Reduction of Mitoferrin Results in Abnormal Development and Extended Lifespan in Caenorhabditis elegans

Iron is essential for organisms. It is mainly utilized in mitochondria for biosynthesis of iron-sulfur clusters, hemes and other cofactors. Mitoferrin 1 and mitoferrin 2, two homologues proteins belonging to the mitochondrial solute carrier family, are required for iron delivery into mitochondria. Mitoferrin 1 is highly expressed in developing erythrocytes which consume a large amount of iron during hemoglobinization. Mitoferrin 2 is ubiquitously expressed, whose functions are less known. Zebrafish with mitoferrin 1 mutation show profound hypochromic anaemia and erythroid maturation arrests, and yeast with defects in MRS3/4, the counterparts of mitoferrin 1/2, has low mitochondrial iron levels and grows poorly by iron depletion. Mitoferrin 1 expression is up-regulated in yeast and mouse models of Fiedreich's ataxia disease and in human cell culture models of Parkinson disease, suggesting its involvement in the pathogenesis of diseases with mitochondrial iron accumulation. In this study we found that reduced mitoferrin levels in C. elegans by RNAi treatment causes pleiotropic phenotypes such as small body size, reduced fecundity, slow movement and increased sensitivity to paraquat. Despite these abnormities, lifespan was increased by 50% to 80% in N2 wild type strain, and in further studies using the RNAi sensitive strain eri-1, more than doubled lifespan was observed. The pathways or mechanisms responsible for the lifespan extension and other phenotypes of mitoferrin RNAi worms are worth further study, which may contribute to our understanding of aging mechanisms and the pathogenesis of iron disorder related diseases

Unveiling the role of Zn dopants in NiFe phosphide nanosheet for oxygen evolution reaction

Transition metal phosphides have been recognized as promising electrocatalysts for oxygen evolution reaction (OER) due to their low cost and high activity. However, the insufficient exposed active region limited the OER performance. Recently, the introduction of sacrificial dopants has been considered an effective strategy to enlarge the surface area. Herein, the Zn dopants are introduced in NiFe phosphide (NiFeZnP) nanosheet, which work as the sacrificial dopants to generate more exposed active NiFe sites and promote the formation of the NiFeOOH active phase during OER process. The optimized Zn-doped NiFeP catalyst shows an overpotential of ≈203 ​mV to reach a current density of 10 ​mA ​cm−2 in 1 ​M KOH, and a stability of 100 ​h at 1000 ​mA ​cm−2. Overall, this work provides a sacrificial Zn doping strategy to prepare highly efficient OER electrocatalysts

Multiple metallic dopants in nickel nanoparticles for electrocatalytic oxygen evolution

Developing efficient oxygen evolution reaction (OER) electrocatalysts is of great importance for sustainable energy conversion and storage. Ni-based catalysts have shown great potential as OER electrocatalysts, but their performance still needs to be improved. Herein, we report the multiple metal doped nickel nanoparticles synthesized via a simple oil phase strategy as efficient OER catalysts. The FeMnMoV–Ni exhibits superior OER performance with an overpotential of 220 ​mV at 10 ​mA ​cm−2 and a long-term stability of 250 ​h in 1 ​M KOH solution. In situ Raman analysis shows that the NiOOH site works as the active center and multiple metallic dopants facilitate the formation of NiOOH. Mo and V dopants promote the formation of high-valence state of Ni sites, and Mn dopants increase the electrochemical active surface area and expose more active sites. This work provides a novel strategy for catalyst design, which is critical for developing multiple metal doped catalysts

The Source of Fracture-Cave Mud Fillings of the Ordovician Yingshan Formation and Its Paleokarst Environment in the Northern Slope of the Tazhong Uplift, Tarim Basin, China: Based on Petrology and Geochemical Analysis

The karst fracture-cave oil and gas reservoirs of the Yingshan Formation in the northern slope of the Tazhong Uplift are well developed and have achieved good exploration results. However, the karst fracture-cave near the top of the Yingshan Formation is basically filled with mud fillings, which seriously affect the reservoir property, and the source and filling environment of the mud fillings have been unclear. Through the petrological and geochemical analysis of the fracture-cave fillings system in the typical wells of the Yingshan Formation, it has been found that (1) the fracture-cave fillings are mainly composed of a mixture of the bedrock dissolution dissociation particles, clay minerals, and calcite cements of the Yingshan Formation, and the content of each component in the different wells or in the cave interval is quite different. (2) Rare earth element analysis shows that the rare earth distribution pattern of the fracture-cave fillings is similar to the bottom marlstone of the Lianglitage Formation, indicating that the fracture-cave fillings should be mainly derived from the early seawater of the deposition during the Lianglitage Formation. (3) Cathodoluminescence, trace element analysis, and previous studies have shown that the formation and fillings of the fractures and caves mainly occurred in the hypergene period, which had the characteristics of an oxidized environment, and that there are two filling effects. First, the limestone of the Yingshan Formation experienced the formation of karst caves due to meteoric freshwater dissolution during the exposure period, and the limestone of the Yingshan Formation was dissolved, resulting in some insoluble clay and residual limestone gravel particles brought into the cave by the meteoric freshwater for filling. Second, the seawater transgression also played an important role during the deposition of the Lianglitage Formation. The clay content in the seawater was high during the early deposition of the Lianglitage Formation, which led to the clay being brought into the caves by the seawater during the deposition of the Lianglitage Formation for further filling; at the same time, calcite deposited into the caves with the clay. The above research promotes the study of the formation mechanism of the karst cave reservoir in the Yingshan Formation and has important theoretical significance for the guiding of the next oil and gas exploration in this area

Ultrasensitive Memristive Synapses Based on Lightly Oxidized Sulfide Films

For biological synapses, high sensitivity is crucial for transmitting information quickly and accurately. Compared to biological synapses, memristive ones show a much lower sensitivity to electrical stimuli since much higher voltages are needed to induce synaptic plasticity. Yet, little attention has been paid to enhancing the sensitivity of synaptic devices. Here, electrochemical metallization memory cells based on lightly oxidized ZnS films are found to show highly controllable memristive switching with an ultralow SET voltage of several millivolts, which likely originates from a two-layer structure of ZnS films, i.e., the lightly oxidized and unoxidized layers, where the filament rupture/rejuvenation is confined to the two-layer interface region several nanometers in thickness due to different ion transport rates in these two layers. Based on such devices, an ultrasensitive memristive synapse is realized where the synaptic functions of both short-term plasticity and long-term potentiation are emulated by applying electrical stimuli several millivolts in amplitude, whose sensitivity greatly surpasses that of biological synapses. The dynamic processes of memorizing and forgetting are mimicked through a 5 x 5 memristive synapse array. In addition, the ultralow operating voltage provides another effective solution to the relatively high energy consumption of synaptic devices besides reducing the operating current and pulse width

Geochemical Characteristics and Paleoenvironmental Signi cance of the Ordovician Paleokarst Reservoir in the Maigaiti Slope of Tarim Basin

The Ordovician carbonatites of the Maigaiti slope have formed the conditions for the development of large oil and gas fields with karst reservoirs. This study systematically analyzed the isotopic characteristics of carbon, oxygen, and strontium and enrichment trace elements regularity to examine the geochemical features of the paleo-karstification products, various periods of paleo-karstification, and paleoenvironmental conditions of the Ordovician. Affected by terrigenous clasts, the Lianglitage Formation is composed of limestone with a relatively high 87Sr/86Sr value and a frequently fluctuating sea level, which exhibits an overall increasing-to-decreasing trend variation. Of all samples affected by the atmospheric freshwater leaching effect, δ18O values were negative, and δ13C values varied greatly toward both ends. The fissure/cave infills were rich in Fe and Mn but poor in Sr, and the Sr/Ba value was considerably less than 1, which confirms the existence of ancient weathered crust and the development of an atmospheric freshwater karst environment. Four different paleo-karstification periods were identified according to the carbon and oxygen isotopic characteristics of calcite. Combined with the trace element characteristics of the infills, the paleo-karstification in the Yingshan Formation was subdivided based on three hydrological environment conditions. Erosion modification of buried acid compaction-released water from late-period corrosion pores, caves, and fissures formed by syndiagenetic paleo-karstification and weathered crust bare paleo-karstification due to atmospheric freshwater leaching can significantly improve the reserving and permeability characteristics of the karst reservoir to develop a large paleokarst reservoir