Pressure Off Research Articles

Taking the pressure off

Ammonia holds promise as a clean energy carrier, but its synthesis requires high pressures and large production scales that are ill-matched to renewable, decentralized energy production. Now, researchers use metal imides to mediate ammonia production in a chemical looping process that operates under mild conditions.

Bilateral simultaneous acute angle closure in an adult Nepalese woman

Purpose: To report a case of bilateral simultaneous angle closure in an adult Nepalese woman without any known secondary cause.
 Methods: Observational case report.
 Results: A 50-year-old Nepalese woman presented with decreased vision, pain, redness, and watering in both eyes with associated coloured haloes, nausea, and vomiting for 10 days. At presentation, her visual acuity was 20/400 in the right eye and hand motions close to face with accurate projection of rays in the left eye. Intraocular pressure was 38 mmHg in the right eye and 48 mmHg in the left eye without any antiglaucoma medications. A slit-lamp examination revealed bilateral circum-corneal conjunctival congestion, corneal edema, and shallow anterior chambers. Both pupils were mid-dilated and non-reactive to light. Gonioscopy showed closed angles in all four quadrants bilaterally. Posterior segment examination revealed normal optic disc with cup-disc-ratio of 0.3 in the right eye, and blurring of disc margin with cup-disc-ratio of 0.3 in the left eye. The patient was started on systemic acetazolamide 250 mg 4 times a day, topical brimonidine 0.2% and timolol 0.5% 2 times a day, and topical dexamethasone 6 times a day in both eyes, following which IOP reduced to 11 and 12 mmHg, respectively, the corneal edema subsided, but the anterior chamber remained shallow. Laser peripheral iridotomy was performed in the right eye and surgical peripheral iridectomy was performed in the left eye. After two weeks, vision improved to 20/30 in both eyes with normal intraocular pressure off antiglaucoma medications. Anterior chambers deepened significantly with clear corneas bilaterally. Gonioscopy at this stage showed essentially open angles with appositional closure in superior and temporal quadrants in the right eye and open angles in all four quadrants in the left eye. Posterior segment evaluation revealed normal optic disc in both eyes.
 Conclusions: Bilateral simultaneous acute angle closure is a rare presentation with very few reported secondary causes. We report a case of bilateral simultaneous angle closure in an adult Nepalese woman without any known secondary cause. The case was successfully managed with laser peripheral iridotomy in the right eye and surgical peripheral iridectomy in the left eye.

How Valuable Are Organic Amendments as Tools for the Phytomanagement of Degraded Soils? The Knowns, Known Unknowns, and Unknowns

Soils functionality (health) and productivity (quality) are severely impaired by the rapid growth of human population and by the fact that most of the cultivable land is intensively used, whether for urbanization or for meet the food requirements, with the consequent rise in solid and liquid wastes and consumption of agricultural soils. However, these issues, far from being independently handled, can be jointly addressed by an integrated and sustainable management of soil resource in the framework of circular economy and phytomanagement. Currently immersed in resource-conserving and regenerative (urban) land management, three fundamental aspects are looked after together: (i) the valorization and safe recovery of organic wastes (e.g. composts, green and animal manures, and biosolids) as soil amendments to abate their landfilling (from residue to resource); (ii) the re-development of degraded soils, often characterized by low organic matter, deficient physical structure and depressed biological status, to keep pressure off agricultural soils (from bare to vegetated soil), and finally; (iii) the promotion of soils health in order to support soil processes and ecosystem services at long-term (integration of ecological and anthropocentric perspectives). Through this review we renewed attention in the benefits (knows), potential risks (known unknowns) and future/affordable uncertainties (unknowns) resulting from soil application of organic amendments (OAs). Traditionally, most studies have used phycal-chemical parameters to assess soil health/quality, whereas less focus has been given to soil biological properties. We highlight the relevance of soil biological properties -both below and above-ground- as key drivers of soil reclamation and hence as more suitable estimators of soil health. Notwithstanding, special attention should be paid on “amendment-plant-microorganism” tripartite interactions. Using a phytomanagement strategy, here we presented a pilot field study that encompasses the addition of bio-stabilized material resulted from mechanical-biological treatment of Municipal Solid Wastes be used in a peri-urban vacant soils with a dual aim of grow biofuel crops and restore soils health. Our results prove that this phytomanagement approach not only would involve positive environmental synergies but also the return of important economic and social gains to degraded landscapes.

Patterns of gene expression in larvae of the giant grouper.

The giant grouper Epinephelus lanceolatus (Bloch 1790) is the largest bony fish found on coral reefs, achieving lengths of over 2 m. It has delicious flesh that is highly prized by the live reef fish trade. Consequently, declining wild populations have been listed as Vulnerable by IUCN. There is now aquaculture of E. lanceolatus but, as is often the case for marine fishes, larval feeding is a major production bottleneck. In particular, knowing how the digestive system develops and how this might determine the feed that larvae can digest to grow satisfactorily. In this issue, Anderson et al. (2018) used a transcriptomic approach to explore molecular processes that underpin development of appetite, feeding and digestion in E. lanceolatus larvae. They focussed on the first two weeks of life, a critical period for larval husbandry during which the larvae first open their mouth and start exogenous feeding. Because transcriptomics typically yield a very large quantity of information, the challenge is to reveal patterns. The authors used Self Organising Maps to hone in on genes that contribute to specific developmental milestones. They developed a conceptual model to show patterns of expression of transcripts in relation to major developmental stages, such as mouth-opening, onset of exogenous feeding, swim bladder development. There were clear trends for digestive enzyme transcripts, which tended to increase their expression in concert with mouth-opening and onset of exogenous feeding. Gene expression for various appetite-regulating factors was highly variable although, in some cases, this could be linked to important developmental milestones. Although such studies are inductive, they provide an essential knowledge base for development of targeted hypothesis-driven research. A major objective would be to find means of improving growth and survival of larvae without having to rely on feeding with copepods, which are expensive to produce in large quantities. Such improvements in methods for larval husbandry, in the farming of this highly-prized species, will take pressure off vulnerable wild stocks. The authors commented that Self Organising Maps can be applied to any project generating high volumes of multi-dimensional data, and are especially useful for time-course studies and pattern visualisation. As such, fish biologists are able to use this approach to more easily hone in on genes that contribute to specific developmental milestones, phenotype, mortality event, whose expression changes in response to particular stimuli.

Family bliss or blitz? Parents’ and children’s mixed emotions towards family holidays

PurposeThis paper aims to explore mixed emotions experienced by parents and children on holiday, how they are dealt with and how they influence the way “family” is “staged” and “done”.Design/methodology/approachThis paper draws on 24 qualitative interviews with Danish parents and a questionnaire study reporting answers from 66 Danish children (11-15-year-old).FindingsProblems external and internal to the family are identified and the latter are associated with more unease particularly among parents. This paper shows that parents invest significant narrative efforts in transcending gaps between ideals and practices. Also children are aware of the gaps between ideals and practices; they seem more matter-of-fact, however, regarding critical aspects of holidays.Research limitations/implicationsThe informants of the study solely represent two-parent hetero-sexual families of Danish origin, and so inclusion of a wider range of families would have added interesting perspectives. Furthermore, children’s perspectives on critical holiday incidents need further research.Practical implicationsCreators of family holiday products and marketing should present a more nuanced imagery taking a more diverse approach to what “family” on holiday looks like. They could take up the challenge of depicting a broader range of family situations, also showing less harmonious moments, using humour, and showing opportunities for some “alone time” for both parents and children should relational overload happen. Also occasional “wifi-free” moments seem to be much appreciated by all family members, and development of offline family experiences would seem to strike a chord.Social implicationsThe contemporary paradigm of intensive parenting along with strong ideals for family holidays make it essential for parents to narratively deal with and legitimize and transform less happy moments. To take pressure off contemporary families, it is important to bring to the fore the less glossy aspects of family holidays.Originality/valueThe originality of this paper is to illustrate the strong efforts applied by families to keep up a certain front to be the family that “ought to be” by nurturing and narrating positive emotions in relation to family holidays. The inclusion of children’s voices gives insights into children’s annoyance with parents’ rowing, relational overload and parents’ occasional lack of attention to children, for example through parental use of mobile phones during holiday togetherness.

Reproductive biology of the brown smooth-hound shark, Mustelus henlei (Chondrichthyes: Triakidae), off northwestern Mexico based on macroscopic and histological analyses

The brown smooth-hound shark Mustelus henlei is one of the most abundant species caught by the artisanal elasmobranch fishery off northwestern Mexico. The present study estimates the reproductive parameters for M. henlei using, for the first time, histological analysis and survey data collected from May 2008 to May 2016. Mustelus henlei was reported in the landings from February to November each year (n = 1,469). Total length (TL) varied between 450 and 1,530 mm (average = 753 mm, SD = 111). The sex ratio (male:female) was similar to the 1:1 ratio. Gravid females were caught during April, August, and November. Average fecundity was 9. Length at maturity was 656 mm TL for females and 636 mm TL for males, and length at maternity, estimated for the first time for this species, was 676 mm TL. The first phases of spermatogenesis and oogenesis were identified through histological analysis of gonads from immature individuals. Semen storage was detected in the oviducal gland of females at the terminal zone, whereas in males spermatozeugmata was detected in the seminal vesicles. According to the species reproductive parameters, M. henlei can be categorized as a species of high biological productivity among elasmobranchs and can thus support certain level of fishing pressure off northwestern Mexico if adequate fishing management and regulatory measures are employed. Some of the reproductive parameters that were estimated for this species in the present study were different from those estimated for other stocks from Mexican and United States waters.
 Key words: reproduction, length at maturity, length at maternity, semen storage, Mustelus henlei.

Digital hydraulic drive for microfluidics and miniaturized cell culture devices based on shape memory alloy actuators

In order to culture and analyze individual living cells, microfluidic cultivation and manipulation of cells become an increasingly important topic. Such microfluidic systems allow for exploring the phenotypic differences between thousands of genetically identical cells or pharmacological tests in parallel, which is impossible to achieve by traditional macroscopic cell culture methods. Therefore, plenty of microfluidic systems and devices have been developed for cell biological studies like cell culture, cell sorting, and cell lysis in the past. However, these microfluidic systems are still limited by the external pressure sources which most of the time are large in size and have to be connected by fluidic tubing leading to complex and delicate systems. In order to provide a miniaturized, more robust actuation system a novel, compact and low power consumption digital hydraulic drive (DHD) has been developed that is intended for use in portable and automated microfluidic systems for various applications. The DHD considered in this work consists of a shape memory alloy (SMA) actuator and a pneumatic cylinder. The switching time of the digital modes (pressure ON versus OFF) can be adjusted from 1 s to min. Thus, the DHDs might have many applications for driving microfluidic devices. In this work, different implementations of DHDs are presented and their performance is characterized by experiments. In particular, it will be shown that DHDs can be used for microfluidic large-scale integration (mLSI) valve control (256 valves in parallel) as well as potentially for droplet-based microfluidic systems. As further application example, high-throughput mixing of cell cultures (96 wells in parallel) is demonstrated employing the DHD to drive a so-called ‘functional lid’ (FL), to enable a miniaturized micro bioreactor in a regular 96-well micro well plate.

Comparison of sprinting vs non-sprinting to wean nasal continuous positive airway pressure off in very preterm infants.

Though nasal continuous positive airway pressure (NCPAP) is commonly used for non-invasive neonatal respiratory support, the optimal method of weaning NCPAP is not established. In this prospective, two-center randomized control trial we hypothesize that gradually increasing spontaneous breathing time off NCPAP increases successful weaning from NCPAP in infants born <31 weeks gestational age. Infants were randomized to one of the two NCPAP weaning protocols, a sprinting, that is, gradually increasing spontaneous breathing time off CPAP, protocol vs a non-sprinting (weaning pressure down) protocol. Eighty-six infants were enrolled in one of the two study groups. Thirty-one infants (77%) in the sprinting group and 30 (75%) in the non-sprinting group were successfully weaned off NCPAP at the first attempt (P>0.05). It took 1.3 (1 to 1.75) (median (IQR)) attempts and 7 (7 to 7) days to wean NCPAP off in the sprinting group vs 1.3 (1 to 1.75) attempts and 7 (7 to 10) days in the non-sprinting group (P>0.05). Additionally, no differences in the secondary outcomes of bronchopulmonary dysplasia, severe retinopathy of prematurity (⩾stage 3), periventricular leukomalacia and length of stay were noted between the two groups. Weaning NCPAP via sprinting or non-sprinting protocol is comparable, not only for successful weaning but also for the occurrence of common neonatal morbidities that impact the long-term outcome in premature infants (ClinicalTrials.gov number, NCT02819050).

An evaluation of the prevalence of Diabetes and Pre-Diabetes in a Cardiac Rehabilitation nurse led PCI clinic at University Hospital Limerick

Introduction: It is estimated that there are approximately 190,000 people in Ireland with diabetes, with type 2 diabetes accounting for approximately 90% of all cases. The Institute of Public Health predicts that the prevalence of diabetes will increase from 4.5% in 2007 to 5.9% of the population by 2020. Recent data shows 5.5% adults aged 50 years and over in Ireland have pre-diabetes, placing them at increased risk of developing type 2 diabetes in the future. Purpose: We set out to evaluate the prevalence of Diabetes & Pre-Diabetes in patients attending the nurse-led Percutaneous Coronary Intervention (PCI) clinic by Cardiac Rehabilitation nurses at UHL and the management/follow-up of these patients once diagnosed. Methods: All patients discharged from the Cardiology department in UHL following PCI are reviewed at the PCI clinic by Cardiac Rehabilitation nurses 4-6 weeks later where Fasting Glucose (FG) & HbA1c were reserved. All patients who attended the Cardiac Rehabilitation nurse led PCI clinic at UHL from Jan 2015 – Sept 2016 were included in this audit (N = 734 patients). Results: A total of 734 patients were included, mean age 65 years. There were significantly more male patients (n=553) than females (n=180). Indication for PCI were as follows: STEMI (n= 176), NSTEMI (n= 150), Angina (n= 330), Dyspnoea (n= 26), Syncope (n= 18), Other (n= 34). There were 107 known diabetic patients in this cohort (14.6% of total patients), mean HbA1c – 63mmol/mol & mean FG 9.3mmol/L. However, of interest was the proportion of patients newly diagnosed as diabetic on the basis of this test. 113 patients had HbA1c ≥48mmol/L and a further 91 patients had FG ≥ 7mmol/L. This resulted in 204 patients (33%) being diagnosed as diabetic. Furthermore, we analysed results of patients in the ‘pre-diabetes’ range - HbA1c 42-47 &/or FG 6.1-6.9. This yielded very interesting results. 140 (22%) patients had HbA1c 42-47mmol/mol & a further 57 (9%) patients had FG 6.1-6.9mmol/L. This resulted in a further 31% of patients being categorized as ‘pre-diabetes’. Patients newly diagnosed Diabetic & those in the Pre-Diabetes range are primarily referred back to their GP - the Cardiac Rehabilitation CNS will write to GP with results and request follow-up. The Cardiac Rehabilitation CNS has forged links with community programmes – DESMOND and CODE where patients can be referred by the CNS directly for further education and support. Conclusion: It is estimated that each year, the Irish state spends €350m on Diabetes care, 59% of which is spent on treating the complications of the disease. Early identification of patients and initiation of treatment can reduce the development of complications of diabetes and therefore testing for diabetes in high risk asymptomatic patients is recommended & very beneficial. The integrated care with community programmes takes pressure off hospital services and ensures a high level of care to patients in the community. References available on request .

Keynoter: Stress Is Inevitable, so Learn to Love It

Keynoter: Stress Is Inevitable, so Learn to Love It

Optimising BP measurement and treatment before elective surgery: taking the pressure off

Optimising BP measurement and treatment before elective surgery: taking the pressure off

Multiple Factors Affect Socioeconomics and Wellbeing of Artisanal Sea Cucumber Fishers.

Small-scale fisheries are important to livelihoods and subsistence seafood consumption of millions of fishers. Sea cucumbers are fished worldwide for export to Asia, yet few studies have assessed factors affecting socioeconomics and wellbeing among fishers. We interviewed 476 men and women sea cucumber fishers at multiple villages within multiple locations in Fiji, Kiribati, Tonga and New Caledonia using structured questionnaires. Low rates of subsistence consumption confirmed a primary role of sea cucumbers in income security. Prices of sea cucumbers sold by fishers varied greatly among countries, depending on the species. Gender variation in landing prices could be due to women catching smaller sea cucumbers or because some traders take advantage of them. Dissatisfaction with fishery income was common (44% of fishers), especially for i-Kiribati fishers, male fishers, and fishers experiencing difficulty selling their catch, but was uncorrelated with sale prices. Income dissatisfaction worsened with age. The number of livelihood activities averaged 2.2–2.5 across countries, and varied significantly among locations. Sea cucumbers were often a primary source of income to fishers, especially in Tonga. Other common livelihood activities were fishing other marine resources, copra production in Kiribati, agriculture in Fiji, and salaried jobs in New Caledonia. Fishing other coastal and coral reef resources was the most common fall-back livelihood option if fishers were forced to exit the fishery. Our data highlight large disparities in subsistence consumption, gender-related price equity, and livelihood diversity among parallel artisanal fisheries. Improvement of supply chains in dispersed small-scale fisheries appears as a critical need for enhancing income and wellbeing of fishers. Strong evidence for co-dependence among small-scale fisheries, through fall-back livelihood preferences of fishers, suggests that resource managers must mitigate concomitant effects on other fisheries when considering fishery closures. That is likely to depend on livelihood diversification programs to take pressure off co-dependent fisheries.

Effect of Model Fuel Impurities for Reformed Jet Fuels on the Hydrogen Oxidation at Platinum Based Catalyst under HT-PEMFC Conditions

Jet fuels like the Jet-A and Jet-A1 fuel for commercial aviation or the military JP-8 fuel are important fuels for many types of application. Recently the replacement of these fuels by synthetic drop-in fuels is being considered. As fuel cell based auxiliary power units are of interest in many of the applications using jet fuels for the main propulsion, the question arises if avoiding some of the impurities which need to be expected in reformed fossil jet fuels can enhance the operation of the fuel cells. To further investigate this question tests have been performed on catalyst and single cell level. Catalyst tests were performed with commercial 20 wt.% Pt/C catalyst from Johnson & Matthey using circular gas diffusion electrodes with about 1 cm diameter which were mounted in a special test cell allowing for inline mass spectrometry during the electrochemical characterisation (1, 2). Parts of the measurements were verified by single cell measurements in a commercial fuel cell test bed (Evaluator C050, Fuelcon AG, Germany). The tested MEAs were commercially procured from either Danish Power Systems (Denmark) or Advent (Greece). For the tests an accelerated stress tests based on start-stop cycling described elsewhere (3) was employed. Three types of impurities were considered each represented by one or two model substances. The first class of impurities are alkenes which can result from the reforming of hydrocarbon fuels of any composition. The effect of alkenes was studied using ethene as model substance. The second type of impurities is aromatic compounds which are contained in fossil jet fuels but not in all replacement fuels. The effect of aromatic compounds was tested with toluene. The last type of impurities is sulphurous compounds which are not prersent in most replacement fuels. Here two types of model substances were investigated. Beside hydrogen sulphide thiophene was tested in combination with toluene as it is both an aromatic compound and a sulphur organic compound. Gaseous impurities were tested using pre-mixed gases purchased from Linde-Gase Germany. Toluene and thiophene were added by bubbling the gas feed through a flask with the toluene solution containing thiophene at ambient temperature so that the saturation partial pressure off 2.9 kPa should have been established. The addition of small amounts of ethene two the hydrogen feedstock caused slightly increased currents in the catalyst testing. The MS data also showed a slight increase of the CO2 production at high potentials (cf. fig 1). Tests with Advent MEAs and hydrogen with 10 ppm of ethene confirmed that no effect became apparent during the test phase of 130 start-stop cycles (cf. fig 2). At low potentials toluene has no effect of the hydrogen oxidation at Pt/C catalyst. At high potentials the activity is however slightly reduced (cf. fig 3). This reduction could be attributed to the oxidation of the thiophene which was present in the toluene. This can be concluded from the observed reduction of the thiophene peak at m/z 83 in the mass spectrum at the relevant potentials shown in fig 4. The effect of H2S has already been studied by Schmidt and Baurmeister (4) as well as by our group (2, 5). On single cell level H2S concentration of 10 – 20 ppm can be tolerated for Pt/C anodes. In total sulphur remains to be the most critical impurity if it occurs at to high concentrations, smaller amounts even of sulphur-aromatic compounds can however be tolerated. The use of fuel cells should thus profit from the introduction of sulphur reduced drop in fuels. In the contribution further results of ongoing single cell tests will be reported. Acknowledgements Financial support by the German Federal Ministry of Defence, Bundeswehr Research Institute for Materials, Fuels and Lubricants (WIWeB) under contract E/E210/AF020/CF062 is gratefully acknowledged. The authors would like to thank Ms. Florian Jung for her support in electrode preparation.

“It just took the pressure off”: The voices of Veterans’ family caregivers in a participant-directed program

ABSTRACTThe Veteran-Directed Home and Community Based Services Program (VD-HCBS) operates using a participant-direction approach, allowing Veterans to self-direct services. Only a small body of literature has explored the impact of these programs on caregivers. This study aimed to explore the experiences of caregivers in VD-HCBS. Telephone focus groups and interviews were conducted with caregivers (n = 23; 52.2% spouses; 8.7% male). Conventional content analysis revealed five categories: Coming home and staying home; Taking the pressure off; Providing security; Giving us time as a couple; and Importance of choice. Stories highlighted sources of stress and mechanisms behind stress relief and support.

Optimizing the Coating Method for Improved Process Control of Silicon/Carbon Composite Anodes

Silicon is often studied as an alternative to graphite for negative electrodes in lithium-ion battery technology due to its high theoretical specific capacity (3579 mAh/g [1]). However, silicon expands during lithiation, which leads to fast degradation and limited practical use of silicon-based anodes. In order to overcome these challenges a deeper understanding of the degradation mechanisms is needed. However, a common problem with electrode testing is the lack of control of factors such as thickness and loading which effectively conceals the variation in degradation behavior of silicon. A change in the silicon treatment is often concealed by more prominent factors such as loading and thickness variations. To better understand the influence of the silicon material and electrode preparation a better control of these factors is needed, i.e. improving the “signal-to-noise ratio” by improving the process control. All components used in the electrode and the interaction between them will influence the processes towards the resulting battery cell. The current work focuses on optimizing one of these processes to improve the homogeneity of the electrode. The coating method can give severe differences in both thickness and loading properties, and it is of great importance to keep these differences as low as possible. Only cells with similar loading and thickness can give comparable results and yield better understanding of the degradation mechanisms in the silicon anodes. In the search of a uniform electrode, the coating methods play a large role and can be optimized. For laboratory based research, tape casting is often the preferred method as it requires simple equipment and the material consumption is low. An alternative coating method is screen printing which has been applied in various industries, such as clothing, photovoltaics and printed electronics due to the low cost and reliable quality. This work compares silicon-based electrodes prepared with two coating methods; tape casting and screen printing. A water-based mixture of 60 % silicon (0.3 µm, produced at IFE [2]), 10 % graphite (KS6L), 15 % carbon black (Super C65) and 15 % binder (CMC) was prepared and deposited on a structured copper foil with the two different coating techniques. Tape casting was used as a reference method, while parameters for the screen printing process, such as mesh size, printing speed, pressure and snap off, were varied to achieve thickness and loading variations. Issues such as slurry preparation and slurry requirements, cleaning procedure and ease of electrode preparation were compared. The electrodes were analyzed in terms of morphology (cross section and surface), resistance, adhesion testing, thickness and loading parameters as well as final cycling properties. Initial results show a more homogeneous thickness distribution from the screen printed electrode, and the loading variations in terms of active material per area are accordingly decreased. The beneficial homogeneity in thickness distribution for the screen printing can be seen in the attached figure, while the electrode coated via tape casting shows a higher variation in thickness over the entire electrode. The improved control of thickness and loading for the screen printed electrodes led to an improved understanding of the degradation mechanism of the electrodes as the noise in cycleability results was reduced. [1] U. Kasavajjula et al. J. Power Sources 163 (2007) 1003-1039 [2] H. F. Andersen et al. ECS Trans. 62(1) (2014) 97–105 Figure 1

Collaboration in neuroscience: the young PI perspective

Collaboration in neuroscience: the young PI perspective

The self-assemble of natural cyclodextrins in aqueous solutions: Application of miniature permeation studies for critical aggregation concentration (cac) determinations

Permeation techniques can be applied to determine the critical aggregation concentration (cac) of natural cyclodextrins (CDs) in aqueous solutions although the method is both laborious and time consuming. In the present study, the permeation technique was modified and the influence of osmotic pressure, sampling time, CD concentration and molecular weight-cut off (MWCO) of the membrane were investigated in two different permeation units, that is Franz diffusion cells and Slide-A-Lyzer™ MINI Dialysis. While both the osmotic pressure and CD concentration affect the steady state flux in both permeation units, effects of sampling time and the MWCO of the mounted membrane were only observed in the Franz diffusion cells. The osmotic effect was negligible in the Slide-A-Lyzer™ MINI Dialysis units. The modified permeation technique using Slide-A-Lyzer™ MINI Dialysis units was then used to determine the cac of natural CDs in water. The cac of αCD, βCD and γCD was 1.19±0.17, 0.69±0.05 and 0.93±0.04% (w/v), respectively. The results indicated that the cac values depended on their intrinsic solubility. Moreover, the cac value of γCD in aqueous hydrocortisone/γCD inclusion complex solution was identical to the γCD cac value determined in pure water.

Is in vitro micrografting a possible valid alternative to traditional micropropagation in Cactaceae? Pelecyphora aselliformis as a case study.

Several taxa of Cactaceae are endangered by overcollection for commercial purposes, and most of the family is included in the Convention on International Trade in Endangered Species of Fauna and Flora (CITES). Micropropagation may play a key role to keep the pressure off wild populations and contribute to ex situ conservation of endangered taxa. One of the limits of micropropagation is the species-specific requirement of plant regulators for each taxon and sometimes even for different genotypes. With the micrografting technique the rootstock directly provides the scion with the necessary hormonal requirements. In this paper we present data on in vitro grafting of Pelecyphora aselliformis Ehrenberg, an Appendix I CITES listed species critically endangered and sought after by the horticultural trade, on micropropagated Opuntia ficus-indica Miller. Apical and sub-apical scions of P. aselliformis were used to perform micrografting with a successful rate of 97 and 81 % respectively. Survival rate after ex vivo transfer was 85 %. We hypothesize that this method could be applied to other endangered, slow growing taxa of Cactaceae thus contributing to the conservation of this endangered family.

What can we do to hold back the waters? [Natural flood defences

Simple measures to slow down the outflow from river catchments can take the pressure off floodprone towns. Computer models hold the key to getting it right. By Christine Evans-Pughe.

EDTA fouling in dead-end ultrafiltration of low level radioactive wastewater

EDTA is widely used as a detergent, and finally enters into wastewater. The influence of EDTA on ultrafiltration of low level radioactive wastewater (LLRW) was investigated under different operation conditions. As the main organic pollutant, EDTA led to unrecoverable membrane fouling and the normalized flux decreased from 100% to 85% depending on its concentration. The clogging caused by EDTA increased the surface roughness of the membrane, leading to the flux reduction. Both nuclide rejections and depositions on the membrane surfaces were enhanced with EDTA addition, due to the strong complexation of the nuclides with EDTA. However, Ag deposition on the membrane decreased slightly in the presence of EDTA, which may be caused by the stronger attraction of Ag to the unmodified membrane than that to the EDTA-modified one. Transmembrane pressure (TMP) and molecular weight cut off (MWCO) of membranes had negligible effects on membrane fouling, while the nuclide rejections by membrane and the depositions of nuclides on membrane both decreased significantly when the TMP increased to 0.2MPa and MWCO increased from 5kDa to 30kDa. Based on these results, it clearly showed that EDTA even at a low concentration had strong effects on the performance of UF treating LLRW. Therefore, it is suggested for industrial application that pretreatments to reduce EDTA or alkaline/ultrasonic washing involved in UF process were necessary to reduce the nuclide depositions on the membrane surfaces and irradiation dose of membrane surface.