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A large amount of literature suggests that all aspects of children’s live will be impacted by excessive parental psychological control, and this paper finds that excessive parental psychological control has an impact on children's peer relationships, family relationships, and adolescent maladjustment. In particular, when parents do not exert psychological control over their adolescents, the adolescents may become involved in drugs and substance abuse as a result of low-quality peer relationships. In addition, this paper focuses on the fact that Chinese families have stronger psychological control than Western families, and that there are bidirectional effects of psychological control in the Chinese family samples. The results discussed in this paper may provide direction for future research, as psychological control is stronger in the Chinese sample and has bidirectional effects.

China is considering Beishan granitic formation (Gansu Province, China) as the site for high-level radioactive waste (HLW) repositories. Thus, it is crucial to understand the transport behavior of radionuclide in Beishan granitic media under disposal conditions. In this context, the co-transport of U(VI) (as the representative of radionuclides) and bentonite colloid (BC, from erosion of compacted bentonite) in particulate Beishan granite was studied as a function of important in-situ factors, such as BC concentration, ionic strength, pH and flow rate. We found that the increase of BC concentration (BC = 240–480 mg/L) did not affect the transport of individual BC, whereas it significantly facilitated the transport of U(VI). The increase of ionic strength (I = 0.001–0.01 M NaCl) or decrease of pH (pH = 7.50–5.40) obviously inhibited the BC transport, where these inhibiting effects were relatively slight for the transport of U(VI). The increase of flow rate significantly facilitated both the transport of BC and U(VI). Finally, a two-site kinetic attachment/detachment model was applied to describe the breakthrough curves of individual and co-transport of BC. The experimental and modeling results of this study have a significant implication on the safety assessment of HLW repositories built in granitic formation.

U(VI) was found to form intrinsic colloids in the natural groundwater. Fluorescence spectra, TEM, SEM techniques and thermodynamic calculation were used to identify the species of U(VI) and characterize the intrinsic uranium colloidal particles in the groundwater. The effect of pH on the formation of U(VI) colloidal particles was studied. It was found that under near-neutral and strong alkaline conditions, several elements, mainly Ca, Na and Si were responsible for the formation of intrinsic U(VI) colloid, and under weak alkaline conditions, U(VI) colloidal particles were not formed due to the formation of calcium uranyl carbonate complex.

Dissolved silicic acid in the environment has strong affinity for actinides (An), but An(III)-silicate colloids have been scarcely investigated. In this study, Eu(III)-silicate colloids, an analogue to An(III)-silicate, were prepared and the aggregation kinetics of the colloids was investigated as a function of Eu content (Si/Eu molar ratio), pH, background electrolyte (NaCl, NaNO

Lithium metal batteries (LMBs) enabled by quasi-solid electrolytes are under consideration for their prospect of reliable safety and high energy density. The limited oxidative stabilization and inferior chemical compatibility of quasi-solid electrolytes toward high-voltage cathodes are a long-standing challenge. Herein, we report that an additive level (0.05 M) of LiPF6 is introduced to a polymeric concentrated quasi-solid electrolyte (10 M LiFSI in poly-1,3-dioxolane [poly-DOL], ethylene carbonate [EC], and ethyl methyl carbonate [EMC]) to build in situ a fluorine-regulated cathode electrolyte interphase (CEI) on a highly catalytic LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode. The CEI with a conformal thickness of ∼7 nm features a fluorine-rich outer layer and manipulative LiF/organofluorine species, which mitigates the detrimental side reactions between the quasi-solid electrolyte and NCM cathode and maintains the structure of cycled NCM, as demonstrated by the characterizations of SEM, TEM, XRD, Raman spectroscopy, AFM, EDS, and XPS. As a result, the LiPF6-contained polymeric concentrated quasi-solid electrolyte not only provides a superior ionic conductivity of 3.1 × 10−4 S cm−1 at 25 °C and a remarkable electrochemical stability window of 5.5 V vs Li/Li+, but also achieves an excellent capacity retention of 74% after 100 cycles for LiǁNCM811 quasi-solid-state LMB, bringing a quasi-solid electrolyte design strategy of engineered CEI chemistry for LMBs.

For the geological repository of high-level radioactive waste (HLW) built in granitic host rock，the control of buffer material (compacted bentonite) erosion and subsequent loss caused by groundwater in granite fissures is an unresolved problem of major concern. We propose here new insight into enhancing the erosion resistance of compacted bentonite by means of its electrostatic interaction with oppositely-charged layered double hydroxide (LDH). The interaction between bentonite and LDH was studied by dropwise addition of colloidal LDH into colloidal bentonite suspension, during which the variation in electrical conductivity, zeta potential and particle size proved a strong interaction between these two materials. Interestingly, in addition to their aggregation, intercalated structures of LDH and montmorillonite were found in the composite (BEN@LDH) by a combined characterization of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM), and were confirmed by density functional theory (DFT) calculation. Colloid generation of compacted BEN@LDH under ultrasonic conditions is negligible comparing with that of compacted bentonite, indicating a significantly higher erosion resistance. Besides, a small amount of LDH by mechanically mixing with bentonite (mass ratio 1:99) can also effectively improve the erosion resistance of compacted bentonite. Moreover, BEN@LDH displayed stronger retention performance towards U(VI) and Se(IV) than bentonite under near-neutral/weakly alkaline conditions. Our results indicate that LDH is a promising additive in compacted bentonite, and this approach may be extended to common geotechnical structures built with clays and soils.

The release of uranyl from uranium tailing sites is a widely concerned environmental issue, with limited investigations on the effect of coexistence of various colloids. Gibbsite colloids extensively exist, together with ubiquitous humic substances, in uranium polluted waters at tailing sites, due to high concentration of dissolved Al in acid mine drainage. In this context, we investigated the co-transport of U(VI), gibbsite colloids and humic acid (HA) as a function of pH and ionic strength at a U(VI) concentration (5.0 × 10−5 M) relevant within mine tailings and related waste. It was found that, owing to electrostatic attraction, gibbsite colloids and HA associated with each other and transported simultaneously regardless of U(VI) presence. Besides the impact of pH and ionic strength, whether gibbsite colloids facilitated U(VI) transport depended on HA concentration. Gibbsite colloids impeded U(VI) transport at relatively low HA concentration (≤5 mg L−1), because associated colloids loaded with U(VI) were positively charged which favored colloid retention on negatively charged quartz sand in the column. U(VI) together with gibbsite colloids and low concentration HA was completely blocked at natural pH and/or high ionic strength. At relatively high HA concentration (20 mg L−1), however, the associated colloids showed negative zeta potential which facilitated U(VI) transport because of repulsion between negatively charged colloids and quartz sand. Meanwhile, high concentration of HA dramatically accelerated the transport of gibbsite colloids. These results implied that gibbsite colloids might imped U(VI) migration at uranium tailing sites unless the aquifers are enriched with abundant humic substances.

Exploring solid electrolytes with promising electrical properties and desirable compatibility toward electrodes for safe and high-energy sodium metal batteries remains a challenge. In this work, these issues are addressed via an in situ hybrid strategy, viz., highly conductive and thermally stable 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide is immobilized in nanoscale silica skeletons to form ionogel via a non-hydrolytic sol-gel route, followed by hybridizing with polymeric poly(ethylene oxide) and inorganic conductor Na3Zr2Si2PO12. Such hybrid design yields the required solid electrolyte, which shows not only a stable electrochemical stability window of 5.4 V vs Na/Na+ but also an extremely high ionic conductivity of 1.5 × 10−3 S cm−1 at 25 °C, which is demonstrated with the interacted and monolithic structure of the electrolyte by SEM, XRD, thermogravimetric (TG), and XPS. Moreover, the capabilities of suppressing sodium metal dendrite growth and enabling high-voltage cathode Mg-doped P2-type Na0.67Ni0.33Mn0.67O2 are verified. This work demonstrates the potential to explore the required solid electrolytes by hybridizing an in situ ionogel, a polymer, and an inorganic conductor for safe and high-energy solid-state sodium metal batteries.

Environmental colloids exist widely in nature media, due to the strong reactivity and mobility. They can act as a carrier for radionuclides and play an important role in the transport of radionuclides in environment. The interaction between environmental colloids and radionuclides is of great significance to nuclear environment safety as well as nuclear emergency. In recent years, the colloids related issues have attracted much attention in the field of environmental radiochemistry. This review targeted on the typical environmental colloids in disposal environment of radioactive waste. Besides, the progress on interaction between environmental colloids and radionuclides was reviewed, the source, stability and transport of environmental colloids were discussed, common approaches for conducting colloidal related research were summarized, and the influence of environmental colloids on radionuclides migration was analyzed. The points in this review are expected to be referable for a comprehensive and in-depth understanding on the geochemical behavior of environmental colloids and radionuclides.

Biochar has attracted much attention for remediating the sites contaminated with heavy metals and radionuclides due to its low cost and high adsorption affinity. However, little is known about how colloidal biochar influences U(VI) transport in the environment. In this study, column experiments were conducted to investigate the individual and co-transport of U(VI) and biochar colloids (BC) in quartz sand heterogeneous media. Results showed that the transport of U(VI) in the individual transport system was pH-dependent and insensitive to ionic strength, whereas the individual BC transport was more sensitive to the changes in ionic strength compared to those in pH, indicating that electrostatic interaction plays a major role during BC transport but chemical interaction dominates U(VI) transport. In the presence of BC, the transport of U(VI) was significantly facilitated because of U(VI) adsorption on BC. The existence of low concentration of U(VI) (2.5 × 10−6 M), however, did not affect the breakthrough curves (BTCs) of BC, except for the co-transport at relatively high ionic strength (100 mM) where BC transport was impeded due to the decrease of colloid suspension stability. Colloid size exclusion effect was evidenced by the evolution of particle size and zeta potential of the effluents. The transport of BC in both the individual and co-transport systems could be described by a two-site kinetic attachment/detachment model. This work implies that a risk assessment of BC facilitated heavy metal transport should be carefully considered when biochar is applied to the remediation of heavy metal contaminated sites.

The hydroboration/Pd-catalyzed migrative Suzuki–Miyaura cross-coupling of 1,3-dienes with electron-deficient aryl halides has been developed, which enables the synthesis of branched allylarenes directly from primary homoallylic alkyl boranes. A ligand-tuned linear- or branch-selective coupling for these aryl halides has also been achieved.

Iron oxide coatings occur commonly in the environment and affect significantly the fate of heavy metals. However, U(VI) transport in water saturated iron oxide-coating porous media has been seldom investigated. In this study, the adsorption and retardation of U(VI) on iron oxide-coated sand were comparatively investigated over a wide range of experimental conditions by batch and column experiments combined with modelling. The presence of iron oxide coatings significantly enhanced U(VI) adsorption which could be described by a two-site surface complexation model. The breakthrough curves of U(VI) in iron oxide coated quartz sand column show a two-plateau profile, which could not be directly reproduced by the commonly used two-site kinetic model. More sites for U(VI) have to be considered, implying that the heterogeneity of surface sites might be more significant in the non-equilibrium transport system than that in the equilibrium adsorption system. In addition, the presence of salicylic acid (SA) facilitated the transport of U(VI) at acidic pH, due to the competition between surface complexation of U(VI) and the complexation of U(VI) with SA in aqueous phase. Overall, this study provides a comprehensive understanding of the migration behavior of U(VI) in water saturated iron oxide-coated sand system.

Although there have been a lot of studies on the adsorption of trivalent actinides on clay minerals, the gaps between surface complexation model (SCM) for the description and prediction of macroscopic adsorption and the coordination structures and configurations of the surface complexes are still not completely bridged. Aiming at a multi-scale description of Am(III) adsorption on bentonite, density functional theory (DFT) calculations and surface complexation modeling were carried out. The results showed that the SCM considering cation exchange reactions and the formation of surface complexes, i.e., ≡SSOAm2+, ≡SSOAm(OH)+ and ≡SSOAm(OH)2 could reproduce all batch experimental data for Am(III) adsorption on Gaomiaozi bentonite, a potential buffer material for China's Beishan high-level radioactive waste repository. The stoichiometric coefficients of 1 in the SCM are deduced, while the surface complexes at the sites of ≡Al(OH)2 on (010) surface and those of ≡AlO(OH) on (110) surface are bidentate according to DFT calculations. The detailed calculations of electronic structures indicated that both covalent bond and electrostatic interaction account for Am(III) coordinating with the surface hydroxyl groups. In addition, it was found that the structures and energy properties of Am(III) complexes on (010) surface are similar to those on (110) surface. Hydrogen bonds between binding waters of Am(III) and the surface hydroxyl groups are formed in all cases, contributing to additional stability of Am(III) surface complexes. Overall, this study provides an improved understanding of Am(III) adsorption on the edge surfaces of bentonite/montmorillonite.

Although various colloids co-exist in the environment, studies on the interaction between different kinds of inorganic colloids and their combined effects on radionuclide transport have scarcely been reported. In the present paper, the influence of colloidal gibbsite, a representative metal hydroxide in groundwater, on the transport of Na-bentonite colloids and their combined effects on U(VI) transport in saturated particulate granite columns were investigated. It was found that in the presence of the colloids, whether single Na-bentonite or the mixture of Na-bentonite and gibbsite, fewer pore volumes were needed for U(VI) breakthrough, indicating a colloid-facilitated U(VI) transport due to high binding affinity of uranyl for the colloids compared to granite. Meanwhile, the breakthrough curves of U(VI) were gradually flattened and the plateau of the curve for Na-bentonite was decreased as the concentration ratio of gibbsite to Na-bentonite increased from 1:10 to 1:6. Consequently, total recoveries of U(VI) and Na-bentonite decreased with more gibbsite in the mixed colloids. The inhibition effect of gibbsite colloids was ascribed to electrostatic interactions between positively charged surfaces of gibbsite colloids and negatively charged surfaces of bentonite colloids and granite granules. The electrostatic attraction between oppositely charged colloids led to an increase of mean size in the mixed suspension which declined colloid transport and the transport of colloid associated U(VI) as well. When the gibbsite-to-bentonite ratio was increased up to 1:5, the recoveries were obviously lower than those of single U(VI) and Na-bentonite transport. The results imply that positively charged materials may be further investigated as additives to decrease the loss of buffer material by groundwater erosion and the migration of radionuclide associated on bentonite colloids.

The goal of this paper is to study the adsorption of Am(III) and Np(V) on the Maoming kaolinite and to provide corresponding adsorption models. The surface properties of Maoming kaolinite were evaluated by continuous potentiometric titration. Comparisons with the titration curves of KGa-1, KGa-2, Zettlitz, St Austell and Twiggs County kaolinite samples indicate that the Maoming kaolinite may have different surface acid-base chemistry than these kaolinite samples. These titration curves of the Maoming kaolinite can be interpreted with both the diffuse double layer model (DDLM) and a non-electrostatic model (NEM). The adsorptions of Am(III) and Np(V) were studied as functions of contact time, solid-to-liquid ratios, pH, ionic strength, and concentration using a batch method. The adsorptions of Am(III) and Np(V) on kaolinite were rapid and equilibrated within 20 and 10 h, respectively. The adsorption of 6 × 10 −10 mol/L Am(III) was shown to be sensitive to both pH and ionic strength, whereas the adsorption of 1 × 10 −6 mol/L Np(V) was sensitive only to pH. The DDLM overestimates the effect of ionic strength on Np(V) adsorption. Finally, the adsorption of Am(III) and Np(V) was quantitatively interpreted using the NEM with the addition of one cation exchange reaction for Am(III). These adsorption data and corresponding models are useful for the safety assessment of an high–level nuclear waste (HLW) repository, which may be built in the clayey formation in China.

The Beishan granitic formation is being investigated as a potential host rock for a high-level radioactive waste repository in China. It is important to understand the retention processes, including influential parameters such as the metal ion concentration, pH, ionic strength (I) and temperature. The present study deals with U(VI) adsorption on Beishan granite using batch-type experiments in a CO2-free atmosphere. U(VI) adsorption on granite is shown to be insensitive to ionic strength. Temperature has a positive effect on U(VI) adsorption indicating that surface reactions are endothermic. Combining X-ray photoelectron spectroscopy (XPS) analysis and adsorption data at 25 °C, a Generalized Composite (GC) model with three surface complexes, SOUO2+, SO(UO2)2(OH)2+ and SO(UO2)3(OH)5, was constructed. The experimental data at 40 °C and 60 °C were fitted by the proposed model to obtain the equilibrium constants (K) of the surface reactions at these two temperatures. The enthalpy changes (ΔH) of the surface reactions were evaluated from the equilibrium constants obtained at three temperatures via the van't Hoff equation. Finally, blind modeling predictions were performed to test the robustness of the proposed model and ΔH. Satisfactory agreement with the literature data confirmed that this GC model with ΔH proving a useful tool to predict U(VI) adsorption on granite samples, especially on Beishan granite at ambient/high temperature.

Remediating uranium contamination becomes a worldwide interest because of increasing uranium release from mining activities. Due to ubiquitous presence of pyrite and the application of iron-based technology, colloidal iron oxy-hydroxides such as akaganeite colloid (AKC) extensively exist in uranium polluted water at uranium tailing sites. In this context, we studied individual and co-transport of U(VI) and AKC in water-saturated sand columns at 50 mg/L AKC and environmentally relevant U(VI) concentrations (5.0 × 10−7 ∼ 5.0 × 10−5 M). It was found that, in addition to the impact of pH and ionic strength, whether AKC facilitated U(VI) transport depended on U(VI) concentration as well. The presence of AKC facilitated U(VI) transport at relatively low U(VI) concentration (5.0 × 10−7 ∼ 5.0 × 10−6 M), which was due to the strong adsorption of U(VI) on AKC and faster transport of AKC than that U(VI) as observed in their individual transport experiments. At relatively high U(VI) concentrations (5.0 × 10−5 M), however, AKC impeded U(VI) transport because U(VI) of high concentration decreased AKC colloidal stability and increased AKC aggregation and attachment. Thus, U(VI) and AKC co-transport was even blocked completely at relatively high pH and ionic strength. The mechanisms behind the co-transport of U(VI) and AKC were also confirmed by assessing the evolutions of aqueous pH and AKC zeta potential and particle size distribution in the column effluents. A two-site non-equilibrium model and a two-site kinetic attachment/detachment model well-described the breakthrough curves of U(VI) and AKC, respectively. Knowledge generated from this study provides a thorough understanding of uranium transport in the absence/presence of AKC, and brings new insights into the influence of contaminant concentration on co-transport in the presence of colloids.

International audience; Humic acid (HA) in the environment may exist in either dissolved or fixed forms. However, laboratory studies usually take only the former into account. Here we synthesized a hybrid of HA and aluminum hydroxide (Al(OH)(3)) to mimic fixed HA, compared the effects of fixed and dissolved HA on Eu(III)/Yb(III) adsorption on Al(OH)(3), and analyzed the adsorption mechanisms using time resolved laser induced fluorescence spectroscopy (TRLFS), X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS). It was found that dissolved HA affected significantly Eu(III)/Yb(III) adsorption on Al(OH)(3), whereas fixed HA showed little apparent effect on the adsorption. The spectra of TRLFS, XPS and EXAFS for Eu(III)/Yb(III) adsorption on Al(OH)(3) in the presence of dissolved/fixed HA could be reproduced by those for Yb(III)/Eu(III) adsorption in the absence of HA and those for Yb(III)/Eu(III) binding to dissolved HA, respectively. Spectroscopic analyses indicated that the different effects of fixed and dissolved HA on Eu(III)/Yb(III) adsorption were due to different surface speciation with the same surface species, which could be interpreted by the decrease of available sites on fixed HA as compared to those on dissolved HA. This study implied that the effects of HA on the adsorption of Eu (III)/Yb(III) as well as other trivalent lanthanides/actinides in the environment might be overestimated if the differences between dissolved and fixed HA were not considered.

Callovo-Oxfordian formation (COX) is as potential host formation for emplacement of long-term nuclear waste repositories in France. The objective of this work is to assess whether a simplified “bottom-up” approach may explain the retention of Ni(II) by the COX considering two levels of ‘upscaling’: (i) from clay surfaces to rock clay fraction and (ii) from clay fraction to whole rock samples. To this end, Ni(II) adsorption was investigated by batch equilibrium, XPS, and EXAFS techniques on a representative sample extracted at the location where the storage is supposed to be built (clay content of about 50%) and on the corresponding carbonate-free i.e. 1.5–47% in weight) show that one cannot neglect the retention properties of the non-clay phases, mainly dominated by calcite, when the clay content becomes the minority. Retention values in the range of 60–300 L/kg can finally be given for describing adsorption properties of trace concentrations of Ni(II) for the clay contents representative of the majority of the Callovo-Oxfordian formation.

This study aims to investigate and model the adsorption of Eu(III) on bentonite in the presence of phosphate. Binary (phosphate/bentonite) and ternary (Eu(III)/phosphate/bentonite) systems were studied as a function of contact time, pH, solid-to-liquid ratio and Eu(III)/phosphate concentration by using a batch experimental method. The adsorption of phosphate on bentonite slightly increased in the pH range of 2.5–6.5, and decreased in the pH range of 6.5–9.4. This adsorption can be quantitatively interpreted by a model considering the formation of three monodentate surface complexes. In the ternary system, a synergistic adsorption was observed in the presence of both phosphate and Eu(III). In addition to the two sub-models describing Eu(III) and phosphate adsorption, the formation of ternary surface complexes had to be considered in order to explain the synergistic effect experimentally observed. The experimental data could be quantitatively explained when Eu(III) ( SOEuH2PO4+ and SOEuHPO4) or phosphate ( SPO4Eu+) are the bridged atoms. Complementary experiments carried out by X-ray photoelectron spectroscopy suggested that the second case is the most probable. The proposed model can be used in order to predict Eu(III) adsorption on buffer/backfilling material in the presence of phosphate.

Granite has been chosen as a promising host rock for geological repository of high-level radioactive waste in many countries. However, the description of radionuclide adsorption on granite is subjected to its complicated composition and still a challenge. We studied the adsorption of Eu(III) and Am(III) on Beishan granite, a preliminary selection of host rock in China, as a function of pH, adsorbate concentration, ionic strength and the composition of background electrolytes. A surface complexation model was set up using Generalized Composite approach based on Eu(III) adsorption in NaCl electrolyte, supported by X-ray photoelectron spectroscopy and verified by Eu(III) adsorption in the presence of CO2 at P CO 2 = 10 - 3.58 atm and in CaCl2 electrolyte. The model was successfully extended to describe Am(III) adsorption in both NaCl and CaCl2 electrolytes. It was also found that temperature effect on Eu(III) adsorption was negligible at 25–80 °C, that the adsorption of Eu(III) on freshly crushed granite with “new” surfaces and aged granite with “old” surfaces were identical to each other, and that the presence of fulvic acid of 2–20 mg/L significantly declined the distribution coefficients of Eu(III) and Am(III) in high pH range. Electron probe micro analyses indicated that biotite had higher affinity for Eu(III) than other major minerals, such as oligoclase, quartz and orthoclase.

A microfluidic system consisting of generic single use cartridges which interface with a workstation allows the automatic performance of all necessary sample preparation, PCR analysis and interpretation of multiplex PCR assays. The cartridges contain a DNA array with 20 different 16mer DNA "universal" probes immobilized at defined locations. PCR amplicons can be detected via hybridization of user-defined "reporter" probes that are complementary at their 3′ termini to one or more of the universal probes and complementary to the target amplicons at their 5′ termini. The system was able to detect single-plex and multiplex PCR amplicons from various infectious agents as well as wild type and mutant alleles of single nucleotide polymorphisms. The system's ease of use was further demonstrated by converting a published PCR assay for the detection of Mycobacterium genitalium in a fully automated manner. Excellent correlation between traditional manual methods and the automated analysis performed by the workstation suggests that the system can provide a means to easily design and implement a variety of customized PCR-based assays. The system will be useful to researchers or clinical investigators seeking to develop their own user defined assays. As the U.S. FDA continues to pursue regulatory oversight of LDTs, the system would also allow labs to continue to develop compliant assays.

Objective: We developed a microfluidic system to simultaneously detect host anti-HIV antibodies and viral RNA in the same specimen in order to satisfy two important diagnostic criteria, especially within resource-limited settings. First, the system can detect acute HIV infection and allow immediate confirmation of a seropositive screening result by detection of HIV RNA. It also addresses the well-known "seroconversion window" during early HIV infection when antibodies are not yet detectable and viral loads are at their highest. Methods: We first developed and optimized two separate manual assays for the detection of host anti-HIV antibodies and viral RNA and then converted them to the microfluidic system. We optimized a commercially available serologic assay to run within the microfluidic device while we incorporated the isothermal LAMP assay to detect the presence of viral RNA. The microfluidic device and instrumentation were developed to simultaneously perform both assays without any user intervention. Results: The finalized system consists of a disposable injection molded and film-laminated microfluidic CARD disposable device and a portable, software controlled instrument, which together can automatically perform all steps of both assays without any user intervention after the initial loading of samples and reagents. The microfluidic CARD cartridge has multiple microchannels, valves, pumps and reservoirs, which perform the immunoassay, isolates viral RNA for detection by magnetic bead based purification, and Reverse Transcriptase loop-mediated isothermal amplification (RT-LAMP). The microfluidic system was able to detect host anti-HIV antibodies and viral RNA in either a blood or saliva sample. Conclusion: The ability to detect antibodies and simultaneously confirm a seropositive HIV-RNA result provides healthcare workers with a complete and accurate appraisal of a patient's infection status in the earliest stages of the disease and represents an important tool for the "Test and Treat" and "Treatment as Prevention" approaches for controlling the HIV epidemic.

A versatile microfluidic platform for the evolving molecular diagnostics industry is described. It incorporates low cost Rheonix CARD(®) (Chemistry and Reagent Device) technology to analyze a variety of clinical specimens. A patented lamination process incorporates all pumps, valves, microchannels and reaction compartments into an inexpensive disposable plastic device. Once an untreated clinical specimen is introduced, all assay steps, including cell lysis, nucleic acid purification, multiplex PCR, and end-point analysis, are automatically performed. Three distinct CARD assays are described which utilize either a low density microarray for multiplex detection of amplicons or an integrated primer extension assay to detect single nucleotide polymorphisms of interest. The STI (Sexually Transmitted Infections) CARD(®) is able to simultaneously detect four sexually transmitted infectious agents (N. gonorrhoeae, C.trachomatis, T. pallidum and T. vaginalis). Human C33A cervical epithelial cells were spiked with different levels of genomic DNA from the four species of interest, singly or in combination, and applied to the CARD device. Using multiplex PCR amplification of the targets followed by microarray detection, the CARD device was able to correctly detect a minimum of 10 copies of each of the four pathogens. The HPV (Human Papillomavirus) CARD(®) was able to detect and distinguish 20 different clinically relevant HPV types using cloned HPV DNA. In addition, the HPV CARD could identify HPV types in vaginal specimens previously demonstrated to contain high or low risk HPV using a currently commercially available testing method. Finally, the detection of specific single nucleotide polymorphisms (SNP) associated with warfarin dosing sensitivity was achieved on the Warfarin Genotyping CARD(®) by analyzing human buccal swabs. Once multiplex PCR was completed, the SNPs were detected using a primer extension assay.

The acid-base chemistry of Beishan (Gansu, China) granite (BS03, 600 m) was studied by potentiometric titration, and the adsorption of Eu(III) on the granite was investigated using a batch technique. It was found that the pHPZNPC of the granite is 9.4 at I = 0.1 M NaCl and decreases to 9.0 at I = 0.4 M NaCl. The profile of parallel titration curves of the granite at variable ionic strengths is roughly comparable to that of montmorillonite under similar conditions. The distribution coefficient ( K d) of Eu(III) on the granite varies with pH, ionic strength and Eu(III) concentration. The K d values of Eu(III) decrease significantly with increasing ionic strength in the low pH range, whereas the effect of ionic strength on the K d values is very weak in the high pH range. The experimental results of Eu(III) adsorption on the granite as a function of pH, ionic strength and Eu(III) concentration were quantitatively interpreted by a model with a cation exchange reaction of Eu3+ on the granite and two inner-sphere surface complexation reactions of Eu(III) on the surface hydroxyl sites. The adsorption of Eu(III) on the granite at I = 0.1 M was predicted by the proposed model, which was compared with the results of Am(III) adsorption on the granite under similar conditions reported by other groups.

A "lab-on-a-chip" system for detecting bacterial pathogens in oral fluid samples is described. The system comprises: (1) an oral fluid sample collector; (2) a disposable, plastic microfluidic cassette ("chip") for sample processing including immunochromatographic assay with a nitrocellulose lateral flow strip; (3) a platform that controls the cassette operation by providing metered quantities of reagents, temperature regulation, valve actuation; and (4) a laser scanner to interrogate the lateral flow strip. The microfluidic chip hosts a fluidic network for cell lysis, nucleic acid extraction and isolation, PCR, and labeling of the PCR product with bioconjugated, upconverting phosphor particles for detection on the lateral flow strip.

Oral squamous cell carcinoma (OSCC) is a disfiguring and deadly cancer. Despite advances in therapy, many patients continue to face a poor prognosis. Early detection is an important factor in determining the survival of patients with OSCC. No accurate, cost-efficient, and reproducible method exists to screen patients for OSCC. As a result, many patients are diagnosed at advanced stages of the disease. Early detection would identify patients, facilitating timely treatment and close monitoring. Mass screening requires a rapid oral cancer diagnostic test that can be used in a clinical setting. Current diagnostic techniques for OSCC require modern laboratory facilities, sophisticated equipment, and elaborate and lengthy processing by skilled personnel. The lab-on-chip technology holds the promise of replacing these techniques with miniaturized, integrated, automated, inexpensive diagnostic devices. This article describes lab-on-chip devices for biomarker-based identification of oral cancer. Similar methods can be employed for the screening of other types of cancers.

ContextAlthough the value of pharmacogenomics to improve patient outcomes has become increasingly clear, adoption in medical practice has been slow, which can be attributed to several factors, including complicated and expensive testing procedures and required equipment, lack of training by private practice physicians, and reluctance of both private and commercial payers to reimburse for such testing.ObjectivesTo evaluate a fully automated molecular detection system for human genotyping assays, starting with anticoagulated whole blood samples, and to perform all sample preparation, assay, and analysis steps automatically with actionable results reported by the system's software.DesignThe genotypes of 254 random individuals were determined by performing bidirectional DNA sequencing, and that information was used to statistically train the imaging software of the automated molecular detection system to distinguish the 3 possible genotypes (ie, homozygous wild type, heterozygous, and homozygous mutant) at each of 3 different loci (CYP2C9*2, CYP2C9*3, and VKORC1).Results—The resulting software algorithm was able to correctly identify the genotypes of all 254 individuals (100%) evaluated without any further user analysis.ConclusionsThe EncompassMDx workstation (Rheonix, Inc, Ithaca, New York) is a molecular detection system that can automatically determine the genotypes of individuals in an unattended manner. Considerably less technical expertise was required to achieve results identical to those obtained using more complex, time-consuming, and expensive bidirectional DNA sequencing. This optimized system may dramatically simplify and reduce the costs of pharmacogenomics testing, thus leading to more-widespread use.

Transport processes in an upright, concentric, annular, electrochemical reactor filled with RedOx electrolyte solution are studied experimentally and theoretically. The electrodes form the two vertical surfaces of the reactor. The theoretical calculations consist of the solution of the Navier–Stokes and the Nernst–Planck equations accounting for species’ diffusion, migration, convection, and electrochemical reactions on the electrodes’ surfaces as a function of the difference in electrodes’ potentials and the average concentration of the electrolyte. Since the convection is driven by density gradients, the momentum and mass transport equations are coupled. The current transmitted through the electrolyte is significantly enhanced by natural convection. The current is measured as a function of the difference in the electrodes’ potentials. To obtain the reaction rate constants, an inverse problem is solved and the reaction rate constants are determined by minimizing the discrepancy between theoretical predictions and experimental observations. As an example, we study the reversible electrochemical reaction Fe +++ + e − = Fe ++ on platinum electrodes.

The pronounced volatility of elemental mercury (Hg0) and some of its compounds, coupled with their extreme toxicity, makes these substances extremely hazardous. Conversion of Hg0 to HgO would signi...

A pneumatically driven, disposable, microfluidic cassette comprised of a polymerase chain reaction (PCR) thermal cycler, an incubation chamber to label PCR amplicons with up-converting phosphor (UPT) reporter particles, conduits, temperature-activated, normally closed hydrogel valves, and a lateral flow strip, was constructed and tested. The hydrogel valves, which were opened and closed with the aid of electrically controlled thermoelectric units, provided a simple means to seal the PCR reactor and suppress bubble formation. The hydrogel-based flow control was electronically addressable, leakage-free, and biocompatible. To test the device, a solution laden with genomic DNA isolated from B. cereus was introduced into the microfluidic cassette and a specific 305 bp fragment was amplified. The PCR amplicons were labelled with the phosphor (UPT) reporter particles, applied to the lateral flow strip, bound to pre-immobilized ligands, and detected with an IR laser that scanned the lateral flow strip and excited the phosphor (UPT) particles that, in turn, emitted light in the visible spectrum. The UPT particles do not bleach, they provide a permanent record, and they readily facilitate the filtering of background noise. The cassette described herein will be used for rapid testing at the point of care.

International audience; Understanding the behavior of 137Cs and 135Cs in soils and geological formations is of considerable interest in the context of nuclear accidents and nuclear waste repositories. Although the clay fraction is known to be responsible for sorption, there are still unanswered questions raised by the literature data concerning (i) the reversibility of the sorption process(es), (ii) the validity of the additivity rule (the overall distribution coefficient (Kd) for a radionuclide on a mixture of minerals is predicted from the distribution coefficients measured on individual minerals) and (iii) the validity of model transposition from dispersed systems to consolidated/intact systems. Because of these uncertainties, the validity of sorption models at equilibrium under in-situ conditions and for very long-term interaction is still pending. These different issues are studied in the present work for the Callovo–Oxfordian (COx) clay-rich rock Formation, which is under investigation in France as a geological barrier for a long-term nuclear waste repository. The work is based on sorption data measured on thirteen samples of different mineralogy taken from five different boreholes at several depths within the COx sedimentary layer. To our knowledge, it is the most extended Cs sorption dataset that has been published for a single clay formation in term of (i) sample locations (and thus natural variability), (ii) sorption conditions (powder dispersed in suspension, compacted powders and intact samples) and (iii) equilibration time (from one week to five years). Moreover, for the first time ever, radioactive Cs sorption results were compared to the natural distribution of non-radioactive Cs isotopes between pore water and the solid phase. The experimental system appeared to be in chemical equilibrium as much as can be expected for an ion-exchange reaction. More particularly, no kinetically-controlled process leading to partial Cs irreversibility was observed, in contrary to what was found in the literature for soils. This difference in behavior may be related to the difference in the illite studied, i.e. a soil-type illite which would be more altered than a sedimentary formation-type illite. No decrease in site capacity was observed between dispersed and intact/compacted states. A model based on exchange reactions with cations interacting with illite (frayed edge, type-II and planar sites) and mixed layer illite–smectite (I/S) (planar sites) using parameters published in the literature enabled the Kd variation to be described as a function of Cs concentration, the mineralogy of the samples, the change in water composition and the temperature (22–80 °C). Our study clearly demonstrates that no frayed edge sites should be considered on the illite fraction of I/S, thus emphasizing the difference of sorption properties between an I/S mixed layer mineral and a corresponding mechanical mix of illite and smectite minerals. The robustness of the model was confirmed by data analysis describing the behavior of naturally-occurring Cs in the formation thereby demonstrating the effectiveness of the Cs sorption processes in a very long-time period prospective. Lastly, the model was used to predict the sorption of trace concentrations of Cs in the COx Formation on the time-scale relevant for nuclear waste disposal performance assessment. As expected, the retention was significant with Kd values ranging from 100 to 2000 L/kg whatever the conditions that were probed and a simulation covering a period of over 105 years could show that the COx Formation is an efficient barrier to prevent Cs transport from the storage facility to the surrounding environment.

An easy to fabricate, thermally-actuated, self-regulated hydrogel valve for flow control in pneumatically driven, microfluidic systems is described. This microvalve takes advantage of the properties of the hydrogel, poly(N-isopropylacrylamide), as well as the aqueous fluid itself to realize flow control. The valve was designed for use in a diagnostic system fabricated with polycarbonate and aimed at the detection of pathogens in oral fluids at the location of the sample collection. The paper describes the construction and characterization of the hydrogel valves and their application for flow control, sample and reagent metering, sample distribution into multiple analysis paths, and the sealing of a polymerase chain reaction (PCR) reactor to suppress bubble formation. The hydrogel-based flow control is electronically addressable, does not require any moving parts, introduces minimal dead volume, is leakage and contaminant free, and is biocompatible.

A self-actuated, flow-cycling polymerase chain reaction (PCR) reactor that takes advantage of buoyancy forces to continuously circulate reagents in a closed loop through various thermal zones has been constructed, tested, and modeled. The heating required for the PCR is advantageously used to induce fluid motion without the need for a pump. Flow velocities on the order of millimeters per second are readily attainable. In our preliminary prototype, we measured a cross-sectionally averaged velocity of 2.5 mm/s and a cycle time of 104 s. The flow velocity is nearly independent of the loop's length, making the device readily scalable. Successful amplifications of 700- and 305-bp fragments of Bacillus cereus genomic DNA have been demonstrated. Since the device does not require any moving parts, it is particularly suitable for miniature systems.

A prototype dual-path microfluidic device (Rheonix CARD) capable of performing simultaneously screening (antigen or antibody) and confirmatory (nucleic acid) detection of pathogens is described. The device fully integrates sample processing, antigen or antibody detection, and nucleic acid amplification and detection, demonstrating rapid and inexpensive “sample-to-result” diagnosis with performance comparable to benchtop analysis. For the chip design, a modular approach was followed allowing the optimization of individual steps in the sample processing process. This modular design provides great versatility accommodating different disease targets independently of the production method. In the detection module, a lateral flow (LF) protocol utilizing upconverting phosphor (UCP) reporters was employed. The nucleic acid (NA) module incorporates a generic microtube containing dry reagents. Lateral flow strips and PCR primers determine the target or disease that is diagnosed. Diagnosis of HIV infection was used as a model to investigate the simultaneous detection of both human antibodies against the virus and viral RNA. The serological result is available in less than 30 min, and the confirmation by RNA amplification takes another 60 min. This approach combines a core serological portable diagnostic with a nucleic acid-based confirmatory test.

The building blocks for an inexpensive, disposable, luminescence-based microfluidic immunoassay cassette are described, and their integration in a point-of-care diagnostic system is demonstrated. Fluid motion in the cassette is driven by depressing finger-actuated pouches. All reagents needed for the immunoassay can be stored in the cassette in liquid form. Prior to use, the cassette consists of two separate parts. A top storage component contains pouches, sealed storage chambers, a metering chamber, and needle seats. The bottom processing component contains connection needles, a mixing chamber, and a detection chamber with immobilized proteins. Subsequent to sample introduction, the storage and processing components are mated. The needles form hydraulic connections between the two parts and, in some cases, close valves. The pouches are then actuated sequentially to induce flow of various reagents and facilitate process operations. The cassette is compatible with different detection modalities. Both a cassette with immunochromatographic-based detection and a cassette with microbead-based detection were constructed and evaluated. The immunochromatographic cassette was used to detect antibodies to HIV in saliva samples. The bead-based cassette was used to detect the proinflammatory chemokine IL-8. The experimental data demonstrates good repeatability and reasonable sensitivity.

An inexpensive, hand-held, point-of-care, disposable, self-contained, immunoassay cassette comprised of air pouches for pumping, a metering chamber, reagents storage chambers, a mixer, and a lateral flow strip was designed, constructed, and tested. The assay was carried out in a consecutive flow format. The detection was facilitated with up-converting, phosphor (UCP) reporter particles. The automated, timely pumping of the various reagents was driven by a spring-loaded timer. The utility of the cassette was demonstrated by detecting antibodies to HIV in saliva samples and further evaluated with a non-contagious, haptenized DNA assay. The cassette has several advantages over dip sticks such as sample preprocessing, integrated storage of reagents, and automated operation that reduces operator errors and training. The cassette and actuator described herein can readily be extended to detect biomarkers of other diseases in body fluids and other fluids at the point of care. The system is particularly suitable for resource poor countries, where funds and trained personnel are in short supply.

The design of a microfluidic lab-on-a-chip system for point-of-care cancer screening and diagnosis of oral squamous cell carcinoma (OSCC) is presented. The chip is based on determining a approximately 30-gene transcription profile in cancer cells isolated from oral fluid samples. Microfluidic cell sorting using magnetic beads functionalized with an antibody against cancer-specific cell-surface antigens (e.g., epithelial cell adhesion molecule [EpCAM]) is described. A comprehensive cancer diagnostics chip will integrate microfluidic components for cell lysis, nucleic acid extraction, and amplification and detection of a panel of mRNA isolated from a subpopulation of cancer cells contained in a clinical specimen.