SLC37A4-CDG : mislocalization of the glucose-6-phosphate transporter to the Golgi causes a new congenital disorder of glycosylation

Loss-of-function of the glucose-6-phosphate transporter is caused by biallelic mutations in SLC37A4 and leads to glycogen storage disease Ib. Here we describe a second disease caused by a single dominant mutation in the same gene. The mutation abolishes the ER retention signal of the transporter and generates a weak Golgi retention signal. Intracellular mislocalization of the transporter leads to a congenital disorder of glycosylation instead of glycogen storage disease

Investigating the role of reducing agents on mechanosynthesis of Au nanoparticles

Control over the bottom up synthesis of metal nanoparticles (NP) depends on many experimental factors, including the choice of stabilising and reducing agents. By selectively manipulating these species, it is possible to control NP characteristics through solution-phase synthesis strategies. It is not known, however, whether NPs produced from mechanochemical syntheses are governed by the same rules. Using the Au NPs mechanosynthesis as a model system, we investigate how a series of common reducing agents affect both the reduction kinetics and size of Au NPs. It is shown that the relative effects of reducing agents on mechanochemical NP synthesis differ significantly from their role in analogous solution-phase reactions. Hence, strategies developed for control over NP growth in solution are not directly transferrable to environmentally benign mechanochemical approaches. This work demonstrates a clear need for dedicated, systematic studies on NP mechanosynthesis.Peer reviewe

Diversity of Cl− Channels

Cl− channels are widely found anion pores that are regulated by a variety of signals and that play various roles. On the basis of molecular biologic findings, ligand-gated Cl− channels in synapses, cystic fibrosis transmembrane conductors (CFTRs) and ClC channel types have been established, followed by bestrophin and possibly by tweety, which encode Ca2+-activated Cl− channels. The ClC family has been shown to possess a variety of functions, including stabilization of membrane potential, excitation, cellvolume regulation, fluid transport, protein degradation in endosomal vesicles and possibly cell growth. The molecular structure of Cl− channel types varies from 1 to 12 transmembrane segments. By means of computer-based prediction, functional Cl− channels have been synthesized artificially, revealing that many possible ion pores are hidden in channel, transporter or unidentified hydrophobic membrane proteins. Thus, novel Cl−-conducting pores may be occasionally discovered, and evidence from molecular biologic studies will clarify their physiologic and pathophysiologic roles

State of the climate in 2018

In 2018, the dominant greenhouse gases released into Earth’s atmosphere—carbon dioxide, methane, and nitrous oxide—continued their increase. The annual global average carbon dioxide concentration at Earth’s surface was 407.4 ± 0.1 ppm, the highest in the modern instrumental record and in ice core records dating back 800 000 years. Combined, greenhouse gases and several halogenated gases contribute just over 3 W m−2 to radiative forcing and represent a nearly 43% increase since 1990. Carbon dioxide is responsible for about 65% of this radiative forcing. With a weak La Niña in early 2018 transitioning to a weak El Niño by the year’s end, the global surface (land and ocean) temperature was the fourth highest on record, with only 2015 through 2017 being warmer. Several European countries reported record high annual temperatures. There were also more high, and fewer low, temperature extremes than in nearly all of the 68-year extremes record. Madagascar recorded a record daily temperature of 40.5°C in Morondava in March, while South Korea set its record high of 41.0°C in August in Hongcheon. Nawabshah, Pakistan, recorded its highest temperature of 50.2°C, which may be a new daily world record for April. Globally, the annual lower troposphere temperature was third to seventh highest, depending on the dataset analyzed. The lower stratospheric temperature was approximately fifth lowest. The 2018 Arctic land surface temperature was 1.2°C above the 1981–2010 average, tying for third highest in the 118-year record, following 2016 and 2017. June’s Arctic snow cover extent was almost half of what it was 35 years ago. Across Greenland, however, regional summer temperatures were generally below or near average. Additionally, a satellite survey of 47 glaciers in Greenland indicated a net increase in area for the first time since records began in 1999. Increasing permafrost temperatures were reported at most observation sites in the Arctic, with the overall increase of 0.1°–0.2°C between 2017 and 2018 being comparable to the highest rate of warming ever observed in the region. On 17 March, Arctic sea ice extent marked the second smallest annual maximum in the 38-year record, larger than only 2017. The minimum extent in 2018 was reached on 19 September and again on 23 September, tying 2008 and 2010 for the sixth lowest extent on record. The 23 September date tied 1997 as the latest sea ice minimum date on record. First-year ice now dominates the ice cover, comprising 77% of the March 2018 ice pack compared to 55% during the 1980s. Because thinner, younger ice is more vulnerable to melting out in summer, this shift in sea ice age has contributed to the decreasing trend in minimum ice extent. Regionally, Bering Sea ice extent was at record lows for almost the entire 2017/18 ice season. For the Antarctic continent as a whole, 2018 was warmer than average. On the highest points of the Antarctic Plateau, the automatic weather station Relay (74°S) broke or tied six monthly temperature records throughout the year, with August breaking its record by nearly 8°C. However, cool conditions in the western Bellingshausen Sea and Amundsen Sea sector contributed to a low melt season overall for 2017/18. High SSTs contributed to low summer sea ice extent in the Ross and Weddell Seas in 2018, underpinning the second lowest Antarctic summer minimum sea ice extent on record. Despite conducive conditions for its formation, the ozone hole at its maximum extent in September was near the 2000–18 mean, likely due to an ongoing slow decline in stratospheric chlorine monoxide concentration. Across the oceans, globally averaged SST decreased slightly since the record El Niño year of 2016 but was still far above the climatological mean. On average, SST is increasing at a rate of 0.10° ± 0.01°C decade−1 since 1950. The warming appeared largest in the tropical Indian Ocean and smallest in the North Pacific. The deeper ocean continues to warm year after year. For the seventh consecutive year, global annual mean sea level became the highest in the 26-year record, rising to 81 mm above the 1993 average. As anticipated in a warming climate, the hydrological cycle over the ocean is accelerating: dry regions are becoming drier and wet regions rainier. Closer to the equator, 95 named tropical storms were observed during 2018, well above the 1981–2010 average of 82. Eleven tropical cyclones reached Saffir–Simpson scale Category 5 intensity. North Atlantic Major Hurricane Michael’s landfall intensity of 140 kt was the fourth strongest for any continental U.S. hurricane landfall in the 168-year record. Michael caused more than 30 fatalities and $25 billion (U.S. dollars) in damages. In the western North Pacific, Super Typhoon Mangkhut led to 160 fatalities and$6 billion (U.S. dollars) in damages across the Philippines, Hong Kong, Macau, mainland China, Guam, and the Northern Mariana Islands. Tropical Storm Son-Tinh was responsible for 170 fatalities in Vietnam and Laos. Nearly all the islands of Micronesia experienced at least moderate impacts from various tropical cyclones. Across land, many areas around the globe received copious precipitation, notable at different time scales. Rodrigues and Réunion Island near southern Africa each reported their third wettest year on record. In Hawaii, 1262 mm precipitation at Waipā Gardens (Kauai) on 14–15 April set a new U.S. record for 24-h precipitation. In Brazil, the city of Belo Horizonte received nearly 75 mm of rain in just 20 minutes, nearly half its monthly average. Globally, fire activity during 2018 was the lowest since the start of the record in 1997, with a combined burned area of about 500 million hectares. This reinforced the long-term downward trend in fire emissions driven by changes in land use in frequently burning savannas. However, wildfires burned 3.5 million hectares across the United States, well above the 2000–10 average of 2.7 million hectares. Combined, U.S. wildfire damages for the 2017 and 2018 wildfire seasons exceeded $40 billion (U.S. dollars)

Struktur-Eigenschaftsbeziehungen in Chalkopyrit-basierten Zwischenband-Solarabsorbermaterialien

Over the last decades the need of electrical energy increased continuously, whereas the percentage of electric energy from renewable sources became larger in the last years. The demand of an energy supply, which is produced by renewable sources completely, is more important than before. Nowadays, solar cells reach power conversion efficiencies of 46% [1] using multi-junction concentrator cells, which are very complicated and expensive in production. The maximum power conversion efficiency for a single junction solar cell is restricted to ~32% [2], named the Shockley Queisser limit. However, the incorporation of transition metals into the wide gap CuGaS2 chalcopyrite type absorber material was proposed to create an intermediate band, which cause two additional absorption ranges and an increase in power conversion efficiency up to 63% [3, 4]. The aim of this study was to determine the solid solubility limits of several transition metals as well as to study their effect on the chalcopyrite type crystal structure and optoelectronic properties. All investigated transition metals were successfully incorporated into the chalcopyrite type structure, by solid state reaction synthesis of pure elements. The lowest solid solubility was obtained from chromium and nickel with 0.003(1)mol% CrS and 0.008(1)mol% NiS in Cu0.5Ga0.5S, which results in no observable changes in the chalcopyrite type crystal structure. A much higher solid solubility limit was observed for manganese with 0.098(1)mol% MnS in Cu0.5Ga0.5S. The pseudo-binary section of Cu0.5(FexGa0.5-x)S was earlier reported [5] to have complete solubility, was showing a phase separation at xi>0.1 into an iron rich and iron poor chalcopyrite type phase, respectively. Two different substitution mechanisms were observed from the iron alloyed chalcopyrite type phases. For those with low initial iron contents (xi<0.1), the trend of chemical composition and lattice parameters indicate a coupled substitution (Cu+Ga↔Fe), whereas higher initial iron contents show a unilateral substitution (Ga↔Fe). The substitution of manganese into the chalcopyrite type structure is rather coupled than unilateral as would be necessary for an intermediate band absorber material. Using the average neutron scattering length analysis method, it was observed that manganese is occupying both cationic sites of the chalcopyrite type structure. From these extrinsic defects (MnGa, MnCu) two optoelectronic active defect states result, located within the band gap of the chalcopyrite type semiconductor, but not corresponding to the proposed intermediate band position. The obtained photoluminescence (PL) spectra was correlated to the predictions given by density functional theory [6]. In addition, correlating the PL spectra with the defect concentration, it can be seen that the dominant PL band at 1.86eV is rather related to the intrinsic GaCu cation anti-site defect than anion vacancies. Based on the obtained anion parameter of the chalcopyrite type phases from X-ray diffraction using the Rietveld method, the effect of copper vacancies on local structural changes was derived and existing calculation models were enhanced to give more precise predictions for overall structural parameter (e.g. tetragonal distortion)

Decompression of host-inclusion systems in UHP rocks: insightsfrom observations and models

International audiencePolymorphic transformations are key tracers of metamorphic processes, also used to estimate thepressure and temperature conditions reached by a rock. In particular, the quartz-coesite transitionis commonly used to define the lower boundary of the ultrahigh-pressure (UHP) metamorphicfield. The partial preservation of coesite included in garnets from UHP rocks bring considerableinsights into the burial and exhumation mechanisms of the continental crust involved inconvergent zone. Coesite was first described in the Western Alps by Chopin[1], in the Dora-Mariawhiteschist, one of the most emblematic UHP rock worldwide. Although the partial preservation ofcoesite inclusions in garnet has long been attributed to the pressure vessel effect, theinterrelationship and relative timing between fracturing and retrogression is still contentious.Here we study the reaction-deformation relationships of coesite inclusions initially enclosed ingarnet and transforming into quartz during the decompression process. We combine 2Dnumerical thermo-mechanical models constrained by pressure-temperature-time (P-T-t) estimatesfrom the Dora-Maira whiteschist. The model accounts for a compressible visco-elasto-plasticrheology including a pressure-density relationship of silica based on thermodynamic data. Thisallows us to study the effect of reaction-induced volume increase during decompression. Ourresults capture the typical fracture patterns of the host garnet radiating from retrogressed coesiteinclusions and can be used to study the relative role of volume change associated with a change ofP-T conditions on the style of deformation during decompression.The mechanisms of the coesite-quartz transformation and geodynamic implications are presentedand validated against geological data. The effect of fluids on the phase transition and theconditions of access of fluids during the transformation are discussed in the light of the results ofthe thermo-mechanical models.This study demonstrates the high potential of thermo-mechanical modelling in enhancing ourunderstanding of the processes involved in the formation and evolution of metamorphic minerals.[1]Chopin (1984) Contributions to Mineralogy and Petrology 86, 2, 107-11