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The paper discusses the environmental impact assessment of key pollutants generated by vessels during maritime transport operations. For the purposes of this study, a vessel is considered as a system that can be broken down into main subsystems and system components. Maritime shipping is a relatively environmentally-friendly means of moving large cargo over long distances. It is the only mode of transport that can successfully take over cargo from hinterland traffic. Mobility improvements have forced people to use more complex energy sources, which has contributed to the development and upgrading of transport infrastructure. From the economic perspective, maritime transport is currently an optimal transport mode. The fast development of this sector, observed especially on the Far Eastern market, entails the elevated risk of polluting the marine environment as a result of ongoing operations as well as accidents. The objective of this paper is to analyse and evaluate the environmental hazards that may arise from the operation of ERRVs (Emergency Response and Rescue Vessels).

The preparation of stimuli-responsive metal nanoparticles is a key challenge in developing smart multifunctional nanoscale devices. The efficient strategy relies on coating of nanoparticles with polymers or surfactants, which are capable of undergoing physicochemical changes in response to external stimuli. Herein, we report a computational strategy towards the development of an atomic-scale molecular dynamics (MD) model for pH-responsive metal nanoparticles comprising an inorganic silver core and a polymeric shell consisting of single-chain poly(acrylic acid) (PAA) of varying sizes. PAA is a weak polyelectrolyte, which contains ionizable carboxylic side-chain groups, capable of donating or accepting protons upon changes in pH, and responds to environmental changes by altering conformations of its macromolecule. We investigated the adsorption behavior of PAA onto silver nanoparticles (AgNPs) upon varying (i) a polymer chain length from 220 up to 1540 units, (ii) the degree of ionization α, ranging from 0 to 1. The latter is determined by the content of neutral and ionized carboxylic groups, mimicking of pH changes, ranging between the two extreme cases: fully neutral (α = 0) and fully ionized (α = 1) states, respectively. Our MD simulations show that, being fully neutral, PAA collapses and adsorbs onto AgNP similar to traditional non-ionizable polymers. However, we found out that the interfacial behavior of PAA could be tuned by changing of the degree of ionization of the carboxylic groups. We observed that electrostatic-driven variations in a shape and chain packing density of PAA were able to trigger the degree of nanoparticle-polymer interactions. Our results show that PAA-grafted AgNPs can provide a simple model for designing of novel pH-responsive composite nanomaterials.

2′-Hydroxy derivatives of 2,5-diaryl-1,3-oxazole are known as environment-sensitive ratiometric excited-state intramolecular proton transfer (ESIPT) fluorescent probes, which are used to monitor physicochemical properties of lipid membranes. However, because of their heterogeneous membrane distribution, accurate experimental determination of the probe position is difficult. To estimate the location of the ESIPT probes in lipid membranes we have performed fluorescence measurements and molecular dynamics (MD) simulations. In the series composed of 2-(2′-hydroxy-phenyl)-5-phenyl-1,3-oxazole (1), 2-(2′-hydroxy-phenyl)-5-(4′-biphenyl)-1,3-oxazole (2), and 2-(2′-hydroxy-phenyl)-phenanthro[9,10-d]-1,3-oxazole (3), the structure of the ESIPT-moiety of 2-(2′-hydroxy-phenyl)-oxazole was varied by either aromatic ring substitution or annealing, leading to the systematical increase in the hydrophobic character of the probes. The comparison of the fluorescence behavior of probes 1–3 in a wide variety of solvents with those in phospholipid vesicles revealed that all three probes prefer to reside inside a membrane. Our MD results demonstrate that the probes locate from the glycerol residues and the polar carbonyl groups of phospholipids up to hydrophobic acyl chain units. It has been found that the probe location correlates well with the size of the aromatic moiety, being gradually shifted from 11.1 A to 7.6 A from the bilayer center for probes 1 to 3, respectively. Our results may be useful for the design of novel fluorescent probes for fluorescence sensing of specific regions within a lipid membrane.

The advent of nanomedicine has rejuvenated the need for increased understanding of the fundamental physicochemical properties of polymeric amphiphiles. Hyaluronic acid (HA) is a hydrophilic polysaccharide that is frequently conjugated to hydrophobic moieties and then used to entrap dyes and therapeutics. Here, we develop computational models to examine the effects of the hydrophobic modification on supramolecular behavior among three systematically designed HA derivatives substituted with alkyl chains of increasing length. Our simulations coalesce with experimentally obtained results to demonstrate the dependence of supramolecular behavior on intramolecular forces. We show that the formation of clearly defined hydrophobic domains in samples of octadecylamine-modified HA compared to HA conjugates with shorter alkyl chains is a result of more favorable hydrophobic interactions. Trends in hydrodynamic radius and polydispersity are observed in experimental results that coalesce with theoretical calculations, suggesting that supramolecular properties are dependent on the physicochemical characteristics of individual polymer strands.

Fluorescent nanomaterials require high colloidal stability for effective use in imaging and sensing applications. We herein report the synthesis of carbazole-based organic fluorescent nanoaggregates, and demonstrate the superior colloidal stability of alkyl-substituted dye aggregates over their non-alkylated analogs. The role of alkyl chains in self-assembly and stability of such nanoaggregates is discussed based on both experimental and molecular dynamics simulation data, and spectral characteristics of the precursor dyes and their aggregates are described. The obtained results provide new insights on development of colloidally stable organic fluorescent nanomaterials with low polydispersity.

International audience; Molecular dynamics computer simulations of the solid-liquid interface of TiO2 and D205 dye (anchored or free) and solvent, such as ionic liquids (1-butyl-3-methylimidazolium with hexafluorophosphate (BmimPF6) and trifluoromethanesulfonate (BmimTFO) anions) or acetonitrile (ACN) are performed in the canonical (NVT) ensemble. For the solvent and TiO2, we used the force fields availabile in the literature or developed by us, while to described the TiO2 and D205 interactions, quantum-chemical calculations were carried out on a small size cluster of TiO2 where the D205 dye was anchored. The simulations were carried systematically in the absence or presence of the D205 dye. In the latter case, we consider the situation where the dye is covalently anchored or free at the interface. The solvent molecules, forming the first layers at the TiO2 interface, have been identified by analyzing the mass density distribution and radial distribution functions. The results show that the solvent molecules are structured in successive layers, the density of which decreases to reach that of the macroscopic one at a long distance normal to the TiO2 interface. These findings show also that the F and O atoms of the anions and the N atom of acetonitrile are at a close distance from the Ti or O atoms of the TiO2 surface, indicating a competition of the solvent and the dye to interact with these atoms. Furthermore, the time traces of the z-axis position of certain atoms of the anchored D205 dye did not show any substantial change suggesting the conformation change is not occurring in the time scale of 50 ns.

This article supplies raw data related to a research article entitled “Joint refinement of FRET measurements using spectroscopic and computational tools” (Kyrychenko et al., 2017) [1], in which we demonstrate the use of molecular dynamics simulations to estimate FRET orientational factors in a benchmark donor-linker-acceptor system of enhanced cyan (ECFP) and enhanced yellow (EYFP) fluorescent proteins. This can improve the recalculation of donor-acceptor distance information from single-molecule FRET measurements.

Cyclodextrins (CDs) are environment-friendly chemicals, which are used as a stabilizing agent for the synthesis of gold nanoparticles (AuNP). However, their binding mechanism and adsorption modes on AuNPs remain not well understood. Herein, the adsorption behavior and favorable binding geometry of γ-cyclodextrin (γ-CD) onto the surface of a quasi-spherical AuNP were studied by all-atom molecular dynamics (MD) simulation. The adsorption of γ-CD onto AuNP was sampled by varying the number of adsorbate molecules from 10 up to 70 and by changing an initial random distribution of adsorbates around AuNP. Our MD simulations reveal that, at the low adsorbate content, γ-CD molecules prefer binding onto the gold surface by its wider toroid rim so that they occupy all available surface area of AuNP. In contrast, we observed that the increase in the adsorbate content resulted in some steric repulsion among adsorbed molecules and their self-aggregation, so that the preferred adsorption mode of γ-CD molecules changes in favor of binding by their toroid side. The analysis of radial distribution functions calculated between gold atoms and γ-CD reveals that anchoring and binding of an adsorbate onto the gold surface occur through multiple non-covalent interactions, among which non-covalent bonding of the primary and secondary hydroxyl groups, as well as the aliphatic carbon moieties play an essential role. Besides, we found that strong binding interactions between AuNP and γ-CD caused some conformation distortions and twisting of the γ-CD macrocycle, which was not observed for smaller-ring analogs of α-CD and β-CD, respectively.

Background A new service model integrates the specialty pharmacy's comprehensive service with the retail pharmacy's patient contact, giving patients options for medication delivery to home, pharmacy, or doctor's office. Objective Evaluate the impact of the new service model on medication adherence. Design Retrospective cohort study Settings One hundred fifteen CVS retail stores in Philadelphia participated in a pilot from May 2012 to October 2013, and 115 matched CVS retail stores from around the nation served as controls. Patients All eligible patients from the intervention and control stores received specialty medications through CVS retail pharmacies prior to implementation of the new service model. Intervention The intervention patients were transitioned from retail pharmacy service to the specialty pharmacy with delivery options. The control patients received standard retail pharmacy services. Main outcome measures Proportion of days covered and first fill persistence were tracked for 12 months before and after program implementation. Results Under the new service model, 228 patients new to therapy in the post period had a 17.5% increase in the rate of obtaining a second fill as compared to matched controls. Patients on therapy in both the pre- and the post-periods had a pre-post increase of 6.6% in average adherence rates and a pre-post increase of 10.8% in optimal adherence rates as compared to 326 matched controls. Conclusion The study demonstrated significant improvement in both adherence to therapy and first-fill persistence among patients in the new service model integrating specialty pharmacy's comprehensive services with the retail pharmacy's patient contact and medication delivery choices.

Introduction La prise en charge medicale des problemes de sante sexuelle et des infections sexuellement transmissibles (IST) est souvent compliquee chez les jeunes ayant debute leur vie sexuelle, en raison des difficultes d’acces aux soins. Selon Sante Publique France, la population des 15–24 ans est particulierement affectee par les IST. L’objectif de cette etude etait de decrire les caracteristiques sociodemographiques des jeunes patients consultant au CeGIDD, de comparer cette population a celle des adultes, de decrire la prevalence des IST au sein de cette population ainsi que le taux de retour pour recevoir les resultats des examens. Materiels et methodes Entre 2017 et 2019, nous avons mene une etude retrospective incluant les jeunes patients consultant au sein d’un CeGIDD parisien. Un jeune patient etait defini comme un consultant âge de 18 ans ou moins. Un echec de rendu de resultat etait defini comme une personne qui n’etait pas revenue chercher ses resultats dans un delai d’1 mois. Les analyses statistiques ont ete menees a l’aide du logiciel SPSS version 22.0. Resultats Parmi les 10 262 consultants, 7,1 % (n = 733) etaient âges de 18 ans ou moins. Parmi les jeunes patients, 55,3 % (n = 405) etaient de sexe masculin, 75,8 % (n = 430) etaient nes en Europe et 80,8 % (n = 596) etaient etudiants. Les jeunes avaient des relations heterosexuelles dans 92,3 % (n = 664) des cas versus 80,0 % (n = 7511) pour les adultes (p = 0,001). Ils n’avaient aucune couverture sociale dans 15,3 % (n = 111) des cas vs 6,5 % (n = 612) pour les plus âges (p = 0,001). Ils n’avaient jamais effectue de test pour le VIH pour 79,8 % (n = 576) d’entre eux vs 29,2 % (n = 2745). Ils avaient deja eu une IST dans 4,9 % des cas (n = 34) vs 20,9 % (n = 1913) (p Conclusion Les caracteristiques des jeunes consultants en CeGIDD sont differentes des patients plus âges avec une prevalence elevee d’infection a CT. Le taux de retour pour recuperer les resultats est plus faible que pour les adultes. Des etudes complementaires doivent etre menees pour identifier les freins et ameliorer le retour et le traitement en cas de resultat positif.

Full Kharkiv archival data from 1972 to 1978 have a volume of almost 250 thousand meteor orbits. Of these, we used a sample of sporadic meteoroids with a volume of 159319 orbits. We selected 214 meteor orbits with the aphelia exceeding 100 AU. The greatest aphelion distance for them was 1997.7 (near 2000) AU. At the same time, meteoroids in these orbits invaded the Earth’s atmosphere and burned, creating ionized meteor tracks. The sensitivity of the Kharkiv orbital radar made it possible to record radio meteors up to +12 ​M from meteoroids in the mass range 10 − 3 - 10 − 6 g. Thus, the selected catalog of 214 meteor orbits represents a kind of toolkit for testing remote areas of the Solar system associated with objects called sednoids. The selected catalog of 214 highly eccentric orbits of weak radio meteors up to +12 ​M is presented in the form of tables with a description of the data. Distributions by various parameters for 214 orbits and 159319 orbits are given.The mapping of the annual cycle of observations may be obtained across a catalog of 6743 sporadic meteor orbits, which were published by Voloshchuk, Kolomiyets, and Cherkas in 2018. It is planned to transfer the Kharkiv archived meteor radar data to the IAU Meteor Data Center using experience of transferring archived data of radio observations of past years, received at the Hissar Observatory in Tajikistan which was published by Narziev in 2018.

Native and modified cyclodextrins (CDs) are routinely used as a capping agent upon the preparation of gold nanoparticles (AuNP); however, their role in the synthesis remains unresolved. Here, the adsorption behavior of β-cyclodextrin (β-CD) onto AuNP was studied by all-atom molecular dynamics (MD) simulations. We found that β-CD binding onto the AuNP surface occurs through multiple non-covalent interactions, among which non-covalent binding of the aliphatic carbon moieties and the hydroxyl oxygen atoms plays a vital role. Surprisingly, the MD analysis revealed that the most preferred binding mode of the β-CD molecules onto the gold surface corresponds to the toroid side geometry. Only minor populations of β-CD molecules were observed, in which the adsorbate molecules are bound onto AuNP by either its primary or secondary rims, respectively. The adsorbed β-CDs formed the multiple-layer coating on AuNP, composed up to three adsorbate layers. We found that for AuNP of the size of 2.9 nm, the maximum water-protecting efficiency of the adsorbate coating occurs upon reaching a value of 40 β-CD molecules, the further increase in the adsorbate content resulted in some self-aggregation of β-CD molecules onto the gold surface. Our findings provide the molecular-level understanding of the adsorption behavior of β-CD onto gold, which is relevant for various applications of CD-capped gold nanostructures.

Duchenne muscular dystrophy (DMD) is a progressive muscle disease with severe cardiac complications. It is believed that cellular oxidative stress and augmented Ca(2+) signaling drives the development of cardiac pathology. Some mitochondrial and metabolic dysfunctions have also been reported. Here we investigate cellular mechanisms responsible for impaired mitochondrial metabolism in dystrophic cardiomyopathy at early stages of the disease. We employed electrophysiological and imaging techniques to study mitochondrial structure and function in cardiomyocytes from mdx mice, an animal model of DMD. Here we show that mitochondrial matrix was progressively oxidized in myocytes isolated from mdx mice. Moreover, an abrupt increase in workload resulted in significantly more pronounced oxidation of mitochondria in dystrophic cells. Electron micrographs revealed a gradually increased number of damaged mitochondria in mdx myocytes. Degradation in mitochondrial structure was correlated with progressive increase in mitochondrial Ca(2+) sequestration and mitochondrial depolarization, despite a substantial and persistent elevation in resting cytosolic sodium levels. Treatment of mdx cells with cyclosporine A, an inhibitor of mitochondrial permeability transition pore (mPTP), shifted both resting and workload-dependent mitochondrial redox state to the levels recorded in control myocytes. It also significantly reduced workload dependent depolarization of mitochondrial membrane in dystrophic cardiomyocytes. Overall, our studies highlight age dependent deterioration of mitochondrial function in dystrophic cardiomyocytes, which seems to be associated with excessive opening of mPTP due to oxidative stress and cellular Ca(2+) overload.

Influence of protic surrounding on the excited state intramolecular proton transfer (ESIPT) reaction was studied both experimentally and theoretically on the example of 4’-methoxy-3-hydroxyflavone (4M3 H F), a model fluorescent dye possessing multi-banded emission spectra. Experimentally determined 4M3 H F ESIPT rates in alcohol solutions correlate with the general acidity of a protic solvent and steric hindrance to intermolecular H-bonding caused by the space dimensions and branching of an alcohol molecule hydrocarbon residue. The role of intermolecular hydrogen bonds was elucidated by quantum-chemical and molecular dynamics modeling: several types of H-bonded complexes were examined systematically aiming to outline their accelerating or retarding effects on ESIPT reaction rate. An intermolecular hydrogen bond to the lone electron pair of the carbonyl group oxygen atom, which is not involved in the intramolecular H-bonding, was shown to be the most important factor for regulation of ESIPT rate in protic or aprotic humid surrounding.

pH-Induced conformational switching is essential for functioning of diphtheria toxin, which undergoes a membrane insertion/translocation transition triggered by endosomal acidification as a key step of cellular entry. In order to establish the sequence of molecular rearrangements and side chain protonation accompanying the formation of the membrane-competent state of the toxin’s translocation (T) domain, we have developed and applied an integrated approach that combines multiple techniques of computational chemistry (e.g., long, µsec-range, all-atom molecular dynamics simulations; continuum electrostatics calculations; and thermodynamic integration) with several experimental techniques of fluorescence spectroscopy. Thermodynamic integration calculations indicate that protonation of H257 causes the greatest destabilization of the native structure (6.9 kcal/mole), which is consistent with our early mutagenesis results. Extensive equilibrium MD simulations with a combined length of over eight µsec demonstrate that histidine protonation, while not accompanied by the loss of structural compactness of the T-domain, nevertheless results in substantial molecular rearrangements characterized by the partial loss of secondary structure due to unfolding of helices TH1 and TH2, and the loss of close contact between the C- and N-terminal segments. The structural changes accompanying the formation of the membrane-competent state ensure an easier exposure of the internal hydrophobic hairpin formed by helices TH8 and TH9, in preparation for its subsequent transmembrane insertion.

International audience; Solubilizing membrane proteins for functional, structural and thermodynamic studies is usually achieved with the help of detergents, which, however, tend to destabilize them. Several classes of non-detergent sur-factants have been designed as milder substitutes for detergents, most prominently amphipathic polymers called 'amphipols' and fluorinated surfactants. Here we test the potential usefulness of these compounds for thermodynamic studies by examining their effect on conformational transitions of the diphtheria toxin T-domain. The advantage of the T-domain as a model system is that it exists as a soluble globular protein at neutral pH yet is converted into a membrane-competent form by acidification and inserts into the lipid bi-layer as part of its physiological action. We have examined the effects of various surfactants on two confor-mational transitions of the T-domain, thermal unfolding and pH-induced transition to a membrane-competent form. All tested detergent and non-detergent surfactants lowered the cooperativity of the thermal unfolding of the T-domain. The dependence of enthalpy of unfolding on surfactant concentration was found to be least for fluorinated surfactants, thus making them useful candidates for thermodynamic studies. Circular dichroism measurements demonstrate that non-ionic homopolymeric amphipols (NAhPols), unlike any other surfactants, can actively cause a conformational change of the T-domain. NAhPol-induced structural rearrangements are different from those observed during thermal denaturation and are suggested to be related to the formation of the membrane-competent form of the T-domain. Measurements of leakage of ves-icle content indicate that interaction with NAhPols not only does not prevent the T-domain from inserting into the bilayer, but it can make bilayer permeabilization even more efficient, whereas the pH-dependence of membrane permeabilization becomes more cooperative. This article is part of a Special Issue entitled: Protein Folding in Membranes.

It is likely that large-conductance Ca²⁺-activated K⁺ (BK(Ca)) channels channelopathy tightly involved in vascular malfunctions and arterial hypertension development. In the present study, we compared the results of siRNAs-induced α-BK(Ca) gene silencing and vascular abnormalities produced by whole-body ionized irradiation in rats. The experimental design comprised RT-PCR and patch clamp technique, thoracic aorta smooth muscle (SM) contractile recordings and arterial blood pressure (BP) measurements on the 30th day after whole body irradiation (6Gy) and following siRNAs KCNMA1 gene silencing in vivo. The expression profile of BK(Ca) mRNA transcripts in SM was significantly decreased in siRNAs-treated rats in a manner similar to irradiated SM. In contrast, the mRNA levels of K(v) and K(ATP) were significantly increased while L-type calcium channels mRNA transcripts demonstrated tendency to increment. The SMCs obtained from irradiated animals and after KCNMA1 gene silencing showed a significant decrease in total K⁺ current density amplitude. Paxilline (500 nM)-sensitive components of outward current were significantly decreased in both irradiated and gene silencing SMCs. KCNMA1 gene silencing increased SM sensitivity to norepinephrine while Ach-induced relaxation had decreased. The silencing of KCNMA1 had no significant effect on BP while radiation produced sustained arterial hypertension. Therefore, radiation alters the form and function of the BK(Ca) channel and this type of channelopathy may contribute to related vascular abnormalities. Nevertheless, it is unlikely that BK(Ca) can operate as a crucial factor for radiation-induced arterial hypertension.

Thiol-stabilized metal nanoparticles possess unique properties in the comparison with larger-scale materials, which enable their use in many promising chemical and biological applications. We have synthesized thiol-coated colloidal gold nanoparticles (AuNP) soluble in non-polar organic solvents by a simplified procedure, in which AuCl 4 - was initially reduced in aqueous phase and then coated with thiol residues and transferred to organic phase. Using the transmission electron micrograph (TEM) imaging, the average diameter of a dodecanethiol-stabilized AuNP was estimated to be 3.75 ± 0.06 nm. Based on the experimental TEM data, a new coarse-grained molecular dynamics model of AuNP was developed. The model was applied for studying self-assembly of AuNPs on a flat graphite surface, enabling further elucidating the structure and packing of the ligand shell around the spherical nanoparticle core.

Successful use of fluorescence sensing in elucidating the biophysical properties of lipid membranes requires knowledge of the distribution and location of an emitting molecule in the bilayer. We report here that 2,6-bis(1H-benzimidazol-2-yl)pyridine (BBP), which is almost non-fluorescent in aqueous solutions, reveals a strong emission enhancement in a hydrophobic environment of a phospholipid bilayer, making it interesting for fluorescence probing of water content in a lipid membrane. Comparing the fluorescence behavior of BBP in a wide variety of solvents with those in phospholipid vesicles, we suggest that the hydrogen bonding interactions between a BBP fluorophore and water molecules play a crucial role in the observed “light switch effect”. Therefore, the loss of water-induced fluorescence quenching inside a membrane are thought to be due to deep penetration of BBP into the hydrophobic, water-free region of a bilayer. Characterized by strong quenching by transition metal ions in solution, BBP also demonstrated significant shielding from the action of the quencher in the presence of phospholipid vesicles. We used the increase in fluorescence intensity, measured upon titration of probe molecules with lipid vesicles, to estimate the partition constant and the Gibbs free energy (ΔG) of transfer of BBP from aqueous buffer into a membrane. Partitioning BBP revealed strongly favorable ΔG, which depends only slightly on the lipid composition of a bilayer, varying in a range from − 6.5 to − 7.0 kcal/mol. To elucidate the binding interactions of the probe with a membrane on the molecular level, a distribution and favorable location of BBP in a POPC bilayer were modeled via atomistic molecular dynamics (MD) simulations using two different approaches: (i) free, diffusion-driven partitioning of the probe molecules into a bilayer and (ii) constrained umbrella sampling of a penetration profile of the dye molecule across a bilayer. Both of these MD approaches agreed with regard to the preferred location of a BBP fluorophore within the interfacial region of a bilayer, located between the hydrocarbon acyl tails and the initial portion of the lipid headgroups. MD simulations also revealed restricted permeability of water molecules into this region of a POPC bilayer, determining the strong fluorescence enhancement observed experimentally for the membrane-partitioned form of BBP.

Phospholipids, labeled covalently by a fluorescent dye, are commonly applied in membrane biophysics. In this work, a molecular dynamics model of sulforhodamine attached covalently to a headgroup of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine is developed. It is found that the incorporation of rhodamine-labeled phospholipids into a DPPC bilayer at the low concentration results in small perturbation of the bilayer. In the dye-labeled membrane, the sulforhodamine moiety binds favorably to a polar membrane interface, forming the tilt angle 44° ± 8° to the bilayer normal. The deep location and binding of a bulk sulforhodamine fluorophore lead, therefore, to some ‘softening’ of the membrane structure.

In semiconductors with inversion asymmetry, spin–orbit coupling gives rise to the well-known Dresselhaus and Rashba effects. If one considers quantum wells with two or more conduction subbands, an additional, intersubband-induced spin–orbit term appears whose strength is comparable to the Rashba coupling, and which remains finite for symmetric structures. We show that the conduction band spin splitting due to this intersubband spin–orbit coupling term is negligible for typical III–V quantum wells.