Firm-Value Effects of Carbon Emissions and Carbon Disclosures-Evidence from Korea.

We examine the association between carbon emissions, carbon disclosures, and firm value for Korean firms, with a particular interest in chaebols, a special type of Korean conglomerate. Using hand-collected carbon emissions and firm-specific data for 841 Korean firms, including 514 chaebols and 335 non-chaebols, we find a significantly positive relationship between carbon emissions and firm value among chaebol affiliates. This result contrasts with previous findings conducted in advanced markets, where investors consider carbon emissions to be destructive. In terms of the voluntary disclosure policy, we find that companies with good environmental performance tend to disclose carbon emissions voluntarily. We further argue that these findings originate from the specific business atmosphere in Korea. Our results support the traditional view of corporations in terms of environmental policy and highlight the importance of firm characteristics and historical developments in the analysis of environmental policy.

Modeling of CO2-LPG WAG with asphaltene deposition to predict coupled enhanced oil recovery and storage performance.

Combined carbon capture and storage and CO2-enhanced oil recovery (CCS-EOR) can reconcile the demands of business with the need to mitigate the effects of climate change. To improve the performance of CCS-EOR, liquefied petroleum gas (LPG) can be co-injected with CO2, leading to a reduction in the minimum miscibility pressure. However, gas injection can cause asphaltene problems, which undermines EOR and CCS performances simultaneously. Here, we systematically examine the mechanisms of asphaltene deposition using compositional simulations during CO2-LPG-comprehensive water-alternating-gas (WAG) injection. The LPG accelerates asphaltene deposition, reducing gas mobility, and increases the performance of residual trapping by 9.2% compared with CO2 WAG. In contrast, solubility trapping performance declines by only 3.7% because of the greater reservoir pressure caused by the increased formation damage. Adding LPG enhances oil recovery by 11% and improves total CCS performance by 9.1% compared with CO2 WAG. Based on reservoir simulations performed with different LPG concentrations and WAG ratios, we confirmed that the performance improvement of CCS-EOR associated with increasing LPG and water injection reaches a plateau. An economic evaluation based on the price of LPG should be carried out to ensure practical success.

Overlayer deposition-induced control of oxide ion concentration in SrFe0.5Co0.5O2.5 oxygen sponges.

Controlling the oxide ion (O2-) concentration in oxides is essential to develop advanced ionic devices, i.e. solid oxide fuel cells, smart windows, memory devices, energy storage devices, and so on. Among many oxides several transition metal (TM)-based perovskite oxides show high oxide ion conductivity, and their physical properties show high sensitivity to the change of the oxide ion concentration. Here, the change in the oxide ion concentration is shown through the overlayer deposition on the SrFe0.5Co0.5O2.5 (SFCO) oxygen sponge film. We grew SFCO films followed by the deposition of two kinds of complex oxide films under exactly the same growth conditions, and observed the changes in the crystal structure, valence states, and magnetic ground states. As the NSMO overlayer grows, strong evidence of oxidation at the O K edge is shown. In addition, the Fe4+ feature is revealed, and the electron valence state of Co increased from 3 to 3.25. The oxide ion concentration of SFCO changes during layer growth due to oxidation or reduction due to differences in chemical potential. The present results might be useful to develop advanced ionic devices using TM-based perovskite oxides.

Effects of Aqueous Solubility and Geochemistry on CO2 Injection for Shale Gas Reservoirs.

In shale gas reservoirs, CH4 and CO2 have finite aqueous solubilities at high-pressure conditions and their dissolutions in water affect the determination of the original gas in place and the CO2 sequestration. In addition, the dissolution of CO2 decreases the pH of connate water, and the geochemical reactions may thus occur in carbonate-rich shale reservoirs. The comprehensive simulations of this work quantify the effects of aqueous solubility and geochemistry on the performance CO2 huff-n-puff process in shale gas reservoir. Accounting for the aqueous solubility of CH4 increases the initial natural gas storage and natural gas production. The effect of the aqueous solubility of CO2 enables to sequester additional CO2 via solubility trapping. Considering the geochemical reactions, the application of the CO2 huff-n-puff process causes the dissolution of carbonate minerals and increases the porosity enhancing the gas flow and the gas recovery. Incorporation of geochemistry also predicts the less CO2 sequestration capacity. Therefore, this study recommends the consideration of aqueous solubility and geochemical reactions for the accurate prediction of gas recovery and CO2 sequestration in shale gas reservoirs during the CO2 huff-n-puff process.

Formation of buried superconducting Mo2N by nitrogen-ion-implantation.

Nitrogen ion implantation is a useful technique to put nitrogen ions into lattices. In this work, nitrogen ion implantation into epitaxial Mo films is performed to create a buried superconducting γ-Mo2N. Atomically flat epitaxial (110) Mo films are grown on (0001) Al2O3. By impinging nitrogen ions, where the beam energy is fixed to 20 keV, we observe (111) γ-Mo2N diffraction and the formation of a γ-Mo2N layer from X-ray reflectivity. Magnetization and transport measurements clearly support a superconducting layer in the implanted film. Our strategy shows that formation of a buried superconducting layer can be achieved through ion implantation and self-annealing.

Different Neuronal Activity Patterns Induce Different Gene Expression Programs.

A vast number of different neuronal activity patterns could each induce a different set of activity-regulated genes. Mapping this coupling between activity pattern and gene induction would allow inference of a neuron's activity-pattern history from its gene expression and improve our understanding of activity-pattern-dependent synaptic plasticity. In genome-scale experiments comparing brief and sustained activity patterns, we reveal that activity-duration history can be inferred from gene expression profiles. Brief activity selectively induces a small subset of the activity-regulated gene program that corresponds to the first of three temporal waves of genes induced by sustained activity. Induction of these first-wave genes is mechanistically distinct from that of the later waves because it requires MAPK/ERK signaling but does not require de novo translation. Thus, the same mechanisms that establish the multi-wave temporal structure of gene induction also enable different gene sets to be induced by different activity durations.

Creating protective appliances for preventing dental injury during endotracheal intubation using intraoral scanning and 3D printing: a technical note.

Digital dentistry has influenced many dental procedures, such as three-dimensional (3D) diagnosis and treatment planning, surgical splints, and prosthetic treatments. Patient-specific protective appliances (PSPAs) prevent dental injury during endotracheal intubation. However, the required laboratory work takes time, and there is the possibility of tooth extraction while obtaining the dental impression. In this technical report, we utilized new digital technology for creating PSPAs, using direct intraoral scanners and 3D printers for dental cast fabrication.

Brain-wide maps of Fos expression during fear learning and recall.

Fos induction during learning labels neuronal ensembles in the hippocampus that encode a specific physical environment, revealing a memory trace. In the cortex and other regions, the extent to which Fos induction during learning reveals specific sensory representations is unknown. Here we generate high-quality brain-wide maps of Fos mRNA expression during auditory fear conditioning and recall in the setting of the home cage. These maps reveal a brain-wide pattern of Fos induction that is remarkably similar among fear conditioning, shock-only, tone-only, and fear recall conditions, casting doubt on the idea that Fos reveals auditory-specific sensory representations. Indeed, novel auditory tones lead to as much gene induction in visual as in auditory cortex, while familiar (nonconditioned) tones do not appreciably induce Fos anywhere in the brain. Fos expression levels do not correlate with physical activity, suggesting that they are not determined by behavioral activity-driven alterations in sensory experience. In the thalamus, Fos is induced more prominently in limbic than in sensory relay nuclei, suggesting that Fos may be most sensitive to emotional state. Thus, our data suggest that Fos expression during simple associative learning labels ensembles activated generally by arousal rather than specifically by a particular sensory cue.

RNA sequencing from neural ensembles activated during fear conditioning in the mouse temporal association cortex.

The stable formation of remote fear memories is thought to require neuronal gene induction in cortical ensembles that are activated during learning. However, the set of genes expressed specifically in these activated ensembles is not known; knowledge of such transcriptional profiles may offer insights into the molecular program underlying stable memory formation. Here we use RNA-Seq to identify genes whose expression is enriched in activated cortical ensembles labeled during associative fear learning. We first establish that mouse temporal association cortex (TeA) is required for remote recall of auditory fear memories. We then perform RNA-Seq in TeA neurons that are labeled by the activity reporter Arc-dVenus during learning. We identify 944 genes with enriched expression in Arc-dVenus+ neurons. These genes include markers of L2/3, L5b, and L6 excitatory neurons but not glial or inhibitory markers, confirming Arc-dVenus to be an excitatory neuron-specific but non-layer-specific activity reporter. Cross comparisons to other transcriptional profiles show that 125 of the enriched genes are also activity-regulated in vitro or induced by visual stimulus in the visual cortex, suggesting that they may be induced generally in the cortex in an experience-dependent fashion. Prominent among the enriched genes are those encoding potassium channels that down-regulate neuronal activity, suggesting the possibility that part of the molecular program induced by fear conditioning may initiate homeostatic plasticity.

Computer-controlled local anesthetic delivery for painless anesthesia: a literature review.

Local anesthesia is administered to reduce pain during dental treatments, but may itself cause pain and contribute to increased dental fear. Computer-controlled local anesthetic delivery (CCLAD) is one the method to reduce patient pain during local anesthesia; it is a device that slowly administers anesthetics by using a computerized device to control the injection speed. This literature review aims to provide an objective assessment of the usefulness of CCLAD for controlling pain by reviewing papers published to date that have used CCLAD.

Management of hyperthyroid patients in dental emergencies: a case report.

The prevalence of thyroid disease, particularly hyperthyroidism, has rapidly increased in Korea in the past 10 years. Therefore, it is important to consider the complete medical history including thyroid disease in patients under dental treatment. Both the drugs used for dental treatment and psychological symptoms associated with treatment can induce emergencies in hyperthyroid patients. This case report considers emergency situations during dental treatment for hyperthyroid patients, and discusses risk factors and related concerns.

Historical trend in heavy metal pollution in core sediments from the Masan Bay, Korea.

The spatiotemporal distribution and their mass accumulation rate (MAR) of heavy metals were investigated to evaluate the time-dependent historical trends of heavy metal concentration. The three short cores used for this study were collected from the catchment area (MS-PC5, 60cm length), the central part (MS-PC4, 40cm length) and the offshore (MS-PC2, 60cm length) of the Masan Bay, Korea. The concentration of heavy metals (Co, Ni, Cu, Zn, Cr and Pb) in catchment area is as much as 1.5-2 times higher than central part of the Bay, and about 2 times higher than offshore area approximately. In particular, MAR of metals (Cu, Zn and Pb) show clear spatiotemporal variation, so that MAR's of heavy metal may provide more accurate information in evaluating the degree of pollution. Temporally, the heavy metal concentration had been increased since the late 1970s, but it seems to decrease again since the 2004yr in catchment area. This may came from concentrated efforts for the government to reduce industrial waste release.

Relaxin is up-regulated in the rat ovary by orthodontic tooth movement.

Relaxin (Rln) is an ovarian hormone that stimulates osteoclastic and osteoblastic activities and connective tissue turnover. To investigate the expression of Rln during orthodontic tooth movement, rats were implanted with orthodontic appliances that connected a spring from the upper incisors to the first molar with a 70 cN force. Rats in each group were killed 6, 48, and 144 h after activating the appliance, and the levels of Rln1 and Rln3 expression in the ovary were determined by real-time RT-PCR, northern blots, western blots, and immunofluorescence analyses. The amount of tooth movement induced by the orthodontic force increased in a time-dependent manner. The levels of Rln1 mRNA increased by 12-, 41-, and 263-fold at 6, 48, and 144 h, respectively, after orthodontic tooth movement. The time-dependent increase in the concentration of Rln 1 protein in the ovary was also confirmed by western blotting. Rln 1 was localized in the granulosa cells of the ovarian follicles, and the immunoreactivity against Rln 1 was increased by the movement. In contrast, the concentration of Rln 3 was below the level of detection. The results of this study suggest that local changes in periodontal tissues induced by orthodontic tooth movement may affect Rln1 expression in the ovary. However, further studies are needed to decipher the mechanisms involved and the possible contribution of the increased level of expression of Rln 1 to the tooth movement.

Nitric oxide modulates osteoblastic differentiation with heme oxygenase-1 via the mitogen activated protein kinase and nuclear factor-kappaB pathways in human periodontal ligament cells.

Nitric oxide (NO) and heme oxygenase-1 (HO-1) play important roles in the regulation of stem cell proliferation and differentiation. However, it has not been examined whether human periodontal ligament (PDL) cells can differentiate into osteoblast-like cells by NO activity mediated via HO-1. The objective of this study was to determine the effect of NO on proliferation and differentiation in human PDL cells, and to identify the underlying mechanism of its actions. Primary human PDL cells were cultured with NO donor sodium nitroprusside (SNP); cell proliferation and differentiation were measured. NO production, cell viability and cell proliferation were evaluated using the Griess reagent, MTT assay and BrdU incorporation, respectively. To analyze differentiation, we measured alkaline phosphatase (ALP) activity, osteocalcin (OC), osteonectin (ON) expression, and bone sialoprotein (BSP) by Western blotting. SNP-induced NO production is associated with inducible nitric oxide synthase induction in a time and dose-dependent manner. SNP resulted in decreased cell proliferation and increased expression of osteogenic differentiation markers such as ALP, OC, ON and BSP. Maximal HO-1 was reached with 0.05 mM SNP and gradually decreased with 1.0 mM. Treatment with an HO-1 inhibitor and selective inhibitors of extracellular regulated kinase 1/2 and nuclear factor-kappaB blocked the SNP-induced growth inhibition, as well as osteoblastic differentiation. These data suggest that NO-induced osteogenic differentiation through HO-1 may be an important mediator of periodontal regeneration or bone tissue engineering.

Effects of substance P on osteoblastic differentiation and heme oxygenase-1 in human periodontal ligament cells.

Although substance P (SP) is associated with osteoclast differentiation and bone resorption, little is known about the osteogenic differentiation-inducing effects of SP in periodontal ligament (PDL) cells. This study investigated whether PDL cells could differentiate into osteoblastic-like cells by SP. The expression of osteoblastic differentiation markers such as osteopontin (OPN), osteonectin (ON), osteocalcin (OCN) and bone sialoprotein (BSP) were evaulated by Western blotting. Additionally, SP-mediated heme oxygenase-1 (HO-1) pathways were further clarified. SP increased HO-1 and osteogenic differentiation in concentration- and time-dependent manners, as determined by OPN, ON, OCN and BSP expression. Furthermore, treatment with inhibitors of p38, ERK MAPK, and NF-kappaB abolished SP-induced osteogenic differentiation and HO-1 expression. SP-induced translocation of Nrf-2 was also observed. The combined results suggest that SP activates the stress-response enzymes HO-1 and Nrf-2, subsequently leading to upregulation of osteogenic differentiation in human PDL cells.

Spin chirality on a two-dimensional frustrated lattice.

The collective behaviour of interacting magnetic moments can be strongly influenced by the topology of the underlying lattice. In geometrically frustrated spin systems, interesting chiral correlations may develop that are related to the spin arrangement on triangular plaquettes. We report a study of the spin chirality on a two-dimensional geometrically frustrated lattice. Our new chemical synthesis methods allow us to produce large single-crystal samples of KFe3(OH)6(SO4)2, an ideal Kagomé lattice antiferromagnet. Combined thermodynamic and neutron scattering measurements reveal that the phase transition to the ordered ground-state is unusual. At low temperatures, application of a magnetic field induces a transition between states with different non-trivial spin-textures.