Ice formation in iron containing hydrogel films

The states of water in polymers, including ice formation, is of increasing interest for a broad range of science and engineering, including the application and the longevity of water-bourne polymeric coatings, cryogenic preservation of cells and organs, ice mediated porous structure formation, freeze-drying process in food preservation, low temperature operation of batteries and supercapacitors, and the tailing pond sedimentation in oil sands production. The freezing point of water is heavily influenced by the polymer-water interaction and the concentration of ionic species in the water and in the polymer backbones. Various species of salt ions are abundant in the operating conditions for the polymeric materials, but their effect on the water in polymers has not been studied exhaustively. Polyampholytes, which contains both cationic and anionic groups in their backbones, are an interesting class of material with its hygroscopic nature with intrinsic self-healing ability. By tuning the salt concentration, the water freezing point in the polyampholytes is expected to be widely tunable, rendering the material as a promising lubrication layer at low temperatures. The overall scope of our work is to understand, in depth, (i) the phenomenon of freezing point depression of water in ion containing polyampholyte hydrogels and (ii) the effect of the restricted ice formation on the surface lubrication of the hydrogel coatings. In the current presentation, I will talk about the scope (i). Here, we hypothesize a simplified model for the water in polyampholyte films to predict the freezing point depression in aqueous solution with multiple solutes that mimics true environmental conditions. Specifically, we aim to predict the freezing point depression of water in polyampholytic hydrogels that contains multiple salt components. First of all, it is important to note that the water molecules can exist in the hydrogel in various forms, ranging from tightly bound molecules adsorbed on polymer network, to weakly bound molecules, to free, bulk-like molecules. The amount of bound water can be determined with the parameters for the synthesis of the polymer network. The fraction of bound and free waters can be quantified by the degree of swelling. Free water can be described as the mixture of water and ions that are not bound to the polymer networks. Its freezing point depression can be precisely predicted with a multisolute osmotic virial equation by Elliott et al [1-4]: (1) where R is the universal gas constant, T is the temperature, Mwater is the molar mass of water, Tmo is the absolute freezing point of pure water, and is the standard molar entropy change of fusion of water. The osmolality, π, can be deduced from multi-solute osmotic virial eqation, which designates fitting parameters for each ionic components in water. The behavior of water is studied with various experimental methods, such as differential scanning calorimetry (DSC) for determining the phase transitions of free and bound water, nuclear magnetic resonance spectroscopy (NMR) for the molecular structure around the water molecules and around the infused ions, and fourier transform infrared spectroscopy (FT-IR) for detecting specific polymer-water interactions, as well as microscopic techniques to directly observe ice formation events. In short, the effect of multicomponent salt on water freezing point depression in polyampholytes can be systematically predicted by (i) decoupling the relative amount of bound and free water as a function of polymer synthesis parameters, (ii) elucidating the nature of bound water and their role in ice formation, and (iii) predicting the freezing point depression of free water component by the multisolute osmotic virial equation

Breakdown of Dynamic Scaling in Thin Film Binary Liquids Undergoing Phase Separation

The kinetics of phase separation in thin polymer blend films displaying discrete and bicontinuous domain morphologies are examined. For discrete domains, the correlation length ξ grows as t1/3, in agreement with a coalescence model. By plotting ξ/d vs t/ti (initiation time), universal growth behavior is obtained for thickness values (d) from 1000 to 190 nm. In contrast, bicontinuous domains grow with a decreasing exponent, 0.62 to 0.28, as d decreases from 900 to 90 nm (i.e., no universal growth). This slowing down with reduced dimensionality suggests suppression of lateral hydrodynamic pumping

Hard/Soft composited materials for stretchable electronics

Convergence between scientific disciplines creates myriads of new opportunities to the problems that traditional approaches have not provided the answers. For example, researches on materials engineering and nanofabrication can shed a light to the current challenges in clinical biomedical science. Specifically, this presentation describes how materials science is employed to solve fundamental and practical problems in the intimate integration of the state-of-art inorganic devices onto living organs or skins for biomedical research. [1] Firstly, bioresorbable elastomers make a basic building block for tissue scaffolds for soft, moving organs (such as heart, blood vessels, and smooth muscles) and for substrate material for resorbable devices for implantation. Poly(glycerol sebacate) (PGS) and its nanocomposite derivatives make up an attractive class of biomaterial owing to their tunable mechanical properties with programmable biodegradability. In practice, however, the application of PGS is often hampered by frequent inconsistency in reproducing process conditions. The inconsistency stems from the volatile nature of glycerol during the esterification process. In this presentation, we suggest that the degree of esterification (DE) can be used to predict precisely the physical status, the mechanical properties, and the degradation of the PGS materials [2]. To provide a processing guideline for researchers, we also provide a physical status map as a function of curing temperature and time (Fig 1). In addition, we demonstrate that the addition of molecularly rigid crosslinking agents and network-structured inorganic nanoparticles are also effective in enhancing the mechanical properties of the PGS-derived materials. Secondly, operation of wearable or implantable bioelectronics requires a power source; piezoelectricity generating device allows the direct harvest of power source from natural movement. We have recently addressed an inexpensive pathway to convert commodity polyurethane foams into piezoelectricity nanogenerators by uniform growth of ZnO nanorods in the pores of the foams, followed by conductive material deposition and encapsulation processes [3]. The hard/soft integrated nanocomposite material has a potential to become an important building block for wearable bioelectronics system. Thirdly, we demonstrate that a skin-adhesive electronic device from hard/soft material integration has a potential to aid patient populations in clinical setup [4]. Here, an emerging technology, called “epidermal electronics”, is introduced, where ultra-thin geometry allows for intimate and comfortable contact to patients’ chin, just like a temporary tattoo (Fig 2). The two objectives of this study were to assess the potential of epidermal electronics technology for swallowing therapy. This study showed comparative signals between the new epidermal sEMG patch and the conventional adhesive patches used by clinicians for swallowing therapy. Convergence between scientific disciplines creates myriads of new opportunities to the problems that traditional approaches have not provided the answers. For example, researches on materials engineering and nanofabrication can shed a light to the current challenges in clinical biomedical science. Specifically, this presentation describes how materials science is employed to solve fundamental and practical problems in the intimate integration of the state-of-art inorganic devices onto living organs or skins for biomedical research. [1] Firstly, bioresorbable elastomers make a basic building block for tissue scaffolds for soft, moving organs (such as heart, blood vessels, and smooth muscles) and for substrate material for resorbable devices for implantation. Poly(glycerol sebacate) (PGS) and its nanocomposite derivatives make up an attractive class of biomaterial owing to their tunable mechanical properties with programmable biodegradability. In practice, however, the application of PGS is often hampered by frequent inconsistency in reproducing process conditions. The inconsistency stems from the volatile nature of glycerol during the esterification process. In this presentation, we suggest that the degree of esterification (DE) can be used to predict precisely the physical status, the mechanical properties, and the degradation of the PGS materials [2]. To provide a processing guideline for researchers, we also provide a physical status map as a function of curing temperature and time (Fig 1). In addition, we demonstrate that the addition of molecularly rigid crosslinking agents and network-structured inorganic nanoparticles are also effective in enhancing the mechanical properties of the PGS-derived materials. Secondly, operation of wearable or implantable bioelectronics requires a power source; piezoelectricity generating device allows the direct harvest of power source from natural movement. We have recently addressed an inexpensive pathway to convert commodity polyurethane foams into piezoelectricity nanogenerators by uniform growth of ZnO nanorods in the pores of the foams, followed by conductive material deposition and encapsulation processes [3]. The hard/soft integrated nanocomposite material has a potential to become an important building block for wearable bioelectronics system. Thirdly, we demonstrate that a skin-adhesive electronic device from hard/soft material integration has a potential to aid patient populations in clinical setup [4]. Here, an emerging technology, called “epidermal electronics”, is introduced, where ultra-thin geometry allows for intimate and comfortable contact to patients’ chin, just like a temporary tattoo (Fig 2). The two objectives of this study were to assess the potential of epidermal electronics technology for swallowing therapy. This study showed comparative signals between the new epidermal sEMG patch and the conventional adhesive patches used by clinicians for swallowing therapy

Hard/Soft composited materials for stretchable electronics

Convergence between scientific disciplines creates myriads of new opportunities to the problems that traditional approaches have not provided the answers. For example, researches on materials engineering and nanofabrication can shed a light to the current challenges in clinical biomedical science. Specifically, this presentation describes how materials science is employed to solve fundamental and practical problems in the intimate integration of the state-of-art inorganic devices onto living organs or skins for biomedical research. [1] Firstly, bioresorbable elastomers make a basic building block for tissue scaffolds for soft, moving organs (such as heart, blood vessels, and smooth muscles) and for substrate material for resorbable devices for implantation. Poly(glycerol sebacate) (PGS) and its nanocomposite derivatives make up an attractive class of biomaterial owing to their tunable mechanical properties with programmable biodegradability. In practice, however, the application of PGS is often hampered by frequent inconsistency in reproducing process conditions. The inconsistency stems from the volatile nature of glycerol during the esterification process. In this presentation, we suggest that the degree of esterification (DE) can be used to predict precisely the physical status, the mechanical properties, and the degradation of the PGS materials [2]. To provide a processing guideline for researchers, we also provide a physical status map as a function of curing temperature and time (Fig 1). In addition, we demonstrate that the addition of molecularly rigid crosslinking agents and network-structured inorganic nanoparticles are also effective in enhancing the mechanical properties of the PGS-derived materials. Secondly, operation of wearable or implantable bioelectronics requires a power source; piezoelectricity generating device allows the direct harvest of power source from natural movement. We have recently addressed an inexpensive pathway to convert commodity polyurethane foams into piezoelectricity nanogenerators by uniform growth of ZnO nanorods in the pores of the foams, followed by conductive material deposition and encapsulation processes [3]. The hard/soft integrated nanocomposite material has a potential to become an important building block for wearable bioelectronics system. Thirdly, we demonstrate that a skin-adhesive electronic device from hard/soft material integration has a potential to aid patient populations in clinical setup [4]. Here, an emerging technology, called “epidermal electronics”, is introduced, where ultra-thin geometry allows for intimate and comfortable contact to patients’ chin, just like a temporary tattoo (Fig 2). The two objectives of this study were to assess the potential of epidermal electronics technology for swallowing therapy. This study showed comparative signals between the new epidermal sEMG patch and the conventional adhesive patches used by clinicians for swallowing therapy. Convergence between scientific disciplines creates myriads of new opportunities to the problems that traditional approaches have not provided the answers. For example, researches on materials engineering and nanofabrication can shed a light to the current challenges in clinical biomedical science. Specifically, this presentation describes how materials science is employed to solve fundamental and practical problems in the intimate integration of the state-of-art inorganic devices onto living organs or skins for biomedical research. [1] Firstly, bioresorbable elastomers make a basic building block for tissue scaffolds for soft, moving organs (such as heart, blood vessels, and smooth muscles) and for substrate material for resorbable devices for implantation. Poly(glycerol sebacate) (PGS) and its nanocomposite derivatives make up an attractive class of biomaterial owing to their tunable mechanical properties with programmable biodegradability. In practice, however, the application of PGS is often hampered by frequent inconsistency in reproducing process conditions. The inconsistency stems from the volatile nature of glycerol during the esterification process. In this presentation, we suggest that the degree of esterification (DE) can be used to predict precisely the physical status, the mechanical properties, and the degradation of the PGS materials [2]. To provide a processing guideline for researchers, we also provide a physical status map as a function of curing temperature and time (Fig 1). In addition, we demonstrate that the addition of molecularly rigid crosslinking agents and network-structured inorganic nanoparticles are also effective in enhancing the mechanical properties of the PGS-derived materials. Secondly, operation of wearable or implantable bioelectronics requires a power source; piezoelectricity generating device allows the direct harvest of power source from natural movement. We have recently addressed an inexpensive pathway to convert commodity polyurethane foams into piezoelectricity nanogenerators by uniform growth of ZnO nanorods in the pores of the foams, followed by conductive material deposition and encapsulation processes [3]. The hard/soft integrated nanocomposite material has a potential to become an important building block for wearable bioelectronics system. Thirdly, we demonstrate that a skin-adhesive electronic device from hard/soft material integration has a potential to aid patient populations in clinical setup [4]. Here, an emerging technology, called “epidermal electronics”, is introduced, where ultra-thin geometry allows for intimate and comfortable contact to patients’ chin, just like a temporary tattoo (Fig 2). The two objectives of this study were to assess the potential of epidermal electronics technology for swallowing therapy. This study showed comparative signals between the new epidermal sEMG patch and the conventional adhesive patches used by clinicians for swallowing therapy

Clinical Comparison of the Auditory Steady-State Response with the Click Auditory Brainstem Response in Infants

ObjectivesOur goal was to determine the effectiveness of using the auditory steady state response (ASSR) as a measure of hearing thresholds in infants who are suspected of having significant hearing loss, as compared with using the click-auditory brainstem response (C-ABR).MethodsWe retrospectively analyzed the audiologic profiles of 76 infants (46 boys and 30 girls, a total of 151 ears) who ranged in age from 1 to 12 months (average age: 5.7 months). The auditory evaluations in 76 infants who were suspected of having hearing loss were done via the C-ABR and ASSR. In addition, for reference, the mean ASSR thresholds were compared to those of 39 ears of infants and 39 ears of adults with normal hearing at 0.5, 1, 2, and 4 kHz.ResultsThe highest correlation between the C-ABR and ASSR thresholds was observed at an average of 2-4 kHz (r=0.94). On comparison between the hearing of infants and adults at 0.5, 1, 2, and 4 kHz, the mean ASSR threshold in infants was 12, 7, 8, and 7 dB higher, respectively, than that in adults.ConclusionASSR testing may provide additional audiometric information for accurately predicting the hearing sensitivity, and this is essential for the management of infants with severe to profound hearing loss

Extensive Systemic Sarcoidosis with Testicular Involvement Mimicking Metastatic Testicular Cancer

Sarcoidosis is an idiopathic, multisystem disease that rarely involves the genitourinary tract. Here we present an unusual case of testicular sarcoidosis with extensive lymphadenopathy that mimicked a metastatic testicular tumor. A 27-year-old male presented with a palpable right testicular mass accompanied by multiple palpable inguinal lymph nodes. The scrotal ultrasound showed a hypoechoic lesion at the inferior portion of the right testis. Extensive enlarged lymph nodes were noted in multiple areas on the abdominal computed tomography. Preoperative testicular tumor markers were within the normal range. Exploration of the right testis with a frozen section analysis of the right testicular mass and of a palpable right inguinal lymph node showed granulomatous inflammation. The testis was salvaged and the final pathological diagnosis was sarcoidosis. Treatment with high-dose corticosteroids resulted in complete resolution of the intratesticular mass and a significant decrease in the extent of the lymphadenopathy