Passive Leakage Research Articles

Supporting patients to manage faecal incontinence.

British Journal of NursingVol. 25, No. 7 RegularsSupporting patients to manage faecal incontinenceSue WoodwardSue WoodwardSearch for more papers by this authorSue WoodwardPublished Online:15 Apr 2016https://doi.org/10.12968/bjon.2016.25.7.370AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareShare onFacebookTwitterLinked InEmail View article References Beeckman D, Woodward S, Rajpaul K, Vanderwee K (2011) Clinical challenges of preventing incontinence-associated dermatitis. Br J Nurs 20(13): 784–6,788,790. doi: https://doi.org/10.12968/bjon.2011.20.13.784 Link, Google ScholarBritish Society of Gastroenterologists (2016) Clinical Commissioning Report: Faecal Incontinence. http://tinyurl.com/gpp8es9 (accessed 5 April 2016) Google ScholarBurch J, Collins B (2010) Using biofeedback to treat constipation, faecal incontinence and other bowel disorders. Nurs Times 106(37): 18–21 Medline, Google ScholarCotterill N, Norton C, Avery KN, Abrams P, Donovan JL (2008) A patient-centered approach to developing a comprehensive symptom and quality of life assessment of anal incontinence. Dis Colon Rectum 51(1):82–7 Crossref, Medline, Google ScholarNational Institute for Health and Care Excellence (2007) Faecal incontinence in adults: management. [CG49]. http://tinyurl.com/zyvoey4 (accessed 5 April 2016) Google ScholarNorton C, Chelvanayagum S, eds (2004) Bowel Continence Nursing. Beaconsfield Publishers, Beaconsfield Google ScholarTariq SH (2007) Constipation in long-term care. J Am Med Dir Assoc 8(4):209–18 Crossref, Medline, Google ScholarWoodward S (2012) Management options for faecal incontinence. Nursing and Residential Care 14(5): 224–229 Link, Google Scholar FiguresReferencesRelatedDetails 14 April 2016Volume 25Issue 7ISSN (print): 0966-0461ISSN (online): 2052-2819 Metrics History Published online 15 April 2016 Published in print 14 April 2016 Information© MA Healthcare LimitedPDF download

Comparison of nicotinamide adenine dinucleotide phosphate-induced immune responses against biotrophic and necrotrophic pathogens in Arabidopsis thaliana

ABSTRACTThe pyridine nucleotide nicotinamide adenine dinucleotide phosphate (NADP) is a universal coenzyme in anabolic reactions and also functions in intracellular signaling by serving as a substrate for production of the Ca2+-mobilizing agent nicotinic acid adenine dinucleotide phosphate (NAADP). It has recently been shown that, in mammalian cells, cellular NADP can be released into the extracellular compartment (ECC) upon environmental stresses by active exocytosis or diffusion through transmembrane transporters in living cells or passive leakage across the membrane in dying cells. In the ECC, NADP can either serve as a substrate for production of NAADP or act directly on purinoceptors to activate transmembrane signaling. In the last several years, extracellular NADP has also been suggested to function in plant immune responses. Here, we compared exogenous NADP-induced immune responses against biotrophic and necrotrophic pathogens in the Arabidopsis thaliana ecotype Columbia and found that NADP addition induces salicylic acid-mediated defense signaling but not jasmonic acid/ethylene-mediated defense responses. These results suggest the specificity of exogenous NADP-activated signaling in plants.

An Improved Square-always Exponentiation Resistant to Side-channel Attacks on RSA Implementation

AbstractMany cryptographic algorithms embedded in security devices have been used to strengthen home- land defense capability and protect critical information from cyber attacks. The RSA cryptosystem with the naive implementation of an exponentiation may reveal a secret key by two types of side-channel attacks, namely passive leakage information analysis and active fault injection attacks. Recently, a square-always exponentiation algorithm in which the multiplication is traded for squarings has been proposed. This novel algorithm for RSA implementation is faster than other regularity-based countermeasures and is resistant to SPA (simple power analysis) and fault injection attacks. This paper shows that the right-to-left version of square-always exponentiation algorithm is vulnerable to several side-channel attacks, namely collision distance-based doubling, chosen-message CPA (collision power analysis), and horizontal CPA-based combined attacks. Furthermore, an improved right-to-left square-always algorith...

ECDSA Passive Attacks, Leakage Sources, and Common Design Mistakes

Elliptic Curves Cryptography (ECC) tends to replace RSA for public key cryptographic services. ECC is involved in many secure schemes such as Elliptic Curve Diffie-Hellman (ECDH) key agreement, Elliptic Curve Integrated Encryption Scheme (ECIES), and Elliptic Curve Digital Signature Algorithm (ECDSA). As for every cryptosystem, implementation of such schemes may jeopardize the inherent security provided by the mathematical properties of the ECC. Unfortunate implementation or algorithm choices may create serious vulnerabilities. The elliptic curve scalar operation is particularly sensitive among these schemes. This article surveys passive attacks against well-spread elliptic curve scalar multiplication algorithms highlighting leakage sources and common mistakes that can be used to attack the ECDSA scheme. Experimental results are provided to illustrate and demonstrate the effectiveness of each vulnerability. Finally, the article describes the link between partial leakage and lattice attack in order to understand and demonstrate the impact of small leakages on the security of ECDSA. An example of side channel and lattice attack combination on NIST P-256 is provided in the case where the elliptic curve scalar multiplication is not protected against DPA/CPA and a controllable device is not accessible.

Purinergic Receptors in Thrombosis and Inflammation.

Under various pathological conditions, including thrombosis and inflammation, extracellular nucleotide levels may increase because of both active release and passive leakage from damaged or dying cells. Once in the extracellular compartment, nucleotides interact with plasma membrane receptors belonging to the P2 purinergic family, which are expressed by virtually all circulating blood cells and in most blood vessels. In this review, we focus on the specific role of the 3 platelet P2 receptors P2Y1, P2Y12, and P2X1 in hemostasis and arterial thrombosis. Beyond platelets, these 3 receptors, along with the P2Y2, P2Y6, and P2X7 receptors, constitute the main P2 receptors mediating the proinflammatory effects of nucleotides, which play important roles in various functions of circulating blood cells and cells of the vessel wall. Each of these P2 receptor subtypes specifically contributes to chronic or acute vascular inflammation and related diseases, such as atherosclerosis, restenosis, endotoxemia, and sepsis. The potential for therapeutic targeting of these P2 receptor subtypes is also discussed.

Atomistic Characterization of the First Step of Calcium Pump Activation Associated with Proton Countertransport

The calcium pump [sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA)] transports Ca(2+) from the cytosol to the SR lumen at the expense of ATP hydrolysis and proton countertransport, thus playing a central role in Ca(2+) homeostasis and muscle contractility. Proton countertransport via deprotonation of transport site residue Glu309 is a critical first step in SERCA activation because it accelerates the E2-E1 structural transition. Previous studies have suggested that flipping of Glu309 toward the cytosol constitutes the primary mechanism for Glu309 deprotonation, but no conclusive data to support this hypothesis have been published. Therefore, we performed three independent 1 μs molecular dynamics simulations of the E2 state protonated at transport site residues Glu309, Glu771, and Glu908. Structural analysis and pKa calculations showed that Glu309 deprotonation occurs by an inward-to-outward side-chain transition. We also found that Glu309 deprotonation and proton countertransport occur through transient (~113 ps) water wires connecting Glu309 with the cytosol. Although both mechanisms are operational, we found that transient water wire formation, and not Glu309 flipping, is the primary mechanism for Glu309 deprotonation and translocation of protons to the cytosol. The outward-to-inward transition of protonated Glu309 and the presence of water wires suggest that protons from the cytosol might be passively transported to the lumen via Glu309. However, structural analysis indicates that passive SR proton leakage into the lumen unlikely occurs through Glu309 in the E2 state. These findings provide a time-resolved visualization of the first step in the molecular mechanism of SERCA activation and proton transport across the SR.

Ionic Components of Wound Current at Mouse Skin Incisional Wounds

It has been assumed that skin wound currents are produced by passive ion leakage from wounded skin. However, what ions contribute to the skin wound current? Thirty male C57BL/6 mice were used in this study. A lancet wound (about 5mm in length) was made by cutting into the full thickness skin. We measured the dynamic time courses of individual ion flux with ion-selective probes at skin wound. The probe is aligned perpendicular to the surface of skin wound. All ions (Na+, Cl-, K+, Ca2+ and H+) showed a small steady efflux at unwounded mouse skin. However, there were large efflux of Na+, Cl-, K+, Ca2+ and H+ 15 minutes after wounding. These values maintained for 534 seconds, which were significantly higher than the ions flux of intact skin (P< 0.05). Our results suggest that Na+, Cl-, K+, Ca2+ and H+ contribute to the wound currents at skin wounds. A most significant observation is that the skin wound currents are carried mainly by the largest sodium and chloride efflux, then potassium, while the calcium and hydrogen are the least.

Influence of different trap solutions on the determination of root exudates in Lupinus albus L.

White lupin is very often used as a model plant for root exudation studies due to its capability to release huge amounts of organic acids and flavonoids. The complex nature of these organic compounds makes not only their analytical determination difficult but also their extraction from soil samples. For these reasons simplified approaches, as hydroponic-based systems are widely used to study the root exudation. Therefore, the composition of a trap solution is crucial to limit artefacts causing over/underestimation of exudation rates and/or a biased molecular composition of the collected compounds. The present study was aimed at assessing the influence of different trap solutions and collection times on the quali- and quantitative root exudation pattern of white lupin (Lupinus albus L.) grown under phosphorus (P) and iron (Fe) deficiency. Our results suggest that, in works aimed at studying root exudation processes, water is the most effective trap solution to collect the exudates like organic acids and flavonoids, especially in short time (e.g. 2 h). For longer times, low concentrations of Ca could be helpful to limit osmotic stress and possible passive leakage and/or diffusion. The use of bacteriostatic compounds as NaN3 and Micropur bias the results, due to interferences either with the metabolism or inhibition of the exudation processes, especially in the case of flavonoids such as quercetin. Also, the use of a pH buffer solution like 2-(N-morpholino)ethanesulfonic acid (MES) should be avoided for its undesired interferences with the release.

TEM_00 mode content measurements on a passive leakage channel fiber

Mode content measurements with a scanning ring cavity were performed in order to determine the TEM00 mode content of the output beam profile of a resonantly enhanced leakage channel fiber. The measurements were performed at 1.0 and 1.5 μm. In addition, the influence of different bending diameters as well as launching conditions has been investigated. Furthermore, a numerical simulation was used to determine the maximum theoretical TEM00 overlap, if only the fundamental fiber mode is guided. The simulation was also used to analyze how the TEM00 overlap for the case of any additional higher order fiber mode can be determined consistently.

Circulating microRNAs and long non-coding RNAs in gastric cancer diagnosis: An update and review.

Gastric cancer (GC) is the fourth most common cancer and the third leading cause of cancer mortality worldwide. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are the most popular non-coding RNAs in cancer research. To date, the roles of miRNAs and lncRNAs have been extensively studied in GC, suggesting that miRNAs and lncRNAs represent a vital component of tumor biology. Furthermore, circulating miRNAs and lncRNAs are found to be dysregulated in patients with GC compared with healthy individuals. Circulating miRNAs and lncRNAs may function as promising biomarkers to improve the early detection of GC. Multiple possibilities for miRNA secretion have been elucidated, including active secretion by microvesicles, exosomes, apoptotic bodies, high-density lipoproteins and protein complexes as well as passive leakage from cells. However, the mechanism underlying lncRNA secretion and the functions of circulating miRNAs and lncRNAs have not been fully illuminated. Concurrently, to standardize results of global investigations of circulating miRNAs and lncRNAs biomarker studies, several recommendations for pre-analytic considerations are put forward. In this review, we summarize the known circulating miRNAs and lncRNAs for GC diagnosis. The possible mechanism of miRNA and lncRNA secretion as well as methodologies for identification of circulating miRNAs and lncRNAs are also discussed. The topics covered here highlight new insights into GC diagnosis and screening.

High mobility group box 1 protein in the central nervous system

High-mobility group box 1 protein (HMGB1) is a multifunctional protein originally identified as a nuclear transcription modifier. Two pathways are leading to HMGB1 release to the extracellular space i.e. active secretion triggered by noxious stimulation and passive leakage due to necrotic membrane damage. Binding with receptors for advanced glycation end products (RAGE) as well as Toll-like receptor 2 (TLR2) and TLR4 leads to nuclear factor ?B (NF-?B) activation and proinflammatory reaction in target cells. Secretion of cytokines, upregulation of adhesion molecules and chemoattraction are triggered by the extracellular HMGB1. Such ubiquitous and numerous protein plays a role in pathogenesis of many common diseases like sepsis, rheumatoid arthritis and pneumonia. Central nervous system (CNS) disorders are also mediated by HMGB1. Multiple studies highlight pivotal role of HMGB1 in acute pathologies of CNS like cerebral ischemia, aneurysmal subarachnoid hemorrhage as well as chronic degenerative disorders such as Alzheimer’s disease and multiple sclerosis. Wide range of HMGB1 antagonists are currently investigated as novel therapeutic agents in sepsis, colitis and stroke. This review article provides basic information about HMGB1 protein and its role in the pathogenesis of CNS diseases.

Sharp reduction in maximum fuel temperatures during loss of coolant accidents in a PBMR DPP-400 core, by means of optimised placement of neutron poisons

In a preceding study, coupled neutronics and thermo-hydraulic simulations were performed with the VSOP-A diffusion code for the standard 9.6wt% enriched 9g uranium fuel spheres in the 400MWth Pebble Bed Modular Reactor Demonstration Power Plant. The axial power profile peaked at about a third from the top of the fuel core and the radial profile peaked directly adjacent to the central graphite reflector. The maximum temperature during a Depressurised Loss of Coolant (DLOFC) incident was 1581.0°C, which is close to the limit of 1600°C above which the leakage of radioactive fission products through the TRISO coatings around the fuel kernels may become unacceptable. This may present licensing challenges and also limits the total power output of the reactor.In this article the results of an optimisation study of the axial and radial power profiles for this reactor are reported. The main aim was to minimise the maximum DLOFC temperature. Reducing the maximum equilibrium temperature during normal operation was a lesser aim. Minimising the maximum DLOFC temperature was achieved by placing an optimised distribution of 10B neutron poison in the central reflector. The standard power profiles are sub-optimal with respect to the passive leakage of decay heat during a DLOFC. Since the radial power profile peaks directly adjacent to the central reflector, the distance that the decay heat needs to be conducted toward the outside of the reactor and the ultimate heat sink is at a maximum. The sharp axial power profile peak means that most of the decay power is concentrated in a small part of the core volume, thereby sharply increasing the required outward heat flux in this hotspot region. Both these features sharply increase the maximum DLOFC temperatures in this hotspot. Therefore the axial distribution of the neutron poisons in the central reflector was optimised so as to push the equilibrium power density profile radially outward and to suppress the axial power peak near the middle of the core, while increasing the power density near the top and bottom of the core. This resulted in a huge reduction in the maximum DLOFC temperature from 1581.0°C to 1297.6°C, which may produce far reaching safety and economic benefits. However, it came at the cost of a 22% reduction in the average burn-up of the fuel. In a separate optimisation attempt a much smaller, but still significant, reduction in the maximum equilibrium temperature, from 1023°C down to 988°C, was achieved.

Transcriptome Analysis Reveals Distinct Patterns of Long Noncoding RNAs in Heart and Plasma of Mice with Heart Failure

ObjectiveTo assess the global changes in and characteristics of the transcriptome of long noncoding RNAs (LncRNAs) in heart tissue, whole blood and plasma during heart failure (HF) and association with expression of paired coding genes.MethodsHere we used microarray assay to examine the transcriptome of LncRNAs deregulated in the heart, whole blood, and plasma during HF in mice. We confirmed the changes in LncRNAs by quantitative PCR.ResultsWe revealed and confirmed a number of LncRNAs that were deregulated during HF, which suggests a potential role of LncRNAs in HF. Strikingly, the patterns of expression of LncRNA differed between plasma and other tissue during HF. LncRNA expression was associated with LncRNA length in all samples but not in plasma during HF, which suggests that the global association of LncRNA expression and LncRNA length in plasma could be biomarkers for HF. In total, 32 LncRNAs all expressed in the heart, whole blood and plasma showed changed expression with HF, so they may be biomarkers in HF. In addition, sense-overlapped LncRNAs tended to show consistent expression with their paired coding genes, whereas antisense-overlapped LncRNAs tended to show the opposite expression in plasma; so different types of LncRNAs may have different characteristics in HF. Interestingly, we revealed an inverse correlation between changes in expression of LncRNAs in plasma and in heart, so circulating levels of LncRNAs may not represent just passive leakage from the HF heart but also active regulation or release of circulatory cells or other cells during HF.ConclusionsWe reveal stable expression of LncRNAs in plasma during HF, which suggests a newly described component in plasma. The distinct expression patterns of circulatory LncRNAs during HF indicate that LncRNAs may actively respond to stress and thus serve as biomarkers of HF diagnosis and treatment.

Effect of tip geometry and tip clearance on aerodynamic performance of a linear compressor cascade

The tip leakage flow between a blade and a casing wall has a strong impact on compressor pressure rise capability, efficiency, and stability. Consequently, there is a strong motivation to look for means to minimize its impact on performance. This paper presents the potential of passive tip leakage flow control to increase the aerodynamic performance of highly loaded compressor blades. Experimental investigations on a linear compressor cascade equipped with blade winglets mounted to the blade tips have been carried out. Results for a variation of the tip clearance and the winglet geometry are presented. Current results indicate that the use of proper tip winglets in a compressor cascade can positively affect the local aerodynamic field by weakening the tip leakage vortex. Results also show that the suction-side winglets are aerodynamically superior to the pressure-side or combined winglets. The suction-side winglets are capable of reducing the exit total pressure loss associated with the tip leakage flow and the passage secondary flow to a significant degree.

Incontinence in full‐thickness rectal prolapse: low level of improvement after laparoscopic rectopexy

The study aimed to quantify incontinence before and after laparoscopic rectopexy in patients suffering from rectal prolapse. Eighty-five patients underwent laparoscopic rectopexy to treat rectal prolapse between 2003 and 2009. Symptomatic and functional data were collected prospectively before and after surgery by self-administered questionnaires including the Cleveland Clinic Fecal Incontinence Score (CCIS) and constipation, gastrointestinal quality of life and urinary incontinence questionnaires. Incontinence was considered to be present when the CCIS remained at ≥ 5 after surgery. After a mean follow-up period of 36 months after surgery, 83% of the patients reported good to excellent results. Continence was improved in 58 (68%), with a significant decrease in the continence score (-3.4 ± 5.8, P = 0.001). However, 50 (58.9%) patients remained incontinent: 47 (55%) reported urge incontinence and 27 (32%) had passive leakage. Incontinence for liquid stool, incontinence for solid stool and the need for protection was seen in 43 (51%), 35 (41%) and 43 (51%) patients. Manometry, defaecography and ultrasonography were not associated with any improvement. In contrast, the patients' average age (60.2 ± 15.8 vs 46.9 ± 15.5 years; P = 0.003), symptom duration before surgery (58.1 ± 70.1 vs 29.5 ± 33.3 months; P = 0.011), preoperative urinary incontinence score (10.7 ± 10.8 vs 4.2 ± 5.7; P = 0.0131) and faecal incontinence score (12.9 ± 4.9 vs 7.1 ± 6; P < 0.0001) were significantly higher in patients suffering from postoperative incontinence. Despite some continence improvement in two-thirds of patients who underwent surgery for rectal prolapse, the level of improvement remained low in more than half of the patients.

The proteome of exudates from germinating Lupinus albus seeds is secreted through a selective dual‐step process and contains proteins involved in plant defence

The general knowledge of defence activity during the first steps of seed germination is still largely incomplete. The present study focused on the proteins released in the exudates of germinating white lupin seeds. During the first 24 h, a release of proteins was observed. Initially (i.e. during the first 12 h), the proteins found in exudates reflected the composition of the seed, indicating a passive extrusion of pre-formed proteins. Subsequently, when the rate of protein release was at its highest, the composition of the released proteome changed drastically. This transition occurred in a short time, indicating that more selective and regulated events, such as secretory processes, took place soon after the onset of germination. The present study considered: (a) the characterization of the proteome accumulated in the germinating medium collected after the appearance of the post-extrusion events; (b) the biosynthetic origin and the modalities that are the basis of protein release outside the seeds; and (c) an assessment of antifungal activity of these exudates. The most represented protein in the exudate was chitinase, which was synthesized de novo. The other proteins are involved in the cellular mechanisms responding to stress events, including biotic ones. This exudate was effectively able to inhibit fungal growth. The results of the present study indicate that seed exudation is a dual-step process that leads to the secretion of selected proteins and thus is not a result of passive leakage. The released proteome is involved in protecting the spermosphere environment and thus may act as first defence against pathogens.

Cardenolides in nectar may be more than a consequence of allocation to other plant parts: a phylogenetic study ofAsclepias

SummaryThe primary function of secondary plant metabolites is thought to be defence against herbivores. The frequent occurrence of these same noxious compounds in floral nectar, which functions primarily to attract pollinators, has been seen as paradoxical.Although these compounds may have an adaptive purpose in nectar, they may also occur as a nonadaptive consequence of chemical defence in other plant parts. If nectar chemistry reflects physiological constraints or passive leakage from other tissues, we expect that the identity and relative concentration of nectar cardenolides to be correlated with those of other plant parts; in contrast, discordant distributions of compounds in nectar and other tissues may suggest adaptive roles in nectar.We compared the concentrations and identities of cardenolides in the nectar, leaves and flowers of 12 species from a monophyletic clade ofAsclepias. To measure putative toxicity of nectar cardenolides, we then examined the effects of a standard cardenolide (digoxin) on the behaviour of bumblebees, a common generalist pollinator ofAsclepias.We found that the average cardenolide concentrations in nectar, leaves and flowers of the 12Asclepiasspecies were positively correlated as predicted by nonadaptive hypotheses. However, significant differences in the identities and concentrations of individual cardenolides between nectar and leaves suggest that the production or allocation of cardenolides may be independently regulated at each plant part. In addition, cardenolide concentrations in leaves and nectar exhibited no phylogenetic signal.Surprisingly, bumblebees did not demonstrate an aversion to digoxin‐rich nectar, which may indicate that nectar cardenolides have little effect on pollination.Although the idea that discordant patterns of secondary metabolites across tissue types may signal adaptive functions is attractive, there is evidence to suggest constraint contributes to nectar secondary chemistry. Further work testing the ecological impacts of such patterns will be critical in determining the functional significance of nectar cardenolides.

An intra-cerebral drug delivery system for freely moving animals

Microinfusions of drugs directly into the central nervous system of awake animals represent a widely used means of unravelling brain functions related to behaviour. However, current approaches generally use tethered liquid infusion systems and a syringe pump to deliver drugs into the brain, which often interfere with behaviour. We address this shortfall with a miniaturised electronically-controlled drug delivery system (20 × 17.5 × 5 mm³) designed to be skull-mounted in rats. The device features a micropump connected to two 8-mm-long silicon microprobes with a cross section of 250 × 250 μm² and integrated fluid microchannels. Using an external electronic control unit, the device allows infusion of 16 metered doses (0.25 μL each, 8 per silicon shaft). Each dosage requires 3.375 Ws of electrical power making the device additionally compatible with state-of-the-art wireless headstages. A dosage precision of 0.25 ± 0.01 μL was determined in vitro before in vivo tests were carried out in awake rats. No passive leakage from the loaded devices into the brain could be detected using methylene blue dye. Finally, the device was used to investigate the effects of the NMDA-receptor antagonist 3-((R)-2-Carboxypiperazin-4-yl)-propyl-1-phosphonic acid, (R)-CPP, administered directly into the prefrontal cortex of rats during performance on a task to assess visual attention and impulsivity. In agreement with previous findings using conventional tethered infusion systems, acute (R)-CPP administration produced a marked increase in impulsivity.

A New Class of Purple Membrane Variants for the Construction of Highly Oriented Membrane Assemblies on the Basis of Noncovalent Interactions

Purple membranes (PM) from Halobacterium salinarum have been discussed for several technical applications. These ideas started just several years after its discovery. The biological function of bacteriorhodopsin (BR), the only protein in PM, is the light-driven proton translocation across the membrane thereby converting light energy into chemical energy. The astonishing physicochemical robustness of this molecular assembly and the ease of its isolation triggered ideas for technical uses. All basic molecular functions of BR, that is, photochromism, photoelectrism, and proton pumping, are key elements for technical applications like optical data processing and data storage, ultrafast light detection and processing, and direct utilization of sunlight in adenosine 5'-triphospate (ATP) generation or seawater desalination. In spite of the efforts of several research groups worldwide, which confirmed the proof-of-principle for all these potential applications, only the photochromism-based applications have reached a technical level. The physical reason for this is that no fixation or orientation of the PMs is required. The situation is quite different for photoelectrism and proton pumping where the macroscopic orientation of PMs is a prerequisite. For proton pumping, in addition, the formation of artificial membranes which prevent passive proton leakage is necessary. In this manuscript, we describe a new class of PM variants with oppositely charged membrane sides which enable an almost 100% orientation on a surface, which is the key element for photoelectric applications of BR. As an example, the mutated BR, BR-E234R7, was prepared and analyzed. A nearly 100% self-orientation on mica was obtained.

Arsenic accumulation and speciation in the submerged macrophyte Ceratophyllum demersum L.

Ceratophyllum demersum L. is a widespread submerged macrophyte in aquatic environments. Simulation experiments were conducted in the laboratory to investigate arsenic (As) accumulation, speciation, and efflux of C. demersum exposed to arsenate and arsenite solutions. Plant shoots showed a significant accumulation of As with a maximum of 862 and 963μgAsg(-1) dry weight after 4days of exposure to 10μM arsenate and arsenite, respectively. Regardless of whether arsenate or arsenite was supplied to the plants, arsenite was the predominant species in plant shoots. Furthermore, a dramatically higher influx rate of arsenate compared with arsenite was observed in C. demersum exposed to As solutions without the addition of phosphate (P). Arsenate uptake was considerably inhibited by P in this study, suggesting that arsenate is taken up by C. demersum via the phosphate transporters. However, arsenite uptake was unaffected by P and markedly reduced in the presence of glycerol and antimonite (Sb), indicating arsenite shares the aquaporin transport pathway. In addition, C. demersum rapidly reduces arsenate to arsenite in the shoot of the plant and extrudes most of them (>60%) to the external solutions. The efflux of arsenite was much higher than that of arsenate; the former is supposed to be both active and passive processes, and the latter through passive leakage. C. demersum is a strong As accumulator and an interesting model plant to study As uptake and metabolism due to the lack of a root-to-shoot translocation barrier.