Background
People behave and interact with others differently when experiencing physical pain. Pain has dramatic effects on one's emotional responses, cognitive functions and social interaction. ...However, little has been known about whether and how physical pain influences interpersonal trust in social interaction. In the present study, we examined the influence of physical pain on trusting behaviour.
Methods
A total of 112 healthy participants were recruited and assigned to physical pain condition (induced by Capsaicin) and control condition (with hand cream), respectively. Thirty minutes after pain induction, three decision‐making tasks were conducted to measure behaviours in social interaction, including trust and trustworthiness (trust game), non‐social risk‐taking (risk game) and altruism (dictator game).
Results
Results showed that physical pain increased interpersonal trust among females, but not among males. Pain did not influence non‐social risk‐taking, altruism or trustworthiness, as evaluated by monetary transfers in those tasks. Moreover, the effect of physical pain on interpersonal trust was fully mediated by expectation of monetary profit.
Conclusions
These findings demonstrate an effect of pain on interpersonal trust and suggest a reciprocity mechanism that the effect may be driven by self‐interest rather than altruistic motivation. The pain effect on trust was evident only in females, implying distinct pain coping strategies used by both genders.
Significance
The present work highlights the social component of pain and extends our understanding of mutual interactions between pain and social cognition.
Summary
Background
Human skin, which is constantly exposed to solar ultraviolet radiation (UVR), has a unique ability to respond by increasing its pigmentation in a protective process driven by ...melanogenesis in human epidermal melanocytes (HEMs). However, the molecular mechanisms used by HEMs to detect and respond to UVR remain unclear.
Objectives
To investigate the function and potential mechanism of opsin 5 (OPN5), a photoreceptor responsive to UVR wavelengths, in melanogenesis in HEMs.
Methods
Melanin content in HEMs was determined using the NaOH method, and activity of tyrosinase (TYR) (a key enzyme in melanin synthesis) was determined by the l‐DOPA method. OPN5 expression in UVR‐treated vs. untreated HEMs and explant tissues was detected by reverse‐transcription quantitative polymerase chain reaction (RT‐qPCR), Western blotting and immunofluorescence. Short interfering RNA‐mediated OPN5 knockdown and a lentivirus OPN5 overexpression model were used to examine their respective effects on TYR, tyrosinase‐related protein 1 (TRP1), TRP2 and microphthalmia‐associated transcription factor (MITF) expression, under UVR. Changes in expression of TYR, TRP1 and TRP2 caused by changes in OPN5 expression level were detected by RT‐qPCR and Western blot. Furthermore, changes in signalling pathway proteins were assayed.
Results
We found that OPN5 is the key sensor in HEMs responsible for UVR‐induced melanogenesis. OPN5‐induced melanogenesis required Ca2+‐dependent G protein‐coupled receptor‐ and protein kinase C signal transduction, thus contributing to the UVR‐induced MITF response to mediate downstream cellular effects, and providing evidence of OPN5 function in mammalian phototransduction. Remarkably, OPN5 activation was necessary for UVR‐induced increase in cellular melanin and has an inherent function in melanocyte melanogenesis.
Conclusions
Our results provide insight into the molecular mechanisms of UVR sensing and phototransduction in melanocytes, and may reveal molecular targets for preventing pigmentation or pigment diseases.
What is already known about this topic?
Ultraviolet radiation (UVR) induces a protective response to DNA damage mediated by melanin synthesis in human epidermal melanocytes (HEMs).
Tyrosinase (TYR), with tyrosinase‐related proteins (TRP1, TRP2), are the key enzymes for melanin synthesis.
Microphthalmia‐associated transcription factor regulates key genes for melanocyte development and differentiation, and can stimulate melanogenesis by activating transcription of TYR and other pigmentation genes, including TRP1.
Opsin 5 (OPN5) is known to function as a photoreceptor responsive to wavelengths in the near UV spectrum.
What does this study add?
UVR induces melanogenesis in HEMs via OPN5.
OPN5 regulates expression of TYR, TRP1 and TRP2 through the calcium‐dependent G protein‐coupled and protein kinase C signalling pathways.
OPN5 has an inherent role in HEMs in mediating melanogenesis.
What is the translational message?
OPN5 was discovered as a key sensor for UVR‐induced melanogenesis in human skin melanocytes.
It could be a target for early treatment of pigmentation or pigment diseases, to provide a more personalized and economically feasible method.
Linked Comment: L.V.M. de Assis and A.M. de Lauro Castrucci. Br J Dermatol 2021; 185:249–250.
Plain language summary available online
Cholesterol homeostasis is crucial for cellular function and organismal health. The key regulator for the cholesterol biosynthesis is sterol-regulatory element binding protein (SREBP)-2. The ...biochemical process and physiological function of SREBP-2 have been well characterized; however, it is not clear how this gene is epigenetically regulated. Here we have identified sirtuin (Sirt)6 as a critical factor for Srebp2 gene regulation. Hepatic deficiency of Sirt6 in mice leads to elevated cholesterol levels. On the mechanistic level, Sirt6 is recruited by forkhead box O (FoxO)3 to the Srebp2 gene promoter where Sirt6 deacetylates histone H3 at lysines 9 and 56, thereby promoting a repressive chromatin state. Remarkably, Sirt6 or FoxO3 overexpression improves hypercholesterolemia in diet-induced or genetically obese mice. In summary, our data suggest an important role of hepatic Sirt6 and FoxO3 in the regulation of cholesterol homeostasis.
Iron (Fe) and nickel (Ni) nanoparticles were prepared by the DC arc-discharge method in a mixture of hydrogen and argon gases, using bulk metals as the raw materials. The microstructure of core/shell ...(metal/metal oxide) in nanoparticle formed after
in situ passivation process. The complex electromagnetic parameters (permittivity
ε
r
=
ε
r
′
+
i
ε
r
″
and permeability
μ
r
=
μ
r
′
+
i
μ
r
″
) of the paraffin-mixed nanocomposite samples (paraffin:nanoparticles=1:1 in mass ratio) were measured in the frequency range of 2–18
GHz. The polarization mechanisms of the space charge and dipole coexist in both the Fe and Ni nanoparticles. The orientational polarization is a particular polarization for Fe nanoparticles and brings a relatively higher dielectric loss. Natural resonance is the main reason for magnetic loss and the corresponding frequencies are 11.6 and 5.2
GHz for the Fe and Ni nanoparticles, respectively. The paraffin composite with Fe nanoparticles provided excellent microwave absorption properties (reflection loss <−20
dB) in the range 6.8–16.6
GHz over the absorber thickness of 1.1–2.3
mm.
In this study, the microstructure and mechanical properties of the 0.56 wt % C transformation-induced plasticity (TRIP) steel are investigated by conducting tensile tests at a wide span of ...deformation temperatures (25–400 °C) and strain rates (0.001–1 s−1). The target is to explore the stability of retained austenite (RA) at various temperatures and strain rates, and the influence of the RA stability on the TRIP effect. Tensile strength decreases with the increasing deformation temperature at a constant strain rate. When temperature changes from 200 °C to 300 °C, tensile strength increases from 1154 ± 10 MPa to 1227 ± 10 MPa. Interestingly, at 300 °C the total elongation at a strain rate of 0.01s−1 can reach 90%, which is twice than that at 25 °C. Moreover, the deformation induced precipitation of carbides reduces the stability of RA, promoting the martensitic transformation. This process counteracts the suppressed TRIP effect with the increase of temperatures. The newly formed precipitates effectively increase work hardening. Thus the TRIP effect and precipitation strengthening jointly lead to excellent mechanical properties of the steel at 300 °C. After deformation, the volume fraction of RA increases with the increasing strain rate at constant temperatures, suggesting that the increasing strain rate suppresses the transformation from RA to martensite.
Abstract
Spectral hardness of gamma-ray bursts can be characterized by either hardness ratio or peak energy, and the inconsistency of these parameters can reflect spectral diversity and complexity. ...We have chosen 310 Swift bursts with well-measured X-ray afterglows to analyze the distributions of their peak energies and hardness ratios before and after absorption of neutral hydrogen. We categorize them into four types according to X-ray temporal patterns and calculate the hardness ratios of both
γ
-rays and X-rays. It is found that the hardness ratios of X-rays are systematically smaller than those of
γ
-rays. We also find that both
γ
-ray hardness ratios and peak energies of bursts of types I, II, and III are identically distributed and are significantly lower than the corresponding measurements of type IV bursts in statistics, which hints that the evolving spectra of type IV bursts are most probably affected by the geometry of outflows. This proves that the influence of neutral hydrogen absorption on the estimation of hardness ratio is negligible even though it can reduce the brightness of
γ
/X-rays somewhat. Furthermore, we verify that almost all the observed spectra of gamma-ray bursts can be described by a broken power-law function and confirm a magnetar origin for the bursts with internal X-ray plateaus.
We report on Chandra X-ray observations of four candidate low-mass black hole (M sub(bh) lap 10 super(6) M sub(middot in circle)) active galactic nuclei (AGNs) that have the estimated Eddington ...ratios among the lowest (~10 super(-2)) found for this class. The aims are to validate the nature of their AGNs and to confirm the low Eddington ratios that are derived from the broad H alpha line, and to explore this poorly studied regime in the AGN parameter space. Among them, two objects with the lowest significance of the broad lines are also observed with the Multi-Mirror Telescope, and the high-quality optical spectra taken confirm them as Seyfert 1 AGNs and as having small black hole masses. X-ray emission is detected from the nuclei of two of the galaxies, which is variable on timescales of ~10 super(3) s, whereas no significant (or only marginal at best) detection is found for the remaining two. The X-ray luminosities are on the order of 10 super(41) erg s super(-1) or even lower, on the order of 10 super(40) erg s super(-1) for non-detections, which are among the lowest regimes ever probed for Seyfert galaxies. The low X-ray luminosities, compared to their black hole masses derived from H alpha , confirm their low accretion rates assuming typical bolometric corrections. Our results hint at the existence of a possibly large population of under-luminous low-mass black holes in the local universe. An off-nucleus ultra-luminous X-ray source in one of the dwarf galaxies is detected serendipitously, with a luminosity (6-9) x 10 super(39) erg s super(-1) in 2-10 keV.
The curlometer was introduced to estimate the electric current density from four‐point measurements in space; anticipating the realization of the four spacecraft Cluster mission which began full ...science operations in February 2001. The method uses Ampère's law to estimate current from the magnetic field measurements, suitable for the high‐conductivity plasma of the magnetosphere and surrounding regions. The accuracy of the method is limited by the spatial separation knowledge, accuracy of the magnetic field measurement, and the relative scale size of the current structures sampled but nevertheless has proven to be robust and reliable in many regions of the magnetosphere. The method has been applied successfully and has been a key element, in studies of the magnetopause currents; the magnetotail current sheet; and the ring current, as well as allowing other current structures such as flux tubes and field aligned currents to be determined. The method is also applicable to situations where less than four spacecraft are closely grouped or where special assumptions (particularly stationarity) can be made. In view of the new four‐point observations of the MMS mission taking place now, which cover a dramatically different spatial regime, we comment on the performance, adaptability, and lessons learnt from the curlometer technique. We emphasize the adaptability of the method, in particular, to the new sampling regime offered by the MMS mission; thereby offering a tool to address open questions on small‐scale current structures.
Key Points
Measurement of 3‐D currents in the magnetosphere
Application in the inner magnetosphere
Relevance for new MMS measurements
Abstract
The mechanisms of propellant gas chemical erosion on gun barrel materials are discussed creatively from a microscopic perspective of molecular diffusion and intermolecular interaction. The ...influence of high-temperature and high-pressure propellant gas atoms on the shallow surface microstructure of the barrel material is theoretically analyzed using the molecular dynamics simulation method, which can be used as a new idea for further study of the gun barrel erosion mechanism. The results show that the diffusion of the propellant gas atoms into the barrel material can be characterized by the significant longitudinal distribution characteristics of propellant gas atoms and the normal stress distribution characteristics in the surface layer of the barrel. Moreover, the diffusion ability of the propellant gas atoms in the surface of the barrel material decreases gradually with the increasing diffusion depth. Under the action of propellant gas atoms, the dislocation structure dominated by face-centered cubic structure (FCC) forms in the shallow surface of the barrel material. The production of initial erosion in the shallow surface of barrel materials can be predicted by the continual growth of the new structure and the stress distribution characteristics of the material. In addition, the temperature variation of the propellant gas contributes significantly to barrel material erosion.
Ultrahigh strength and good ductility are obtained for two low-alloy transformation-induced-plasticity steels fabricated by the quenching and partitioning (Q&P) processing, respectively. Compared to ...0.19 wt.% C steel in which γ → α'-martensite transformation is the dominant mechanism under deformation, the relatively high C content of austenite in 0.47 wt.% C steel is responsible for the transformation from γ to ε-martensite, suggesting that the transformation is not solely determined by the stacking fault energy. The study shows that during the Q&P process, strong and ductile steels with specific transformation procedures can be obtained by adjusting volume fraction and carbon content of the retained austenite.
PDF
