Nonneuronal isoforms of STOP protein are responsible for microtubule cold stability in mammalian fibroblasts

A number of cycling mammalian cells, such as NIH 3T3, contain abundant subsets of cold-stable microtubules. The origin of such microtubule stabilization in nonneuronal cells is unknown. We have previously described a neuronal protein, stable tubule-only polypeptide (STOP), that binds to microtubules and induces cold stability. We find that NIH 3T3 fibroblasts contain a major 42-kDa isoform of STOP (fibroblastic STOP, F-STOP). F-STOP contains the central repeats characteristic of brain STOP but shows extensive deletions of N- and C-terminal protein domains that are present in brain STOP. These deletions arise from differences in STOP RNA splicing. Despite such deletions, F-STOP has full microtubule stabilizing activity. F-STOP accumulates on cold-stable microtubules of interphase arrays and is present on stable microtubules within the mitotic spindle of NIH 3T3 cells. STOP inhibition by microinjection of affinity-purified STOP central repeat antibodies into NIH 3T3 cells abolishes both interphase and spindle microtubule cold stability. Similar results were obtained with Rat2 cells. These results show that STOP proteins have nonneuronal isoforms that are responsible for the microtubule cold stability observed in mammalian fibroblasts.     

Studies of metal ion binding by apo-metallothioneins attached onto preformed self-assembled monolayers using a highly sensitive surface plasmon resonance spectrometer

The use of a flow-injection surface plasmon resonance (FI-SPR) spectrometer equipped with a bicell detector or a position-sensitive device for determining coordination of heavy metal ions (Cd(2+) and Hg(2+)) by surface-confined apo-metallothionein (apo-MT) molecules is described. To facilitate the formation of a compact MT adsorbate layer with a uniform surface orientation, MT molecules were attached onto a preformed alkanethiol self-assembled monolayer. The method resorts to the generation of apo-MT at the surface by treating the MT-covered sensor chip with glycine-HCl and the measurement of the apo-MT conformation changes upon metal ion incorporation. Domain-specific metal ion binding processes by the apo-MT molecules were observed. Competitive replacement of one metal ion by another can be monitored in real time by FI-SPR. The tandem use of an immobilization scheme for forming a sub-monolayer of MT molecules at the sensor surface and the highly sensitive FI-SPR instrument affords a low concentration detection level. The detection level for Cd(2+) (0.1 μM or 15 ppb) compares favorably with similar studies and the methodology complements to other well-established sensitive analytical techniques. The extent of metal incorporation by apo-MT molecules was also determined.     

Ferroelectric Phase Transition,Interfaces Quality,and Stress Evolution of TiOx/BaxSr1−xTiO3 Structures

Ba(Sr,Ti)O₃ material presents a remarkable property that lies in the possibility to change the permittivity by applying a dc electric field, i.e., BST is a tunable material. That makes BST a very interesting material for the development of reconfigurable devices in microelectronics. In this study, we focus our work on Ba(Sr,Ti)O₃ with Ba/Sr = 30/70, the films are deposited by radio‐frequency magnetron sputtering on Al₂O₃ (0001). A buffer layer of TiO_x is used to control the film orientation. The influence of this buffer layer on the dielectric properties, the interfaces quality with respect to the film thickness, and the temperature is analyzed. An increase of 30% of the relative permittivity was measured and a tunability of 50% was attained at 300 KV/cm. The dielectric measurements on BST/TiO_x as a function of the temperature show a shift of the Curie temperature (T_c = ?40°C) in comparison to BST without TiO_x layer (T_c = ?80°C). We demonstrate that the Curie temperature does not correspond to the maximum permittivity. The important stress measured on the films (930 MPa) could explain this behavior.     

Mesoporous Silica Nanoparticles: Selective Surface Functionalization for Optimal Relaxometric and Drug Loading Performances

Mesoporous silica nanoparticles (MSNs) have emerged as promising biomaterials for drug delivery and cell tracking applications, for which MRI is the medical imaging modality of choice. In this contribution, MRI contrast agents (DTPA‐Gd) and polyethylene glycol (PEG) are grafted selectively at the surface of MSNs, in order to achieve optimal relaxometric and drug loading performances. In fact, DTPA and PEG grafting procedures reported until now, have resulted in significant pore obstruction, which is detrimental to the drug delivery function of MSNs. This usually induces a dramatic decrease in surface area and pore volume, thus limiting drug loading capacity. Therefore, these molecules must be selectively grafted at the outer surface of MSNs. In this study, 3D pore network MSNs (MCM‐48‐type) are synthesized and functionalized with a straightforward and efficient grafting procedure in which DTPA and PEG are selectively grafted at the outer surface of MSNs. No pore blocking is observed, and more than 90% of surface area, pore volume and pore diameter are retained. The thus‐treated particles are colloidally stable in SBF and cell culture media, they are not cytotoxic and they have high drug loading capacity. Upon labeling with Gd, the nanoparticle suspensions have strong relaxometric properties (r₂/r₁ = 1.47, r₁ = 23.97 mM^?1 s^?1), which confers a remarkable positive contrast enhancement potential to the compound. The particles could serve as efficient drug carriers, as demonstrated with a model of daunorubicin submitted to physiological conditions. The selective nanoparticle surface grafting procedures described in the present article represent a significant advance in the design of high colloidal stability silica‐based vectors with high drug loading capacity, which could provide novel theranostic nanocompounds.     

Non-Newtonian fluid flow model for ceramic tape casting

The current device of miniaturisation and higher device counts in integrated circuit (IC) packages has significantly increased the use of both multilayer ceramic packages (MLCP) and multilayer capacitors (MLC). Currently, one of the main methods used for the manufacture of flat ceramic packages with precise thickness control and consistency is the tape casting technique. Since these tapes can be cast with thickness of about 100 μm, it is crucial that the control of green tape thickness is precise, and that these thickness values are reproducible consistently. The flow of the slurry onto the casting surface can be modelled as a two dimensional fluid flow through a parallel channel. By choosing a suitable constitutive model, the predictions of the proposed model and existing models were compared with experimental results. The proposed model accurately described the fluid flow characteristics of the process, and had good agreement with experimental results.     

Average reservoir pressure determination for homogeneous and naturally fractured formations from multi-rate testing with the TDS technique

Average reservoir pressure is an important parameter which is utilized in almost all reservoir and production engineering studies. It also plays a relevant role in the majority of well intervention jobs, field appraisal, well sizing and equipment and surface facilities design.The estimation of the average reservoir pressure is normally obtained from buildup tests. However, it has a tremendous economic impact caused by shutting-in the well during the entire test. Since buildup tests are the most particular case of multi-rate tests, these are also used for estimation of the average reservoir pressure. Among them, two-rate tests present drawbacks because it is operationally difficult to keep constant the flow rates. Conventional methods for determination of the average reservoir pressure can be readily extended to multi-rate tests once the rigorous time is converted to equivalent time by time superposition.In this article a new, easy and practical methodology is presented for the determination of the average pressure in both homogeneous and naturally fractured reservoirs from multi-rate tests conducted in vertical oil wells located inside a close drainage region. The methodology which follows the philosophy of the TDS technique uses a normalized pressure and pressure derivative point found on any arbitrary point during the pseudosteady-state flow regime to readily provide the average reservoir pressure value.For verification of the effectiveness of the proposed solution, several field and simulated examples were worked out. We found that the average reservoir pressure results obtained from the proposed methodology match very well with those estimated from either conventional techniques or simulations.     

Phloem sap collection from lettuce (Lactuca sativa L.): Methodology and yield

Three methods to collect phloem sap on different lettuce lines were optimized and are described in detail. The success ratio for stylectomy of aphids was over 80% through the combination of a specially designed setup and electrical penetration graphs to monitor phloem sap ingestion. For unknown reasons on some lettuce lines stylets never showed sustained exudation. There were clear differences in stylet exudation between two aphid species on the same lettuce line. Honeydew collection in hexadecane made accurate quantitative analysis possible; samples were large and clean, but biotransformed. The EDTA chelation method produced large samples, but dilution, oxidation, and impurities from the wound surface reduced the reliability.     

SQLf: a relational database language for fuzzy querying

An important issue in extending database management systems functionalities is to allow the expression of imprecise queries to enable these systems to satisfy the user needs more closely. This paper deals with imprecise querying of regular relational databases. The basic idea is to extend an existing query language, namely SQL. In this context, two important points must be considered: one concerns the integration in the extended language of many propositions that have been made elsewhere, in particular those concerning fuzzy aggregation operators; and the second point is to know whether the equivalences which are valid in SQL still hold in the extended language. Both these topics are investigated in this paper