SH Regions Research Articles

Retrieval and validation of the Secchi disk depth values (Zsd) from the Sentinel-3/OLCI satellite data in the Persian Gulf and the Gulf of Oman.

In this study, the Secchi disk depth (Zsd) values as an indicator of seawater clarity/transparency were estimated using the ESA (European Space Agency) Sentinel-3A and Sentinel-3B OLCI (S3/OLCI) satellite data in the Persian Gulf and the Gulf of Oman (PG&GO). To do so, two procedures were evaluated including an existing methodology developed by Doron et al. (J Geophys Res: Oceans 112(C6) 2007 and (Remote Sens Environ 115:2986-3001 2011) and an empirical model proposed in this research formed by employing the blue (B4) and green (B6) bands of S3/OLCI data. In this regard, a total number of 157 field-measured Zsd values (114 training points for calibration of the models and 43 control points for accuracy assessment of them) were observed during eight research cruises conducted by the research vessel, the Persian Gulf Explorer, in the PG&OS between 2018 and 2022. The optimum methodology was then selected based on the statistical indicators including R2 (coefficient of determination), RMSE (root mean square error), and MAPE (mean absolute percentage error). However, after the indication of the optimal model, the data of all 157 observations were utilized for the calculation of unknown parameters of the model. The final results demonstrated that compared to the existing empirical model proposed by Doron et al. (J Geophys Res: Oceans 112(C6) 2007 and (Remote Sens Environ 115:2986-3001 2011), the developed model in this study which was formed based on the linear and ratio terms of B4 and B6 bands, has more efficiency in the PG&GO. Consequently, a model in form of Zsd = e1.638B4/B6-8.241B4-12.876B6+1.26 was suggested for the estimation of Zsd values from S3/OLCI in the PG&GO (R2 = 0.749, RMSE = 2.56m, and MAPE = 22.47%). The results also showed that the annual oscillation of the Zsd values in the GO (5-18m) is evidently higher compared with those in the PG (4-12m) and the SH (7-10m) regions.

Seasonal and regional signatures of ENSO in upper tropospheric jet characteristics from reanalyses

AbstractThe relationship of upper tropospheric jet variability to El Niño / Southern Oscillation (ENSO) in reanalysis datasets is analyzed for 1979–2018, revealing robust regional and seasonal variability. Tropical jets associated with monsoons and the Walker circulation are weaker and the zonal mean subtropical jet shifts equatorward in both hemispheres during El Niño, consistent with previous findings. Regional and seasonal variations are analyzed separately for subtropical and polar jets. The subtropical jet shifts poleward during El Niño over the NH eastern Pacific in DJF, and in some SH regions in MAMand SON. Subtropical jet altitudes increase during El Niño, with significant changes in the zonal mean in the NH and during summer/fall in the SH. Though zonal mean polar jet correlations with ENSO are rarely significant, robust regional/seasonal changes occur: The SH polar jet shifts equatorward during El Niño over Asia and the western Pacific in DJF, and poleward over the eastern Pacific in JJA and SON. Polar jets are weaker (stronger) during El Niño in the western (eastern) hemisphere, especially in the SH; conversely, subtropical jets are stronger (weaker) in the western (eastern) hemisphere during El Niño in winter and spring; these opposing changes, along with an anticorrelation between subtropical and polar jet windspeed, reinforce subtropical/polar jet strength differences during El Niño, and suggest ENSO-related covariability of the jets. ENSO-related jet latitude, altitude, and windspeed changes can reach 4(3)°, 0.6(0.3) km, and 6(3) ms−1, respectively, for the subtropical (polar) jets.

Maternal origin and genetic diversity of Algerian domestic chicken (Gallus gallus domesticus) from North-Western Africa based on mitochondrial DNA analysis

Local chicken populations are a major source of food in the rural areas of Algeria. However, their origin has not been well characterized. The objectives of this study were to assess genetic diversity and maternal origin of domestic chicken from five agro-ecological regions of western Algeria: coastal (CT), inland plains (IP), highlands (HL), mountains (MT) and sahara (SH, including Oasis, Req and Erg regions). A set of 88 mitochondrial DNA (mtDNA) D-loop sequences including the hypervariable region I (HV1) were analyzed. From the 397 bp D-loop sequence, 20 variable sites that defined 13 haplotypes were identified in Algerian domestic chicken. The haplotype and nucleotide diversity were estimated as 0.597 and 0.003, respectively. Phylogenetic and network analyses indicated the presence of two clades or haplogroups (A and E). Only one clade A haplotype was observed exclusively in the population of mountains, while, Clade E haplotypes were found in almost all Algerian chicken with twelve different haplotypes. These findings suggest that Algerian chickens derived from the most ubiquitous haplogroup which have its root in the Indian subcontinent. Our results provide important information about the origin of the North-West African chicken and the historical dispersal of the first chicken populations into African continent.

Hypergyrating Droplets Generated on a Selective Laser-Textured Heterogeneous Wettability Surface.

An impacting droplet on water-repellent surfaces experiences spreading, retraction, and bouncing phases, among which the spontaneous droplets gyrating is very interesting and has promising applications. Here, we present an ultrahigh-speed gyrating droplet generation method via torque transmission on a heterogeneous wettability surface. Hybrid superhydrophobic-superhydrophilic (SH-SHL) patterns were fabricated by selective laser texturing on aluminum alloy substrates. The maximum static contact angles (CAs) of the SH region and SHL region were 163.3 ± 2 and 0 ± 1°, and the advancing and receding CAs were 162.2 ± 1 and 159.9 ± 1°, respectively. The hybrid SH-SHL pattern coupling with the translational kinetic energy of impacting droplet and the rotational momentum of the rotating substrate has been proved as a high-efficiency energy conversion method to construct hypergyrating droplets. A hypergyrating speed exceeding 96 700 rpm (13 times of the latest reported value) was achieved in droplets impact on the hybrid SH-SHL-patterned heterogeneous wettability surface, and the maximum energy transformation ratio (α) of the rotating specimen driven torque to the rebounded gyrating droplet is 83.40%. The regulation of the maximum gyrating speed of a bouncing droplet could be controlled by the pattern size and the substrate driving speed, which suggests a practical approach in the energy transformation, a new type of cleaning strategy, and other industrial applications.

Optical properties of the nanocomposite of molybdenum disulphide monolayers/cellulose nanofibrils

Studies on nanocomposites of cellulose nanofibrils (CNFs) and transition-metal dichalchogenides (TMD) monolayers are still rare in the literature. Among the TMDs, the molybdenum disulphide (MoS2) monolayers have been employed in a great variety of applications, such as sensors, photovoltaic devices, and transistors. The synthesis of the MoS2/CNF nanocomposite was performed through a liquid exfoliation process and the optical and morphological properties of MoS2/CNF films were characterized by confocal microscopy and UV–Vis absorption and the nanocomposite morphology was characterized by atomic force microscopy (AFM) and by field emission scanning electron microscopy (FESEM) techniques. UV–Vis measurements showed that the CNF addition caused a narrowing in the MoS2 flakes absorption band at 1.89 eV and 2.0 eV energy values, similar to those present in a MoS2 monolayer. Morphological analyses of the MoS2/CNF composite by FESEM indicate that the CNF addition reduces the MoS2 flakes anisotropy and corroborates the absorption narrowing bands. Stationary Photoluminescence (PL) and Second Harmonic Generation (SHG) were carried out by Confocal Microscopy indicating the presence of few layers composing the MoS2 flakes. The PL and SHG arise due to the liquid exfoliation process, which produces heterogenic flakes with randomic numbers of MoS2 layers. Results showed that the addition of up to 10% w/w of CNFs gives rise to a high fluorescence gain. However, the amount of SH regions increases as a function of the addition of CNFs above 10% w/w.

Thiols as Hydrogen Bond Acceptors and Donors: Spectroscopy of 2-Phenylethanethiol Complexes.

Evidence and understanding of sulfur-centered hydrogen bonding, especially where the donor is a thiol, lags far behind that for conventional OH interactions. To help address this deficiency, conformer specific IR spectra of 2-phenylethanethiol (PET) and associated 1:1 solvent complexes have been measured in SH, OH, and CH stretch regions using resonant-two-photon-ionization (R2PI) and IR-UV ion dip spectroscopic techniques. The aromatic and aliphatic CH stretch regions show signature differences between anti and gauche conformers. Supported by ab initio calculations, a PET-water cluster with an OH···S arrangement and a PET-diethyl ether cluster expressing an SH···O interaction were identified. The SH stretch band of the SH···O complex is red-shifted and undergoes significant intensity enhancement compared to the bare molecule, which is characteristic of hydrogen bonding. These findings offer insight into the nature of the thiol functional group as a potential hydrogen bond donor and acceptor.

High density SNP and DArT-based genetic linkage maps of two closely related oil palm populations.

Oil palm (Elaeis guineensis Jacq.) is an outbreeding perennial tree crop with long breeding cycles, typically 12years. Molecular marker technologies can greatly improve the breeding efficiency of oil palm. This study reports the first use of the DArTseq platform to genotype two closely related self-pollinated oil palm populations, namely AA0768 and AA0769 with 48 and 58 progeny respectively. Genetic maps were constructed using the DArT and SNP markers generated in combination with anchor SSR markers. Both maps consisted of 16 major independent linkage groups (2n = 2× = 32) with 1399 and 1466 mapped markers for the AA0768 and AA0769 populations, respectively, including the morphological trait "shell-thickness" (Sh). The map lengths were 1873.7 and 1720.6cM with an average marker density of 1.34 and 1.17cM, respectively. The integrated map was 1803.1cM long with 2066 mapped markers and average marker density of 0.87cM. A total of 82% of the DArTseq marker sequence tags identified a single site in the published genome sequence, suggesting preferential targeting of gene-rich regions by DArTseq markers. Map integration of higher density focused around the Sh region identified closely linked markers to the Sh, with D.15322 marker 0.24cM away from the morphological trait and 5071bp from the transcriptional start of the published SHELL gene. Identification of the Sh marker demonstrates the robustness of using the DArTseq platform to generate high density genetic maps of oil palm with good genome coverage. Both genetic maps and integrated maps will be useful for quantitative trait loci analysis of important yield traits as well as potentially assisting the anchoring of genetic maps to genomic sequences.

Cool-temperature-mediated activation of phospholipase C-γ2 in the human hereditary disease PLAID

Deletions in the gene encoding signal-transducing inositol phospholipid-specific phospholipase C-γ2 (PLCγ2) are associated with the novel human hereditary disease PLAID (PLCγ2-associated antibody deficiency and immune dysregulation). PLAID is characterized by a rather puzzling concurrence of augmented and diminished functions of the immune system, such as cold urticaria triggered by only minimal decreases in temperature, autoimmunity, and immunodeficiency. Understanding of the functional effects of the genomic alterations at the level of the affected enzyme, PLCγ2, is currently lacking. PLCγ2 is critically involved in coupling various cell surface receptors to regulation of important functions of immune cells such as mast cells, B cells, monocytes/macrophages, and neutrophils. PLCγ2 is unique by carrying three Src (SH) and one split pleckstrin homology domain (spPH) between the two catalytic subdomains (spPHn-SH2n-SH2c-SH3-spPHc). Prevailing evidence suggests that activation of PLCγ2 is primarily due to loss of SH-region-mediated autoinhibition and/or enhanced plasma membrane translocation. Here, we show that the two PLAID PLCγ2 mutants lacking portions of the SH region are strongly (>100-fold), rapidly, and reversibly activated by cooling by only a few degrees. We found that the mechanism(s) underlying PLCγ2 PLAID mutant activation by cool temperatures is distinct from a mere loss of SH-region-mediated autoinhibition and dependent on both the integrity and the pliability of the spPH domain. The results suggest a new mechanism of PLCγ activation with unique thermodynamic features and assign a novel regulatory role to its spPH domain. Involvement of this mechanism in other human disease states associated with cooling such as exertional asthma and certain acute coronary events appears an intriguing possibility.

Local heat/mass transfer measurements on effusion plates in impingement/effusion cooling with rotation

This paper describes an investigation of the local heat/mass transfer for rotating impingement/effusion cooling. A study was conducted of parameters such as jet orientation and surface geometry. An experiment using the naphthalene sublimation method provided the local heat/mass transfer coefficients on the effusion plate. The heat/mass transfer distributions for the axial orientation were similar to those for the stationary cases, while the trailing orientation produced different Sherwood number features, with divided high Sh regions and one low Sh region around the stagnation area. The concave surface provided better and more uniform heat/mass transfer than the flat surface.

Raman spectroscopic evidence for nuclear disulfide in isolated lenses of hyperbaric oxygen-treated guinea pigs

Our laboratory treats guinea pigs with hyperbaric oxygen (HBO) as a model for investigating the formation of nuclear cataract. Previous analyses of lens supernatants using this model have shown an increase in disulfide (–SS–) and loss of sulfhydryl (–SH) in the lens nucleus of O 2-treated animals. In this paper, we have used the non-invasive technique of Raman spectroscopy to confirm these findings in intact, freshly-excised lenses. Guinea pigs were treated 3 times per week with HBO for a total of 50 (4 months of treatment) or 85 (7 months of treatment) times to induce an increased level of lens nuclear light scattering. Intact lenses were analyzed by Raman spectroscopy using a 514.5 nm laser and collecting the scattered light in a 90° geometry. The laser beam was focused either in the lens nucleus or equatorial cortex. Changes in the levels of –SS– (503 cm −1) and –SH (2577 cm −1) vibrations were measured. Raman spectra were analyzed by fitting Lorentzian profiles to the observed data in the –SS– and –SH regions. –SS– levels in the O 2-treated nucleus were found to have increased by a factor of 2.1 ( p = 0.0001) and 2.5 ( p = 0.001) after 50 and 85 HBO treatments, respectively, compared to age-matched controls. Based on previous biochemical analyses, the –SS– increase was due mainly to the formation of protein disulfide (PSSP) with contribution also from protein/thiol mixed disulfides, but not from oxidized glutathione. –SH levels in the O 2-treated nucleus decreased by 13% ( p = 0.007) and 35% ( p = 0.001) after 50 and 85 HBO treatments, respectively, compared to age-matched controls. No significant increase in –SS– or loss of –SH was observed in the lens cortex of the O 2-treated guinea pigs. The Raman spectroscopy results rule out the possibility that artifactual production of –SS– and loss of –SH occurred during homogenization of lenses in previous studies. The data provide additional evidence to support a link between O 2, disulfide-crosslinking of lens crystallins in the nucleus, and nuclear cataract.

Fos imaging reveals ageing-related changes in hippocampal response to radial maze discrimination testing in mice.

A two-stage radial arm maze (RAM) task has been designed recently to demonstrate a specific age-related memory deficit in mice. It highlights the contrast between normal and deficient memory expression in a spatial discrimination problem depending on how to-be discriminated arms were presented to the animal. This specific deficit has been interpreted as a preferential loss in a relational/declarative form of memory, thereby implying an underlying hippocampal dysfunction. To test this hypothesis, neuronal activation measured by Fos immunostaining was compared in aged (21-23 months) and adult (4-6 months) mice trained in the aforementioned task and killed after a retention session consisting in age-insensitive probe trials, performed 6 days later (6-day RAM). Two comparison conditions were included: (i) repeated locomotor training on a treadmill (TM); (ii) the same RAM training, except for the use of a longer (30 days instead of six) retention interval (30-day RAM). Although all RAM groups displayed similar levels of performance at the end of the experiment, immediately before the mice were killed, significant between-group differences in brain activation were observed. In adult mice, 6-day RAM testing was associated with greater septal and hippocampal (CA1, CA3, DG) Fos expression than the TM condition. Lengthening the retention interval from 6 days to 30 days resulted in a significant decrease in RAM testing-induced Fos expression in most of the septo-hippocampal regions. With respect to adult mice, aged mice displayed reduced Fos expression (except for DG) and a lack of interrelationships between levels of Fos produced in each of the SH regions, in the 6-day RAM testing condition. Conversely, there was no effect of ageing on Fos expression associated with either TM training or 30-day RAM testing. These results are interpreted as reflecting age- (or time-) related alterations in recruiting of brain structures that underlie a relational/declarative form of memory expression.

The Influence of Deletion Mutations on Phospholipase C-γ1 Activity

Phospholipase C-γ1, a substrate for many growth factor receptor and nonreceptor tyrosine kinases, produces second messenger molecules that are elements of signal transduction pathways related to cell proliferation. The influence of deletion mutations, which do not intrude on the domains required for catalytic function, on the basal activity of this enzyme is reported. Removal of the first 74 amino-terminal residues increases phospholipase C activity, while deletion of the carboxy-terminal 81 residues decreases enzyme activity. Deletion of the SH2-SH2-SH3 central region, which separates the two domains (X, Y) responsible for catalytic function, also increases enzymatic activity. Interestingly, addition of a recombinant SH2-SH2-SH3 fragment of phospholipase C-γ1 to the holoenzyme inhibits its phospholipase activity at pH 7.0, but not at pH 5.0. However, addition of individual SH2 or SH3 domains does not influence activity of the holoenzyme. All three deletion mutants, in contrast to the holoenzyme, are relatively resistant to V8 proteolysis and activation induced by the epidermal growth factor receptor tyrosine kinase, which require, respectively, specific proteolysis and phosphorylation sites within the SH region. This suggests a conformational change is induced in the SH region by deletion at either the amino- or carboxy-terminus.

A novel nonreceptor tyrosine kinase, Srm: cloning and targeted disruption.

We have isolated a novel nonreceptor tyrosine kinase, Srm, that maps to the distal end of chromosome 2. It has SH2, SH2', and SH3 domains and a tyrosine residue for autophosphorylation in the kinase domain but lacks an N-terminal glycine for myristylation and a C-terminal tyrosine which, when phosphorylated, suppresses kinase activity. These are structural features of the recently identified Tec family of nonreceptor tyrosine kinases. The Srm N-terminal unique domain, however, lacks the structural characteristics of the Tec family kinases, and the sequence similarity is highest to Src in the SH region. The expression of two transcripts is rather ubiquitous and changes according to tissue and developmental stage. Mutant mice were generated by gene targeting in embryonic stem cells but displayed no apparent phenotype as in mutant mice expressing Src family kinases. These results suggest that Srm constitutes a new family of nonreceptor tyrosine kinases that may be redundant in function.