Production Of Resins Research Articles

Investigation on a novel preparation process of B-COPNA resin from catalytic cracking diesel

As one of main products in fluid catalytic cracking unit, catalytic cracking diesel (light cycle oil, LCO) has inferior combustion performance, improper to be used as vehicle diesel. Condensed polynuclear aromatic resin of moderate condensation degree (B-COPNA) has a wide range of application prospects, but is seriously limited by the manufacturing cost. A novel process was proposed to convert polycyclic aromatic hydrocarbons in LCO into B-COPNA resin using PXG and PTS as crosslinking agent and catalyst, respectively. The composition of LCO was analyzed first, and the effects of operating conditions such as reaction temperature, reaction time, crosslinking agent and catalysts content on the viscosity and yield of B-COPNA resin were investigated to optimize the process. The molecular structure of B-COPNA resin is characterized by FT-IR spectra, NMR spectra, TOF-MS and elemental analysis. The combustion performance of LCO and the heat resistance of B-COPNA were evaluated and compared. The result shows that LCO is rich in aromatic hydrocarbons with 2-3 rings, making it an ideal raw material for COPNA resin. The optimized conditions of preparation experiments were 240 °C, 5 h, 1:1.8 (PXG:LCO) and 3 wt% of catalyst content with a B-COPNA resin yield of 67.2%. After the crosslinking reaction, the heat resistance temperature of B-COPNA resin product was up to 417 °C, while the cetane value of LCO increased to 43.6, an increase of 42.95%. Hence, it was confirmed that the current process can achieve a high value-added utilization of LCO by converting into B-COPNA resin, which has a superior combustion to bring extra high economic value to petrochemical industry.

Toxicological and chemoprevention studies of Dalbergia ecastaphyllum (L.) Taub. stem, the botanical source of Brazilian red propolis.

Dalbergia ecastaphyllum (L.) Taub. is a semi-prostrate species associated with estuaries, mangroves and dunes. This plant species has great ecological and economic importance, especially concerning apiculture pasture and Brazilian red propolis production. In this study, non-clinical toxicological evaluations of the hydroalcoholic extract of D. ecastaphyllum stems (DEHE), the resin production source, were conducted. In addition, the action of DEHE on genomic instability and colon carcinogenesis was investigated. The extract's chemical profile was analysed by HPLC, and medicarpin, vestitol and neovestitol were found as major compounds. DEHE showed an IC50 equivalent to 373.2 µg/ml and LC50 equal 24.4mg/L, when evaluated using the XTT colorimetric test and the zebrafish acute toxicity assay, respectively. DEHE was neither genotoxic nor cytotoxic at the highest dose, 2000mg/kg, by peripheral blood micronucleus test. The treatments DEHE (6 and 24mg/kg) led to the reduction of micronuclei induced by doxorubicin (DXR) in mice. Furthermore, significantly higher serum levels of reduced glutathione were observed in animals treated with DEHE plus DXR, revealing an antioxidant effect. Treatments with DEHE (48mg/kg) led to a significant reduction in pre-neoplastic lesions induced by the 1,2-dimethylhydrazine (DMH) carcinogen in the rat colon. Immunohistochemical analysis revealed significantly lower levels of expression of COX-2 (86%) and PCNA (83%) in the colon of rats treated with DEHE plus DMH, concerning those treated with the carcinogen. These results indicate the involvement of anti-inflammatory and antiproliferative pathways in the protective effect of DEHE.

Assessing the performance of analytical methods for propolis – A collaborative trial by the international honey commission

Propolis is a resinous beehive product with extraordinary bioactivity and chemical richness, linked with the botanical sources of the resin. The potential of this product keeps captivating the scientific community, conducting to continuous and growing research on plant sources, composition, or applications in agriculture, cosmetics, pharmacy, odontology, etc. In all cases, the quality assessment is a requirement and relies on methods to extract the bioactive substances from the raw propolis and quantify different components. Unfortunately, besides the absence of international quality requirements, there is also a lack of standardized analytical procedures, despite the presence of several methodologies with unknown reliability, often not comparable. To overcome the current status, the International Honey Commission established an inter-laboratory study, with propolis samples from around the globe, to harmonize analytical methods and evaluate their accuracy. A common set of protocols was matched between twelve laboratories from nine countries, for quantification of ash, wax, and balsamic content in raw propolis, and spectrophotometric evaluation of total phenolics, flavone/flavonol, and flavanone/dihydroflavonol in the extract. A total of 3428 results (97% valid data), were used to assess the methods’ accuracy following ISO-5725 guidelines. The within-laboratory precision, revealed good agreement levels for the majority of the methods, with relative variance below 5%. As expected, the between-laboratory variance increased, but, with exception of the flavanone method that revealed a clear lack of consistency, all the others maintained acceptable variability levels, below 30%. Because the performance of ultrasounds procedures was low, they cannot be recommended until further improvements are made.

The impact of preconceptional exposure of F0 male mice to bisphenol A alone or in combination with X-rays on the intrauterine development of F2 progeny

Bisphenol A (BPA) is used for the production of polycarbonates and epoxy resins. Exposure to chemical and physical environmental factors may influence the health of exposed individuals, and of the next generations.This paper describes the prenatal effects in the F2 generation of mice after exposure of F0 pubescent or mature males to BPA (5 mg/kg bw, 10 mg/kg bw, 20 mg/kg bw), X-rays (0.05 Gy) or a combination of both factors in low doses (0.05 Gy + 5 mg/kg bw BPA) for 8 weeks. F1 males were mated with females from the same group but from a different litter. The females were sacrificed before parturition and examined for the number of implantations, live foetuses, as well as early and late post-implantation deaths. The fertility of males and the percentage of pregnant females in each group were also assessed.Exposure of pubescent F0 males to 10 mg/kg bw of BPA decreased the frequency of fertile males. Following exposure of pubescent males, the frequency of pregnant females decreased in the groups of 10 mg/kg bw and 20 mg/kg bw of BPA, whereas after exposure of adult F0 males in the groups of 5 mg/kg bw and 20 mg/kg bw of BPA, no significant changes in the frequency of total, live and dead implantations in all the experimental groups were found.The results observed in regard to prenatal development of the F2 generation suggest that sperm of the sons of F0 pubescent males exposed to BPA contains genetic defects that affect the possibility of fertilization. The results of both pubescent and mature males exposed to BPA showed that fertilized eggs died before implantation, probably due to defects induced in the sperm. This confirmed that BPA induced transgenerational effects in male germ cells.

Prediction of formaldehyde and residual methanol concentration in formalin using near infrared spectroscopy

Amino resins are produced by two main processes: the strong acid process and the alkaline-acid process. Both use formaldehyde and a base (e.g. sodium hydroxide) in their formulation. In this work, Forward Interval Partial Least Squares methodology was applied to create prediction models for the determination of the concentration of formaldehyde and residual methanol (that is present in the formaldehyde solution) used in the production of amino resins. Near infrared (NIR) spectra were acquired at two different temperatures: 18 and 35°C. A Partial Least Squares calibration models were established with the measured values from reference methods: namely, sodium sulfite (formaldehyde) and gas chromatography (methanol). The performances of the best models were compared using the root mean square error of cross validation (RMSECV) and coefficient of determination for prediction (r2). The best results obtained a r2 above 0.994. The RMSECV values obtained were 0.063% (m/m) and 0.031% (m/m) for the formaldehyde and methanol concentration, respectively. External validation was performed using different formaldehyde solution samples. The NIR methodology presented in this work proved to be effective and enables a significant time reduction, when compared to the reference methods, in the measurement of formaldehyde and methanol concentrations.

Evaluation of BPA effects on autophagy in Neuro-2a cells.

Bisphenol A (BPA), which is used for the industrial production of polycarbonate plastics and epoxy resins, is found in many commercially available products. Plasticizer BPA produces chemical substances worldwide, and knowledge of its effects on humans and animals is increasing. In the present work, the morphology of cells was observed by optical microscopy and phalloidin staining to evaluate the toxic effect of BPA on Neuro-2a cells. Autophagy has an important role in the regulation of cell metabolism. To study the effect of BPA on the autophagy in Neuro-2a cells, the expression distribution of LC3 was detected by immunofluorescence, and the expression levels of p62 and Beclin1 were determined using western blot and quantitative real-time PCR (qRT-PCR), respectively. Optical microscopy and phalloidin staining revealed that the cells became rounded and small and that the dendritic spine of the cells were reduced at high BPA doses. Immunofluorescence analysis demonstrated that the expression of LC3 fluorescence intensity was weak at increasing BPA concentrations. Western blot results showed that the relative expression of protein p62 increased significantly and that the relative expression levels of the Beclin1 and the LC3 proteins significantly decreased with increasing BPA concentration. qRT-PCR results showed that the relative expression level of autophagy-related p62 mRNA increased significantly and that the relative expression level of Beclin1 mRNA decreased significantly with increasing BPA concentration. The above results indicated that BPA treatment exerted dose-dependent toxic effects on Neuro-2a cells, and BPA inhibited the autophagy level of Neuro-2a cells, thereby providing a new perspective in studying the toxic effect of BPA on Neuro-2a cells.

Resource allocation for supply chains based on Pareto-optimal two-stage cross-efficiency model

The contradiction between the scarcity of common resources and the infinity of human demand for these resources has a significant impact on social development. Therefore, resource allocation can make the best use of limited resources in economic activities. Taking the two-stage supply chain where the outputs from the upstream supplier are taken as the inputs for the downstream manufacturer as an example, this paper applies the cross-efficiency model to comprehensively evaluate the efficiency scores of supply chains in the process of resource allocation and explores the relationship between the cross-efficiency of the supply chain and that of two enterprises within this supply chain. Furthermore, the self-interested behavior of enterprises is taken as the Pareto improvement principle to propose a Pareto-optimal two-stage cross-efficiency model, and this model can be used to optimally allocate the limited resources among two-stage supply chains. A common set of weights is determined to make all supply chains DEA efficient. Finally, the proposed model is illustrated to be feasible and effective through a practical application of 27 Iranian resin production companies.

UPAYA PENINGKATAN PRODUKTIVITAS GETAH PINUS (Pinus merkusii) MENGGUNAKAN STIMULANSIA EKSTRAK LENGKUAS (Alpinia galanga) DAN JAHE (Zingiber officinale)

With the increasing world demand for pine resin, one of the efforts that can be made to increase the production of pine resin is to use stimulants of sap / stimulants. So far, in the activity of tapping pine sap, inorganic stimulants are used, but the main components are sulfuric acid and nitric acid or a mixture of which is a strong oxidizing agent that can damage human skin, wood and the environment if used in the long term and excessively. Alternative use of stimulants from natural ingredients that are safe, relatively inexpensive, and easy to obtain, such as galangal (Alpinia galanga) and ginger (Zingiber officinale). This research was conducted to determine the effect of stimulant administration of galangal and ginger extracts on increasing the productivity of pine sap. The results of this study showed that the highest sap productivity was produced by pine trees using ginger organic stimulants with a 50% concentration of 11.15 g / koakan / day. The quality of pine sap that has the best quality is produced by the stimulant of ginger, while the use of the stimulant of galangal has second quality based on SNI 7837: 2016.

The Cradle-to-Cradle Life Cycle Assessment of Polyethylene terephthalate: Environmental Perspective.

Over the last several years, the number of concepts and technologies enabling the production of environmentally friendly products (including materials, consumables, and services) has expanded. One of these ways is cradle-to-cradle (C2C) certifiedTM. Life cycle assessment (LCA) technique is used to highlight the advantages of C2C and recycling as a method for reducing plastic pollution and fossil depletion by indicating the research limitations and gaps from an environmental perspective. Also, it estimates the resources requirements and focuses on sound products and processes. The C2C life cycle measurements for petroleum-based poly (ethylene terephthalate) (PET) bottles, with an emphasis on different end-of-life options for recycling, were taken for mainland China, in brief. It is considered that the product is manufactured through the extraction of crude oil into ethylene glycol and terephthalic acid. The CML analysis method was used in the LCIA for the selected midpoint impact categories. LCA of the product has shown a drastic aftermath in terms of environmental impacts and energy use. But the estimation of these consequences is always dependent on the system and boundary conditions that were evaluated throughout the study. The impacts that burden the environment are with the extraction of raw material, resin, and final product production. Minor influences occurred due to the waste recycling process. This suggests that waste degradation is the key process to reduce the environmental impacts of the production systems. Lowering a product’s environmental impact can be accomplished in a number of ways, including reducing the amount of materials used or choosing materials with a minimal environmental impact during manufacture processes.

Selection of Pinus spp. progenies in Lavras (Minas Gerais, Brazil) at 36 months of age

Background: The selection of superior genotypes and adapted to the edaphoclimatic conditions of the region of the introduction produces gains in productivity for forest stands. The objective of this study was to select progenies of Pinus spp. planted in Lavras, Minas Gerais (MG), Brazil. Methods: The experimental site was located on dystrophic Haplic Cambisol. The progeny test was designed as a randomised complete block with 30 replicates and single plot. The treatments corresponded to one progeny of Pinus massoniana, three Pinus caribaea var. bahamensis and 33 Pinus caribaea var. hondurensis arranged with a 3x3 m spacing. The traits height (H), diameter at breast height (DBH) and crown projection area (CPA) were measured at 36 months of age. Results: The results showed that heritability in the narrow sense was 0.24 for DBH, 0.27 for H and 0.50 for CPA. The DBH and H traits showed a high-magnitude positive correlation. The P7, P15, P27, P31 and P33 progenies showed better performance than the other progenies for the evaluated traits. Direct and indirect selection showed similar gains, which favors the use of indirect selection; i.e., when selecting progenies for DBH, progenies with better performance in H are also selected. Additionally, DBH may be used at advanced ages given the difficulty of measuring height. The progeny of Pinus caribaea var. hondurensis showed superior performance compared with Pinus caribaea var. bahamensis and Pinus massoniana for the region of Lavras, MG. Conclusions: This study suggests the possibility of expanding the production of Pinus caribaea var. hondurensis in the region of Lavras with progenies P7, P15, P27, P31 and P33, because in the initial assessments they showed greater adaptability to the edaphoclimatic conditions. Nevertheless, performing a future selection with the aim of evaluating resin production is recommended.

Lower-Cost, Lower-Carbon Production of Circular Polydiketoenamine Plastics

The efficiency by which monomers may be recovered during the chemical recycling of plastic waste has thus far dominated the discussion over which future polymer chemistries might be more sustainable than those in use today. However, at scale, other factors emerge as equally important, such as the costs of primary versus secondary resin production as well as the energy and carbon intensity of circular manufacturing processes. We apply systems analysis to identify problematic chemical processes used for the primary production of plastics designed for infinite recyclability: polydiketoenamine (PDK) resins from novel triketone and amine monomers. Leveraging this knowledge, we advance a less intensive process for triketone production, which lowers the cost of primary PDK production by 57% and results in 66% less life-cycle greenhouse gas (GHG) emissions. Using the automotive sector as a case study, we discuss the impact of replacing nonrecyclable polyurethane with circular PDK over the next 60 years. We find that the cumulative GHG emissions associated with introducing PDK are half those of staying the course with polyurethane. However, the extent to which circularity is realized through targeted collection and sorting plays the dominant role in determining how much of those savings is practically achievable.

Optimization of anion exchange purification for the large-scale production of plasmid DNA for gene therapy and DNA vaccine applications

Watch the video or read the poster to learn: Considerations for pDNA purification How to prepare and implement a DoE approach to identify optimal conditions for various chromatography mediaHow to optimize recovery and impurity removal in the pDNA capture stepHow to achieve a scalable and flexible pDNA purification processDr Jenny England is a Staff Scientist in the Applications and Innovation group in Purification and Pharma Analytics at Thermo Fisher Scientific. Jenny is a biophysicist by training and earned her PhD from Georgetown University. After graduate school, she did a post doc at the National Cancer Institute that focused on structure-based drug design for protein kinase complexes. Jenny currently leads the application group for process development of the POROS resin products for antibody, mRNA, plasmid, and viral vector purification. Additionally, Jenny evaluates new and emerging technologies that can be applied to solve unmet customer needs in the bioproduction workflow.

К МЕТОДИКЕ УСТАНОВЛЕНИЯ ИНТЕНСИВНОСТИ ВЫДЕЛЕНИЯ ТЕРПЕНТИНА ПРИ ЕГО ЗАГОТОВКЕ В ОСУШАЕМЫХ СОСНЯКАХ

An experimental open-type tapping was carried out in pine stands located in the Sokolsky district of the Vologda region. The objects of study are represented by plantations located on the sites, passed in 1972 by hydrotechnical reclamation, as well as similar forests after continuous thinning. The dominant species in the tree layer is pine, the share of spruce and birch does not reach 10%. The release of turpentine was studied in pine forests on a mesotrophic peat deposit. The tapping was carried out using the ascending method of applying the substrates. The main attention was paid to improving the method for determining the resin productivity of Scots pine. In the course of the study, the following tasks were solved: 1) four permanent test plots were laid in drained pine plantations, in addition, continuous thinning was performed on two sites; 2) for research purposes, an experimental double-sided harvesting of pine turpentine was carried out on each trial plot; 3) the influence of hydrotechnical reclamation and thinning on the amount of released pine turpentine has been determined; 4) specifying coefficients have been developed for the mathematical calculation (forecast) of turpentine yield with a 50% trunk load with tapping cuts. Based on the results of the study, a number of correction factors have been proposed to determine the resin productivity of pines, taking into account their taxation diameter, since the mathematical calculation of the turpentine yield under a trunk load with tapping cuts of 50% carr is often overestimated. The positive effect of hydrotechnical reclamation on the increase in the breast height diameter of pine was confirmed. The average yield of pine resin is about 22% higher, relative to the stand without silvicultural care, in a drained pine forest after silvicultural maintenance

QTL mapping for growth-related traits by constructing the first genetic linkage map in Simao pine

BackgroundSimao pine is one of the primary economic tree species for resin and timber production in southwest China. The exploitation and utilization of Simao pine are constrained by the relatively lacking of genetic information. Construction a fine genetic linkage map and detecting quantitative trait locis (QTLs) for growth-related traits is a prerequisite section of Simao Pine's molecular breeding program.ResultsIn our study, a high-resolution Simao pine genetic map employed specific locus amplified fragment sequencing (SLAF-seq) technology and based on an F1 pseudo-testcross population has been constructed. There were 11,544 SNPs assigned to 12 linkage groups (LGs), and the total length of the map was 2,062.85 cM with a mean distance of 0.37 cM between markers. According to the phenotypic variation analysis for three consecutive years, a total of seventeen QTLs for four traits were detected. Among 17 QTLs, there were six for plant height (Dh.16.1, Dh16.2, Dh17.1, Dh18.1–3), five for basal diameter (Dbd.17.1–5), four for needle length (Dnl17.1–3, Dnl18.1) and two for needle diameter (Dnd17.1 and Dnd18.1) respectively. These QTLs individually explained phenotypic variance from 11.0–16.3%, and the logarithm of odds (LOD) value ranged from 2.52 to 3.87.ConclusionsIn our study, a fine genetic map of Simao pine applied the technology of SLAF-seq has been constructed for the first time. Based on the map, a total of 17 QTLs for four growth-related traits were identified. It provides helpful information for genomic studies and marker-assisted selection (MAS) in Simao pine.

AMBER DROPLETS IN THE SOUTHERN ALPS (NE ITALY): A LINK BETWEEN THEIR OCCURRENCES AND MAIN HUMID EPISODES IN THE TRIASSIC

The Anisian amber from the “Voltzia beds” of the Recoaro area, produced by Voltzia recubariensis, represents the most ancient Triassic amber known so far. The discovery of amber in the Anisian localities of Kühwiesenkopf/Monte Prà della Vacca and Piz da Peres, in the Dolomites area, fills a gap in the amber fossil record and gives an important contribution to the knowledge of Triassic amber. The finding of amber droplets, both dispersed in the sediment and anatomically connected to shoot fragments of V. recubariensis, demonstrates that during the Anisian this species was a major resin-producer and that the favorable conditions for the preservation of resin and plant remains were present at regional scale. The contribution of Voltziales to Middle Triassic resin production in Northern Italy is also testified by the Ladinian amber from the “Wengener Schichten” of Wengen/La Valle, produced by Voltzia ladinica, whereas the Late Triassic amber was mainly produced by cheirolepidiaceous conifers. The finding of organic body trapped in the amber of Kühwiesenkopf/Monte Prà dalla Vacca is noteworthy, although difficult to interpret, and shows once again its capability to entrap and preserve witnesses of past life. Moreover, the correspondence between the Triassic amber occurrences and regional/global scale humid shifts, suggests a cause-and-effect relationship, in which the rise of amber production/preservation potential is related to climate/environmental changes, particularly in marginal marine/costal environments.

Estimated material metabolism and life cycle greenhouse gas emission of major plastics in China: A commercial sector-scale perspective

Plastics are one of the most greenhouse gas (GHG) intensive and the fastest growing industries in the manufacturing sector. Environmental tradeoffs of plastics occur through all stages of their life cycles, accelerating climate breakdown and threatening our ability to maintain a sustainable climate. Herein, material flow analysis (MFA) of three major synthetic resins (PVC, PP, PE) in China was first conducted from production to end-of-life. Meanwhile, life cycle assessment (LCA) was applied to investigate “cradle-to-gate” environmental impacts of these synthetic resins, and then GHG emissions during each plastic life stage were quantified by the integrated LCA-MFA framework. Results suggested that GHG emissions during resin production were 5.42, 4.72 and 3.43 kg CO2eq for 1 kg PVC, PP and PE, respectively. Taken together, China generated 304 million metric tons (Mt) CO2eq in 2020 by synthetic resin production, and additional 44 and 55 Mt CO2eq were emitted due to further plastic product manufacturing and end-of-life management, respectively. Packaging was identified as the major GHG contributor during the use phase, which should be critically monitored for GHG management. The study provides a new perspective to reveal environmental hotspots that drive GHG emissions among plastic life cycles and guides policy-makers towards effective carbon control and sustainable plastic management.

Structural Analysis of Lignin-Based Furan Resin.

The global “carbon emission peak” and “carbon neutrality” strategic goals promote us to replace current petroleum-based resin products with biomass-based resins. The use of technical lignins and hemicellulose-derived furfuryl alcohol in the production of biomass-based resins are among the most promising ways. Deep understanding of the resulting resin structure is a prerequisite for the optimization of biomass-based resins. Herein, a semiquantitative 2D HSQC NMR technique supplemented by the quantitative 31P NMR and methoxyl group wet chemistry analysis were employed for the structural elucidation of softwood kraft lignin-based furfuryl alcohol resin (LFA). The LFA was fractionated into water-insoluble (LFA-I) and soluble (LFA-S) parts. The analysis of methoxyl groups showed that the amount of lignin was 85 wt% and 44 wt% in LFA-I and LFA-S fractions, respectively. The HSQC spectra revealed the high diversity of linkages formed between lignin and poly FA (pFA). The HSQC and 31P results indicated the formation of new condensed structures, particularly at the 5-position of the aromatic ring. Esterification reactions between carboxyl groups of lignin and hydroxyl groups of pFA could also occur. Furthermore, it was suggested that lignin phenolic hydroxyl oxygen could attack an opened furan ring to form several aryl ethers structures. Therefore, the LFA resin was produced through crosslinking between lignin fragments and pFA chains.

Study on the Synthesis of Water-dispersible Acrylic Resin Containing Hydroxyl Group`

Hydroxy acrylic resin is a long-chain polymer material formed by cleavage and recombination of double bonds of various acrylates and methacrylates under the action of initiators. Among them, MMA and BA provide the rigidity of the molecular chain and For flexibility, HEMA provides the hydroxyl groups required for cross-linking and curing, and MAA gives the resin water solubility. By rationally designing different monomer dosages, resin products with high gloss and high hardness are prepared, and through paint making experiments, the paint film Performance is tested.

Traumatic ducts size varies genetically and is positively associated to resin yield of Pinus oocarpa open-pollinated progenies

Abstract Mexico ranks 5th in worldwide resin production. Pinus oocarpa is the most widely tapped pine tree in Mexico. Michoacán (central-western Mexico) is the first nationwide state producer of resin. Despite the P. oocarpa relevance, there is no genetic improvement program in the country for resin production. We evaluated the degree of genetic control for growth, anatomical traits, resin yield, and the correlation among them at an early age (five-years-old for growth, six for resin, and anatomical traits) in a P. oocarpa half-sib progeny trial. Families were originated from selected mother trees, based on their resin yield. We found significant genetic variation among families for stem volume (h 2 i = 0.12, h 2 f = 0.35), traumatic ducts (diameter: h 2 i = 0.63, h 2 f = 0.51; area: h 2 f = 0.81), and resin yield (individual and family narrow-sense heritability: h 2 i = 0.20, h 2 f = 0.52), and a positive correlation between diameter and area of traumatic ducts with resin yield (Pearson correlation: r= 0.73, p= 0.04; r= 0.71, p= 0.0497; respectively). Results suggest that the early selection (six-years-old) of superior P. oocarpa families, based on resin yield (estimated by microchipping technique), and/or based on larger diameter and area of traumatic ducts, appears to be a feasible strategy to develop seed orchards able to provide genetically improved seeds for intensive resin tree plantations. That would be an important alternative for a state as Michoacán, Mexico, where natural P. oocarpa stands are being replaced for avocado orchards for exportation.

Reversed Phase-HPLC Method for Low Level Quantitation of Dimethyl dibenzylidene Sorbitol

Dimethyl dibenzylidene sorbitol (DMDBS) is one of the most commonly used nucleating agent in polypropylene formulations. In present study, a simple and robust reversed phase liquid chromatography (RP-LC) based analytical method was developed for the quantitative low-level determination of DMDBS. The best separation was achieved on a RP-HPLC column TSK gel G2000 SW, 7.5mm x 30cm, Particle Size 10 and#181;m from TOSOH Bioscience. A 0.05 M NH4AC (pH = 6.6) + 10% ACN solution was used as mobile phase at a flow rate of 1.2 ml/min. UV detection was performed at 216 nm. Retention time was found to be 13.056 min. for DMDBS. The response was a linear function of concentration over the range of 2.00 to 8.00 and#181;g/ml with correlation coefficient of 0.9996 for DMDBS. The LOD and LOQ for DMDBS were found to be 1.00 and#181;g/mL and 2.00 and#181;g/mL respectively. The method is simple, rapid and robust, which is suitable for application in quality control and can also be used for the estimation of DMDBS as a leachable/ extractable from polypropylene (PP) resin and resin products like medical device containers.