Low Sm Research Articles

Flash Drought Intensification due to Enhanced Land–Atmospheric Coupling in India

Abstract Land–atmospheric feedback influences the occurrence and severity of flash droughts. However, the observed and projected changes in flash droughts and associated land–atmospheric coupling have not been examined over India. Moreover, the causes of the rapid depletion of soil moisture during flash droughts are not well known. We identify major flash droughts and associated soil moisture–vapor pressure deficit (SM–VPD) coupling in India using ERA5 and simulations from global climate models (CMIP6-GCMs). The summer monsoon season (June–September) witnesses more than 60% of the flash drought events and a relatively higher rate of flash drought development. The flash drought frequency has mainly decreased during India’s observed climate (1980–2019), which is projected to decline further in the future warming climate. On the other hand, the flash drought development rate has significantly increased during the observed period, which is projected to enhance further under the warming climate. SM–VPD coupling during the flash drought onset-development phase is considerably higher (threefold to fivefold) than during the normal condition (in the absence of flash drought). The high (low) SM–VPD coupling explains the faster (slower) flash drought development rate in the observed and future warming climate. The strength of SM–VPD coupling has increased in the recent period and is projected to increase further in the future warming climate. The increased SM–VPD coupling can intensify future flash droughts in India, especially during the summer monsoon season, with considerable implications for agriculture, water resources, and ecosystems. Significance Statement This study aims to understand better the role of land–atmospheric coupling in explaining flash drought characteristics (frequency and development rate) in India. Strong land–atmospheric (SM–VPD) feedback might influence the regional weather patterns during flash drought, which often negatively impacts humans and the ecosystem. We explain the causes and drivers of increasing (decreasing) flash drought development rate (frequency) in India. The long-term change in SM–VPD coupling drives the frequency of flash drought, whereas an anomalous instantaneous change in coupling controls the flash drought development rate. More intense flash droughts contributed by the increased land–atmospheric coupling are projected in the future. Predicting the SM–VPD coupling metric can facilitate more time for preparedness, resulting in minimizing the flash drought impacts.

Thigh muscle by CT images as a predictor of mortality in patients with newly diagnosed colorectal cancer

This study aimed to evaluate the prognostic value of thigh muscle assessed by CT images to predict overall mortality in patients with colorectal cancer (CRC). This was a multicenter cohort study including adults (≥ 18 years old) newly diagnosed with CRC, who performed a diagnostic computed tomography (CT) exam including thigh regions. CT images were analyzed to evaluate skeletal muscle (SM in cm2), skeletal muscle index (SMI in cm2/m2), and skeletal muscle density (SMD in HU). Muscle abnormalities (low SM, SMI, and SMD) were defined as the values below the median by sex. Kaplan–Meyer curves and hazard ratios (HRs) for low SM, SMI and SMD were evaluated for overall mortality, stratified by sex. A total of 257 patients were included in the final analysis. Patients’ mean age was 62.6 ± 12.1 years, and 50.2% (n = 129) were females. In males, low thigh SMI was associated with shorter survival (log-rank P = .02). Furthermore, this low thigh SMI (cm2/m2) was independently associated with higher mortality rates (HR adjusted 2.08, 95% CI 1.03–4.18). Our additional findings demonstrated that low SMD was independently associated with overall mortality among early-stage patients (I–III) (HR adjusted 2.78, 95% CI 1.26–6.15).

Constrained trait variation by water availability modulates radial growth in evergreen and deciduous Mediterranean oaks

Spatial and temporal variation in functional traits allows trees to adjust to shifting environmental conditions such as water stress. However, the change of traits, both mean and variances, along water availability gradients and across growing seasons, as well as their covariation with tree performance, have been rarely assessed. We examined intraspecific trait variation in coexisting evergreen (Quercus ilex ssp. ilex and Q. ilex ssp. ballota) and deciduous (Quercus faginea and Quercus humilis) Mediterranean oaks along a wide water availability gradient in northeastern Spain during six years. We measured leaf area (LA), shoot twig mass (Sm), leaf mass per area (LMA) and the ratio of shoot twig to leaf biomass (Sm:Lm). We characterized tree performance through basal area increment (BAI) and drought resilience indices. Higher variation was found within individuals than between individuals across populations and years. Within species, we found trait adjustments toward more conservative water-use (low LA and Sm and high LMA) with increasing drier conditions. Intraspecific trait variation was constrained by water availability, particularly on the deciduous species. In Q. ilex, trait variance of LMA positively covaried with annual BAI, whereas variance of LA, Sm and Sm:Lm was positively related to resistance and resilience against the severe 2012 drought in deciduous oaks. Our results support a tradeoff between the ability to tolerate drought and the capacity to cope with unpredictable changes in the environment through increased intraspecific trait variation, which may have implications on tree performance in the face of increased extreme events.

Functional diversity along disturbance and environmental gradients in Ethiopian moist Afromontane forest

Considering multiple measures to fully capture functional diversity is important. However, the effects of disturbance gradients on diversity have been controversial, as species diversity alone may not fully capture these effects. This study aimed to evaluate trait-based diversity across disturbance gradients in the moist Afromontane forest of Ethiopia, Yayu Coffee Forest Biosphere Reserve (YCFBR). Vegetation data and relevant traits related to plant-life strategies, competition, and responses to disturbances were collected. A multiple regression model was used to test the response of functional diversity to disturbances and environmental gradients. The results revealed functional diversity in plant communities, including dendrogram-based functional diversity for plot-based (FDp), functional richness (FRic), functional evenness (FEve), functional divergence (FDiv), functional dispersions (FDis), and community-weighted mean of maximum tree height (CWM.Hmax), showed decreasing patterns with increasing disturbance intensity in the YCFBR. Additionally, the findings highlighted that FDis and Hmax are the most vulnerable functional traits to anthropogenic factors and are less tolerant in disturbed ecosystem environments. Therefore, reducing disturbances is crucial to maintaining higher levels of these functional diversities. For example, the results showed that the CWM.Hmax declined from 27.25 m to 15 m, indicating a shift towards shorter plant species. In contrast, the community-weighted mean of woody density (CWM.WD), the community-weighted mean of specific leaf area (CWM.SLA), and the community-weighted mean of seed mass (CWM.SM) increased significantly with an increase in disturbance intensity. For instance, CWM.SM and CWM.SLA changed from 5 to 14.25 (g) and 90 to 130 (cm2/g), respectively. These indices may serve as indicators of ecosystem resilience at disturbed forest ecosystem sites. Furthermore, the regression results indicated that FDp, FRic, FEve, FDiv, FDis, CWM.WD, and CWM.Hmax showed increasing patterns with increasing species richness, which suggests that protecting and promoting species diversity can contribute to maintaining high levels of functional diversity. The mixed effects model revealed that anthropogenic disturbance and elevational gradients had significant effects on functional diversity in the YCFBR. Therefore, when managing and conserving biodiversity in heterogeneous environments, both anthropogenic factors and environmental variables need to be considered. Species with low SLA and SM are recommended for the restoration of disturbed ecosystems. Overall, this study demonstrates that trait-based functional diversity is useful for predicting the adaptation potentials of species in heterogeneous environments and disturbance gradients.

Family doctors' and dentists' access and dissemination of medical information through social media.

The study purpose is to analyze how doctors in contract with the Health Insurance House in Romania use social media (SM) to access and disseminate medical information. Family doctors and dentists who had a contract with the Romanian National Health Insurance House during the year 2017 represented the targeted sample. Eight thousand four hundred ninety-seven e-mail addresses and 5,422 telephone numbers were identified and collected from the National Health Insurance House web page. The invitation to participate in the study (including the link to the online questionnaire) was sent via SMS, WhatsApp, and /or e-mail from 24 May to 14 July 2017. The experimental design was cross-sectional. In the statistical analysis the following generations were defined: "Baby Boomers", aged between 51-70 years, Generation X as people aged 38-51, and Millennials under 38 years. One hundred and twenty valid questionnaires were analyzed. The profile of the respondent was: woman (61%), from urban (71%), and specialist (50%) working in a private practice (70%). The majority of respondents use Facebook (85%). Generation X connect more to SM from public places than Baby Boomers (p = 0.007). Respondent doctors seek medical information on SM monthly (83%), but rarely give advice through SM to colleagues (28%) or contribute to patients' medical education (32%). Most physicians interact with their patients through SM (59%), but do not discuss with them how to search for health information. Social media has low professional usage among the respondents who perform their medical activity in Romania and is mainly used to search for medical information, but it does not contribute to patients' medical education. As expected, age is a factor that determines the susceptibility of SM usage.

CH3COOH.TiO2: An excellent catalyst for the green nitration of toluene by N2O4

The solvent-free nitration of toluene with N2O4 gas over solid acid catalysts is a green reaction for preparing the mono-nitrotoluene (NT) isomers. The acid-modified catalysts are more efficient than common catalysts for this type of reaction. For this purpose, a titanium dioxide (TiO2) catalyst is synthesized with a sol-gel method and modified by acetic acid to increase catalytic properties. The acid-modified TiO2 (CH3COOH·TiO2) is characterized by different analyses. To optimization of toluene nitration conditions, reaction temperature (X1) (30 < X1 < 60 °C), N2O4/toluene molar ratio (X2) (0.5 < X2 < 2), and the amount of catalyst (X3) (0.05 < X3 < 0.3 g) factors were investigated by Minitab software with the CCD-RSM. Three responses including the selectivity of meta-NT isomer (Sm), the ratio of para-NT to ortho-NT selectivity (Sp/o), and the selectivity of by-products (Sbp) were considered for the optimization. Statistical parameters were applied to evaluate the goodness of fitting for the models. Optimum values for X1, X2, and X3 parameters are 57.9 °C, 1.91, and 0.25 g, respectively. The conversion of toluene under these conditions is 93.2%. The comparison of Sm, Sp/o, and Sbp in CH3COOH.TiO2 (1.51%, 0.8, and 5.48%, respectively) with Fe2O3 (8.5%, 0.43, and 20.57%, respectively), SiO2 (8.43%, 0.48, and 16.24%, respectively), TiO2 (5.9%, 0.57, and 13.87%, respectively), TiO2–Fe2O3 (4.72%, 0.64, and 9.18%, respectively), and TiO2–SiO2 (4.42%, 0.67, and 5.73%, respectively) catalysts show that this catalyst has a low Sm and Sbp as well as a higher Sp/o than other mentioned catalysts. The mechanism of the mentioned reaction is reviewed in the presence of CH3COOH·TiO2 catalyst. The high stability of the CH3COOH·TiO2 is proved by the reusability test, and it is found that its stability against inactivation is more than the TiO2 catalyst.

Influence of low concentration Sm doping on optical and catalytic performance of titania

The work focuses on exploring the effect of the concentration of Sm dopant (0.2–0.6 at.%) on structural, optical and photocatalytic properties of the spin coated titania based thin films annealed at different temperatures. The optical interpretation involves the influence of Sm doping on optical constants and luminescence behaviour of the samples. The comprehensive work on optical bandgap, Urbach energy and electron-phonon interaction strength was conducted for Sm doped samples. The optical band gap was found to increase with the increasing concentration of Sm, but decreased with high temperature annealing. Using ellipsometry measurement, refractive index of the samples was obtained. The orbital level information was gathered using X-Ray Photoelectron Spectroscopy (XPS) study with a special emphasis on the evolution of physico-chemical properties as function of Sm doping. The XPS study confirms the presence of Sm in the titania host material and it helped in estimating defects induced by Sm doping. The photocatalytic study of Sm doped titania thin films was carried out by using methylene blue (MB) and Rhodamine B (RhB) dye and we have found an enhanced photocatalytic activity for the 0.4 at.% Sm doped samples.

Dispersion of Trace Elements as Consequence of insitu Weathering in granite-derived Tropical Soils in Southwestern Nigeria

Trace elements composition of granite and tropical soils formed by in-situ weathering over the basement complex of Ikere-Ekiti, Ado-Ekiti and Igbrara-Odo areas of SW Nigeria is evaluated and reported. The granitoids exhibit chemical features such as is common to other granite bodies across the basement areas. The soil profiles typically have four different horizons with contrasting physical characteristics. Analytical result from ICP-MS technique revealed compositional variation along vertical direction within depth of the profiles. Trace element as average for the granite reveals low Tm (0.5 ppm), Eu (2.1 ppm), Co (5.1 ppm), Sc (7.2 ppm), Hf (7.6 ppm), Sm (12.6 ppm), and Th (30.5 ppm) values, while La (110 ppm), Ce (216 ppm), Cr (235.5 ppm), and Ba (963 ppm) show enrichments. All the soils have Sm, Eu, Th, Hf and Co contents below 10 ppm; Sc, La and Ce values fall between 10-100 ppm, while Cr and Ba contents fall between 200-1500 ppm. Variation between trace contents in granite and the derived soils as revealed along depths of the profile indicates greater mobility of Th, Sc and Ba during chemical weathering while Eu and Tm are least mobile. Pronounced compositional variation occur at relatively shallow (0-1m) depth in near surface area all the profiles.

Microsurgical resection versus stereotactic radiosurgery for low-grade intracranial arteriovenous malformations: A 27-year institutional experience

The role of microsurgery and radiosurgery in the management of low-grade (Spetzler-Martin grade 1 and 2) arteriovenous malformations (AVMs) remains controversial. We aimed to compare outcomes of low-grade AVMs following microsurgery and radiosurgery using a database of AVM patients presenting between 1990 and 2017. Procedure-related complications, obliteration, and functional status at last follow-up were compared between groups. Hemorrhage-free survival was compared using Kaplan-Meier analysis with subgroup analyses by rupture status on presentation. The study involved 233 patients, of which 113 and 120 were treated with microsurgery and radiosurgery, respectively. The complication rates were statistically comparable between both treatment modalities. Mean follow-up time was 5.1 ± 5.2 years. In the complete cohort, there was no significant difference in hemorrhage-free survival between microsurgery and radiosurgery (log-rank p = 0.676, Breslow p = 0.493). When excluding procedure-related hemorrhage and partial resection, hemorrhage-free survival was significantly higher in the surgically treated cohort (log-rank = 0.094, Breslow p = 0.034). The obliteration rate was significantly higher in the surgical cohort (96% vs. 57%, p < 0.001), while functional status was similar. Microsurgery may offer superior hemorrhage-free survival in the early post-treatment period and demonstrates equivalent long-term hemorrhage control and functional outcome at 5 years compared to radiosurgery with nearly complete obliteration rates. Persistent neurologic deficits following microsurgery and symptomatic cerebral edema represent important treatment risks despite low SM grading. Appropriate patient selection even when dealing with low-grade AVMs is advised, as judicious patient selection and emphasis on technical success can minimize procedure-related hemorrhage and the incidence of subtotal resection.

An extended 3-3-1 model with two scalar triplets and linear seesaw mechanism

Low energy linear seesaw mechanism responsible for the generation of the tiny active neutrino masses, is implemented in the extended 3-3-1 model with two scalar triplets and right handed Majorana neutrinos where the gauge symmetry is supplemented by the $A_4$ flavor discrete group and other auxiliary cyclic symmetries, whose spontaneous breaking produces the observed pattern of SM charged fermion masses and fermionic mixing parameters. Our model is consistent with the low energy SM fermion flavor data as well as with the constraints arising from meson oscillations. Some phenomenological aspects such as the $Z^\prime$ production at proton proton collider and the lepton flavor violating decay of the SM-like Higgs boson are discussed. The scalar potential of the model is analyzed in detail and the SM-like Higgs boson is identified.

Combined association of skeletal muscle mass and grip strength with cardiovascular diseases in patients with type 2 diabetes.

Appendicular skeletal muscle mass (ASM) and grip strength (GS) have been suggested to be related to cardiovascular diseases (CVDs), but their association with type 2 diabetes (T2D) remains unclear. Therefore, we examined the combined association of ASM and GS with the prevalence of CVD in patients with T2D. A total of 1230 patients with T2D were recruited and divided into four groups based on the sex-specific median values of ASM adjusted for body mass index (ASM/BMI; short: SM) and GS: high SM/high GS (HSM/HGS), high SM/low GS (HSM/LGS), low SM/high GS (LSM/HGS), and low SM/low GS (LSM/LGS). The LSM/LGS group was older and had higher values of systolic blood pressure, homeostasis model assessment of insulin resistance, waist circumference, and C-reactive protein but lower high-density lipoprotein cholesterol concentrations than the HSM/HGS group. After adjusting for potential confounders, the odds ratios (ORs) and 95% CIs for CVD, coronary heart disease (CHD), ischemic stroke, and peripheral arterial disease (PAD) in the LSM/LGS group were 2.90 (1.89-4.47), 2.39 (1.46-3.92), 1.77 (0.84-3.71), and 5.83 (1.58-21.48), respectively. After adjusting for variable confounders among patients with higher glycosylated hemoglobin (HbA1c) (≥7.1%), the ORs and 95% CIs for CVD and CHD in the LSM/LGS group were 7.27 (3.37-15.67) and 6.17 (2.65-14.37), respectively. The combination of low SM and GS was strongly associated with CVD, CHD, and PAD in patients with T2D, especially in those with higher HbA1c levels.

New loading method for high precision Sm isotope analysis of nuclear materials using thermal ionization mass spectrometry

This work demonstrates an analytical protocol for high precision Sm isotope analysis by thermal ionization mass spectrometry (TIMS) using a Pt activator. The method permits precise measurements of small aliquots (1–20 ng) of Sm on single Re filament using a modified static-total evaporation technique. This study represents the first attempt to use such protocols for Sm isotope analyses while reducing the loading size of Sm for TIMS. The method could potentially be deployed to study geological, meteorites and lunar samples containing low Sm concentrations, to monitor neutron irradiation exposure based on 149,150Sm, or to measure Sm isotopic composition in other types of nuclear samples.

Nonlinear feedback controller for the synchronization of (chaotic) systems with known parameters

This paper proposes, designs, and analyses a novel nonlinear feedback controller that realizes fast, and oscillation free convergence of the synchronization error to the equilibrium point. Oscillation free convergence lowers the failure chances of a closed-loop system due to the reduced chattering phenomenon in the actuator motion, which is a consequence of low energy sm ooth control signal. The proposed controller has a novel structure. This controller does not cancel nonlinear terms of the plant in the closed-loop; this attribute improves the robustness of the loop. The controller consists of linear and nonlinear parts; each part executes a specific task. The linear term in the controller keeps the closed-loop stable, while the nonlinear part of the controller facilitates the fast convergence of the error signal to the vicinity of the origin. Then the linear controller synthesizes a smooth control signal that moves the error signals to zero without oscillations. The nonlinear term of the controller does not contribute to this synthesis. The collaborative combination of linear and nonlinear controllers that drive the synchronization errors to zero is innovative. The paper establishes proof of global stability and convergence behavior by describing a detailed analysis based on the Lyapunov stability theory. Computer simulation results of two numerical examples verify the performance of the proposed controller approach. The paper also provides a comparative study with state-of-the-art controllers.

Characterization of excessive Sm3+containing barium titanate prepared by tartrate precursor method

The BaSm43xTi1−xO3(BST) samples, where (x = zero, 0.05, 0.1, 0.15, 0.2 and 0.3), have been successfully synthesized by tartrate precursor method at annealing temperature of 600°C under atmospheric pressure. The results revealed that the Sm content causes a decrease in both tetragonality and average grain size of BST samples. The electrical resistivity of BST samples is improved by low Sm content, reaching maximum value at x = 0.15 and then decreases with higher Sm content, suggesting that the conduction has two types of polaron hoping and semiconductor band conduction mechanisms at low and at high temperature ranges, respectively. It is demonstrated that the majority of charge carriers are p-type. The dielectric properties varies nonmonotonically with samarium content, showing strongly enhancement in dielectric constant for high Sm doping samples. It is recommended that BST samples are attractive for capacitor and energy storage applications.

SUBSTANTIATION OF ENERGY EFFICIENT WATER SUPPLY IN CLOSED IRRIGATION SYSTEMS

Relevance of research. The research is aimed at improving the energy efficiency of automated water supply in irrigation systems. The purpose and objectives of research. The purpose of the research is to reduce the specific energy consumption for pumping water by pumping stations (PS) in closed irrigation systems (CIS). The task is to substantiate the efficiency of the method of automated control of water supply to the CIS when regulating the pressure at the outlet of the pumping station, which is set by the sum of hydraulic losses in the network from the pumping station to irrigation equipment (IE), static and free pressure at the dictating hydrant of CIS. The logical-mathematical model and technological conditions of energy-efficient water supply management "when it need" in CIS are given. The technical requirements for pumping units (PU) and auxiliary technological equipment of PS are presented in the application of automated water supply control with the use of frequency converters (FC).Research methods: experimental, mathematical modeling. Substantiation of the feasibility of introduction of automated electric drive with FC, as one of the measures of energy efficiency improvement, was carried out based on the results of energy audits of the PU and the CIS with the use of measuring equipment on the request of inter-district water management administration. The object of the energy audit is the CIS, which has been in operation since 1979. The PS is equipped with four PU with centrifugal section pumps 150-CVE-350-23/3 (D = 350 mm) and drive motors of the brand MAF315SK-4 with a rated power of 132 kW. During the period of operation the reconstruction and restoration of the CIS took place. “Dnepr” sprinkling machines have been replaced by modern low pressure SM and drip irrigation systems. With the replacement of irrigation equipment, asbestos-cement field pipelines with diameters D = 400 mm were replaced too with the plastic ones of D = 200 mm. The configuration, hydraulic characteristics of the CIS and modes of operation of the PU were changed. The efficiency of the pumps 150-CVE-350-23/3 decreased by 10-15% during the long-term operation of the PU. Research results. For energy efficient water supply management, it is proposed to: replace four worn pumps 150-CVE-350-23/3 with three pumps of domestic production ЦН400-105б; implement a system of automated water supply management at the CIS with the use of FC. Conclusions. The effectiveness of the application of a new method of water supply control in the CIS, which provides for automatic control of the pressure at the outlet of the PS, is given by the sum of hydraulic losses in the network from the PS to the IE, static and free pressure at the dictating inlet of the operating IE, using the proven FC. Introduction of automated electric drive with the FC on the PS-4 of the “Repin” CIS enables to reduce the daily power consumption from 12% to 25%.

Molecular phenotyping of rejection-related changes in mucosal biopsies from lung transplants.

Diagnosing lung transplant rejection currently depends on histologic assessment of transbronchial biopsies (TBB) with limited reproducibility and considerable risk of complications. Mucosal biopsies are safer but not histologically interpretable. Microarray-based diagnostic systems for TBBs and other transplants suggest such systems could assess mucosal biopsies as well. We studied 243 mucosal biopsies from the third bronchial bifurcation (3BMBs) collected from seven centers and classified them using unsupervised machine learning algorithms. Using the expression of a set of rejection-associated transcripts annotated in kidneys and validated in hearts and lung transplant TBBs, the algorithms identified and scored major rejection and injury-related phenotypes in 3BMBs without need for labeled training data. No rejection or injury, rejection, late inflammation, and recent injury phenotypes were thus scored in new 3BMBs. The rejection phenotype correlated with IFNG-inducible transcripts, the hallmarks of rejection. Progressive atrophy-related changes reflected by the late inflammation phenotype in 3BMBs suggest widespread time-dependent airway deterioration, which was especially pronounced after two years posttransplant. Thus molecular assessment of 3BMBs can detect rejection in a previously unusable biopsy format with potential utility in patients with severe lung dysfunction where TBB is not possible and provide unique insights into airway deterioration. ClinicalTrials.gov NCT02812290.

A 3-3-1 model with low scale seesaw mechanisms

We construct a viable 3-3-1 model with two SU(3)_L scalar triplets, extended fermion and scalar spectrum, based on the T^{prime } family symmetry and other auxiliary cyclic symmetries, whose spontaneous breaking yields the observed pattern of SM fermion mass spectrum and fermionic mixing parameters. In our model the SM quarks lighter than the top quark, get their masses from a low scale Universal seesaw mechanism, the SM charged lepton masses are produced by a Froggatt-Nielsen mechanism and the small light active neutrino masses are generated from an inverse seesaw mechanism. The model is consistent with the low energy SM fermion flavor data and successfully accommodates the current Higgs diphoton decay rate and predicts charged lepton flavor violating decays within the reach of the forthcoming experiments.

High FA2H and UGT8 transcript levels predict hydroxylated hexosylceramide accumulation in lung adenocarcinoma

Lung cancer causes more deaths than any other cancer. Sphingolipids encompass metabolically interconnected species whose balance has pivotal effects on proliferation, migration, and apoptosis. In this study, we paralleled quantification of sphingolipid species with quantitative (q)PCR analyses of metabolic enzymes in order to identify dysregulated routes of sphingolipid metabolism in different subtypes of lung cancers. Lung samples were submitted to histopathological reexamination in order to confirm cancer type/subtype, which included adenocarcinoma histological subtypes and squamous cell and neuroendocrine carcinomas. Compared with benign lesions and tumor-free parenchyma, all cancers featured decreased sphingosine-1-phosphate and SMs. qPCR analyses evidenced differential mechanisms leading to these alterations between cancer types, with neuroendocrine carcinomas upregulating SGPL1, but CERT1 being downregulated in adenocarcinomas and squamous cell carcinomas. 2-Hydroxyhexosylceramides (2-hydroxyHexCers) were specifically increased in adenocarcinomas. While UDP-glycosyltransferase 8 (UGT8) transcript levels were increased in all cancer subtypes, fatty acid 2-hydroxylase (FA2H) levels were higher in adenocarcinomas than in squamous and neuroendocrine carcinomas. As a whole, we report differing mechanisms through which all forms of lung cancer achieve low SM and lysosphingolipids. Our results also demonstrate that FA2H upregulation is required for the accumulation of 2-hydroxyHexCers in lung cancers featuring high levels of UGT8.

Sediment accumulation patterns on the slopes and abyssal plain of the southern Gulf of Mexico

Here we present new results on the spatial distribution patterns of lithogenic and biogenic components and sedimentation processes in the deep-water region (966–3741 m) of the southern Gulf of Mexico (sGM). A collection of 44 cores retrieved from the continental slopes and the abyssal plain were dated with the aid of accelerator mass spectrometry (AMS) 14C determinations on planktic foraminifera. We applied a mixing box model (MBM) to estimate the mixed layer age (TML), the mean sediment accumulation rate (Sm), and the mixing depth (XML) for each core. Observed ranges for these variables were Sm (3.4–17.7 cm/kyr), TML (393–6021 yr) and XML (2.4–24.3 cm). Deep-sea sediments in the study region fall into three main groups, which reflect the importance of the main sediment components, lithogenic and biogenic, and sedimentation processes at depth in the sGM. Cores clustered in Group 1 include most of the stations in the abyssal plain, show the oldest TML, relatively low Sm, and a relatively higher ratio between the carbonate and terrigenous components (mostly silt and clay). Group 2 cores were collected from stations in the transitional region, between the abyssal plain and the continental slopes, show relatively higher Sm, a younger TML and a relatively lower ratio between the carbonate and the terrigenous content than cores from G1. Group 3 cores were collected from different water depths on the continental slopes, show the highest Sm, younger TML, and the highest terrigenous content. These distinct groupings enabled us to recognize anomalous properties in certain cores, with implications on the local processes that alter their sedimentation processes at those sites. Our results highlight the importance of the terrigenous input to this basin, as one of the main controls of the burial rates with important implications on the possible fate of anthropogenic inputs and its sequestration in the deep-sea sediments of the sGM.

Plasma membrane sphingomyelin modulates thymocyte development by inhibiting TCR-induced apoptosis.

Sphingomyelin (SM) in combination with cholesterol forms specialized membrane lipid microdomains in which specific receptors and signaling molecules are localized or recruited to mediate intracellular signaling. SM-microdomain levels in mouse thymus were low in the early CD4+CD8+ double-positive (DP) stage prior to thymic selection and increased >10-fold during late selection. T-cell receptor (TCR) signal strength is a key factor determining whether DP thymocytes undergo positive or negative selection. We examined the role of SM-microdomains in thymocyte development and related TCR signaling, using SM synthase 1 (SMS1)-deficient (SMS1-/-) mice which display low SM expression in all thymocyte populations. SMS1 deficiency caused reduced cell numbers after late DP stages in TCR transgenic models. TCR-dependent apoptosis induced by anti-CD3 treatment was enhanced in SMS1-/- DP thymocytes both in vivo and in vitro. SMS1-/- DP thymocytes, relative to controls, showed increased phosphorylation of TCR-proximal kinase ZAP-70 and increased expression of Bim and Nur77 proteins involved in negative selection following TCR stimulation. Addition of SM to cultured normal DP thymocytes led to greatly increased surface expression of SM-microdomains, with associated reduction of TCR signaling and TCR-induced apoptosis. Our findings indicate that SM-microdomains are increased in late DP stages, function as negative regulators of TCR signaling and modulate the efficiency of TCR-proximal signaling to promote thymic selection events leading to subsequent developmental stages.