Preparation and Properties of Nanocellulose from Organosolv Straw Pulp

Abstract The object of this work is to present a study of nanocellulose preparation from organosolv straw pulp (OSP) and its properties. OSP was obtained through thermal treatment in the system of isobutyl alcohol–H2O–KOH–hydrazine followed by processing in the mixture of acetic acid and hydrogen peroxide for bleaching and removal of residual non-cellulosic components. We have obtained nanocellulose from OSP through acid hydrolysis with lower consumption of sulfuric acid and followed by ultrasound treatment. The structural change and crystallinity degree of OSP and nanocellulose were studied by means of SEM and XRD techniques. It has been established that nanocellulose has a density up to 1.3 g/cm3, transparency up to 70%, crystallinity degree 72.5%. The TEM and AFM methods shown that nanocellulose have diameter of particles in the range from 10 to 40 nm. Thermogravimetric analysis confirmed that nanocellulose films have more dense structure and smaller mass loss in the temperature range 220–260 °C compared with OSP. The obtained nanocellulose films had high Young’s modulus up to 11.45 GPa and tensile strength up to 42.3 MPa. The properties of obtained nanocellulose from OSP exhibit great potential in its application for the preparation of new nanocomposite materials

Получение соломенной целлюлозы в среде изобутанола

Проблематика. Зменшення витрат деревини та викидів шкідливих речовин у довкілля за рахунок екологічно безпечних способів делігніфікації рослинної сировини. Мета дослідження. Визначення впливу технологічних параметрів процесу одержання органосольвентної солом’яної пшеничної целюлози та дії каталізаторів (антрахінону і гідразину) на процес делігніфікації та основні показники якості целюлози, кінетичні показники. Методика реалізації. Варіння органосольвентної солом’яної целюлози з використанням каталізаторів проводили в стальних автоклавах об’ємом 0,25 дм³, занурених у гліцеринову баню за температури 140–180 °С упродовж 30–150 хв. Результати дослідження. Отримана органосольвентна солом’яна целюлоза з використанням як каталізатора антрахінону і гідразину характеризуються відповідно такими фізико-механічними показниками: розривна довжина – 7900–6900 м; індекс продавлювання – 4,33–4,52 кН/г; опір згину – 128–600 подвійних перегинів. Встановлено, що використання гідразину порівняно з антрахіноном дає змогу отримати целюлозу з меншим вмістом лігніну, золи та пентозанів. Визначено, що процес делігніфікації в системі ізобутанол–КОН–вода–каталізатор описується кінетичним рівнянням другого порядку. Розраховано кінетичні характеристики (константи швидкості та енергії активації) процесу делігніфікації пшеничної соломи і показники вилучення лігніну із рослинної сировини. Висновки. Одержана органосольвентна солом’яна целюлоза придатна для виготовлення масових видів картонно-паперової продукції, а після проведення процесів вибілювання та облагороджування – для подальшої хімічної переробки на різні похідні целюлози.Background. Decreasing of wood consumption and hazardous wastes in environment due to ecologically safe methods of plant raw material delignification. Objective. Identification of technological parameters influence on obtaining of organosolvent straw pulp and impact of catalysts (anthraquinone and hydrazine) on the delignification process, main quality indices of pulp, kinetic characteristics. Methods. Pulping of organosolvent straw pulp with using of catalysts was performed in 0.25 dm³ steel autoclaves placed in glycerol bath heated at temperature 140—180 °C and 30—150 minutes duration. Results. Obtained organosolvent straw pulp with anthraquinone and hydrazine catalysts are characterized by such physical and mechanical properties: breaking length — 7900—6900 m; burst index — 4.33—4.52 kN/g; folding strength — 128—600 double folds. It was established that using of hydrazine catalyst allows obtaining pulp with lesser lignin, ash and pentosans content then with anthraquinone. It was determined that delignification in isobutanol—KOH—water—catalyst system is described by second-order kinetic equation. Kinetic characteristics (reaction rate and energy of activation) of wheat straw delignification and characteristics of lignin removal from plant raw material were calculated. Conclusions. Obtained organosolvent straw pulp is suitable for production of paper and cardboard products and after bleaching and alkali treatment — for further chemical treatment into different cellulose derivatives.Проблематика. Уменьшение расходов древесины и выбросов вредных веществ в окружающую среду экологически безопасными способами делигнификации растительного сырья. Цель исследования. Определение влияния основных технологических параметров процесса получения органосольвентной соломенной пшеничной целлюлозы и действия различных катализаторов (антрахинона и гидразина) на процесс делигнификации и основные показатели качества целлюлозы, кинетические показатели. Методика реализации. Варку органосольвентной соломенной целлюлозы с использованием катализаторов проводили в стальных автоклавах объемом 0,25 дм³, погруженных в глицериновую баню, нагретую до температуры 140–180 °С, на протяжении 30–150 мин. Результаты исследования. Полученная органосольвентнная соломенная целлюлоза с использованием в качестве катализатора антрахинона и гидразина характеризуются соответственно такими физико-механическими показателями: разрывная длина – 7900–6900 м; индекс продавливания – 4,33–4,52 кН/г; сопротивление сгибу – 128–600 двойных перегибов. Установлено, что использование гидразина в сравнении с антрахиноном позволяет получить целлюлозу с меньшим содержанием лигнина, золы и пентозанов. Определено, что процесс делигнификации в системе изобутанол–КОН–вода–катализатор описывается кинетическим уравнением второго порядка. Рассчитаны кинетические характеристики (константы скорости и энергии активации) процесса делигнификации пшеничной соломы и показатели удаления лигнина из растительного сырья. Выводы. Полученная органосольвентная соломенная целлюлоза пригодна для изготовления массовых видов картонно-бумажной продукции, а после проведения процессов отбеливания и облагораживания – для дальнейшей химической переработки в производные целлюлозы

From Violation to Reconstruction: The Process of Self-Renewal Associated with Chronic Fatigue Syndrome

Chronic Fatigue Syndrome (CFS) is a contested condition that generates scepticism and occupies a marginalised position within medical and social contexts. The thesis examines the illness experiences, and specifically the experiences of self, for people affected with CFS. Using qualitative inquiry, a substantive theory related to the process of self-renewal and adaptation associated with CFS is explicated. The theory encompasses the trajectory of CFS from onset to chronicity, and in exceptional instances, recovery. Illness narratives were derived from in-depth, semi-structured interviews of 19 adults, including 16 people affected with, and 3 people recovered from, CFS. Data was coded and analysed using a grounded theory approach. Analysis generated two parallel narratives that defined the illness experience of CFS: the narrative of the illness biographies and the narrative of self, specifically the struggling and diminished self seeking renewal. The illness biographies encompassed the stories of symptoms and their explanations, the encounters that ensued and their contentious milieu. The narrative of self was the primary narrative. It articulated the negative consequences to self and personhood associated with CFS, named the Violation of Self, and the consequent efforts of participants to decrease the struggle and violation by use of the Guardian Response and the Reconstructing Response. The Guardian Response provided protection and self-reclamation. The Reconstructing Response fostered self-renewal and meaning. The two narratives were bridged by the threats of CFS. That is, the illness biographies were accompanied by threats of disruption related to chronic illness, and by threats of invalidation that arose from CFS as a contested condition. In turn, these threats provided the catalyst to the violation and responses as described in the narrative of self. Under different conditions the relative strengths of violation, guardianship or reconstruction fluctuated, and it was these fluctuations that presented the participants with the ongoing struggle of CFS

A Combined Synthetic-Fibrin Scaffold Supports Growth and Cardiomyogenic Commitment of Human Placental Derived Stem Cells

Aims: A potential therapy for myocardial infarction is to deliver isolated stem cells to the infarcted site. A key issue with this therapy is to have at one\u27s disposal a suitable cell delivery system which, besides being able to support cell proliferation and differentiation, may also provide handling and elastic properties which do not affect cardiac contractile function. In this study an elastic scaffold, obtained combining a poly(ether)urethane-polydimethylsiloxane (PEtU-PDMS) semi-interpenetrating polymeric network (s-IPN) with fibrin, was used as a substrate for in vitro studies of human amniotic mesenchymal stromal cells (hAMSC) growth and differentiation. Methodology/Principal Findings: After hAMSC seeding on the fibrin side of the scaffold, cell metabolic activity and proliferation were evaluated by WST-1 and bromodeoxyuridine assays. Morphological changes and mRNAs expression for cardiac differentiation markers in the hAMSCs were examined using immunofluorescence and RT-PCR analysis. The beginning of cardiomyogenic commitment of hAMSCs grown on the scaffold was induced, for the first time in this cell population, by a nitric oxide (NO) treatment. Following NO treatment hAMSCs show morphological changes, an increase of the messenger cardiac differentiation markers [troponin I (TnI) and NK2 transcription factor related locus 5 (Nkx2.5)] and a modulation of the endothelial markers [vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR)]. Conclusions/Significance: The results of this study suggest that the s-IPN PEtU-PDMS/fibrin combined scaffold allows a better proliferation and metabolic activity of hAMSCs cultured up to 14 days, compared to the ones grown on plastic dishes. In addition, the combined scaffold sustains the beginning of hAMSCs differentiation process towards a cardiomyogenic lineage

Therapeutic potential of transplanted placental mesenchymal stem cells in treating Chinese miniature pigs with acute liver failure

<p>Abstract</p> <p>Background</p> <p>Stem cell-based therapy to treat liver diseases is a focus of current research worldwide. So far, most such studies depend on rodent hepatic failure models. The purpose of this study was to isolate mesenchymal stem cells from human placenta (hPMSCs) and determine their therapeutic potential for treating Chinese experimental miniature pigs with acute liver failure (ALF).</p> <p>Methods</p> <p>hPMSCs were isolated and analyzed for their purity and differentiation potential before being employed as the donor cells for transplantation. ALF models of Chinese experimental miniature pigs were established and divided into four groups: no cell transplantation; hPMSCs transplantation via the jugular vein; X-ray-treated hPMSCs transplantation via the portal vein; and hPMSCs transplantation via the portal vein. The restoration of biological functions of the livers receiving transplantation was assessed via a variety of approaches such as mortality rate determination, serum biochemical analysis, and histological, immunohistochemical, and genetic analysis.</p> <p>Results</p> <p>hPMSCs expressed high levels of CD29, CD73, CD13, and CD90, had adipogenic, osteogenic, and hepatic differentiation potential. They improved liver functions <it>in vivo </it>after transplantation into the D-galactosamine-injured pig livers as evidenced by the fact that ALT, AST, ALP, CHE, TBIL, and TBA concentrations returned to normal levels in recipient ALF pigs. Meanwhile, histological data revealed that transplantation of hPMSCs via the portal vein reduced liver inflammation, decreased hepatic denaturation and necrosis, and promoted liver regeneration. These ameliorations were not found in the other three groups. The result of 7-day survival rates suggested that hPMSCs transplantation via the portal vein was able to significantly prolong the survival of ALF pigs compared with the other three groups. Histochemistry and RT-PCR results confirmed the presence of transplanted human cells in recipient pig livers (Groups III, IV).</p> <p>Conclusions</p> <p>Our data revealed that hPMSCs could not only differentiate into hepatocyte-like cells <it>in vitro </it>and <it>in vivo</it>, but could also prolong the survival time of ALF pigs. Regarding the transplantation pathways, the left branch of the portal vein inside the liver was superior to the jugular vein pathway. Thus, hPMSCs transplantation through the portal vein by B-ultrasonography may represent a superior approach for treating liver diseases.</p

The Protein Network Surrounding the Human Telomere Repeat Binding Factors TRF1, TRF2, and POT1

Telomere integrity (including telomere length and capping) is critical in overall genomic stability. Telomere repeat binding factors and their associated proteins play vital roles in telomere length regulation and end protection. In this study, we explore the protein network surrounding telomere repeat binding factors, TRF1, TRF2, and POT1 using dual-tag affinity purification in combination with multidimensional protein identification technology liquid chromatography - tandem mass spectrometry (MudPIT LC-MS/MS). After control subtraction and data filtering, we found that TRF2 and POT1 co-purified all six members of the telomere protein complex, while TRF1 identified five of six components at frequencies that lend evidence towards the currently accepted telomere architecture. Many of the known TRF1 or TRF2 interacting proteins were also identified. Moreover, putative associating partners identified for each of the three core components fell into functional categories such as DNA damage repair, ubiquitination, chromosome cohesion, chromatin modification/remodeling, DNA replication, cell cycle and transcription regulation, nucleotide metabolism, RNA processing, and nuclear transport. These putative protein-protein associations may participate in different biological processes at telomeres or, intriguingly, outside telomeres