PCL composite showed improved overall infill, and significantly increased radial and angular bone infill versus the PCL cage alone. Bone infill was further enhanced in the composite for defects that penetrated the medullary cavity, suggesting recruitment of marrow-derived cells. These results indicate a multiscale mineralized collagen-PCL composite offers strategic advantages for regenerative repair of craniofacial bone defects.

In the past few years, new technologies have arisen that enable higher efficiency of gene editing. With the increase ease of using gene editing technologies, it is important to consider the best method for transferring new genetic material to livestock animals. Microinjection is a technique that has proven to be effective in mice but is less efficient in large livestock animals. Over the years, a variety of methods have been used for cloning as well as gene transfer including; nuclear transfer, sperm mediated gene transfer (SMGT), and liposome-mediated DNA transfer. This review looks at the different success rate of these methods and how they have evolved to become more efficient. As well as gene editing technologies, including Zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and the most recent clustered regulatory interspaced short palindromic repeats (CRISPRs). Through the advancements in gene-editing technologies, generating transgenic animals is now more accessible and affordable. The goals of producing transgenic animals are to 1) increase our understanding of biology and biomedical science; 2) increase our ability to produce more efficient animals; and 3) produce disease resistant animals. ZFNs, TALENs, and CRISPRs combined with gene transfer methods increase the possibility of achieving these goals.

In mice, microinjection is the most common gene transfer method used. Unfortunately, this strategy does not translate as well to livestock. Another potential method is sperm-mediated gene transfer, which takes advantage of sperm’s natural ability to bind to naked DNA. Gene transfer using sperm-mediated gene transfer has been shown in pigs (Gandolfi et al. 1989 J. Reprod. Fert. Abstr. Ser. 4) and cattle (Perez et al. 1991 Biotecnol. Apl. 8, 90–94). Based on these observations, we examined the efficiency of exogenous DNA binding to sperm using liposomes. In this experiment, we analysed methods to select thawed bovine sperm for DNA binding and evaluated the binding of exogenous DNA to those sperm. To determine the optimal sperm-selection method, the sperm were analysed using a computer-assisted sperm analyzer (CASA), the parameters selected were: total motility, rapid motility, and progressive motility. To measure the binding of DNA we used an indirect analysis using NanoDrop technology (Thermo Scientific, Wilmington, DE, USA) to compare the different DNA concentrations among groups. Liposome preparation was done using a cationic lipid, 3-(trimethyl ammonium iodide) 1,2 dimystryl-propanediate and a neutral lipid, l-a Dioleoyl phosphatidyl-ethanolamine prepared according to the protocol of Russell (1997). Percoll or swim-up methods were used to select sperm after thawing (Rubessa et al. 2016), followed by incubation (3 h) with the liposome-DNA complexes according to liposome preparation protocol (Russell, 1997). We used enhanced green fluorescent protein in combination with the liposomes as a marker for exogenous DNA binding. Five treatments per selection method were analysed: 1) immediately after processing (Control), 2) After 3 h of incubation with no liposomes, 3) incubation with liposomes and no DNA, 4) incubation with 1 ng of DNA, and 5) incubation with 10 ng of DNA. This was repeated five times. The CASA results for total motility and rapid motility showed a greater amount of significant differences (P

Reproductive biotechnology frequently requires improvements in our ability to isolate DNA from fewer and fewer cells. It is now possible to find several commercially available kits to meet this demand, but they frequently come at a relatively high cost. The aim of this project was to evaluate the efficiency of a simple handmade protocol to extract DNA from a small number of cells. To evaluate this method we chose 3 different bovine cell lines, Mac T-cells, sperm, and fibroblasts, for the analysis. Five different quantities (30, 100, 150, 300, and 500 cells) were evaluated for each cell line. The endpoints examined were the purity of the extracted DNA by NanoDrop analysis and visualisation of bands on agarose gels after PCR. The samples were initially diluted in 20 µL of PBS. The cell lysis buffer contained 15 mM Tris-HCl (pH 8.9), 50 mM KCl, 2.5 mM MgCl2, 0.1% Triton X-100, and 150 µg mL−1 of proteinase K. Twenty microlitres of lysis buffer were added to each sample. The tubes were then incubated at 55°C for 1 h. Last, proteinase K was inactivated by incubation at 90°C for 10 min. After extraction, 3 samples from each cell quantity for each replicate were evaluated by NanoDrop. After NanoDrop analysis, a standard PCR procedure was carried out using the homologue gene, tRep-137, as the amplification target. As a control, the Gene Wizard DNA extraction kit was used for all cell treatments. The DNA fragments resulting from PCR were separated for visualisation on agarose gels. Five replicates of the experiment were performed with 3 individual samples for each cell quantity evaluated. There were 80 total samples evaluated, including 5 control samples (1 per replicate). The PCR results were analysed using chi-square analysis with Fisher correction. An α-level of 0.05 was selected a priori for significant differences. The agarose gel analysis showed that each cell line gave different results. The data presented in Table 1 shows that this protocol is less effective for Mac T-cells, but satisfactory for both sperm and fibroblast cells. When the quality of the DNA extracted was evaluated with the NanoDrop method, DNA was found in all samples, but the purity of the samples was very low. None of the samples had a 260/280 ratio over 1, the range being 0.6 to 0.8. This high impurity could explain why not all samples showed PCR product bands on the gel. The next step will be to purify the DNA by removing all of the protein from the samples after isolation from the cells. In conclusion, these data show that it is possible to extract DNA at a low cost from a small number of cells. Table 1. The mean (SD in parentheses) percentage of samples with PCR bands for each cell line and each cell quantity

In cattle, a mutation in the NHL-repeat containing 2 genes causes a heritable abnormality referred to as developmental duplications. Calves homozygous for this mutation are affected with a broad range of phenotypes resulting from abnormal neural crest cell migration, most commonly manifested as polymelia, the presence of additional limbs. This mutation has become highly prevalent in Angus beef cattle, as lines of cattle with high genetic merit have been shown to have an increased allele frequency of the mutation. The mutation has been identified as a single nucleotide polymorphism resulting in a valine to alanine substitution in a highly conserved protein-coding region of the gene. CRISPR/Cas9 genome editing technology has been shown to induce changes in the genome by using a guide RNA to target a specific site paired with a Cas-9 protein to create a break in the DNA. These breaks are repaired by either nonhomologous end joining or homology-directed repair. The aim of this preliminary study was to determine the editing efficiency of CRISPR/Cas-9 proteins paired with site-specific guide RNA using cell lines derived from animals homozygous and heterozygous for the NHLRC2 mutation. Bovine fetal fibroblasts of both genotypes were grown in DMEM/F10 media supplemented with 10% fetal bovine serum, 0.01 µg mL−1 of basic fibroblast growth factor, 1 mL L−1 penicillin streptomycin, and 1 mL L−1 of amphotericin B. Cells were plated in a 6-well plate at 80,000 cells/well 48 h before transfection. Two 20-nucleotide guide RNA targeting the genome near the developmental duplications mutation were designed and ligated into pSpCas9(BB)-2A-GFP CRISPR plasmids. Six microliters of Fugene 6 was added to 150 µL of Opti-MEM followed by 2 µg of plasmid DNA and complexed at 37°C for 15 min before being added to each well. At 24 h after transfection, cells were detached with trypsin and sorted by fluorescence-activated cell sorting. When wells were confluent, DNA was extracted using 65 µL of QuickExtract DNA extraction solution. The 500-bp fragment surrounding the mutation was amplified and subjected to a restriction enzyme digest. Fragments with the exact sequence of the mutation were cleaved, whereas normal genotypes or edited genotypes without the mutation sequence remain uncleaved. Fragments were size separated on a 2% agarose gel. Band intensity under ultraviolet illumination was calculated with GelReader and the ratios of cleaved versus uncleaved fragments were compared with the ratio of control (unedited cell lines) for both guide RNA and both heterozygous and homozygous cell lines. Based on this preliminary data, CRISPRs with guide RNA 1 edited the genome at the target site at 13.3 and 12.2% for heterozygous and homozygous cell lines, respectively, and guide RNA 2 affected the target site at 2.5 and 4.1% for heterozygous and homozygous, respectively. These data show that the designed guide RNA paired with CRISPRs are able to elicit changes at the desired locus. In order to understand what repair mechanisms were employed at these loci, the next step is to subclone and sequence PCR products.

Sperm selection is a fundamental step for IVF, influencing treatment and the health of offspring. Over the years, several techniques have been tested to recover highly motile sperm, including centrifugation with discontinuous gradients and numerous filtration procedures. In our previous paper, we showed that it is possible, in ~20 min, to select a high quality sperm population using an electric charge in a microchannel device. This method produced the same blastocyst rates as a discontinuous gradient (DG), but in less time [25 min less; Rubessa et al. 2016 Andrology (Los Angeles) 5]. This technique takes advantage of one of the physiological characteristics of high quality sperm; that is, the head has a negative electric charge. The aim of the present experiment was to analyse the characteristics of the sperm selected with our device. We compared 2 standard sperm procedures and our device, with semen assessed using a computer-assisted sperm analyzer to evaluate the principal sperm parameters. Standard procedures were used to select sperm by DG and swim-up (SU). Thawed semen was pipetted into the microchannel of our device and then exposed to the electric charge (10 V) for 10 min [Rubessa et al. 2016 Andrology (Los Angeles) 5]. For each replicate, 3 straws of frozen bovine semen were thawed at 37°C for 40 s and pooled. The pooled sample was divided into 3 aliquots: one for each technique, 5 replicates of the experiment were performed. Data were analysed by ANOVA using the general linear model (GLM) procedure (SPSS Inc., Chicago, IL, USA). Bonferroni’s post hoc test was used to perform statistical multiple comparison. The α-level was set at 0.05. The results show an effect of the method all motility parameters are not significantly different, although some of the motility parameters were statistically different (P

In 2050, the expected size of the human population is 9 billion, the demand for food will increase, and the demand for milk will increase along with it. Genetically modifying animals is a tool that can be used to meet this growing demand. In the United States, Holstein is the leading breed for milk production and Holsteins produce on average 24 291 pounds of milk per year, whereas Jerseys, the other major dairy breed, produce on average 16 997 pounds. Their ability to produce large quantities of milk is linked to 2 mutations. These mutations are on the α-lactalbumin (α-lac) gene; the α-lac exon (+1) corresponds to the transcription start point of α-lac, (+15) and (–1689) are the positions corresponding to the single nucleotide polymorphism associated with increased milk production. Holstein cows have an adenine at both of these positions in contrast to the other cattle breeds with lower milk production, which have either a cytosine or guanine at either position. Inserting an adenine at position (+15) and (–1689) in cows without this mutation could lead to increased milk production and a better response to market demands. The purpose of this experiment was to test the cutting efficiency of candidate clustered regularly interspaced short palindromic repeats (CRISPR) that will later be used in knock-in experiments. CRISPRs were used because the CRISPR-Cas9 system is inexpensive, easily programmed, and efficient. In this preliminary study, we worked with Holstein MAC-T cells, which already contain the mutation at both positions. CRISPRs were used on this cell line to cut the DNA at a site near the mutation. Based on the genomic DNA sequence of these MAC-T cells, 3 guide RNAs were designed. Cells were then transfected with the designed CRISPRs by a variety of transfection methods, including Fugene™ (Promega, Madison, WI, USA), electroporation, and Lipofectamine (ThermoFisher Scientific, Waltham, MA, USA). Green fluorescent protein was used to determine the efficiency of transfection; 30% efficiency was seen for Fugene™, whereas electroporation and Lipofectamine™ had 70% efficiency. To select for successfully transfected cells, puromycin selection was applied. The DNA was later extracted and sent in for sequencing. Next, the website TIDE was used to compare the transfected MAC-T cells to normal MAC-T cells. The TIDE software measures the editing efficiency and looks for major insertions or deletions in pools of DNA by comparing 2 sequences to quantify the editing efficacy of CRISPR-Cas9. Our results showed that CRISPRs successfully cut the DNA near the α-lac mutation region with a total efficiency of 13.8%. The desired next step will be to insert a single-strand oligonucleotide (ssODN) donor to make a single basepair mutation. The ultimate aim of this research would be to insert these mutations into other cattle species in order to increase their milk production.

Bovine leukosis virus (BLV) is a pathogen that affects the bovine immune system and leads to lymphosarcoma, leukemia, decreased milk production, and increased culling rates in cattle. BLV-infected cattle herds can be found worldwide; in the United States, specifically, 38% of beef herds, 84% of all dairy herds, and 100% of large-scale dairy operation herds are infected (Buehring et al. 2014 Emerg. Infect. Dis. 5, 772–782). The main transmission between cattle in herds is affected leukocytes in blood. Several farm practices, such as dehorning, rectal palpation, and vaccinating can lead to the pathogen transmission. Due to international trade laws and biosecurity concerns, semen from a BLV-positive bull is illegal to sell within certain countries. Prior studies have looked at use of seropositive bulls in AI with little risk in affecting the dam (Burger et al. 2000 AVJR 60, 819). Other studies used semen that was artificially infected with the virus then used for IVF (Bielanski et al. 2000 Vet. Rec. 146, 255–256). The aim of this research was to evaluate naturally infected BLV donor semen using abattoir-derived oocytes and the possible contamination of in vitro-produced (IVP) embryos. Semen was collected and frozen by a private company. Three seropositive bulls and 1 negative control bull were selected. All positive bulls were selected based on availability of seropositive BLV status. Prior to the experiment, all bulls used were evaluated for motility, concentration, and morphology. The negative control was used in prior IVF experiments that produced acceptable results for use in this experiment. Frozen sperm were thawed at 37°C for 40 s and pelleted by centrifugation (25 min at 300 × g) on a Percoll discontinuous gradient (45–80% in Tyrode’s modified medium without glucose and BSA). The matured oocytes were purchased from DeSoto Biosciences (Seymour, TN, USA) and were IVF according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347–1355). Using 200 oocytes per replicate, the 3 positive bulls and 1 control bull were allocated 50 oocytes per bull in each replicate. After 20 to 22 h of gametes co-incubation, zygotes were denuded and cultured for 7 days in SOF, followed by the evaluation of embryos (from tight morula until hatching blastocyst). Positive bull #1 produced and tested 48 embryos. Positive bull #2 produced and tested 41 embryos. Positive bull #3 produced and tested 46 embryos. The negative control produced and tested 55 embryos. Embryonic DNA extraction was performed using standard procedures (Sattar et al. 2011 Reprod. Domest. Anim. 46, 1090–1097). Nested PCR followed the Fechner evaluations methods (Fechner et al. 1996 J. Vet. Med. B 43, 621–630). To detect BLV presence, electrophoresis was used with a 2% agarose gel containing 0.1% ethidium bromide. A total of 190 embryos were evaluated that were produced in 3 replicates. All samples analysed showed no evidence of BLV. In conclusion, use of BLV seropositive donor semen showed no transmission of the virus upon IVF of the oocytes.

Lactoferrin (LF) is an antimicrobial protein that is produced at high levels in human secretions, including milk, but is present at very low levels in the milk of ruminants. Lactoferrin is an iron-binding protein, and because iron is required by some bacteria to grow, lactoferrin can reduce the growth of certain bacteria. Lactoferrin can inhibit the growth of gram-negative bacteria, gram-positive bacteria, yeast, and some antibiotic-resistant pathogens. Lactoferrin also has bacteriocidal activity, killing the organism by inducing membrane perturbations often in conjunction with other antimicrobial agents such as lysozyme. Due to these properties, lactoferrin has the potential to increase the health of lactating animals as well as extend the shelf life of the milk. A herd of cows were genetically engineered to produce milk containing recombinant human lactoferrin (rhLF-milk) at approximately the same concentration found in human milk. In this study, growth of bacteria in raw milk samples from 2 control cows was compared with that from 2 cows that produce rhLF-milk. The experiment examined the shelf life of milk at room temperature over a 72-h period and the shelf life of milk left at 4°C over 3 weeks by plating aliquots on agar plates and counting the number of bacterial colonies that grew on plates after 24 and 48 h. The milk left at room temperature was plated at 0, 24, 48, and 72 h. The milk left in at 4°C was measured at 0, 4, 7, 11, 14, 18, and 21 days. Statistical evaluations were conducted using SAS statistical software, version 9.3 (SAS Institute Inc., Cary, NC, USA). Bacterial data were compared using the repeated-measures function in SAS and the Greenhouse-Geisser epsilon test to determine differences. For all tests, P-values

Copolyesters containing rigid aromatic units based on 4,4'-sulfonylbisphenol (bisphenol S) have been prepared by melt mixing poly(propylene terephthalate) (PPT) with an ethoxylated bisphenol S (sulfonyldiphenol). The insertion of the bisphenol units inside the polymer chain occurred quantitatively and no side reaction has been observed. The copolymers displayed good thermal stability. The main effect of copolymerization was a lowering in the degree of crystallinity and a decrease of the melting temperature with respect to PPT. On the contrary, an increment of T-g as the content of bisphenol S units increased due to the stiffening effect of the moieties deriving from bisphenol S. The Wood equation described well the correlation between T-g and composition.

Poly(butylene succinate/diglycolate) copolymers by reactive blending were subjected to molecular and solid-state characterization to study the effects of transesterification reactions. 13C-nuclear magnetic resonance analysis evidenced the formation of block copolymers. Thermal measurements showed that all the samples were semicrystalline, with a soft amorphous phase and a rigid crystal phase. Wide-angle x-ray diffraction measurements indicated that the copolymers are characterized by cocrystallization. The mechanical properties were found related to crystallinity degree. The random copolymer, characterized by the lowest crystallinity degree, exhibits the lowest elastic modulus and the highest deformation at break. Therefore, solid-state properties of poly(butylene succinate/diglycolate) copolymers can be tailored by acting on the molecular architecture. POLYM. ENG. SCI., 2013. (c) 2012 Society of Plastics Engineers

Poly(butylene succinate/diglycolate) random copolymers (P(BSxBDGy)) of various compositions were synthesized and characterized from the molecular, thermal, structural and mechanical point of view. All the polymers showed a good thermal stability and at room temperature they appeared as semicrystalline materials. The main effect of copolymerization was a lowering in the crystallinity and a decrease of T-m respect to homopolymers. The dependence of T-m on composition for copolymers with high butylene succinate unit content was well described by Baur's equation. WAXD measurements indicated that two different crystalline phases are present, depending on composition: copolymers with high BS unit content are characterized by PBS crystal phase, whereas those rich in BDG co-units crystallized in PBDG lattice. Amorphous samples showed a monotonic increment of; as the content of BDG units is increased and this can be explained on the basis of interchain interactions, due to the high electronegativity of ether-oxygen atoms. A Fox-type equation was found to fit the T-g data of completely amorphous samples, permitting the extrapolation of pure PBS T-g value for the completely amorphous polymer. (C) 2012 Elsevier Ltd. All rights reserved.

Poly[butylene-co-(triethylene succinate)] block copolymers (PBSPTES), prepared by reactive blending of the parent homopolymers (PBS and PTES) in the presence of Ti(OBu)4, were analysed by nuclear magnetic resonance (NMR), wide angle X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry techniques, in order to investigate the effects of the transesterification reactions on the molecular structure and thermal properties. 1H-NMR analysis evidenced the formation of copolymers whose degree of randomness increased with mixing time. After melt quenching, all the copolymers were found to be semicrystalline with the exception of a random copolymer. The results obtained indicated that the block size has a fundamental role in determining the rate of crystallization and therefore the phase behavior of the block copolymers. Copyright (c) 2012 Society of Chemical Industry

The melting behavior and crystallization kinetics of PBN–PDEN and PBN–PTDEN copolymers were investigated using differential scanning calorimetry. Multiple endotherms were observed in all of the copolymers under investigation, originating from melting and recrystallization processes. By applying the Hoffman–Weeks method, the Tm1 of the a and b¢-PBN phases were derived. The Tm1 value of the b¢-form, which has not been determined before, is significantly higher, as expected, because the b¢-phase is thermodynamically favored and more tightly packed. The isothermal crystallization kinetics were analyzed according to the Avrami treatment. The presence of either oxygen or sulfur atoms in the PBN polymeric chain was found to reduce its crystallizability. In particular, the crystallization rate regularly decreased as the co-unit content was increased. Lastly, the a-PBN phase was found to crystallize faster than b¢-one, which is expected, as it the more kinetically favored phase.

The results of studies of the physico-chemical changes of a polyester, poly(ethylene isophthalate), subjected to gamma irradiation up to 1 MGy, are reported. Viscometric measurements were carried out to monitor variations of the molecular weight. Changes in the amorphous fraction of the polymer were observed by means of differential scanning calorimetry. Positron annihilation lifetime spectroscopy was used to show possible modifications of the free volume as a consequence of irradiation. The results allow us to conclude that the polymer shows a good resistance to radiation damage.

Radiation methods are largely used for polymerisation and polymer modification, since irradiation induces transformations in the structure of materials which can be exploited to improve their performance. On the other hand, combined action of ionising radiation and oxygen may lead to degradation of the polymer, with worsening of properties such as mechanical strength or electrical insulation resistance. Therefore, the change of the chemical and physical properties of polymers under irradiation is a dynamic topic of research. In this work there are discussed data on the physical features of a polyester, poly(ethylene isophthalate) (PEI), subjected to gamma irradiation up to 1 MGy. PEI is a semicrystalline polymer with a structure similar to polyethylene terephthalate. Viscosity and differential scanning calorimetry measurements were carried out which allowed the monitoring of changes in the structure in terms of variations in the molecular weight, as well as of the percentage crystallinity depending on the dose. Furthermore, positron annihilation lifetime spectroscopy supplied information on the free volume present in the amorphous phase of the irradiated polymer.

Thin films, with thicknesses from 10 to 400 nm of linear aliphatic polyesters (X, Y), based on propylenediol (X = 3) and on dicarboxylic acid of different chain length (Y = 2, 3, and 4 CH2 units) were prepared by spin coating of CHCl3 polymer solutions with different polymer concentrations. Morphology and structure of the spin coated thin films were investigated by atomic force microscopy (AFM) and by grazing incidence X-ray scattering techniques at small, (GISAXS) and wide angles (GIWAXS). AFM revealed a strong dewetting for all three polymers for coatings thinner than 100 nm. The polymer films are clearly semicrystalline for thicknesses higher than 50 nm. GIWAXS of the thicker films revealed their oriented crystalline nature. An edge-on-lamellae morphology is clearly shown by the AFM-phase images even for relatively thin films. SAXS with the beam parallel to the sample plane also support the presence of lamellae perpendicular to the substrate. The use of a μ-beam helped to interpret the GIWAXS patterns and allowed to obtain oriented WAXS patterns from melt solidified filaments. Thus, a crystal chain packing is proposed for the three polymers and consequently the indexing of the observed reflections. Accordingly, the polymer chains lie parallel to the substrate being the bc plane of the monoclinic crystal unit cell parallel to the substrate. © 2010 American Chemical Society., MICINN (Grants MAT2009-07789 and FPI BES-2006-12807), Spain. The experiments performed at BW4 in HASYLAB (DESY) were supported by the European Community (Contract RII3-CT-2004-506008 (IA-SFS)).

The miscibility of poly(propylene succinate)/poly(propylene adipate) blends was investigated by means of DSC, WAXS and NMR techniques. Poly(propylene succinate) and poly(propylene adipate) were found to be completely immiscible in as blended-state. The miscibility changes upon extended mixing at elevated temperature: for enough long mixing time, the original two phases gradually merged into a single one because of transesterification reactions. The NMR analysis showed that the transesterifications led to block copolymers whose average sequence length decreased as the mixing time is increased at a fixed temperature. Upon very long mixing time (150 min), all PPS and PPA chains are fully transformed into a random copolymer characterized by a single amorphous phase.

Poly(butylene/diethylene naphthalate) copolymers (PBN-PDEN) were synthesized in bulk according to the polycondensation procedure and examined by NMR, GPC, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and XRD. At room temperature they appeared as semicrystalline materials; the copolymerization caused a lowering in the Tg value, a decrement of Tm and of the crystallization rate. Pure α or β′ form was obtained at low and high DEN unit content, respectively; crystalline form transition never occurred in the solid state, analogously to PBN. After cooling from the melt, the pure α form was always evidenced in PBN-PDEN10 and PBN-PDEN20, whereas the pure β′ crystal phase develops in the copolymer containing 40 mol % DEN units, independently on the cooling rate. In the case of PBN-PDEN30 a pure α or β′ form was obtained at low and high cooling rate, respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1356–1367, 2009

Poly(butylene/diethylene succinate) block copolymers (PBSPDGS), prepared by reactive blending of the parent homopolymers (PBS and PDGS) in the presence of Ti(OBu)(4), were analyzed by H-1-NMR, TGA and DSC, in order to investigate the effects of the transesterification reactions on the molecular structure and thermal properties. H-1-NMR analysis evidenced the formation of copolymers whose degree of randomness increases with the mixing time. The thermal analysis of the melt-quenched samples showed that the melting peak, due to the crystalline phase of PBS, tends to disappear with increasing mixing time and therefore with decreasing the block length in the copolymers. As concern miscibility, a single homogeneous amorphous phase always occurred, independently on block length. Nevertheless, a phase separation, due to the tendency of the PBS blocks to crystallize, was evidenced in the copolymers with long butylene succinate sequences. The results obtained indicated that the block size had a fundamental role in determining the crystallizability and, therefore, phase behavior of the block copolymers. (C) 2008 Elsevier Ltd. All rights reserved.

The crystal structure of poly(dithiotriethylene adipate) has been determined through the best fitting of calculated and experimental X-ray diffraction powder profiles. A triclinic cell was found with dimensions a = 4.942 (7) A, b = 4.702 (2) A, c = 20.56 (2) A, α = 88.9 (2)°, β = 61.0 (1)°, γ = 67.8 (1)°, P-1 space group, and one chain in the unit cell. A full extended trans conformation of the chain fitted satisfactory the experimental data, yielding to a discrepancy factor Rp = 0.073. A comparison between the crystal structures of poly(dithiotriethylene adipate) and poly (thiodiethylene adipate) is proposed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2677–2682, 2005

The full-profile refinement of X-ray diffraction patterns was used to investigate two poly(thiodiethylene terephthalate) (PSDET) samples with different thermal history in order to thoroughly analyze their polymorphic aspects. In each sample, a crystalline (a or b) and a microcrystalline (a0 or b0) phase were identified together with an amorphous component. The crystal structures of all the ordered phases were determined. The data indicated an appreciable difference between the two crystalline forms, while the microcrystalline were rather similar. The results reported in this paper agree with the hypothesis that the polymorphic and morphological aspects of PSDET have to be correlated with the order degree and reorganization of crystallites and microcrystallites.

Poly(propylene terephthalate) (PPT) was subjected to aging at high temperatures (150–190°C) in air and some mechanical (impact strength), physical (weight loss), and electrical (dc conductivity and ac electrical strength) properties were determined as a function of aging time and temperature. Some chemical–physical characteristics (such as the average molecular weight, the carboxyl end-group content, and crystallinity degree) were investigated during the degradation process, as well. From the collected data, the thermal endurance parameters (i.e., the temperature index and the halving interval), which are key parameters in the determination of materials reliability and design of electrical insulating system, were derived according to IEC 216 Standard, and compared with those relevant to other thermoplastic polyesters. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2848–2854, 2004

The melting behavior and crystallization kinetics of poly(thiodiethylene adipate) (PSDEA) were investigated with differential scanning calorimetry and hot-stage optical microscopy. The observed multiple endotherms, commonly displayed by polyesters, were influenced by the crystallization temperature (Tc) and ascribed to melting and recrystallization processes. Linear and nonlinear treatments were applied to estimate the equilibrium melting temperature for PSDEA with the corrected values of the melting temperature. The nonlinear estimation yielded a higher value by about 9 °C. Isothermal crystallization kinetics were analyzed according to Avrami's treatment. Values of Avrami's exponent close to 3 were obtained, independently of Tc, in agreement with a crystallization process originating from predetermined nuclei and characterized by three-dimensional spherulitic growth. As a matter of fact, space-filling spherulites were observed by optical microscopy at all Tc's. The rate of crystallization became lower as Tc increased, as usual at a low undercooling, the crystallization process being controlled by nucleation. Moreover, the crystal structure of PSDEA was determined from powder X-ray diffraction data by full profile fitting. A triclinic unit cell containing two polymer chains arranged parallel to the c axis was found. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 553–566, 2004

The complex multiple melting behavior of poly(thiodiethylene terephthalate) (PSDET) was investigated by means of differential scanning calorimetry, X-ray diffraction and hot-stage optical microscopy. The phenomenon was ascribed to the existence of two different crystal structures (a and b), each of them being able to melt and recrystallize under the experimental conditions adopted. Linear and nonlinear treatments were applied in order to estimate the equilibrium melting temperature for a PSDET, by using the corrected values of Tm. The nonlinear estimation led to a higher value by about 25 8C. Isothermal crystallization kinetics of each crystalline form were analyzed according to Avrami’s treatment. In both cases, values of Avrami’s exponent, n, close to 3 were obtained, in agreement with a crystallization process originating from predeterminated nuclei and characterized by three dimensional spherulitic growth. The rate of crystallization of each crystalline structure was found to become lower as the crystallization temperature is increased, as usual at low undercooling, where the crystallization process is controlled by nucleation.