NIR-enhanced Pt single atom/g-C_(3)N_(4)nanozymes as SOD/CAT mimics to rescue ATP energy crisis by regulating oxidative phosphorylation pathway for delaying osteoarthritis progression

Osteoarthritis(OA)progresses due to the excessive generation of reactive oxygen and nitrogen species(ROS/RNS)and abnormal ATP energy metabolism related to the oxidative phosphorylation pathway in the mitochondria.Highly active single-atom nanozymes(SAzymes)can help regulate the redox balance and have shown their potential in the treatment of inflammatory diseases.In this study,we innovatively utilised ligand-mediated strategies to chelate Pt^(4+)with modified g-C_(3)N_(4)byπ-πinteraction to prepare g-C_(3)N_(4)-loaded Pt single-atom(Pt SA/C_(3)N_(4))nanozymes that serve as superoxide dismutase(SOD)/catalase(CAT)mimics to scavenge ROS/RNS and regulate mitochondrial ATP production,ultimately delaying the progression of OA.Pt SA/C_(3)N_(4)exhibited a high loading of Pt single atoms(2.45 wt%),with an excellent photothermal conversion efficiency(54.71%),resulting in tunable catalytic activities under near-infrared light(NIR)irradiation.Interestingly,the Pt-N_(6) active centres in Pt SA/C_(3)N_(4)formed electron capture sites for electron holes,in which g-C_(3)N_(4)regulated the d-band centre of Pt,and the N-rich sites transferred electrons to Pt,leading to the enhanced adsorption of free radicals and thus higher SOD-and CAT-like activities compared with pure g-C_(3)N_(4)and g-C_(3)N_(4)-loaded Pt nanoparticles(Pt NPs/C_(3)N_(4)).Based on the use of H_(2)O_(2)-induced chondrocytes to simulate ROS-injured cartilage in vitro and an OA joint model in vivo,the results showed that Pt SA/C_(3)N_(4)could reduce oxidative stress-induced damage,protect mitochondrial function,inhibit inflammation progression,and rebuild the OA microenvironment,thereby delaying the progression of OA.In particular,under NIR light irradiation,Pt SA/C_(3)N_(4)could help reverse the oxidative stress-induced joint cartilage damage,bringing it closer to the state of the normal cartilage.Mechanistically,Pt SA/C_(3)N_(4)regulated the expression of mitochondrial respiratory chain complexes,mainly NDUFV2 of complex 1 and MT-ATP6 of ATP synthase,to reduce ROS/RNS and promote ATP production.This study provides novel insights into the design of artificial nanozymes for treating oxidative stress-induced inflammatory diseases.

Oil as narcotic or as medicine:the DISEASE metaphor in political cartoons on energy crisis

The present paper explores how the issue of the current energy crisis in the wake of the Covid-19 and Ukraine war was constructed by political cartoons.Adopting Critical Multimodal Metaphor Scenario Analysis,this paper focuses on the DISEASE metaphor scenario,one of the most recurring scenarios in political cartoons on this topic,and specifically emphasizes how the METHOD OF TREATMENT,one of the structural elements in the scenario,is represented.The analysis reveals that two predominant scenarios cOnstitute the representations of the METHOD OF TREATMENT:NARCOTIC Scenario and MEDICINE scenario.They differ in entailments:one frames fossil energy as detrimental narcotic while the other frames it as therapeutic medicine.By means of the two scenarios,these cartoons convey strong criticism of the major involvers in the energy crisis,namely,the E.U.,Russia,and the U.S.The cartoons make full use of the dynamic interplay of visual and/or verbal metonymy,metaphor,and narrative to elicit associations,assumptions and evaluations in the viewers,helping facilitate understanding and constructing a view of the crisis reality.The present analysis sheds light on the way cartoonists reshape the public point of view in the framing of specific event(s).

Projecting impact of CPEC on Pakistan’s electric power crisis

The commencement of China–Pakistan Economic Corridor has led to the appreciation of Pakistan’s economic outlook from 5.4%to 5.8%by the World Bank.The upgraded outlook is a welcome sign but it is still trivial,essentially attributable to the electric power crisis,which approximately trims 2%of Pakistan’s economic growth annually.Almost 60%of the CPEC(China–Pakistan Economic Corridor)funds are directed at Pakistan’s energy sector,hence,demanding careful attention of both researchers and policy analysts alike.The study is based upon a meta-analytic review of literature concerning CPEC and Pakistan’s energy sector.The results of the study demonstrate that CPEC is an easing agent for Pakistan’s energy crisis(82.30%).The results also highlight points of concern,including inadequate planning(47%),dilapidated electricity distribution system causing losses(64.7%),and an unsustainable energy mix(64.7%).The study further validates the findings via Spearman’s Rho-Correlation.The rρvalue for the possible“resolution of Pakistan’s energy crisis”is 0.5426 achieving a significance level of 98%and a corresponding p-value of 0.0252.The significant negative rρvalue attained is−0.4894 which establishes the fact that lack of planning can hinder the energy crisis resolution.

New Trends in International Energy Security in the Context of Profound Changes Unseen in a Century

Major changes such as the pandemic, games among great powers, and the Ukraine crisis alongside scientific and technological progress, economic transformation, social change, and cultural development have led to new features and trends in the international energy field. Historic fluctuations in international energy prices and adjustments in energy relations have taken place in the past two years. The energy system has fallen into disorder and discomfort;volatility in the energy market has triggered a strong domino effect, and major countries have taken unprecedented measures to address it. These changes have pushed international energy politics to a new development track. In a certain period of time in the future, the political and security aspects of energy will once again come to the fore. The long-term nature and complexity of the energy transition have become more obvious. In international energy politics, turbulence and uncertainty will be the new normal. A new binary opposition may emerge in the international energy landscape as well, with constant changes taking place in the connotation and extension of energy security. Academic and strategic circles should think deeply about how to dialectically discuss the relation between energy transition and the major changes of a scale unseen in a century, energy transition and energy security, and geopolitics and energy politics, among others, and consider the integration of development and security and the realization of common energy security as important principles for operating and developing energy strategies and promoting global energy governance.

Suspension of Australian National Electricity Market in 2022 Necessitates Mechanism Evolution Ensuring Power Supply Security

The National Electricity Market(NEM)in Australia was suspended during June 15-23,2022,with a primary attribution to the lack of available generation capacity.This incident is noteworthy because it was the first market suspension in NEM’s history and took place in a major energy exporting country.In this letter,we review the outline and impacts of the incident.From the perspectives of market regulation,electricity supply,and electricity demand,we identify three underlying causes of the market suspension and offer four recommendations for the market mechanism evolution to ensure power supply security.

One-step synthesis of monodispersed Pt nanoparticles anchored on 3D graphene foams and its application for electrocatalytic hydrogen evolution

Although platinum-based materials are regarded as the state-of-the-art electro-catalysts for hydrogen evolution reaction(HER),high cost and quantity scarcity hamper their scale-up utilization in industrial deployment.Herein,a one-step strategy was developed to synthesize multi-walled carbon nanotubes and reduced graphene oxide supported Pt nanoparticle hydrogel(PtNP/rGO-MWCNT),in which only ascorbic acid was used as the reductant for one-pot reduction of both GO and chloroplatinic acid.The hydrogel can be directly used as a flexible binder-free catalytic electrode to achieve high performance of HER.Compared to conventional strategies,the current strategy not only significantly reduces the Pt loading to 3.48 wt%,simplifies the synthesis process,but also eliminates the use of any polymer binders,thus decreasing the series resistance and improving catalytic activity.An overpotential of only 11 mV was achieved on as-prepared PtNP/rGO-MWCNT to drive a geometrical current density of 10 mA/cm2 in0.5 mol/L H2 SO4,with its catalytic activity being kept over 15 h.In acidic medium,the HER activity of the PtNP/rGO-MWCNT catalyst exceeds most of the reported Pt-based electro-catalysts and is 3-fold higher than that obtained on commercial Pt/C electrode.

Metformin alleviates cholestasis-associated nephropathy through regulating oxidative stress and mitochondrial function

Background and aim:Cholestasis-associated renal injury or cholemic nephropathy(CN)is a serious clinical problem.Previous studies mentioned that oxidative stress and mitochondrial impairment play a role in CN.There is no specific pharmacological intervention for CN.Metformin is an anti-diabetic drug administered for decades.On the other hand,novel pharmacological properties have emerged for this drug.The effect of metformin on oxidative stress parameters has been well-recognized in different experimental models.It has also been found that metformin positively affected mitochondrial function.The current study aimed to evaluate the effects of metformin in an animal model of CN.Methods:Rats underwent bile duct ligation(BDL)and were treated with metformin(250 and 500 mg/kg)for 14 consecutive days.Two weeks after the BDL operations,urine,serum,and kidney samples were collected and analyzed.Results:Markers of oxidative stress,including reactive oxygen species(ROS)formation,lipid peroxida-tion,protein carbonylation,depleted antioxidant capacity,and decreased glutathione(GSH)levels were detected in BDL animals.Moreover,mitochondrial indices,including adenosine triphosphate(ATP)level,dehydrogenase activity,mitochondrial membrane potential,and mitochondrial permeability,were impaired in the kidney of cholestatic rats.Renal histopathological alterations in cholestatic animals included tubular degeneration and interstitial inflammation,cast formation,and fibrosis.It was found that metformin significantly alleviated oxidative stress and improved mitochondrial indices in the kidney of cholestatic rats.Tissue histopathological alterations were also mitigated in metformin-treated groups.Conclusions:Metformin could be a candidate for managing CN.The nephroprotective role of metformin is primarily associated with its effects on oxidative stress parameters and mitochondrial function.