Retention System Research Articles

Priority areas for the development of field fodder production in view of the climate crisis

This article covers the topical issue of the general impact of climate change on Ukrainian agriculture and on the field fodder production industry specifically, as well as the problems of adapting agriculture to modern environmental conditions. The authors set out to substantiate promising ways of developing modern field fodder production considering climate change. For this, the study employed the abstract-logical method, system analysis, methods of systematisation and classification, and a range of economic and statistical research methods (comparison, series of dynamics, method of structural groupings). Both negative and positive manifestations of the climate crisis in crop production were highlighted, and possible measures to counteract risks and ways to use potential opportunities to develop field fodder production given the impact of climate change were systematised. Particular attention was paid to the global practices of agriculture in the face of climate change, namely, the components of a climate-smart crop production system. The study also described the main promising measures of adaptation of field fodder production to climate change: irrigation of agricultural land, arrangement of snow retention systems in the fields, rainwater harvesting, selection and introduction of new varieties of fodder crops, effective crop rotation, increase in sowing of drought-resistant fodder crops, optimisation of agricultural technologies to reduce losses of fodder crops at the stages of harvesting and storage, application of organic farming, the latest soil fertilisation technologies and the use of nanotechnology in soil cultivation. The findings of this study can be used by managers of specific agricultural enterprises, as well as by advisory services and government agencies in the field of agricultural policy implementation.

Assessment of Efficacy of Various Bracket Base Retention Qualities on Shear Bond Strength.

Numerous manufacturers have improved bracket retention systems as a result of the frequent bond failure that occurs during orthodontic treatment. One of the elements affecting the adhesive's bond strength is the bracket retention mechanism. This study's objective was to assess how various bracket base retention characters affected shear bond strength. Four distinct base features for brackets were evaluated. The basic design was examined using a scanning electron microscope. On the Universal testing equipment, brackets were glued to human teeth and then released. The findings indicate that the polymer-coated base's overall mean SBS, which had a mean value of 21.64 ± 4.14 MPa, was considerably greater than that of the other brackets (P 0.05). The foil meshpad, photochemically etched base, and laser-structured base had mean SBS values of 15.12 ± 5.75 MPa, 16.86 ± 3.76 MPa, and 19.32 ± 4.23MPa, respectively. Following laser-structured base and photochemically etched base brackets in terms of shear bond strength were polymer-coated base brackets. The shear bond strength was the lowest in the plain foil mesh pads.

Robust energy storage system for stable in wind and solar

Energy storage systems (ESS) have become a conspicuous research hotspot since they store power and supply it during peak hours. Existing storage systems must be replaced by advanced energy storage with improved performance, energy management, and a control interface due to issues with size, dependability, and charging/discharging. The suggested robust energy retention system uses a battery and a super-capacitor to generate power from wind and solar energy. A Multiport DC converter with a buck-boost capacitor is used to properly discharge the stored energy to DC loads via a DC bus. The inverter is then delivered to a Power Flow Controller (PFC) and a Voltage Source Inverter (VSI). The Gravitational Search Algorithm (GSA) method optimizes the power controller settings based on the fluctuation of the system's active and reactive power. The optimization method ensures improved power flow while dealing with the least amount of power variance in imbalanced load situations. Based on the power variation, the proposed method generates appropriate control signals for the inverter system. The covers convert the inverter and reduce harmonics with a controller. Furthermore, the inverter AC supplied to the AC bus is converted into reactive power by an inductive load, and unwanted signals and harmonics are extracted using a Cascaded C-type filter. As a result, the described method has preserved total harmonic distortion, electrical efficiency, and finer transient stability.

Assessing the potential of composite confining systems for secure and long-term CO2 retention in geosequestration

A potential geologic target for CO2 storage should ensure secure containment of injected CO2. Traditionally, this objective has been achieved by targeting reservoirs with overlying seals-regionally extensive, low permeability units that have been proven capable of retaining buoyant fluid accumulations over geologic time. However, considering that the amount of CO2 is limited by a decadal injection period, vertical migration of CO2 can be effectively halted by a composite system of discontinuous shale/silt/mudstone barriers in bedded sedimentary rocks. Here, we studied the impact of depositional architectures in a composite confining system on CO2 migration and confinement at reservoir scale. We stochastically generated lithologically heterogeneous reservoir models containing discontinuous barriers consistent with statistical distributions of net-sand-to-gross-shale ratio (NTG) and horizontal correlation lengths derived from well log data and observations of producing hydrocarbon fields in Southern Louisiana. We then performed an extensive suite of reservoir simulations of CO2 injection and post-injection to evaluate the sensitivity of CO2 plume migration and pressure response of the composite system to a series of geologic and fluid parameters including the lateral continuity of barriers, NTG, permeability anisotropy within the sand body, and capillary pressure contrast between the sand and shale facies. The results indicate that lateral continuity of barriers and NTG are the dominant controls on CO2 plume geometry and pressure build-up in the reservoir, while the impact of NTG is particularly pronounced. The significance of intraformational barriers becomes apparent as they facilitate the local capillary trapping of CO2. Those barriers improve the pore space occupancy by promoting a more dispersed shape of the plume and ultimately retard the buoyancy-driven upward migration of the plume post injection.

A surrogate deterioration model of debris retention systems towards cost-effective maintenance strategies and increased protection efficacy

Protection systems are usually implemented in mountains aiming to resist natural dangerous phenomena. As any other critical infrastructure, protection systems should always withstand and operate efficiently as they guarantee the safety of people and protect socio-economic assets. However, the efficacy of these systems decreases with the increase of the deterioration level of the interdependent components, which constitute them. To provide desirable operation over their lifetime, the management of protection systems is of paramount importance. A major key issue in such critical infrastructure management is to optimize the cost effectiveness of maintenance actions while maintaining a sufficient protection efficacy. This study proposes a decision-aiding model to assess different maintenance strategies applied to a protection system against debris flows. The model is constructed using physics-based stochastic Petri nets. It incorporates (1) a stochastic deterioration model, which is a surrogate model of a physics-based model developed for building deterioration trajectories of the system and (2) maintenance model that permits assessing the cost and efficiency of maintenance strategies. This study addresses the case of a debris retention system, in which the progressive filling of its basin by debris materials is modeled. This is followed by assessing several maintenance strategies concerning the cleaning of the basin. A simple sensitivity analysis is also carried out in order to check the effect of the uncertainty that invades the model’s inputs on maintenance decisions. A numerical analysis is performed using real data of the retention system located in the Claret torrent in France and subjected to debris flows over a period of 50 years.

The inoculation of thermophilic heterotrophic nitrifiers improved the efficiency and reduced ammonia emission during sewage sludge composting

In this study, three thermophilic heterotrophic nitrifiers were isolated and inoculated into the semi-permeable membrane-covered composting of sewage sludge as thermophilic microbial (TM) agent. The physicochemical properties and microbial communities as well as the metabolism of microorganisms during composting were analyzed. Compared to CK, the inoculation of TM agent prolonged the thermophilic stage from 4 days to 7 days, increased the degradation of organic matters by 14.06 %, and promoted humification of compost. Meanwhile, TM agent reduced the NH3 emission by 34.64 % while the NO3−-N content was 2.72 folds that of CK, resulting lower nitrogen loss. Additionally, an obvious succession of microbial communities occurred and the inoculation of TM agent enriched organic matters-degrading microorganisms (Bacillus, Thermobispora, Planifilum and Tepidimicrobium) and decreased the abundance of pathogens (Aspergillus and Cephalotrichum). Besides, many microorganisms related to nitrogen transformation were detected during the composting. The analysis of functional genes revealed that the nitrification was facilitated while denitrification process might be inhibited, establishing an efficient nitrogen retention system. This research provided an effective agent for sludge composting and indicated that the inoculation of thermophilic nitrifiers was a promising strategy to improve composting efficiency and reduce nitrogen loss.

1.N. Workshop: Improving the wellbeing of the health workforce in Europe: Issues and lessons from Ireland

Abstract Health systems have been subject to a series of crises over the last fifteen years from economic austerity to the COVID-19 pandemic and now the cost of living crisis. At the same time many high-income countries have bolstered their own deficient supply of health workers by importing skilled health professionals from other countries. The health workforce has borne the brunt of each of these shocks and it is no surprise that there is demotivation, burnout and high attrition across staff cadres across Europe. Not enough is known about the root causes of these phenomena and therefore what can be done to effectively enhance workforce wellbeing and engagement and also assist health systems to deal effectively with the legacy of pent up demand from the pandemic which is threatening to overwhelm services. This session seeks to identify and evaluate the different factors that have led to disengagement of staff and assess strategies to improve staff wellbeing, retention and health system recovery, based on quantitative and qualitative research. Three case studies from Ireland distinguish different elements of the problem: 1) an investigation of the dimensions of disengagement and their underlying causes after austerity across staff cadres with particular focus on bullying and discrimination 2) an evaluation of turnover amongst nurses post COVID and the factors which are linked to this, and 3) an examination of racial attitudes and discrimination towards non-Irish health professionals in Irish hospitals. Each study highlights particular factors which have caused disengagement and evaluates their consequences and causes. Together they paint a powerful picture of a health system and its workforce struggling to cope with crisis after crisis, mismanagement and ambitious change programmes. A fourth presentation will compare and contrast this picture with analysis from other high-income countries and examine optimal investment strategies to solve the heath workforce problems. This high-level analysis places the Irish case studies in perspective and allows a more thorough evaluation of key factors and strategies to turn round the situation across Europe. Each presenter will be given a strict deadline of 10 minutes each by the chair and then the audience will be invited to debate the problems identified and strategies proposed to discuss: (i) the appropriate course of action for health systems in Europe at this time, (ii) the conditions under which strategies will achieve the desired results for the health workforce and (iii) how and whether a coordinated approach across Europe would be more effective. Key messages • This session will improve understanding of the causes of burnout, disengagement and high turnover amongst the health workforce in order to address these problems. • Strategies for investing in the education, protection and wellbeing of the European health workforce will be evaluated to assist with our readiness for future shocks.

Violence against healthcare workers: a health system approach and international comparative study

Abstract Background Violence against healthcare workers is a global health problem threatening healthcare workforce retention and health system resilience in a fragile post-COVID ‘normalisation’ period. There is an urgent need for action to make violence against healthcare a greater priority. Our novel contribution to the debate is a comparative health system and policy approach, aiming to explore major trends and identify policy gaps. Methods We have chosen a most different systems comparative approach concerning the epidemiological, political, and geographic contexts. Brazil (under the Bolsonaro government) and the United Kingdom (under the Johnson government) serve as examples of countries that were strongly hit by the pandemic in epidemiological terms while also displaying policy failures. New Zealand and Germany represent the opposite. A rapid assessment was undertaken based on secondary sources and country expertise. Results We found similar problems across countries. A global crisis makes healthcare workers vulnerable to violence. Furthermore, insufficient data and monitoring hamper effective prevention, and lack of attention may threaten women, the nursing profession, and migrant and minority groups the most. There were also relevant differences. No clear health system pattern can be identified. At the same time, professional associations and partly the media are strong policy actors against violence. Conclusions All countries in our sample failed to respond effectively to growing violence and improve the prevention and protection of healthcare workers. Much more involvement from political leadership is needed; attention to the political dimension and all forms of violence are essential. Violence against HCWs is and will remain a problem long after the pandemic subsides. If political action is not taken, healthcare workers will have an additional reason to leave their profession and workplace, thus reinforcing the healthcare workforce crisis. Key messages • Getting prevention of violence against healthcare workers and effective protection right, enhances the retention of the existing workforce and will attract new generations of healthcare workers. • Governments must prioritise developing feasible and effective policy responses to tackle the risk factors that healthcare workers face at the workplace and on social media.

DEVELOPMENT AND EVALUATION OF FLOATING BEADS OF BACLOFEN AS A GASTRORETENTIVE DOSAGE FORM

Gastro retentive delivery systems are designed to be retained in the stomach for a prolonged time and release their active ingredients and thereby enable sustained and prolonged input of the drug to the upper part of the gastrointestinal (GI) tract. The goal of any drug delivery system is to provide a therapeutic amount of drug to proper site in the body to achieve promptly and then maintain a desired drug concentration. Baclofen is a gamma-aminobutyric acid (GABA) agonist used as a skeletal muscle relaxant used for the relief of painful and uncomfortable muscle spasms caused by a variety of conditions. Twelve different formulation of Baclofen floating beads were successfully developed using emulsion solvent diffusion method. The beads had good yield and showed high, drug entrapment efficiency. The flow properties of beads were within the acceptable range and therefore would be easily filled into capsules. Study concludes successfully delivery of Baclofen by the means of floating beads.

Effect of using high molecular weight crosslinker on the physical properties of super porous hydrogel composite

Superporous hydrogel composite is widely utilized and investigated as a gastro retentive drug delivery system. Materials used in Superporous hydrogel formulation have a profound effect on its properties’, N-methylene bisacrylamide is the crosslinker of choice for the preparation of SPH.
 The purpose of this study is to determine if using a new high molecular weight crosslinker such as polyethylene glycol diacrylate will affect the physical characteristics of SPH and drug release behavior. For the preparation of super porous hydrogel polyvinyl alcohol, acrylamide, polyethylene glycol diacrylate 700, N, N-Methylene bisacrylamide, sodium bicarbonate, and tween 20 were used. Trifluoperazine HCl was used as a model drug. The buoyancy, porosity, density, drug release, drug content, swelling ratio, and swelling time were studied and compared. All the physical characteristics and medication release profiles were impacted by changing the formulation parameters. The formula with the best physical qualities had 300 µl of acrylamide (40 percent w/v), 20 mg of polyvinyl alcohol, 200 µl of Tween 20 (v/v), 5 µl of polyethylene glycol diacrylate 700, 45 µl ammonium persulfate, 45 µl TEMED and 50 mg of sodium bicarbonate. Around 80% of the drug was released over the course of 12 hours according to zero order kinetics. By modifying the formulation parameters using polyethylene glycol diacrylate, Superporous hydrogel was successfully manufactured and has the best properties to be employed as a gastro retentive drug delivery system.

Discharge of iodine-containing contrast media into the environment - problem analysis and implementation of measures to reduce discharge by means of separation toilets - experience from a pilot project.

Environmental aspects and sustainability are becoming increasingly important. In addition to energy consumption, the consumption and environmental discharge of contrast agents pose a particular challenge. Because of their desired stability, X-ray contrast agents (XCAs) are deposited in surface water at a rate of up to 400 tons per year. In a pilot project, a set of measures (installation of specific separation toilets, the establishment of feedback systems, interviews, questionnaires, and observation) was implemented to sensitize patients and staff to the problem of XCAs during outpatient CT examinations and a retention and recovery system for XCAs was evaluated. In the initial baseline phase, a separation toilet with an additional collection system and a feedback/button system was installed. The built-in feedback system indicated that the separation toilets were used by approx. 16 % of patients without measures. In two subsequent intervention phases, accompanying measures significantly (p < 0.01) increased the use of these separation toilets to 21 % and 25 %, respectively. The measures to reduce the discharge of XCAs were positively assessed by both staff and patients. Measures to reduce the discharge of XCAs into the environment have a high acceptance among staff and patients. The subsequent installation of separation toilets is one possibility to achieve on-site retention of XCAs. However, this measure is likely to be of high value only if patients stay on site for a correspondingly long time, as is the case in cardiology, for example. · The input of X-ray contrast agents into the environment is relevant in light of the quantity. · Measures to reduce the discharge of X-ray contrast agents into the environment have been investigated in pilot projects. · The (subsequent) installation of separation toilets is possible and allows retention of X-ray contrast agents. · This measure is considered useful by patients and staff. · The financing of these measures needs to be clarified. · Beer M, Schuler J, Kraus E et al. Discharge of iodine-containing contrast media into the environment - problem analysis and implementation of measures to reduce discharge by means of separation toilets - experience from a pilot project. Fortschr Röntgenstr 2023; 195: 1122 - 1127.

Mechanically Robust Interface at Metal/Muscovite Quasi van der Waals Epitaxy.

Quasi van der Waals epitaxy is an approach to constructing the combination of 2D and 3D materials. Here, we quantify and discuss the 2D/3D interface structure and the corresponding features in metal/muscovite systems. High-resolution scanning transmission electron microscopy reveals the atomic arrangement at the interface. The theoretical results explain the formation mechanism and predict the mechanical robustness of these metal/muscovite quasi van der Waals epitaxies. The evidence of superior interface quality is delivered according to the outstanding performance of the designed systems in both retention (>105 s) and cycling tests (>105 cycles) through electromechanical measurements. With high-temperature X-ray reciprocal space mapping, the unique anisotropy of thermal expansion is discovered and predicted to sustain the thermal stress with a sizable thermal actuation. A maximum bending curvature of 264 m-1 at 243 °C can be obtained in the silver/muscovite heteroepitaxy. The electrothermal and photothermal methods show a fast response to thermal stress and demonstrate the interface robustness.

Seasonal patterns of vertical flux in the northwestern Barents Sea under Atlantic Water influence and sea-ice decline

The northern Barents Sea is a productive Arctic inflow shelf with a seasonal ice cover and as such, a location with an efficient downward export of particulate organic matter through the biological carbon pump. The region is under strong influence of Atlantification and sea-ice decline, resulting in a longer open water and summer period. In order to understand how these processes influence the biological carbon pump, it is important to identify the seasonal and spatial dynamics of downward vertical flux of particulate organic matter. In 2019 and 2021, short-term sediment traps were deployed between 30 and 200 m depth along a latitudinal transect in the northwestern Barents Sea during March, May, August and December. Vertical flux of particulate organic carbon, δ13C and δ15N values, Chl-a, protists and fecal pellets were assessed. We identified a clear seasonal pattern, with highest vertical flux in May and August (178 ± 202 and 159 ± 79 mg C m−2 d−1, respectively). Fluxes in December and March were < 45 mg C m−2 d−1. May was characterized by diatom- and Chl a-rich fluxes and high spatial variability, while fluxes in August had a higher contribution of fecal pellets and small flagellates, and were spatially more homogenous. Standing stocks of suspended particulate organic matter were highest in August, suggesting a more efficient retention system in late summer. The strong latitudinal sea-ice gradient and the influence of Atlantic Water probably led to the high spatial variability of vertical flux in spring, due to their influence on primary productivity. We conclude that the efficiency of the biological carbon pump in a prolonged open-water period depends on the reworking of small, slow sinking material into efficiently sinking fecal pellets or aggregates, and the occurrence of mixing.

Application of modified olivine to a two-stage gasification process to evaluate the effects on hydrogen generation and retention of heavy metals

An environmentally-friendly and efficient waste-to-energy and heavy metal retention system was successfully developed in this study. The natural resource-olivine was applied to be the bed material of second-stage gasifier, and the effects of second-stage gasifier temperature, and steam/biomass ratio on the hydrogen (H2) production ratio of syngas and heavy metal retention were discussed in detail. The optimal hydrogen production ratio (30.3%) was achieved when second-stage temperature, steam/biomass ratio (S/B ratio) were respectively controlled at 900 °C, and 0.25. The characterization analysis results evidenced that the Fe and Mg from pristine olivine and calcined olivine can facilitate the waste-to-hydrogen during the gasification reaction. Moreover, the NiO and Ni loaded on the surface of the calcine olivine could not only facilitate the water–gas shift reaction for H2 production, but also provide strong binding sites for the linkage of ether and cleavage of the C–O bond, leading to formation of CH4. The formed CH4 would be further dissociated over the metallic Ni/olivine, resulting in a significantly improved H2 production efficiency. In general, the order based on the H2 ratio of the syngas at the second-stage was calcined Ni-loaded olivine > calcined olivine > olivine; the heavy metal retention efficiency of three bed materials was in the order of Cu > Pb > Zn.

Complete Removable Prosthesis Stabilized on Implants: Interest and Use of the Locator® Attachment

The complete removable denture retained by implants is a widely used therapeutic option, recognized for its functional and psychological esthetic rendering. Currently, the practitioner has an arsenal of retention systems at his disposal (axial attachments, anchor bars...) and since 2000, the Locator® attachment has been added to the large number of axial attachments. Thus, this article proposes to describe it and to expose, through two clinical cases, the process of its placement.

Utilization of online systems to promote youth participation in research: A methodological study.

Online surveys can align with youth's increased use of the internet and can be a mechanism for expanding youth participation in research. This is particularly important during the coronavirus disease 2019 (COVID-19) pandemic, when in-person interactions are limited. However, the advantages and drawbacks of online systems used for research need to be carefully considered before utilizing such methodologies. To describe and discuss the strengths and limitations of an online system developed to recruit adolescent girls for a sexual health research study and conduct a three-month follow up survey. This methodology paper examines the use of an online system to recruit and follow participants three months after their medical visit to evaluate a mobile sexual and reproductive health application, Health-E You/Salud iTuTM, for adolescent girls attending school-based health centers (SBHCs) across the United States. SBHC staff gave adolescent girls a web link to an online eligibility and consent survey. Participants were then asked to complete two online surveys (baseline and 3-month follow-up). Surveys, reminders, and incentives to complete them were distributed through short message service (SMS) text messages. Upon completing each survey, participants were also sent an email with a link to an electronic gift card as a thank-you for their participation. Barriers to implementing this system were discussed with clinicians and staff at each participating SBHC. This online recruitment and retention system enabled participant recruitment at 26 different SBHCs in seven states across the United States. Between September 2021 and June 2022, 415 adolescent girls were screened using the Qualtrics online survey platform, and 182 were eligible to participate. Of those eligible, 78.0% (n = 142) completed the baseline survey. Participants were racially, geographically, and linguistically diverse. Most of the participants (89.4%) were non-White, and 40.8% spoke Spanish. A total of 62.0% (n = 88) completed the 3-month follow-up survey. Limitations of this system included reliance on internet access (via Wi-Fi or cell service), which was not universally available or reliable. In addition, an individual unrelated to the study obtained the survey link, filled out multiple surveys, and received multiple gift cards before the research team discovered and stopped this activity. As a result, additional security protocols were instituted. Online systems for health research can increase the reach and diversity of study participants, reduce costs for research personnel time and travel, allow for continued study operation when in-person visits are limited (such as during the COVID-19 pandemic), and connect youth with research using technology. However, there are challenges and limitations to online systems, which include limited internet access, intermittent internet connection, data security concerns, and the potential for fraudulent users. These challenges should be considered prior to using online systems for research.

Conservation tillage practices affect soil microbial diversity and composition in experimental fields.

Conservation tillage is a widely used technique worldwide, but the effects of conservation tillage on bacterial community structure are poorly understood. We explored proportional alterations in the bacterial community under different tillage treatments. Hence, this study utilized high-throughput sequencing technique to investigate the structure and assembly processes of microbial communities in different tillage treatments. Tillage treatments included tillage no-straw retention (CntWt), no-tillage with straw retention (CntWntS), tillage with straw retention (CntWtS), no-tillage and no-straw retention (CntWnt). The influence of tillage practices on soil bacterial communities was investigated using Illumina MiSeq sequencing. Different tillage methods and straw retention systems significantly influenced soil parameters such as total potassium and pH were not affected by tillage practices, while straw retention significantly affected soil parameters including nitrogen content, available phosphorus and available potassium. Straw retention decreased bacterial diversity while increased bacterial richness. The effect of straw retention and tillage on bacterial communities was greater than with no tillage. Phylogenetic β-diversity analysis showed that deterministic homogeneous selection processes were dominated, while stochastic processes were more pronounced in tillage without straw retention. Ecological network analysis showed that microbial community correlation was increased in CntWntS and CntWnt. Straw retention treatment significantly increased the relative abundance of bacterial taxa Proteobacteria, Bacteroidetes, and OD1, while Nitrospirae, Actinobacteria, and Verrucomicrobia significantly decreased. The conservation tillage practices significantly affect soil properties, bacterial composition, and assembly processes; however, further studies are required to investigate the impact of different crops, tillage practices and physiological characteristics on bacterial community structure and functions.

Effect of modification of formulation variables on physical characterization of superporouse hydrogel

Superporouse hydrogel (SPH) is widely used and investigated as a gastro retentive drug delivery system to extend drug residence time in the stomach&#x0D; &#x0D; However, their mechanical strength represents a problem because they need to withstand the peristaltic movement of the stomach. Properties of SPH are widely affected by the materials used for their synthesis. The aim of the research is to study the effect of changing the foaming agent and foam stabilizer amount on physical properties, in particular mechanical strength, and drug release from SPH. Trifluoperazine HCl will be used as model drug in the study.&#x0D; SPH formulations was prepared using fixed amount of acrylamide (AM) and polyvinyl alcohol (PVA) as monomers, polyethylene glycol diacrylate (PEGDA) as cross-linker, TRFP as model drug and variable amount of sodium bicarbonate (NaHCO3) as foaming agent, and tween 20 as foam stabilizer. Ammonium persulphate (APS) / tetramethyl ethylenediamine (TEMED) system was used as polymerization initiator. The effect of changing foaming agent and foam stabilizer on mechanical strength, buoyancy, porosity, density, drug release, drug content, swelling ratio, and swelling time was investigated.&#x0D; Modifying both factors affected all the physical properties and drug release profile. When tween 20 was increased the mechanical strength, density and floating lag time was increased with a reduction in porosity and drug release. While increasing NaHCO3 reduced mechanical strength, density and floating lag time with increased porosity and faster drug release was observed. Optimum physical properties were observed in formula 2 which had 230 µl of Tween 20 (v/v) and 50 mg of NaHCO3 in which the mechanical strength was 579±0.4, floating lag time 14 min and 80% of the drug was released within 12 hr.&#x0D; As a conclusion SPH with improved mechanical strength, physical properties and drug release pattern can be achieved by changing foam stabilizer and foaming agent amount in the formulations.

Research on Operation Efficiency Prediction and Optimization of Biological Retention System Based on GA-BP Neural Network Model

Bioretention systems are an important measure in sandy city construction to remove pollutants. This study collected all the operating data samples of bioretention ponds currently in operation in China and used the Mantel test and Redundancy Analysis (RDA) to optimize the main factors that affect the changes in pollutant-removal efficiency. Genetic Algorithms (GA) were used to optimize the Back Propagation (BP) neural network model, and a predictive index system was established to predict the efficiency of removing typical pollutants (ammonia nitrogen and nitrite nitrogen) by bioretention ponds. The operating efficiency of bioretention ponds was evaluated and predicted based on the GA-BP neural network model. The results indicated that the highest positive correlation with the operating efficiency of the bioretention system was X3 (rainfall duration), with a correlation coeffi-cient of 0.79, while the highest negative correlation was with X7 (percentage of strong percolating soil) and X12 (the proportion of mineral fillers), with correlation coefficients of −0.89. The overall regression coefficients of the GA-BP model for predicting the efficiency of removing typical pollu-tants (ammonia nitrogen and nitrite nitrogen) were 0.9397 and 0.9303, respectively, indicating high accuracy and representativeness. The overall regression index of the model is 0.9298, and the overall predicted removal rates of typical pollutants in the blank area are 78.72%, 70.31%, and 86.92%, re-spectively. The model can provide a basis and reference for the construction and planning of bio-retention ponds in areas lacking them.

A decade of microbial community dynamics on sinking particles during high carbon export events in the eastern Fram Strait

Marine sinking particles sequester atmospheric carbon dioxide to the deep ocean via the biological carbon pump. Understanding how environmental shifts drive changes in the microbial composition of particles, and how these affect the export of organic matter from the surface to the deep ocean, is critical, especially in the rapidly changing Arctic Ocean. Here, we applied next generation sequencing of the 18S and 16S rRNA genes to sediment trap samples from around 200 m water depth in the eastern Fram Strait, covering a time frame of more than one decade (2000-2012). The aim was to characterize their microbial composition during annual highest particulate organic carbon flux events. The bimodal annual spring and summer export fluxes were representative of the strong seasonality in the region. Furthermore, the study period was characterized by considerable interannual variation, marked especially by a warm water anomaly between 2005 and 2007. During this period changes in the hydrography and sea ice cover also led to measurable changes in the microbial composition of particles. The warm water period was marked by a decrease in diatoms affiliated with Chaetoceros, an increase of small phytoplankton and an increase in sequence abundance of the bacterial taxa Oceanospirillales, Alteromonadales and Rhodobacterales on the particles. The resulting changes in microbial composition and the associated microbial network structure suggest the emergence of a more developed retention system in the surface ocean. Our results provide the first long-term assessment of the microbial composition of sinking particles in the Arctic Ocean, and stress the importance of sea ice and hydrography for particle composition and subsequent flux of organic matter to deeper waters.