Engineered Micro-Environments and Vibrational Culture Systems for Vocal Fold Tissue Engineering

Voice is produced by the conversion of aerodynamic energy from exhalation to acoustical energy for voice production by the vocal folds (membranous connective tissue) located in the larynx. The quality of voice depends on the biomechanical properties of the multi-layered vocal fold tissue which derive from its extracellular matrix (ECM) organization and composition. The wound healing response to vocal fold injuries is characterized by scarring and subsequent dysphonia due to alterations in the biomechanical properties of the tissue. The work presented here is motivated by the importance of voice in maintaining quality of life and the inability of current treatment techniques to restore long-term, normal phonatory voice following injury induced scarring. We hypothesize that vibration is the epigenetic stimulus regulating the unique extracellular matrix (ECM) composition of the human vocal fold tissue and that rapid restoration of the vibratory microenvironment using mechano-mimetic scaffolds will facilitate:- (a) inhibition of scarring and (b) stimulation of fibroblast regeneration of the normal vocal fold tissue architecture/ECM composition and thereby restore long-term, normal phonaory voice. Our objective was to create in situ photopolymerizable, degradable, mechano-mimetic hydrogels/semi-interpenetrating networks (semi-IPNs) which may be introduced into critical size vocal fold defects using minimally invasive methods. Towards this end, we created hyaluronic acid (HA) based hydrogels and polyethylene glycol (PEG)-diacrylate based hydrogels/semi-IPNs, which were found to approximate the viscoelastic mechanical properties of the native human vocal mucosa (vibratory component) and the vocal ligament (strain component), respectively. Cell culture studies indicated that these hydrogel/semi-IPN materials supported cell spreading, cell proliferation, and ECM deposition throughout the 3-dimensional crosslinked network. In an attempt to assess the ability of the HA-based hydrogels to support human fibroblast formation of vocal mucosa-specific matrix in response to physiologically relevant high frequency vibration, fibroblast encapsulated hydrogels were subjected to 2 hrs of vibration per day using a custom built vibrational bioreactor. Our results indicated that the exposure of HA hydrogel-encapsulated fibroblasts to physiologically relevant high frequency vibration stimulated a pattern of gene expression and ECM synthesis (upregulation of GAGs, downregulation of fibrous matrix proteins) consistent with the composition of the human vocal mucosa. In the future, these HA-based hydrogels introduced into the human vocal mucosa during the acute phase of wound healing by minimally invasive methods may bring about regeneration of the native human vocal mucosa ECM composition and thereby restore normal phonation

Chile Se Moviliza: Protest Movements and Inequality in Post-Dictatorship Chile

On March 11, 1990, Augusto Pinochet, one of Latin America’s most infamous dictators, left office after Chileans ordered him to step down in a nationwide plebiscite. Since Pinochet harshly punished any and all dissenters, protests re-emerged in Chile as a popular form of political action. In this thesis, I examine the relationship between economic and political inequality and the frequency of protests and peaceful demonstrations in the country. I examine the theory behind why people protest, and later examine the history of individual protest movements (such as the Chilean Education Movement). Lastly, I run a regression to evaluate the relationship between GINI coefficient (a popular measure of income inequality) and the frequency of peaceful demonstrations since the end of the dictatorship. Though the regression does not indicate that there is a significant relationship between the two, survey data suggests that Chileans view protest as a legitimate and effective form of political action, and that they have little faith in the government and party system to represent their interests. Thus, I posit that Chileans protest because existing social and political infrastructures are not functioning as they should

Effect of water table fluctuations on petroleum contamination distribution

Research was conducted to study the effects of raising the water table level at different rates on petroleum contamination distribution. The experiments were carried out using a two-dimensional sand tank model. The experimental Light Non Aqueous Phase Liquid (LNAPL) was No. 2 Diesel fuel and the experimental media was sand (Sieve 20). A known quantity of fuel (5.65 Liters) was leaked into the tank at a leak rate of 0.75 L/hr. The water table level was raised at four different rates, 0.2, 1.4, 9.8, and 20 cm/hr. As the water table level was raised, the LNAPL layer rose to a certain height before breakthrough of water through the LNAPL layer occurred. The height at which breakthrough occurred was higher for the fastest rate of water table rise. The time to breakthrough of water through the LNAPL layer was longest for the slowest rate. The time to breakthrough of water through the LNAPL layer approached a similar value for the faster rise rates, 9.8 cm/hr and 20.0 cm/hr. The soil samples were analyzed for Total Petroleum Hydrocarbon (TPH) and the results of the soil sample analysis showed that for faster water table level rise rates, the hydrocarbon concentration at each sampling location was higher. (Abstract shortened by UMI.)

Numerical Investigation of Scaling Effects of a Ramjet-Powered Projectile

Ramjet flowpath miniaturization is a potentially useful technology for integration into munitions to increase range, accuracy, and lethality. The emphasis of this effort is to numerically characterize the performance of a miniature hydrogen-fueled and ethylene-fueled ramjet flowpath during Mach 3 and Mach 3.5 sea-level flight. The effect of geometric scale on ramjet performance is evaluated using high-fidelity RANS CFD models. Sensitivity to nonequilibrium laminar and turbulence-limited chemistry, and transitional turbulence treatments are evaluated. The physical sources of small scale performance limitations are identified for both fuel types. Finally, flowpath integration for small-scale applications is briefly addressed

Victims of stalking in India: A study of girl college students in Tirunelveli City

The word 'stalking' was not commonly known in India, until Priyadharshini Mattoo's case (1996) hit the headlines. Eve teasing, a colloquial word for gender harassment is popularly known and Tamil Nadu Prohibition of Eve-Teasing Act, 1998 on that was developed after the brutal killing of a girl named Sarika Shah in Chennai. Though, stalking is there in the past, it was not acknowledged with this terminology and it was always merged with Eve teasing. On the other hand, stalking is much graver than Eve teasing and it is an obsessive behaviour. After the Matoo's case, the Indian Criminal Justice System awoke and the National Commission for Women is ready with a draft Bill (Sexual Assault Prevention Bill) to make the Indian Penal Code more effective against the menace of stalkers. Research studies related to stalking in India are sparse and there is a need to study this phenomenon in depth. This paper presents some results from a study of stalking victims among Girl College students at Tirunelveli City, Tamil Nadu, India. In-depth questionnaire data are drawn on to investigate the course and nature of prolonged stalking in 150 self-defined victims. Findings indicate a pattern of repeated intrusions, the stalking harassment methods, lack of reporting behaviour, and effects of stalking on the victims

Zebrafish studies identify serotonin receptors mediating antiepileptic activity in Dravet syndrome.

Dravet syndrome is a life-threatening early-onset epilepsy not well controlled by antiepileptic drugs. Drugs that modulate serotonin (5-HT) signalling, including clemizole, locaserin, trazodone and fenfluramine, have recently emerged as potential treatment options for Dravet syndrome. To investigate the serotonin receptors that could moderate this antiepileptic activity, we designed and synthesized 28 novel analogues of clemizole, obtained receptor binding affinity profiles, and performed in vivo screening in a scn1lab mutant zebrafish (Danio rerio) model which recapitulates critical clinical features of Dravet syndrome. We discovered three clemizole analogues with 5-HT receptor binding that exert powerful antiepileptic activity. Based on structure-activity relationships and medicinal chemistry-based analysis, we then screened an additional set of known 5-HT receptor specific drug candidates. Integrating our in vitro and in vivo data implicates 5-HT2B receptors as a critical mediator in the mechanism of seizure suppression observed in Dravet syndrome patients treated with 5-HT modulating drugs

Fragile Future: Youth Insecurities and Their Relations with Police in Afghanistan and Pakistan

Youth are the backbone of any nation, and they are decisive in its development or destruction. A considerable portion of the population in both Afghanistan and Pakistan consists of youth. This paper discusses the impacts of unemployment, poverty, drug abuse, corruption, conflicts, and extremism on the experiences of young people in these countries. Vulnerabilities can become risk factors that, in turn, can increase the likelihood of youth being involved with the police. Although vulnerability and insecurity are common to both young women and men, girls and young women face additional challenges that increase their vulnerability to insecurities, such as gender-based violence. This article details how livelihood and personal insecurities are closely intertwined and further considers how these insecurities involve the police in one way or another. It argues that local community-oriented police initiatives and civil society organisation contributions can increase cooperation between youth and law enforcement agencies in addressing these challenges in a collaborative and trustful manner

Interfacial viscoelasticity, yielding and creep ringing of globular protein–surfactant mixtures

Protein–surfactant mixtures arise in many industrial and biological systems, and indeed, blood itself is a mixture of serum albumins along with various other surface-active components. Bovine serum albumin (BSA) solutions, and globular proteins in general, exhibit an apparent yield stress in bulk rheological measurements at surprisingly low concentrations. By contrasting interfacial rheological measurements with corresponding interface-free data obtained using a microfluidic rheometer, we show that the apparent yield stress exhibited by these solutions arises from the presence of a viscoelastic layer formed due to the adsorption of protein molecules at the air–water interface. The coupling between instrument inertia and surface elasticity in a controlled stress device also results in a distinctive damped oscillatory strain response during creep experiments known as“creep ringing”. We show that this response can be exploited to extract the interfacial storage and loss moduli of the protein interface. The interfacial creep response at small strains can be described by a simple second order system, such as the linear Jeffreys model, however the interfacial response rapidly becomes nonlinear beyond strains of order 1%. We use the two complementary techniques of interfacial rheometry and microfluidic rheometry to examine the systematic changes in the surface and bulk material functions for mixtures of a common non-ionic surfactant, polysorbate 80, and BSA. It is observed that the nonlinear viscoelastic properties of the interface are significantly suppressed by the presence of even a relatively small amount of surfactant (c[subscript surf] > 10[superscript −3] wt.%). Preferential interfacial adsorption of the mobile surfactant at these surfactant concentrations results in complete elimination of the bulk apparent yield stress exhibited by surfactant-free BSA solutions.Akzo Nobel (Firm