Nanocellulose as building block for novel materials

This thesis describes the fabrication of novel green materials using nanocellulose as the building block. Bacterial cellulose (BC) was used as the nanocellulose predominantly in this work. BC is highly crystalline pure cellulose with an inherent fibre diameter in the nano-scale. A single BC nanofibre was found to possess a Young’s modulus of 114 GPa. All these properties are highly favourable for using BC as a nanofiller/reinforcement in green nanocomposite materials. In this work, the surface of BC was rendered hydrophobic by grafting organic acids with various aliphatic chain lengths. These surface-modified BC was used as nanofiller for poly(L-lactide) (PLLA). Direct wetting measurements showed that the BC nanofibre-PLLA interface was improved due to the hydrophobisation of BC with organic acids. This led to the production of BC reinforced PLLA nanocomposites with improved tensile properties. Nanocellulose can also be obtained by grinding of wood pulp, producing nanofibrillated cellulose (NFC). The surface and bulk properties of one type of NFC and BC were compared in this work. Furthermore, the reinforcing ability of NFC and BC was also studied and it was observed that there is no significant difference in the mechanical performance of NFC or BC reinforced nanocomposites. A novel method based on slurry dipping to coat sisal fibres with BC was developed to modify the surface of natural fibres. This method can produce either (i) a densely BC coating layer or (ii) “hairy” BC coated sisal fibres. Randomly oriented short BC coated sisal fibre reinforced hierarchical composites were manufactured. It was found that hierarchical (nano)composites containing BC coated sisal fibres and BC dispersed in the matrix were required to produce composites with improved mechanical properties. This slurry dipping method was also extended to produce robust short sisal fibre preforms. By infusing this preform with a bio-based thermosetting resin followed by curing, green composites with significantly improved mechanical properties were produced. BC was also used as stabiliser and nano-filler for the production of macroporous polymers made by frothing of acrylated epoxidised soybean oil followed by microwave curing

Influence of biological origin on the tensile properties of cellulose nanopapers

From Springer Nature via Jisc Publications RouterHistory: received 2021-02-11, accepted 2021-05-09, registration 2021-05-09, pub-electronic 2021-05-22, online 2021-05-22, pub-print 2021-07Publication status: PublishedFunder: Engineering and Physical Sciences Research Council; doi: http://dx.doi.org/10.13039/501100000266; Grant(s): EP/K014676/1Funder: Academy of Finland; Grant(s): 310943Funder: Aalto UniversityAbstract: Cellulose nanopapers provide diverse, strong and lightweight templates prepared entirely from sustainable raw materials, cellulose nanofibers (CNFs). Yet the strength of CNFs has not been fully capitalized in the resulting nanopapers and the relative influence of CNF strength, their bonding, and biological origin to nanopaper strength are unknown. Here, we show that basic principles from paper physics can be applied to CNF nanopapers to illuminate those relationships. Importantly, it appeared that ~ 200 MPa was the theoretical maximum for nanopapers with random fibril orientation. Furthermore, we demonstrate the contrast in tensile strength for nanopapers prepared from bacterial cellulose (BC) and wood-based nanofibrillated cellulose (NFC). Endemic amorphous polysaccharides (hemicelluloses) in NFC act as matrix in NFC nanopapers, strengthening the bonding between CNFs just like it improves the bonding between CNFs in the primary cell wall of plants. The conclusions apply to all composites containing non-woven fiber mats as reinforcement. Graphic abstract

Supporting decision making process with "Ideal" software agents: what do business executives want?

According to Simon’s (1977) decision making theory, intelligence is the first and most important phase in the decision making process. With the escalation of information resources available to business executives, it is becoming imperative to explore the potential and challenges of using agent-based systems to support the intelligence phase of decision-making. This research examines UK executives’ perceptions of using agent-based support systems and the criteria for design and development of their “ideal” intelligent software agents. The study adopted an inductive approach using focus groups to generate a preliminary set of design criteria of “ideal” agents. It then followed a deductive approach using semi-structured interviews to validate and enhance the criteria. This qualitative research has generated unique insights into executives’ perceptions of the design and use of agent-based support systems. The systematic content analysis of qualitative data led to the proposal and validation of design criteria at three levels. The findings revealed the most desirable criteria for agent based support systems from the end users’ point view. The design criteria can be used not only to guide intelligent agent system design but also system evaluation

Next-generation of targeted AAVP vectors for systemic transgene delivery against cancer

Bacteriophage (phage) have attractive advantages as delivery sys-tems compared to mammalian viruses, but have been consideredpoor vectors because they lack evolved strategies to confrontand overcome mammalian cell barriers to infective agents. Wereasoned that improved efficacy of delivery might be achievedthrough structural modification of the viral capsid to avoid pre-and post-internalization barriers to mammalian cell transduction.We generated multifunctional hybrid AAV/phage (AAVP) particlesto enable simultaneous display of targeting ligands on the phage’sminor pIII proteins and also degradation-resistance motifs on thevery numerous pVIII coat proteins. This genetic strategy of directedevolution, bestows a next-generation of AAVP particles that fea-ture resistance to fibrinogen adsorption or neutralizing antibodies,and ability to escape endolysosomal degradation. This results insuperior gene transfer efficacyin vitroand also in preclinicalmouse models of rodent and human solid tumors. Thus, the uniquefunctions of our next-generation AAVP particles enable improvedtargeted gene delivery to tumor cells

Laparoendoscopic Single-Site Surgeries: A Single-Center Experience of 171 Consecutive Cases

PURPOSE: We report our experience to date with 171 patients who underwent laparoendoscopic single-site surgery for diverse urologic diseases in a single institution. MATERIALS AND METHODS: Between December 2008 and August 2010, we performed 171 consecutive laparoendoscopic single-site surgeries. These included simple nephrectomy (n=18; robotic surgeries, n=1), radical nephrectomy (n=26; robotic surgeries, n=2), partial nephrectomy (n=59; robotic surgeries, n=56), nephroureterectomy (n=20; robotic surgeries, n=12), pyeloplasty (n=4), renal cyst decortications (n=22), adrenalectomy (n=4; robotic surgeries, n=2), ureterolithotomy (n=10), partial cystectomy (n=3), ureterectomy (n=1), urachal mass excision (n=1), orchiectomy (n=1), seminal vesiculectomy (n=1), and retroperitoneal mass excision (n=1). All procedures were performed by use of a homemade single-port device with a wound retractor and surgical gloves. A prospective study was performed to evaluate outcomes in 171 cases. RESULTS: Of the 171 patients, 98 underwent conventional laparoendoscopic single-site surgery and 73 underwent robotic laparoendoscopic single-site surgery. Mean patient age was 53 years, mean operative time was 190.8 minutes, and mean estimated blood loss was 204 ml. Intraoperative complications occurred in seven cases (4.1%), and postoperative complications in nine cases (5.3%). There were no complications classified as Grade IIIb or higher (Clavien-Dindo classification for surgical complications). Conversion to mini-incision open surgery occurred in seven (4.1%) cases. Regarding oncologic outcomes, no cancer-related events occurred during follow-up other than one aggressive progression of Ewing sarcoma. CONCLUSIONS: Laparoendoscopic single-site surgery is technically feasible and safe for various urologic diseases; however, surgical experience and long-term follow-up are needed to test the superiority of laparoendoscopic single-site surgeryope

Pattern of Failure in Bladder Cancer Patients Treated with Radical Cystectomy: Rationale for Adjuvant Radiotherapy

Thus far, the role of adjuvant radiotherapy (RT) after radical cystectomy (RC) in urinary bladder cancer patients has yet to be defined. The purpose of this study is to analyze patterns of failure, and suggest the rationale for RT. Between 1986 and 2005, a total of 259 patients treated with RC and pelvic lymph node dissection was enrolled. The age range was 27-82 yr (median, 62 yr). Node positivity increased according to tumor staging. Patients were divided into the following two groups based on pathologic analysis: organ-confined disease group (n=135) and extravesical/lymph node-positive disease group (n=80). Pelvic failures (PF) were observed in 8 (4.9%) in organ-confined disease group, and 21 (21.7%) in extravesical/lymph node-positive disease group. Five-year PF-free survival rates were 91.2% in organ-confined disease group and 68.0% in extravesical/lymph node-positive disease group. Five-year cancer-specific survival rates were 86.2% in organ-confined disease group and 53.9% in extravesical/lymph node-positive disease group. In conclusion, a relatively high PF rate was observed in extravesical lymph node-negative and lymph node-positive disease patients in this study. Adjuvant pelvic RT may be considered to reduce pelvic failures in extravesical lymph node-positive bladder cancer. Future prospective trials are required to test the clinical benefit of adjuvant RT

Robot-Assisted Laparoscopic Radical Prostatectomy: Four Cases

The role of the da Vinci™ robot is being defined in minimally invasive urologic surgery. Robot-assisted laparoscopic radical prostatectomy (rLRP) has emerged as a feasible treatment option for patients with organ-confined prostate cancer. We performed the first four rLRPs on four prostate cancer patients in the Republic of Korea. This is a report of its techniques and outcomes. In all four cases, the surgery was successfully completed with a mean operative time of 392.5 minutes. The mean estimated blood loss was 312.5mL, and catheterization lasted 14 to 21 days. There were no major intraoperative or postoperative complications. The mean hospital stay was 11 days. The rLRP is a safe and feasible approach. It will become one of the standard options for the management of localized prostate cancer

On the use of nanocellulose as reinforcement in polymer matrix composites

AbstractNanocellulose is often being regarded as the next generation renewable reinforcement for the production of high performance biocomposites. This feature article reviews the various nanocellulose reinforced polymer composites reported in literature and discusses the potential of nanocellulose as reinforcement for the production of renewable high performance polymer nanocomposites. The theoretical and experimentally determined tensile properties of nanocellulose are also reviewed. In addition to this, the reinforcing ability of BC and NFC is juxtaposed. In order to analyse the various cellulose-reinforced polymer nanocomposites reported in literature, Cox–Krenchel and rule-of-mixture models have been used to elucidate the potential of nanocellulose in composite applications. There may be potential for improvement since the tensile modulus and strength of most cellulose nanocomposites reported in literature scale linearly with the tensile modulus and strength of the cellulose nanopaper structures. Better dispersion of individual cellulose nanofibres in the polymer matrix may improve composite properties