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Membrane bioreactors (MBRs) show great promise for productivity improvement and energy conservation in conventional bioprocesses for wastewater reclamation. In order to attain high productivity in a bioprocess, it is crucial to retain the microorganisms in the bioreactors by preventing wash out. This enables recycling of the microorganisms, and is consequently saving energy. The main feature of MBRs is their permeable membranes, acting as a limitative interface between the medium and the microorganisms. Permeation of nutrients and metabolites through the membranes is thus dependent on the membrane characteristics, i.e. porosity, hydrophilicity,and polarity. The present thesis introduces membranes for MBRs to be used in a continuous feeding process, designed in the form of robust, durable, and semi-hydrophilic films that constitute an effective barrier for the microorganisms, while permitting passage of nutrients and metabolites. Polyamide 46 (polytetramethylene adipamide), a robust synthetic polymer, holds the desired capabilities, with the exception of porosity and hydrophilicity. In order to achieve adequate porosity and hydrophilicity, bulk functionalization of polyamide 46 with different reagents was performed. These procedures changed the configuration from dense planar to spherical, resulting in increased porosity. Hydroxyethylation of the changed membranes increased the surface tension from 11.2 to 44.6 mJ/m2. The enhanced hydrophilicity of PA 46 resulted in high productivity of biogas formation in a compact MBR, due to diminished biofouling. Copolymerization of hydrophilized polyamide 46 with hydroxymethyl 3,4-ethylenedioxythiophene revealed electroconductivity and hydrophilic properties, adequate for use in MBRs. To find either the maximal pH stability or the surface charge of the membranes having undergone carboxymethylation, polarity and the isoelectric point (pI) of the treated membranes were studied by means of a Zeta analyzer. The hydroxylated PA 46 was finally employed in a multilayer membrane bioreactor and compared with hydrophobic polyamide and PVDF membranes. The resulting biogas production showed that the hydroxylated PA 46 membrane was, after 18 days without regeneration, fully comparable with PVDF membranes.

A reposição de dentes perdidos por meio de próteses implanto-suportadas tornou-se uma opção de tratamento previsível e aceitável tanto para pacientes parcialmente como totalmente desdentados. Após sua instalação, os implantes de titânio interagem com fluidos biológicos e tecidos, sendo que a direta aposição óssea sobre a superfície do titânio é fundamental para o carregamento desses implantes. As características superficiais dos implantes podem influenciar na interação implanteosso, na taxa e qualidade da osseointegração. O objetivo desse estudo clínico retrospectivo foi avaliar a taxa de sobrevivência de implantes osseointegrados com superfície Acqua e verificar se existe interferência de determinadas variáveis na perda de implantes: região de instalação, tipo de reabilitação protética, tipo de carregamento, tempo de carregamento, experiência do cirurgião, enxertos ósseos, tipo de sítio para instalação, uso de tabaco e diabetes. Foram avaliados 131 pacientes, totalizando 331 implantes instalados com conexão interna tipo cone Morse e superfície Acqua. Os dados foram coletados de prontuários clínicos e tabulados e nenhum paciente foi excluído devido a qualquer doença sistêmica, gênero, raça, hábitos parafuncionais e tabagismo. A análise estatística incluiu estatísticas descritivas para todos os parâmetros clínicos avaliados e foi aplicado o método exato de Fisher. Foram avaliados implantes instalados anteriormente a março de 2014 e o tempo de acompanhamento do carregamento dos implantes foi de 0 a 55 meses. Entre as variáveis avaliadas apenas o tipo de reabilitação protética influenciou de forma significativa na falha de implantes. Sete implantes (2,11%) foram considerados perdidos, totalizando uma taxa de sobrevivência de 97,89%. Os implantes com superfície Acqua apresentaram alto índice de sobrevivência nas mais diversas situações e com a associação de diversos fatores de risco, provando ser uma superfície confiável e apropriada para a aplicação na prática clínica diária. / The replacement of lost teeth by dental implant has become a predictable and acceptable treatment option for patients either partially or fully edentulous. After place, titanium implants surface interact with biological fluids and tissues, and direct bone apposition on the titanium surface is critical for loading these implants. The surface characteristics of implants can influence the implant-bone interaction in the rate and quality of osseointegration. The aim of this retrospective clinical study was to evaluate the dental implants survival rate with Acqua surface and check for interference of certain variables in the loss of implants: placed region, type of prosthetic rehabilitation, loading type, load time, surgeon experience, bone grafts, installation site, tobacco use and diabetes. One hundred thirty one patients, totaling 331 implants inserted with internal Morse taper connection and Acqua surface. Data were collected from medical records and tabulated and no patient was excluded due to any systemic disease, gender, race, parafunctional habits and smoking. Statistical analysis included descriptive statistics for all clinical parameters evaluated and was applied Fishers exact test. Were evaluated implants placed prior to March 2014 and the follow-up time of loading of the implants was 0-55 months. Among the variables evaluated only the type of prosthetic rehabilitation influenced significantly in implant failure. Seven implants (2.11%) were considered lost, amounting to a survival rate of 97.89%. Implants with Acqua surface showed high survival rate in different situations and with the association of various risk factors, proving to be a reliable and suitable surface for application in clinical practice.

A reposição de dentes perdidos por meio de próteses implanto-suportadas tornou-se uma opção de tratamento previsível e aceitável tanto para pacientes parcialmente como totalmente desdentados. Após sua instalação, os implantes de titânio interagem com fluidos biológicos e tecidos, sendo que a direta aposição óssea sobre a superfície do titânio é fundamental para o carregamento desses implantes. As características superficiais dos implantes podem influenciar na interação implanteosso, na taxa e qualidade da osseointegração. O objetivo desse estudo clínico retrospectivo foi avaliar a taxa de sobrevivência de implantes osseointegrados com superfície Acqua e verificar se existe interferência de determinadas variáveis na perda de implantes: região de instalação, tipo de reabilitação protética, tipo de carregamento, tempo de carregamento, experiência do cirurgião, enxertos ósseos, tipo de sítio para instalação, uso de tabaco e diabetes. Foram avaliados 131 pacientes, totalizando 331 implantes instalados com conexão interna tipo cone Morse e superfície Acqua. Os dados foram coletados de prontuários clínicos e tabulados e nenhum paciente foi excluído devido a qualquer doença sistêmica, gênero, raça, hábitos parafuncionais e tabagismo. A análise estatística incluiu estatísticas descritivas para todos os parâmetros clínicos avaliados e foi aplicado o método exato de Fisher. Foram avaliados implantes instalados anteriormente a março de 2014 e o tempo de acompanhamento do carregamento dos implantes foi de 0 a 55 meses. Entre as variáveis avaliadas apenas o tipo de reabilitação protética influenciou de forma significativa na falha de implantes. Sete implantes (2,11%) foram considerados perdidos, totalizando uma taxa de sobrevivência de 97,89%. Os implantes com superfície Acqua apresentaram alto índice de sobrevivência nas mais diversas situações e com a associação de diversos fatores de risco, provando ser uma superfície confiável e apropriada para a aplicação na prática clínica diária. / The replacement of lost teeth by dental implant has become a predictable and acceptable treatment option for patients either partially or fully edentulous. After place, titanium implants surface interact with biological fluids and tissues, and direct bone apposition on the titanium surface is critical for loading these implants. The surface characteristics of implants can influence the implant-bone interaction in the rate and quality of osseointegration. The aim of this retrospective clinical study was to evaluate the dental implants survival rate with Acqua surface and check for interference of certain variables in the loss of implants: placed region, type of prosthetic rehabilitation, loading type, load time, surgeon experience, bone grafts, installation site, tobacco use and diabetes. One hundred thirty one patients, totaling 331 implants inserted with internal Morse taper connection and Acqua surface. Data were collected from medical records and tabulated and no patient was excluded due to any systemic disease, gender, race, parafunctional habits and smoking. Statistical analysis included descriptive statistics for all clinical parameters evaluated and was applied Fishers exact test. Were evaluated implants placed prior to March 2014 and the follow-up time of loading of the implants was 0-55 months. Among the variables evaluated only the type of prosthetic rehabilitation influenced significantly in implant failure. Seven implants (2.11%) were considered lost, amounting to a survival rate of 97.89%. Implants with Acqua surface showed high survival rate in different situations and with the association of various risk factors, proving to be a reliable and suitable surface for application in clinical practice.

Electrospinning produces submicron fibers from a wide range of polymer/solvent systems that enable a variety of different applications. In electrospinning process, a straight polymer/solvent charged jet is initially formed, followed by a circular moving jet in the shape of a cone, called the bending region. The process physics in the bending region are difficult to study since the jet diameter cannot be measured directly due to its rapid motion and small size (~microns and smaller), and due to complex coupling of multiple forces, mass transport, and changing jet geometry. Since the solutions studied are hydrophilic, they readily absorb ambient moisture. This thesis explores the role of the bending region in determining the resulting electrospun fiber diameter through a combined experimental and modeling analysis for a variety of hydrophilic polymer/solvent solutions. Electrospinning experiments were conducted over a broad range of operating conditions for 4 different polymer/solvent systems. Comparison of the final straight jet diameters to fiber diameters reveals that between 30% to 60% jet thinning occurs in the bending region. These experiments also reveal that relative humidity significantly affects the electrospinning process and final fiber diameter, even for non-aqueous solutions. A model is developed to obtain insight into the bending region process physics. Important ones include understanding the mass transport for non-aqueous hydrophilic jets (including solvent evaporation and water absorption on the jet surface, radial diffusion, and axial advection), and the coupling between the mass and force balances that determines the final fiber diameter. The absorption and evaporation physics is validated by evaporation experiments. The developed model predicts fiber diameter to within of 8%, even though the solution properties and operating conditions that determines net stretching forces and net evaporation rates vary over a large range. Model analysis reveals how the net evaporation rate affects the jet length and net stretching force, both of which ultimately determine the fiber diameter. It is also shown that the primary impact of RH on the process is through occupation of the surface states that limits solvent evaporation rate, rather than the amount of water absorbed. Correlation functions between process conditions, solution properties and the resulting fiber diameters are discussed.

Due to the excellent properties of biodegradability and biocompatibility, aliphatic polycarbonate and polyesters are very promising either as biomaterials or as environmentally friendly materials to address growing ecological concerns. The first chapter describes an overview of ring-opening polymerization, enzymatic polymerization and their application on the polymerization of cyclic carbonate and lactones. The second chapter describes the synthesis of enantiomerically pure functional polycarbonate from a novel seven-membered-cyclic carbonate (5S, 6S)- Dimethyl 5,6- isopropylidene-1,3-dioxepin-2-one (ITC) derived from naturally occurring L-tartaric acid. The monomer was synthesized in three steps and screened for polymerization with four commercially available lipases. Block co-polymerization of ITC with ε-caprolactone in 'one-shot feeding' is reported in the third chapter. It is the first report of 'one-shot' block copolymerization of ε-caprolactone with a cyclic carbonate monomer. The deprotection of the ketal groups resulted in copolymers containing free hydroxy groups in the polymer backbone. In chapter four, star-shaped poly(ε-caprolactone)'s (PCL) series based on two tetra-hydroxy resorcinarenes initiators were reported. These polymers were synthesized by the ring-opening polymerization. The data suggest that the initiator core directed the PCL-arms toward more interactions resulting in increasing in the rigidity of star-polymers compare to linear-PCL.

This study presents a simple process for producing resistance-based humidity sensors utilizing dopamine (DA) coated gold nano-particles (AuNPs) as the sensing material. The sensing material for typical humidity sensors are solid state metal oxides, graft-polymers or salt-doped polymers. However, these humidity sensors may suffer from low sensing response or slow time response since water molecules have to diffuse into the sensing materials to induce the electrical property changes. Alternatively, AuNPs have large surface area for water molecule absorption and can be potentially for high performance humidity sensing. Nevertheless, the surface property of AuNPs is hydrophobic and needs to be modified. In this regards, this work uses a highly hydrophilic molecule of dopamine to modify the surface of AuNP into hydrophilic to enhance the humidity sensing performance. Highly hydrophilic bio-molecule of dopamine is physically bonded onto 4-6 nm AuNPs to enhance the humidity sensing performance. Results show that the DA coated AuNPs have nice humidity sensing responses in the measuring range of 20-90%RH. The measured resistance response shows >1500 times greater than the sensor using the same AuNPs without DA coating. The developed humidity sensor shows rapid time responses for water absorption (13 s) and desorption (30 s), respectively. Moreover, a 3-day long-term measurement at low, medium and high humidity ranges also shows the good stability of the developed sensor. The method developed in this study provides a simple and low-cost method to produce high-performance humidity sensors with DA-coated AuNPs.

In our laboratory, we using simple synthetic methods to synthesize one series of amphiphilic discotic liquid crystal which has the dipole-dipole forces. We not only research the effect about the length of hydrophilic chain, but also explore the arrangement of this series through some cross-comparison.

An experimental investigation was carried to examine the flow/ thermal field characteristics with/without phase change in the microchannels and compared with the traditional results. There are three parts in this study. The first part investigated the 2-D flow field measured by the micro particle image velocimetry (£gPIV) in a single PMMA microchannel fabricated by an ArF excimer laser. The slip boundary condition in the microchannel wall was also discussed. The second part studied the influence of surface condition (hydrophilic vs hydrophobic) on the flow/thermal field in a micro cooling device which included twenty parallel microchannels, which was fabricated by SU-8 microfabrication technique and replicated by the PDMS replica technique. The UV/ozone device was used to change the PDMS microchannels¡¦ surface condition from hydrophobic to hydrophilic and the £gPIV/£gLIF system was also used to measure the velocity and temperature distribution. The third part investigated the two-phase subcooled flow boiling phenomena (onset of nucleate boiling, boiling curve, flow patterns, bubble departure diameter and frequency) in the seventy-five parallel microchannels fabricated by SU-8 microfabrication technique, and aimed to raise the critical heat flux (CHF) and heat transfer coefficient to enhance the cooling efficiency. Three major methods were used in this study, as follows: (1) To add the cavity angle of £c = 60¢X, 90¢X, and 120¢X on the microchannel side walls. (2) To coat 2 £gm diamond film on the Cu heated surface. (3) To add 1 vol. % Multi-walled Carbon Nanotube (MCNT) into the working medium (deionized water). The goal of this paper is to develop a high heat flux cooling technique and apply the experimental results to solve the cooling problem resulting from the exceedingly high heat flux from the electronic component.

Polymer carriers composed of poly(methacrylic acid – grafted – ethylene glycol) (P(MAA-g-EG)) hydrogels modified with poly(butyl acrylate) (PBA) to form IPNs or photopolymerized in the presence of poly(methyl methacrylate) (PMMA) nanoparticles were investigated for their use in the oral delivery of therapeutic agents for cancer treatment. The P(MAA-g-EG) hydrogel provided pH-responsive and hydrophilic properties while PBA or PMMA polymers provided hydrophobic properties. An inulin- doxorubicin conjugate was also synthesized to provide local, direct targeting for the treatment of colon cancer. The pH-responsive behavior of these polymer systems was investigated using equilibrium and dynamic swelling experiments. In gastric conditions (low pH) all materials were in a collapsed state and in intestinal conditions (neutral pH) these material were swollen. The equilibrium swelling ratios decreased with increasing hydrophobic content for both IPNs and compositions of P(MAA-g-EG) containing nanoparticles. The loading efficiencies of doxorubicin, a chemotherapeutic drug, were as high as 56% for IPNs and the IPN structure and hydrophobicity influenced the loading efficiency values. The loading efficiency of doxorubicin using P(MAA-g-EG) containing nanoparticles was as high as 64% and increased with increasing weight percent of PMMA nanoparticles in the P(MAA-g-EG) hydrogel. In gastric conditions (low pH), IPNs released a majority of the encapsulated doxorubicin (up to 70%) as compared to the P(MAA-g-EG) containing nanoparticles (up to 27%). P(MAA-g-EG) containing nanoparticles was used to load and release the inulin-doxorubicin conjugate. Loading efficiency was 54% and release profiles behaved similarly as doxorubicin. Both polymer systems were biocompatible with Caco-2, HT29-MTX, and SW620 cell models over concentration ranging from 1 mg/mL to 5 mg/mL and exposure times lasting from 2 hr to 24 hr. The 75/25 IPN exhibited the highest degree of mucoadhesion and the P(MAA-g-EG)-5.0NP the lowest. Using the same cell lines and cytotoxicity assays, the inulin-doxorubicin conjugate was determined to be more toxic than free doxorubicin at equal doxorubicin concentrations. Doxorobuicin and inulin-doxorubicin conjugate were tested for transport across Caco-2/HT29-MTX cell monolayers with and without the presence of unmodified P(MAA-g-EG) or P(MAA-g-EG)-5.0NP microparticles. The presence of the microparticles did not increase transport across the cell monolayer which is advantageous for local, direct delivery to the colon. / text