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Long-chain alkenones (LCAs) produced by phylogenetically classified Groups 1 and 3 Isochrysidales are increasingly used for paleotemperature and/or paleosalinity reconstructions in oligohaline lakes and marine environments. However, there are considerable difficulties in the paleoenvironmental interpretation of LCAs from Group 2 Isochrysidales thriving in saline lakes. The biggest challenge lies in our poor understanding of the complexity and ecological niches of individual Group 2 subclades in saline lakes. Here, we perform comprehensive analysis of haptophyte-specific 18S rRNA sequences and distributions of LCAs, and long-chain alkenoates (LCEs) in surface sediments and suspended particulate matter (SPM) from 37 saline lakes in northern China. These lakes span a large salinity gradient from 0.5 to 308‰. Combined with published genomic data of Group 2 Isochrysidales, our phylogenetic analysis reveals three Group 2 subclades occupying distinct ecological niches: one ice-related bloomer Group 2i and two warm-season bloomers Groups 2w1 and 2w2. Group 2i, the earliest seasonal bloomer, frequently co-occurs with Group 2w1 in sediments from saline lakes with relatively low to intermediate salinity waters, whereas Group 2w2 blooms in hypersaline waters. Based on existing data, C39:4 methyl alkenone is a chemotaxonomic biomarker for Group 2i. %C37:4 (relative abundance of C37:4 to the total C37 alkenones) values in the three Group subclades follow the order: Group 2i > Group 2w2 > Group 2w1. The %C37:4 in sediment cores of saline lakes does not directly record past salinity changes, but instead reflects variable contributions in production by these three subclades. This could indirectly and partially reflect overall salinity changes in some lakes dominated by Groups 2i and 2w1, but can be more complicated in lakes dominated by other assemblages. For our sites, we also demonstrate that direct use of C37 alkenone unsaturation indices ( U 37 K , U 37 K ' , and U 37 K ' ' ) for paleotemperature reconstructions in saline lakes is generally not feasible, except for cases where alkenone-producing Isochrysidales are dominated by one single species/subclade and seasonal production effects can be circumvented. We propose two possible alternative proxies for paleotemperature reconstructions in saline lakes: 1) unsaturation ratios of C41 and C42 alkenones, as these compounds are predominantly produced by a limited number of Group 2 species, such as Isochrysis nuda ( Liao et al., 2020 ); 2) C38Et/C36OEt ratio (ratio of C38 ethyl alkenones and C36 ethyl alkenoates), which appears to have similar temperature sensitivity for Groups 2w1 and 2w2, in lakes with no Group 2i inputs. Our study provides new insights into the phylogenetic classifications of Group 2 Isochrysidales and their ecological/environmental niches, which are fundamental for more quantitative and rigorous applications of LCAs and LCEs in saline lakes as paleosalinity and paleotemperature proxies.

RATIONALE Derivatization with dimethyl disulfide (DMDS) followed by GC-MS analysis is a well-established method for locating double bond position on the alkyl chain of mono-unsaturated compounds such as alkenes. For alkenes containing more than one double bond, however, the conventional DMDS derivatization approach forms poly- or cyclized DMDS adducts whose mass spectra are difficult to interpret in terms of double bond positions. In this study, we report an efficient experimental procedure to produce mono-DMDS adducts for polyunsaturated alkenes with two to six double bonds. GC-MS analyses of these mono-DMDS adducts yield highly characteristic mass fragments, allowing unambiguous assignments of double bond positions on the alkyl chain. We also apply our new approach (i.e., preferential formation of mono-DMDS adducts during derivatization with DMDS) to determine the double bond positions of unsaturated alkenes produced by laboratory cultured Isochrysis litoralis, a haptophyte algal species. METHODS Alkenes from different sources were derivatized with DMDS at 25 °C for 20 to 160 minutes. The mass spectra of mono-DMDS adducts were obtained by GC-EI-MS analysis of reaction products which contain chromatographically resolved mono-DMDS adducts. RESULTS Mass spectra of corresponding mono-DMDS adducts contain prominent diagnostic ions that allow a conclusive elucidation of double bond positions. In culture samples of Isochrysis litoralis, a series of novel mono- to tri-unsaturated C31 alkenes (9-C31:1 , 6, 9-C31:2 , 6, 22-C31:2 , 6, 25-C31:2 , 9, 22-C31:2 , 6, 9, 25-C31:3 ) were discovered for the first time. CONCLUSIONS A highly efficient DMDS derivatization approach is developed to yield abundant mono-DMDS adducts of polyunsaturated alkyl alkenes for elucidating double bond positions using GC-MS.

The therapeutic strategies for acute myeloid leukemia (AML) patients ineligible for remission induction chemotherapy have been improving in the past decade. Therefore, it is important to define ineligibility for remission induction chemotherapy. We retrospectively assessed 153 consecutive adult de novo AML patients undergoing remission induction chemotherapy and defined early mortality as death within the first 60 days of treatment. The 153 patients were stratified into the early mortality group (n = 29) and the non-early mortality group (n = 124). We identified potential factors to which early mortality could be attributed, investigated the cumulative incidence of early mortality for each aspect, and quantified the elements. The early mortality rate in our study cohort was 19.0%. Age ≥ 65 years (odds ratio (OR): 3.15; 95% confidence interval (CI): 1.05–9.44; p = 0.041), Eastern Cooperative Oncology Group performance status ≥ 2 (OR: 4.87; 95% CI: 1.77–13.41; p = 0.002), and lactate dehydrogenase ≥ 1000 IU/L (OR: 4.20; 95% CI: 1.57–11.23; p = 0.004) were the risk factors that substantially increased early mortality in AML patients. Patients with two risk factors had a significantly higher early mortality rate than those with one risk factor (68.8% vs. 20.0%; p < 0.001) or no risk factors (68.8% vs. 9.2%; p < 0.001). In conclusion, older age, poor clinical performance, and a high tumor burden were risks for early mortality in AML patients receiving remission induction chemotherapy. Patients harboring at least two of these three factors should be more carefully assessed for remission induction chemotherapy.

Silver(I)-mercaptopropyl (Ag-MP) functionalized silica gel has demonstrated its effectiveness in separating various unsaturated organic compounds including unsaturated fatty acid ethyl esters (FAEEs), triglycerols (TAGs) and long-chain alkyl ketones (alkenones). While Ag-MP stationary phase displays many advantages over the conventional silver ion-impregnated silica gel (e.g., stability, high recovery, etc.), potential drawbacks of Ag-MP include relatively low retentions for unsaturated molecules, which could limit chromatographic resolutions under certain circumstances. In this study, we evaluate a new silver-thiolate stationary phase: silver(I)-dimercaptotriazine (Ag-DMT) functionalized silica gel targeting the separation of unsaturated compounds. We show Ag-DMT affords substantially higher retention factors, peak resolutions and capacities for TAGs and FAEEs than Ag-MP does. Ag-DMT also yields higher purity eicosapentaenoic acid (EPA) from fish oil FAEE mixtures than Ag-MP. In addition, Ag-DMT resolves double bond positional and cis/trans-isomers of C18:1 fatty acid methyl esters (FAMEs) as well as unsaturated methyl/ethyl alkenones with different number of double bonds. Based on van't Hoff plots, enthalpy changes during the adsorption of unsaturated FAEEs onto Ag-DMT are ~2 times higher than those on Ag-MP. Such difference may be attributed to the stronger electron-withdrawing effect of the thiol group on DMT, which results in more positively charged silver ions hence greater interactions with unsaturated molecules. The stronger interaction between double bonds and Ag-DMT is further corroborated by density-functional theory (DFT) calculations. Ag-DMT shows its high stability for repeated uses in the separation of TAGs over 319 runs, with peak resolutions decreasing by

Summary We demonstrate new C38 and C39 found in Lake Van and Lake Fryxell are methyl-branched alkenones (brC38Me and brC39Et). Previous assignments of these compounds as straight chain C38Me and C39Et were incorrect. Double bond positions, determined based on mass spectra of corresponding DMDS adducts, are Δ 4, Δ 7, Δ 14, Δ 21 and Δ 28 for penta-unsaturated branched alkenones. Based on published DNA data and changes of branched alkenone percentages of Lake Van, we hypothesize that branched alkenones function as storage of energy and are produced by a yet unknown species of Isochrysidales. UKbr38Me based on brC38Me alkenones has a similar trend with UK37 in the past 270 ka of Lake Van, suggesting the high temperature sensitivity of branched alkenones, same as other straight chain alkenones. Such proxies based on branched alkenones might be more reliable than UK37 and UK'37 to provide temperature record in sites with mixed alkenone productions.

Alkenones are biomarkers produced solely by algae in the order Isochrysidales that have been used to reconstruct sea surface temperature (SST) since the 1980s. However, alkenone-based SST reconstructions in the northern high latitude oceans show significant bias towards warmer temperatures in core-tops, diverge from other SST proxies in down core records, and are often accompanied by anomalously high relative abundance of the C37 tetra-unsaturated methyl alkenone (%C37:4). Elevated %C37:4 is widely interpreted as an indicator of low sea surface salinity from polar water masses, but its biological source has thus far remained elusive. Here we identify a lineage of Isochrysidales that is responsible for elevated C37:4 methyl alkenone in the northern high latitude oceans through next-generation sequencing and lab-culture experiments. This Isochrysidales lineage co-occurs widely with sea ice in marine environments and is distinct from other known marine alkenone-producers, namely Emiliania huxleyi and Gephyrocapsa oceanica. More importantly, the %C37:4 in seawater filtered particulate organic matter and surface sediments is significantly correlated with annual mean sea ice concentrations. In sediment cores from the Svalbard region, the %C37:4 concentration aligns with the Greenland temperature record and other qualitative regional sea ice records spanning the past 14 kyrs, reflecting sea ice concentrations quantitatively. Our findings imply that %C37:4 is a powerful proxy for reconstructing sea ice conditions in the high latitude oceans on thousand- and, potentially, on million-year timescales., Some algae produce compounds called alkenones that can reconstruct sea surface temperature through geological time, but in high latitudes unknown species complicate use of this proxy. Here the authors find a lineage of sea ice algae that produces alkenones and can be used as a paleo-sensor for sea ice abundance.

Alkenoates and alkenones are polyunsaturated long-chain esters and ketones produced by members of the Isochrysidales, an order of haptophyte microalgae. Based on phylogenetic data, members of Isochrysidales have been classified into three groups, with each group showing major differences in preferred growth environments (e.g., salinity). Systematic identification of chemotaxonomic differences among the three groups of Isochrysidales is thus important for paleoenvironmental reconstructions and disentangling mixed alkenone temperature signals. Here, we systematically examined alkenone/alkenoate profiles in culture samples of Group 2 and Group 3 Isochrysidales and environmental sample of Group1 Isochrysidales. Using GC columns with stationary phases of contrasting polarities, we discovered for the first time C37 and C38 ethyl alkenoates (C37OEt and C38OEt) in Group 2 and/or 3 Isochrysidales, extending the longest alkenoate chain length of C36OEt in previous publications. We show that Group 3 Isochrysidales only produce C37OEt, whereas Group 2 Isochrysidales produce both C37OEt and C38OEt alkenoates. Because Group 1 Isochrysidales do not produce alkenoates, C38OEt are specific biomarkers for Group 2 species. The identification of C37OEt and C38OEt in sediments from saline lakes and Chesapeake Bay where sequences of Group 2 DNA have been recovered further validates the use of C38OEt as a Group 2-specific biomarker.

Long-chain alkenones, a class of highly specific and widely used lipid biomarkers found in ocean and lake sediments, have been so far found as straight-chain alkyl ketones with 2 to 4 double bonds. Jaraula et al. (2010) reported assignments of a series of tri- to penta-unsaturated alkenones as straight-chain C38 methyl (C38Me) and C39 ethyl (C39Et) alkenones in Lake Fryxell, Antarctica. The same series of compounds were later found in sediments from Lake Van (Randlett et al., 2014). The structure assignments by Jaraula et al (2010) were primarily based on strong ions at [M−43]+ for C38 alkenones and [M−57]+ for C39 alkenones, which were interpreted as a loss of CH3CO and CH3CH2CO groups. However, such fragmentation is atypical for common straight-chain methyl and ethyl alkenones. In this study, we reanalyzed Lake Van sediment samples. We show these new C38 and C39 alkenones elute earlier than the common straight-chain C38Me and C39Et alkenones on a mid-polarity GC column. After hydrogenation, mass spectra of these new alkenones show distinct peaks at m/z 72 or 86 caused by McLafferty rearrangement, indicating a methyl substitution at the α position of the carbonyl group in these C38 and C39 alkenones (i.e., α-methyl-branched C38Me and C39Et). Our new assignments as methyl-branched alkenones are further confirmed by the synthesis of an analog α-methyl C25 methyl ketone and comparison of mass spectra. Double bond positions for branched C38:5Me (brC38:5Me) are found to be Δ4, Δ7, Δ14, Δ21 and Δ28 based on the mass spectrum of corresponding dimethyl disulfide adducts. Analysis of Lake Van alkenone data reveals that U b r 38 M e K ∗ based on brC38Me shows a trend similar to U 37 K for the past 270 ka, suggesting that the degree of unsaturation of branched alkenones is also sensitive to temperature.

Human susceptibility to visual discomfort of solid-state lighting was investigated by statistically analyzing for commercial phosphor-converted white light-emitting diodes (PC-WLEDs) with considering optical characteristics such as correlated color temperature (C.C.T., or Tcp), chromaticity, lumen, color rendering Index (C.R.I.) , radiation pattern. These statistic analyses of human factor engineering were based on the surveys and visual measurements among 500 male and female volunteers of ages 18 to 22. The levels of these optical parameters were standardized for indication of the discomfort degree or sensitivity to human visual susceptibility. The results showed that, compared to male human eyes’, female ones could have 20% more sensitive to color rendering on R985 Index, 15% higher in color temperature; however, 30% less sensitive to lumen, and 30% lower recognition ability to radiation pattern. Consequently, it becomes more important for LED manufacturers and solid-state lighting designers to take consideration of such human factor engineering into their products and services.

It was reported that sol-gel processed SiO 2 -coating effects of Ce 3+ : YAG phosphor on and thermal reliability enhancements in terms of quantum efficiency and optical characteristics. This study found improved light extraction efficiencies of glass phosphor, and increased quantum efficiency 3.95% of SGCeYDG in comparison to un-coated CeYDLTG. In the thermal reliability tests, Lumen degradation and chromaticity shift (u E) in the SGCeYDG thermally agd at 150, 250, 350, and 450 : , respectively, are also presented and compared with those of CeYDG. The results clearly demonstrated that the SGCeYDG exhibited better thermal stability on lumen degradation, and chromaticity shift than CeYDG’s. The navel high performance thermal-stable glass has been essentially critical to the application areas of LED modules where high-power leading high-operation-temperature and absolute thermal reliability are required for developing the next-generation solid-state lighting industry Keywords: Keywords: Aging test, Ce:YAG, glass phosphor, sol-gel

During development, certain Drosophila sensory neurons undergo dendrite pruning that selectively eliminates their dendrites but leaves the axons intact. How these neurons regulate pruning activity in the dendrites remains unknown. Here, we identify a coiled-coil protein Spindle-F (Spn-F) that is required for dendrite pruning in Drosophila sensory neurons. Spn-F acts downstream of IKK-related kinase Ik2 in the same pathway for dendrite pruning. Spn-F exhibits a punctate pattern in larval neurons, whereas these Spn-F puncta become redistributed in pupal neurons, a step that is essential for dendrite pruning. The redistribution of Spn-F from puncta in pupal neurons requires the phosphorylation of Spn-F by Ik2 kinase to decrease Spn-F self-association, and depends on the function of microtubule motor dynein complex. Spn-F is a key component to link Ik2 kinase to dynein motor complex, and the formation of Ik2/Spn-F/dynein complex is critical for Spn-F redistribution and for dendrite pruning. Our findings reveal a novel regulatory mechanism for dendrite pruning achieved by temporal activation of Ik2 kinase and dynein-mediated redistribution of Ik2/Spn-F complex in neurons., Author Summary In Drosophila, the nervous systems undergo extensive neuronal remodeling during metamorphosis, as many larval neurons die and adult neurons are generated while some larval neurons survive and prune their branches. Pruning that removes specific parts of neuronal branches without causing cell death is a self-destruct process, thus requiring precise regulation to prevent undesired damage to the nervous systems. Certain Drosophila sensory neurons that undergo dendrite pruning, specifically eliminating the dendrites but leaving the axons intact, provide us an opportunity to study the mechanism of how pruning activity is regulated in the dendrites. We reasoned that the distinctive microtubule polarity in dendrites and axons might be involved and factors are required to regulate the pruning activity in the dendrites through their interaction with microtubules. Here, we identified Spindle-F that mediates Ik2-dependent pruning activity in the dendrites by linking Ik2 to the microtubule motor dynein complex. We showed that elevation of Ik2 activity during dendrite pruning promotes Ik2/Spindle-F/dynein complex moving along the microtubules. We also showed that the formation and redistribution of Ik2/Spindle-F/dynein complex are essential for dendrite pruning. Our study reveals a connection between the polarized microtubules of dendrites and the pruning activity through Spindle-F for dendrite pruning.