Monolithic digital patterning of polydimethylsiloxane with successive laser pyrolysis.

The patterning of polydimethylsiloxane (PDMS) into complex two-dimensional (2D) or 3D shapes is a crucial step for diverse applications based on soft lithography. Nevertheless, mould replication that incorporates time-consuming and costly photolithography processes still remains the dominant technology in the field. Here we developed monolithic quasi-3D digital patterning of PDMS using laser pyrolysis. In contrast with conventional burning or laser ablation of transparent PDMS, which yields poor surface properties, our successive laser pyrolysis technique converts PDMS into easily removable silicon carbide via consecutive photothermal pyrolysis guided by a continuous-wave laser. We obtained high-quality 2D or 3D PDMS structures with complex patterning starting from a PDMS monolith in a remarkably low prototyping time (less than one hour). Moreover, we developed distinct microfluidic devices with elaborated channel architectures and a customizable organ-on-a-chip device using this approach, which showcases the potential of the successive laser pyrolysis technique for the fabrication of devices for several technological applications.

Performance feedback and obsessive passion: The moderating role of human capital.

Based on the behavioral theory of the firm, we research how performance feedback influences the formation of CEOs' passion. We articulate that previous performance directly increases CEOs' passion. Specifically, positive affective outcomes (performance above aspiration-level) advance CEOs' positive feelings and motivation toward the domains of success (obsessive passion). For instance, when a firm accomplishes performance objectives, such as reaching sales goals, CEOs' positive feelings toward developing current products would be boosted. Moreover, negative affective outcomes (performance below aspiration-level) would also positively impact CEOs' passion since the CEOs would endeavor to reduce the difference between performance and their aspiration-level. As such, performance feedback is a critical antecedent of CEOs' obsessive passion. In addition, we apply human capital as a moderator between performance feedback and CEOs' obsessive passion. Results based on multiphase survey data from 189 CEOs of Korean small- and medium-sized enterprises indicate that both positive and negative performance feedback positively increase CEOs' obsessive passion. Moreover, human capital negatively moderates the relationship between positive performance feedback and CEOs' obsessive passion and positively moderates the relationship between negative performance feedback and CEOs' obsessive passion.

Glycerol Triacetate-Based Flame Retardant High-Temperature Electrolyte for the Lithium-Ion Battery.

Rechargeable batteries that can operate at elevated temperatures (>70 °C) with high energy density are long-awaited for industrial applications including mining, grid stabilization, naval, aerospace, and medical devices. However, the safety, cycle life, energy density, and cost of the available high-temperature battery technologies remain an obstacle primarily owing to the limited electrolyte options available. We introduce a flame-retardant electrolyte that can enable stable battery cycling at 100 °C by incorporating triacetin into the electrolyte system. Triacetin has excellent chemical stability with lithium metal, and conventional cathode materials can effectively reduce parasitic reactions and promises a good battery performance at elevated temperatures. Our findings reveal that Li-metal half-cells can be made that have high energy density, high Coulombic efficiency, and good cycle life with triacetin-based electrolytes and three different cathode chemistries. Moreover, the nail penetration test in a commercial-scale pouch battery using this new electrolyte demonstrated suppressed heat generation when the cell was damaged and excellent safety when using the triacetin-based electrolyte.

Descriptive norms and entrepreneurial intentions: the mediating role of anticipated inaction regret.

Previous research has mainly focused on the cognitive-based theory of planned behavior (TPB) model to predict entrepreneurial intentions. However, given the close relationship between cognition and emotion, researchers may need to pay more attention to how emotional reactions help predict entrepreneurial intentions. To fill this gap, we apply both cognitive (i.e., descriptive norms) and emotional (i.e., anticipated inaction regret) aspects to understand predictors of entrepreneurial intentions. Specifically, we employ the affect-as-information perspective as a complementary theoretical lens to TPB to test whether the role of descriptive norms on entrepreneurial intentions is affected by anticipated inaction regret as a form of emotional reaction to descriptive social norms. We conducted two survey-based studies with diverse samples (i.e., online Mturk panels of adults in the US and undergraduate students in Korea). This study demonstrates (1) a positive and significant relationship between descriptive norms and entrepreneurial intentions and (2) a mediating role of anticipated inaction regret between descriptive norms and entrepreneurial intentions. Our results contribute to the entrepreneurial intentions literature by exploring the mechanism between cognition and emotion, and highlighting an indirect emotional link (i.e., anticipated inaction regret) in understanding entrepreneurial intentions.

Multimodal E-Textile Enabled by One-Step Maskless Patterning of Femtosecond-Laser-Induced Graphene on Nonwoven, Knit, and Woven Textiles.

Personal wearable devices are considered important in advanced healthcare, military, and sports applications. Among them, e-textiles are the best candidates because of their intrinsic conformability without any additional device installation. However, e-textile manufacturing to date has a high process complexity and low design flexibility. Here, we report the direct laser writing of e-textiles by converting raw Kevlar textiles to electrically conductive laser-induced graphene (LIG) via femtosecond laser pulses in ambient air. The resulting LIG has high electrical conductivity and chemical reliability with a low sheet resistance of 2.86 Ω/□. Wearable multimodal e-textile sensors and supercapacitors are realized on different types of Kevlar textiles, including nonwoven, knit, and woven structures, by considering their structural textile characteristics. The nonwoven textile exhibits high mechanical stability, making it suitable for applications in temperature sensors and micro-supercapacitors. On the other hand, the knit textile possesses inherent spring-like stretchability, enabling its use in the fabrication of strain sensors for human motion detection. Additionally, the woven textile offers special sensitive pressure-sensing networks between the warp and weft parts, making it suitable for the fabrication of bending sensors used in detecting human voices. This direct laser synthesis of arbitrarily patterned LIGs from various textile structures could result in the facile realization of wearable electronic sensors and energy storage.

Ultra-thin light-weight laser-induced-graphene (LIG) diffractive optics.

The realization of hybrid optics could be one of the best ways to fulfill the technological requirements of compact, light-weight, and multi-functional optical systems for modern industries. Planar diffractive lens (PDL) such as diffractive lenses, photonsieves, and metasurfaces can be patterned on ultra-thin flexible and stretchable substrates and be conformally attached on top of arbitrarily shaped surfaces. In this review, we introduce recent research works addressed to the design and manufacturing of ultra-thin graphene optics, which will open new markets in compact and light-weight optics for next-generation endoscopic brain imaging, space internet, real-time surface profilometry, and multi-functional mobile phones. To provide higher design flexibility, lower process complexity, and chemical-free process with reasonable investment cost, direct laser writing (DLW) of laser-induced-graphene (LIG) is actively being applied to the patterning of PDL. For realizing the best optical performances in DLW, photon-material interactions have been studied in detail with respect to different laser parameters; the resulting optical characteristics have been evaluated in terms of amplitude and phase. A series of exemplary laser-written 1D and 2D PDL structures have been actively demonstrated with different base materials, and then, the cases are being expanded to plasmonic and holographic structures. The combination of these ultra-thin and light-weight PDL with conventional bulk refractive or reflective optical elements could bring together the advantages of each optical element. By integrating these suggestions, we suggest a way to realize the hybrid PDL to be used in the future micro-electronics surface inspection, biomedical, outer space, and extended reality (XR) industries.

Entrepreneurship Education and Founding Passion: The Moderating Role of Entrepreneurial Family Background.

In this paper, we examine the relationship between entrepreneurship education and entrepreneurial passion. Despite the advancement of entrepreneurship education literature and the increasing focus on entrepreneurship education in business schools, we lack empirical exploration on how entrepreneurship education can impact students' passion for founding new organizations. We hypothesize that students who take entrepreneurship classes would develop high levels of founding passion due to a great perception of skills and abilities that increase positive emotions and decrease negative emotions about the entrepreneurship process. Moreover, we draw on the literature on role models to suggest that students' entrepreneurial family background (students whose immediate family members are entrepreneurs) strengthens the influence of entrepreneurship education on entrepreneurial passion. Utilizing survey data collected from 160 university students, we found that entrepreneurship education positively influences students' founding passion and that this relationship is strengthened when students have entrepreneurs in their immediate family.

Evaluating an on-line cleaning agent for mitigating organic fouling in a reverse osmosis membrane.

Cleaning-in-place (CIP) is a representative fouling management process from which the filtration performances of fouled membranes can be recovered. However, CIP can cause significant inefficiency in water production because frequent system restabilization is necessary for cleaning processes. This study applied a newly developed on-line cleaning agent (OCA, a feed water additive for fouling mitigation), to reduce the number of CIP by enhancing water productivity. Reverse osmosis filtration was performed to evaluate the effect of on-line cleaning on the mitigation of organic fouling originating from humic acid (HA) and bovine serum albumin. OCA increased the permeate flux in proportion to OCA concentration. In particular, OCA effectively reduced the fouling layer thickness by 22% when fouling was influenced by HA-Ca2+ complexation, increasing water production by 5%. It also had a minor influence on bovine serum albumin fouling, producing a 1.4% increase in permeate flux. Furthermore, the pore blockage-cake filtration model was used to evaluate OCA cleaning performance through the reduction in fouling layer resistance and the growth parameter. The results demonstrated the advantages of OCA utilization for mitigating cake layer development. These findings imply that OCA can be an effective cleaning additive, especially in seawater and groundwater treatment processes with a high proportion of HA and calcium ions.

Synergistic Effects of Phosphorus and Boron Co-Incorporated Activated Carbon for Ultrafast Zinc-Ion Hybrid Supercapacitors.

The rapid expansion of the development of the electrochemical capacitor appliance and its industry areas has created the need for long cycling stability of over 30 000 cycles along with an ultrafast performance (referred to as ultrafast longevity). In recent years, zinc-ion hybrid supercapacitors (ZICs) are considered to be emerging energy storage applications thanks to their high specific capacity and remarkable cycling stability. However, ZICs still face serious challenges in overcoming the ultrafast performance and lifetime limitations related to the cathode materials, activated carbon (AC), due to inadequate electrical properties and poor wettability between the electrolyte and the electrode, which cause reductions in specific capacity and lifetime rapidly at high current densities during cycling. To address these drawbacks, a novel phosphorus (P) and boron (B) codoped AC (designated P&B-AC) is presented herein with enhanced electrical properties due to B-doping along with improved wettability due to P-doping to provide an ultrafast longevity ZICs. The prepared ZICs display a superior electrochemical performance with an excellent specific capacity of 169.4 mAh g-1 at 0.5 A g-1, a remarkable ultrafast performance of 84.0 mAh g-1 at 10 A g-1, and outstanding ultrafast longevity indicated by an 88% capacity retention for up to 30 000 cycles at 10 A g-1. The excellent energy storage ability is firmly ascribed to the P and B codoping synergistic effect, leading to a superior diffusion capability of Zn ion and charge-transfer process of the AC cathode.

Continuous-Wave Laser-Induced Transfer of Metal Nanoparticles to Arbitrary Polymer Substrates.

Laser-induced forward transfer (LIFT) and selective laser sintering (SLS) are two distinct laser processes that can be applied to metal nanoparticle (NP) ink for the fabrication of a conductive layer on various substrates. A pulsed laser and a continuous-wave (CW) laser are utilized respectively in the conventional LIFT and SLS processes; however, in this study, CW laser-induced transfer of the metal NP is proposed to achieve simultaneous sintering and transfer of the metal NP to a wide range of polymer substrates. At the optimum laser parameters, it was shown that a high-quality uniform metal conductor was created on the acceptor substrate while the metal NP was sharply detached from the donor substrate, and we anticipate that such an asymmetric transfer phenomenon is related to the difference in the adhesion strengths. The resultant metal electrode exhibits a low resistivity that is comparable to its bulk counterpart, together with strong adhesion to the target polymer substrate. The versatility of the proposed process in terms of the target substrate and applicable metal NPs brightens its prospects as a facile manufacturing scheme for flexible electronics.

Micropatterning of Metal Nanoparticle Ink by Laser-Induced Thermocapillary Flow.

Selective laser sintering of metal nanoparticle ink is a low-temperature and non-vacuum technique developed for the fabrication of patterned metal layer on arbitrary substrates, but its application to a metal layer composed of large metal area with small voids is very much limited due to the increase in scanning time proportional to the metal pattern density. For the facile manufacturing of such metal layer, we introduce micropatterning of metal nanoparticle ink based on laser-induced thermocapillary flow as a complementary process to the previous selective laser sintering process for metal nanoparticle ink. By harnessing the shear flow of the solvent at large temperature gradient, the metal nanoparticles are selectively pushed away from the scanning path to create metal nanoparticle free trenches. These trenches are confirmed to be stable even after the complete process owing to the presence of the accompanying ridges as well as the bump created along the scanning path. As a representative example of a metal layer with large metal area and small voids, dark-field photomask with Alphabetic letters are firstly created by the proposed method and it is then demonstrated that the corresponding letters can be successfully reproduced on the screen by an achromatic lens.

Shear-Assisted Laser Transfer of Metal Nanoparticle Ink to an Elastomer Substrate.

Selective laser sintering of metal nanoparticle ink is an attractive technology for the creation of metal layers at the microscale without any vacuum deposition process, yet its application to elastomer substrates has remained a highly challenging task. To address this issue, we introduced the shear-assisted laser transfer of metal nanoparticle ink by utilizing the difference in thermal expansion coefficients between the elastomer and the target metal electrode. The laser was focused and scanned across the absorbing metal nanoparticle ink layer that was in conformal contact with the elastomer with a high thermal expansion coefficient. The resultant shear stress at the interface assists the selective transfer of the sintered metal nanoparticle layer. We expect that the proposed method can be a competent fabrication route for a transparent conductor on elastomer substrates.

Petatewalide B, a novel compound from Petasites japonicus with anti-allergic activity.

ETHNOPHARMACOLOGICAL RELEVANCE: The giant butterbur Petasites japonicus is used to treat asthma and allergic diseases in traditional Korean, Japanese, and Chinese medicine. AIM OF THE STUDY: To elucidate the anti-allergic effect of Petasites genus, we studied effects of several compounds from Petasites japonicus leaves and found a novel bakkenolide-type sesquiterpine. In the present study, anti-allergic and anti-inflammatory effects of the new compound was examined using in vivo and in vitro experiments. MATERIALS AND METHODS: The novel compound was isolated from Petasites japonicus leaves and named petatewalide B. Antigen-induced degranulation and Ca(2+) mobilization were measured in RBL-2H3 mast cells by measuring ß-hexosaminidase activity and fluorescence change of Ca(2+) probe, fura-2. Induction of inducible nitric oxide synthase and cyclooxygenase 2 was measured by Western blotting in peritoneal macrophages. In addition, ovalbumin-induced asthma model was used for in vivo efficacy test of petatewalide B. Membrane potential was estimated by measuring fluorescence change of DiBAC in C6 glioma cells. RESULTS: Petatewalide B inhibited the antigen-induced degranulation of ß-hexosaminidase in RBL-2H3 mast cells, but did not affect antigen-induced Ca(2+) increase in the cells. Petatewalide B also showed inhibition of the LPS-induced induction of iNOS, but not COX-2 in mouse peritoneal macrophages. Nitric oxide production was also inhibited by petatewalide B in macrophages. In the ovalbumin-induced asthma model, petatewalide B strongly inhibited accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar lavage fluid. Petatewalide B increased the membrane potential of C6 glioma cells in a concentration-dependent manner. CONCLUSION: Petatewalide B from Petasites genus not only has anti-allergic and anti-inflammatory effects but also induces a transient increase of membrane potential in C6 glioma cells.

Anti-allergic effect of α-cubebenoate isolated from Schisandra chinensis using in vivo and in vitro experiments.

AIM OF THE STUDY: In Oriental countries, the dried fruits of Schisandra chinensis are extensively used in traditional medicine to treat asthma, gonorrhea, and other diseases. Recently, α-cubebenoate was isolated as an anti-inflammatory component from Schisandra chinensis. In the present study, the authors examined the anti-allergic effect of α-cubebenoate using in vivo and in vitro experiments. MATERIALS AND METHODS: α-Cubebenoate was isolated from an extract of Schisandra chinensis fruits. Antigen-induced degranulation and Ca(2+) mobilization were measured in RBL-2H3 mast cells. In addition, BALB/c mice were sensitized with ovalbumin and aluminum hydroxide, and then challenged with ovalbumin for three consecutive days. α-Cubebenoate (1mg/kg) was administered intraperitoneally 30min before each ovalbumin challenge. RESULTS: In RBL-2H3 mast cells, α-cubebenoate inhibited antigen-induced degranulation and increase of intracellular Ca(2+) concentrations. In the ovalbumin-induced asthma model, α-cubebenoate suppressed bronchiolar structural changes induced by ovalbumin challenge. Furthermore, α-cubebenoate strongly inhibited accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar lavage fluid. α-Cubebenoate also suppressed Th2 cytokines (IL-4 and IL-13) and TGF-ß1 in lung tissues and in immune cells at the mRNA and protein levels. CONCLUSION: α-Cubebenoate has an inhibitory effect on allergic inflammation and could be utilized as an agent for the treatment of asthma.

Therapeutic effects of s-petasin on disease models of asthma and peritonitis.

To explore the anti-allergic and anti-inflammatory effects of extracts of Petasites genus, we studied the effects of s-petasin, a major sesquiterpene from Petasites formosanus (a butterbur species) on asthma and peritonitis models. In an ovalbumin-induced mouse asthma model, s-petasin significantly inhibited the accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar fluids. S-petasin inhibited the antigen-induced degranulation of ß-hexosamidase but did not inhibit intracellular Ca(2+) increase in RBL-2H3 mast cells. S-petasin inhibited the LPS induction of iNOS at the RNA and protein levels in mouse peritoneal macrophages. Furthermore, s-petasin inhibited the production of NO (the product of iNOS) in a concentration-dependent manner in the macrophages. Furthermore, in an LPS-induced mouse model of peritonitis, s-petasin significantly inhibited the accumulation of polymorpho nuclear and mononuclear leukocytes in peritoneal cavity. This study shows that s-petasin in Petasites genus has therapeutic effects on allergic and inflammatory diseases, such as, asthma and peritonitis through degranulation inhibition in mast cells, suppression of iNOS induction and production of NO in macrophages, and suppression of inflammatory cell accumulation.

Identification of a novel anti-inflammatory compound, α-cubebenoate from Schisandra chinensis.

AIMS OF THE STUDY: Extracts of Schisandra chinensis have been used as an anti-fatigue and tonic agent. Because chronic fatigue syndrome is related to inflammatory and oxidative stress, we assessed whether Schisandra chinensis has anti-inflammatory constituents and studied the effect of a novel α-cubebenoate isolated from Schisandra chinensis. MATERIALS AND METHODS: α-Cubebenoate was isolated from an extract of Schisandra chinensis fruits. The inductions of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) by lipopolysaccharide (LPS) were quantified by RT-PCR and Western blotting in mouse peritoneal macrophages. Nitric oxide (NO) and prostaglandin E2 (PGE2) were also measured in the media by Griess reagent and EIA method. A mouse model of LPS-induced peritonitis was used to test the in vivo efficacy of α-cubebenoate. RESULTS: α-Cubebenoate (5-10µg/ml) inhibited the inductions of iNOS and COX-2 in mouse peritoneal macrophages at the mRNA and protein levels. LPS-induced productions of NO and PGE2 were inhibited by α-cubebenoate (5-10µg/ml). In addition, α-cubebenoate inhibited the LPS-induced activation of JNK, but not those of ERK and p38 MAPK in mouse peritoneal macrophages. Furthermore, in the LPS-induced in vivo peritonitis model, α-cubebenoate (1mg/kg) strongly inhibited the accumulation of polymorph nuclear lymphocytes in the peritoneal cavity. CONCLUSION: α-Cubebenoate inhibited LPS-induced expression of iNOS and COX-2 in a concentration-dependent manner, thereby suppressing productions of NO and PGE2 in vitro in peritoneal macrophages. α-Cubebenoate also inhibited LPS-induced accumulation of polymorph nuclear lymphocytes in LPS-induced peritonitis model in vivo. α-Cubebenoate may act as an anti-fatigue constituent of Schisandra chinensis through anti-inflammation and could be of therapeutic use as a treatment for inflammatory diseases.

An analytical study of Mammalian bite wounds requiring inpatient management.

BACKGROUND: Mammalian bite injuries create a public health problem because of their frequency, potential severity, and increasing number. Some researchers have performed fragmentary analyses of bite wounds caused by certain mammalian species. However, little practical information is available concerning serious mammalian bite wounds that require hospitalization and intensive wound management. Therefore, the purpose of this study was to perform a general review of serious mammalian bite wounds. METHODS: We performed a retrospective review of the medical charts of 68 patients who were referred to our plastic surgery department for the treatment of bite wounds between January 2003 and October 2012. The cases were analyzed according to the species, patient demographics, environmental factors, injury characteristics, and clinical course. RESULTS: Among the 68 cases of mammalian bite injury, 58 (85%) were caused by dogs, 8 by humans, and 2 by cats. Most of those bitten by a human and both of those bitten by cats were male. Only one-third of all the patients were children or adolescents. The most frequent site of injury was the face, with 40 cases, followed by the hand, with 16 cases. Of the 68 patients, 7 were treated with secondary intention healing. Sixty-one patients underwent delayed procedures, including delayed direct closure, skin graft, composite graft, and local flap. CONCLUSIONS: Based on overall findings from our review of the 68 cases of mammalian bites, we suggest practical guidelines for the management of mammalian bite injuries, which could be useful in the treatment of serious mammalian bite wounds.

Anti-allergic and anti-inflammatory effects of bakkenolide B isolated from Petasites japonicus leaves.

AIMS OF THE STUDY: To elucidate the anti-allergic and anti-inflammatory effects of Petasites genus, we studied the effects of several compounds isolated from Petasites japonicas leaves. MATERIALS AND METHODS: Bakkenolide B was isolated from Petasites japonicus leaves. Antigen-induced degranulation was measured in RBL-2H3 mast cells by measuring ß-hexosamidase activity. Induction of inducible nitric oxide synthase and cyclooxygenase 2 was measured by Western blotting in peritoneal macrophages. Ovalbumin-induced asthma model was used for in vivo efficacy test of bakkanolide B. RESULTS: We found that bakkenolide B, a major component of the leaves, concentration-dependently inhibited RBL-2H3 mast cell degranulation. Bakkenolide B also inhibited the gene inductions of inducible nitric oxide synthase and cyclooxygenase 2 in mouse peritoneal macrophages. Furthermore, in an ovalbumin-induced asthma model, bakkenolide B strongly inhibited the accumulation of eosinophils, macrophages, and lymphocytes to bronchoalveolar lavage fluid. CONCLUSION: Bakkenolide B has suppressive properties for allergic and inflammatory responses and may be utilized as a potent agent for the treatment of asthma.