Significant Loss Of Stability Research Articles

Opportunities for Early Intervention to Support Families With Children of Early Age in Wartime: Parents' View

After the beginning of the full-scale Russian invasion of Ukraine, the situation for families with young children with developmental delays or disabilities and children at risk was characterized by a significant loss of stability and predictability, which are necessary conditions for the child's development. The war destroyed the foundations of stable life, daily routines and relationships in families, on which the early childhood intervention is based. With the beginning of the war, the question arose about the ability of the early intervention service to carry out effective activities in support and accompaniment of families raising young children developmental delays or disabilities and children at risk. The purpose of the study was to determine the features of the functioning and possibilities of the early intervention service in support and accompaniment of families with young children in a war situation. A questionnaire was developed for the research. The analysis of the obtained results was carried out using the method of constant comparison. It has been proven that the early intervention service makes it possible to provide support to parents, ensure their awareness, emotional stability, sensitivity, and supports the parents' ability to "see" the child, understand his real needs. And this creates favorable conditions for the formation of child-parent relations, allows strengthening the existing and finding new family resources for experiencing traumatic events related to the war situation.

Investigation of the Physicochemical and Biological Stability of the Adalimumab Biosimilar CT-P17.

CT-P17 (Celltrion, Inc., Incheon, Republic of Korea) is a biosimilar of reference adalimumab (Humira®; AbbVie Inc., North Chicago, IL, USA), which has recently received regulatory approval from the European Medicines Agency. This analysis was designed to evaluate the stability profile of CT-P17 compared with reference adalimumab and the currently licensed adalimumab biosimilars ABP501 (Amjevita®/Amgevita®; Amgen Inc., Thousand Oaks, CA, USA) and SB5 (Imraldi®; Biogen Inc., Cambridge, MA, USA) when stored at low temperature (5°C) or room temperature (25°C) with 60% relative humidity for up to 28days. Multiple orthogonal and complementary tests demonstrated that CT-P17 was stable for 28days under all tested conditions, as well as for protein concentrations tested (50 vs 100mg/mL), type of delivery device (autoinjector vs prefilled syringe), and manufacturing date (recently manufactured vs aged for 17months). There were slight differences among products in terms of charge variants, oxidation level, purity, and number of subvisible particles; however, overall, the quality of each product was maintained over 28days. Our data suggest that CT-P17 may be used without any significant loss of stability when stored at 5°C or 25°C with 60% relative humidity for up to 28days, and was not impacted by protein concentration tested and delivery device. Comparative stability data suggest that the appropriate maximum storage period for CT-P17 may be up to 28days at room temperature with 60% relative humidity.

Synthesis of MCM-41 supported cobalt (II) complex for the formation of polyhydroquinoline derivatives

A new and green heterogeneous MCM-41@PDCA-Co catalyst has been prepared via immobilization of cobalt (II) complex onto the surface of MCM-41. This was characterized by different techniques such as FT-IR, TEM, TGA, low angle Powder XRD, MP-AES and nitrogen sorption. The MCM-41@PDCA-Co has been applied in the synthesis of polyhydroquinoline (PHQs) and its derivatives in 98% yield which is four component reaction under solvent free condition at 100 °C. The synthesized catalyst can be easily recovered from the reaction mixture by simple filtration method. This can be reused several times without any significant loss in stability and activity.

Relationship between Implant Geometry and Primary Stability in Different Bony Defects and Variant Bone Densities: An In Vitro Study.

Aim: This in vitro study aimed to evaluate the effects of implant designs on primary stability in different bone densities and bony defects. Methods: Five implant types (tapered-tissue-level, tissue-level, zirconia-tissue-level, bone-level, and BLX implants) were used in this assessment. The implants were inserted into four different artificial bone blocks representing varying bone-density groups: D1, D2, D3, and D4. Aside from the control group, three different types of defects were prepared. Using resonance frequency analysis and torque-in and -out values, the primary stability of each implant was evaluated. Results: With an increased defect size, all implant types presented reduced implant stability values measured by the implant stability quotient (ISQ) values. Loss of stability was the most pronounced around circular defects. Zirconia and bone-level implants showed the highest ISQ values, whereas tissue level titanium implants presented the lowest stability parameters. The implant insertion without any thread cut led to a small improvement in primary implant stability in all bone densities. Conclusions: Compared with implants with no peri-implant defects, the three-wall and one-wall defect usually did not provide significant loss of primary stability. A significant loss of stability should be expected when inserting implants into circular defects. Implants with a more aggressive thread distance could increase primary stability.

Nickel cobaltite nanoparticles: preparation, characterization, and catalytic activity

The preparation and characterization of binary spinel nickel cobaltite, NiCo2O4 are presented by two methods. The prepared NiCo2O4 nanocomposites were tested for 1,3-dipolar cycloaddition reaction of different benzyl halides with phenylacetylene. The heterogeneity of the NiCo2O4 catalytic system was investigated using a hot filtration test, indicating that there is virtually no catalyst leaching into the reaction solution under the applied reaction conditions. Furthermore, our results show that the catalytic system can be reused four times without significant loss of stability or any additional treatment.

Effect of storage conditions on long-term stability of Ag nanoparticles formed via green synthesis

Spherical Ag nanoparticles (AgNPs) with a diameter of 20 nm or smaller were biologically synthesized using algae Parachlorella kessleri. The effect of storage conditions on the long-term stability of AgNPs was investigated. UV/Vis spectrophotometry, transmission electron microscopy, and dynamic light scattering measurements revealed that the long-term stability of AgNPs was influenced by light and temperature conditions. The most significant loss of stability was observed for the AgNPs stored in daylight at room temperature. The AgNPs stored under these conditions began to lose their stability after approximately 30 d; after 100 d, a substantial amount of agglomerated particles settled to the bottom of the Erlenmeyer flask. The AgNPs stored in the dark at room temperature exhibited better long-term stability. Weak particle agglomeration began at approximately the 100th day. The AgNPs stored in the dark at about 5°C exhibited the best long-term stability; the AgNPs stored under such conditions remained spherical, with a narrow size distribution, and stable (no agglomeration) even after 6 months. Zeta-potential measurements confirmed better dispersity and stability of AgNPs stored under these conditions.

Synthesis and characterization of a Pd(0) Schiff base complex anchored on magnetic nanoporous MCM-41 as a novel and recyclable catalyst for the Suzuki and Heck reactions under green conditions

A Pd Schiff base complex was immobilized onto the surface of magnetic MCM-41 (Fe3O4@MCM-41@Pd(0)-P2C) as a novel, eco-friendly, and recyclable heterogeneous nanocatalyst and fully characterized by FT-IR, VSM, EDS, transmission electron microscopy, scanning electron microscopy, thermogravimetric analyses, ICP-OES, and X-ray powder diffraction analysis. The Fe3O4@MCM-41@Pd(0)-P2C was investigated as a catalyst for the one-pot Suzuki and Heck reactions in PEG as a green solvent to provide the target products in excellent yields. The main advantages of using this catalyst include a short reaction time, green reaction conditions, a simple experimental procedure, non-use of hazardous organic solvents, low loading of the catalyst, and the ability to use various substrates. More importantly, the catalyst could be easily separated from the reaction mixture with the assistance of an external magnet and could be recovered and reused several times without significant loss of stability and activity.

Bidentate salen Cu(II) complex functionalized on mesoporous MCM-41 as novel nano catalyst for the oxidative coupling of thiols into disulfides using urea hydrogen peroxide (UHP)

Functionalized Copper(II) complex into nano dimensional mesoreactor was successfully prepared. The Copper(II) complex with N–O donor Schiff base ligand was readily trapped into mesoporous silica MCM-41 through the post grafting method. N–O Chelating Schiff-base-MCM-41 has been derived from 5-bromo-salicylaldehyde and 3-aminopropyltriethoxysilane which was functionalized on MCM-41 via silicon alkoxide route. This compound was characterized by FT-IR, TGA, small angle X-ray diffraction patterns, ICP/MS analysis and N2 sorption–desorption analysis. The catalytic property of Cu–salen–MCM-41 was considered for the preparation of disulfides using urea hydrogen peroxide as oxidant. The reaction progress is simple and proceeds under mild and heterogeneous conditions in acetonitrile at the ambient of temperature. The corresponding disulfides have been achieved with high purity and good to excellent yields; also, no over oxidation to sulfoxide or sulfone was observed in all cases. The catalyst can be recovered and reused several times without significant loss of stability and activity.

Dynamic quantification of tibio-femoral rotation in postero-lateral bundle insufficiency of the anterior cruciate ligament: a cadaver study.

Anterior cruciate ligament (ACL) injury represents one of the most common diagnoses in orthopaedic sports medicine. In the past, anatomic knowledge about the different bundles within the cruciate ligaments triggered new treatment concepts, such as double-bundle ACL reconstruction. Recently, besides complete tearing, partial ACL ruptures and bundle augmentation became a focus. However, only little is known regarding rotational stability of the knee with an isolated torn postero-lateral (PL) bundle. Therefore, the aim of the present study was the torsiometric analysis of tibio-femoral restraint patterns of the PL-insufficient knee joint. Fresh human whole body cadavers were enrolled. After diagnostic arthroscopy to ensure the structural integrity of the cruciate ligaments, knee joints underwent torsiometry at 0°, 30°, and 90° degree flexion. Then stepwise the PL bundle and the anteromedial (AM) bundle were arthroscopically resected, while torsiometry of the PL- as well as of the ACL-deficient knee joints was repeated. An area under the curve (AUC) was calculated. All statistical analyses were conducted using a p-value of 0.05 as level of significance. The comparison of charged and equilibrated curves during internal rotation revealed significant results at low flexion (30° flexion) angles between the ACL intact versus PL absent conditions (p = 0.04). In addition, charged and equilibrated curves during external rotation at 90° flexion, thus high angles, resulted in a significant difference when comparing the ACL-intact with the PL-deficient condition (p = 0.01). In the present cadaver study using the Torsiometer tool we found a distinct destabilization of the rotational restraints in full knee extension only after total ACL resection. In contrast, no significant findings resulted after an isolated dissection of the PL bundle during internal deflection. Nevertheless, a significant loss of stability was found during unstressed external deflection after isolated PL bundle dissection. Therefore patients, undergoing PL augmentation might benefit regarding rotational instability patterns.

Synthesis, catalytic activity, and leaching studies of a heterogeneous Pd-catalyst including an immobilized bis(oxazoline) ligand

The synthesis and characterization of a novel catalytic system including Pd(OAc)2 attached to a bis(oxazoline) (=BOX) ligand that is covalently bonded to 3-mercaptopropyl-functionalized silica gel is presented. The catalyst was tested for Suzuki–Miyaura reactions of different aryl halides with phenylboronic acid. The heterogeneity of the catalytic system was investigated using different approaches, indicating that there is virtually no Pd leaching into the reaction solution under the applied reaction conditions. Furthermore, our results show that the catalytic system can be reused multiple times without significant loss of stability or structure.

STABILITY OF FAMOTIDINE IN POLYPROPYLENE SYRINGES USING A STABILITY-INDICATING HPLC ASSAY

Famotidine syringes (2 mg/mL) were prepared under sterile conditions in accordance with United States Pharmacopeia (USP). To test the stability, syringes were kept for 30 d under three different temperature conditions: room temperature (22–25°C), refrigerated (2–6°C), and frozen (−20°C). Three samples from each temperature were withdrawn and were assessed for stability on days 0, 7, 15, 22, and 30 as per the USP guidelines. Physical stability was assessed by visual examination and pH values. The assay of famotidine was examined by a stability-indicating HPLC method and a significant loss of stability was defined as 10% or greater decrease in famotidine content over time. Physical stability results illustrated that no precipitation, cloudiness, or color change was observed in famotidine syringes at all the temperatures studied. Results from the assay content by HPLC showed that famotidine injections retain greater than 90% of the initial concentrations for 30 d when stored at room temperature and frozen; and 22 d when refrigerated. Thus, we can conclude that when stored at room temperature or frozen, diluted famotidine injections (2 mg/mL in sterile water) in 12 mL polypropylene syringes are stable for at least 30 d and for 22 d when refrigerated.

Use of Stabilizing Mutations To Engineer a Charged Group within a Ligand-Binding Hydrophobic Cavity in T4 Lysozyme

Both large-to-small and nonpolar-to-polar mutations in the hydrophobic core of T4 lysozyme cause significant loss in stability. By including supplementary stabilizing mutations we constructed a variant that combines the cavity-creating substitution Leu99 --> Ala with the buried charge mutant Met102 --> Glu. Crystal structure determination confirmed that this variant has a large cavity with the side chain of Glu102 located within the cavity wall. The cavity includes a large disk-shaped region plus a bulge. The disk-like region is essentially nonpolar, similar to L99A, while the Glu102 substituent is located in the vicinity of the bulge. Three ordered water molecules bind within this part of the cavity and appear to stabilize the conformation of Glu102. Glu102 has an estimated pKa of about 5.5-6.5, suggesting that it is at least partially charged in the crystal structure. The polar ligands pyridine, phenol and aniline bind within the cavity, and crystal structures of the complexes show one or two water molecules to be retained. Nonpolar ligands of appropriate shape can also bind in the cavity and in some cases exclude all three water molecules. This disrupts the hydrogen-bond network and causes the Glu102 side chain to move away from the ligand by up to 0.8 A where it remains buried in a completely nonpolar environment. Isothermal titration calorimetry revealed that the binding of these compounds stabilizes the protein by 4-6 kcal/mol. For both polar and nonpolar ligands the binding is enthalpically driven. Large negative changes in entropy adversely balance the binding of the polar ligands, whereas entropy has little effect on the nonpolar ligand binding.

Rate of chloramine decay at pipe surfaces

Characterizing the rate of chloramine loss at pipe surfaces is crucial for predicting the rate of decay within the distribution system (DS). Chloramines in finished water are relatively stable, yet they do autodecompose. However, significant loss of stability can occur in the DS where interaction with pipe surfaces is a major source of chloramine loss. Myriad factors complicate in situ measurement of the surface reaction rate including spatially varying pipe material, age, and condition, as well as temporally varying hydraulics. In this study, a bench‐scale, pipe section reactor was used to determine chloramine surface reaction rate constants for cementlined ductile‐iron pipe and tuberculated, unlined cast‐iron pipe. Chloramine decay was found to be first order for both of these pipe materials. Surface reaction rates were calculated by accounting for the influence of water velocity on mass transfer of chloramine to the pipe surface, and therefore the overall chloramine decay rate. Temperature and pH were varied to determine the effect on surface reaction rates for a range of conditions common to the DS.

Biomechanical evaluation of conventional anulus fibrosus closure methods required for nucleus replacement

Nucleus replacement implants became increasingly attractive as an alternative to fusion, discectomy, or total disc replacement. The goals of nucleus replacement are to restore disc height and flexibility and to preserve the anatomy. However, implant extrusions have been reported and are the major concern. In this study the authors investigated different conventional surgical methods for anulus closure: suture alone, and fibrin glue and cyanoacrylate glue, alone and with suture. The in vitro testing was conducted using 30 lumbar spinal segments obtained from calves. In each specimen, an incision was made; the nucleus was removed and subsequently replaced by a collagen matrix. The incisions were treated with anulus closure methods in 5 groups of animals. Flexibility was assessed in a spine tester. Subsequently, specimens were exposed to cyclic fatigue loading by using a hydraulic loading frame. Specimens were excentrically loaded in sine waveform up to a maximum of 100,000 cycles with 4-24 Nm at 5 Hz while being rotated at 360 degrees/minute. Removal of the nucleus caused a significant loss of stability. The segmental stability could be restored after the implantation. Fatigue testing indicated that suturing was able to sustain 3400 cycles. Fibrin glue failed earlier than cyanoacrylate glue. Both combinations (suture with glue) provided longer stability to the anulus closure. The results suggested that closing the anulus incision with suture or fibrin glue alone might not be appropriate. The authors found that the best method was cyanoacrylate glue with suture. Although this method provided the longest duration of closure, it could not sustain the maximum number of fatigue cycles. Conventional methods could improve the outcome compared with using no closure. Nonetheless, the authors' findings highlight the demand for an appropriate anulus reconstruction method or device with good long-term reliability.

Expression, characterization, and reaction of recombinant monkey metallothionein-1 and its C33M mutant.

After we modified the protocol of purification, monkey metallothionein-1 (mkMT-1) and its mutant at position 33 (C33M mutant) were efficiently expressed and purified by using the glutathione-S-transferase fusion protein system. The protein yield has been considerably improved (8 mg/L culture for mkMT-1 and 10 mg/L culture for C33M mutant). The recombinant MT-1 and C33M mutant were characterized by ESI-MS, UV, and CD spectra. The reactions of MI-1 and C33M mutant with 5,5'-dithiobis(2-nitrobenzoic acid) and EDTA also have been carefully studied. The pH titration of MT-1 and C33M mutant has been studied by UV and CD spectra. The mutation of cysteine-to-methionine at position 33 mostly maintains the alpha-domain structure similar to that in wild-type mkMT-1, but the C33M mutant has significant loss of stability and cooperative properties of the domain.

Interpretation of photocurrent transients in amorphous semiconductors

This paper reviews recent work in the development and improvement of techniques to determine the energy distribution of localised states (DOS) in semiconductors from their transient photocurrent (TPC) response, in a multi-trapping context. We first outline the development of general transform-based techniques, which may be applied to cases in which carriers are replenished from device contacts, where both trapping and release processes are significant. We then outline the development of a `post-transit' analysis restricted to situations in which carriers are extracted at contacts, where only carrier release processes are significant. In both cases we demonstrate that by eliminating approximations previously employed to aid computational stability we can achieve analytical DOS spectroscopies capable of much finer energy resolution, without significant loss of stability. The techniques described are applied to experimental photocurrent decay data on a-Si:H.

Thermodynamic and Structural Compensation in “Size-switch” Core Repacking Variants of Bacteriophage T4 Lysozyme

Previous analysis of randomly generated multiple mutations within the core of bacteriophage T4 lysozyme suggested that the “large-to-small” substitution Leu121 to Ala (L121A) and the spatially adjacent “small-to-large” substitution Ala129 to Met (A129M) might be mutually compensating. To test this hypothesis, the individual variants L121A and A129M were generated, as well as the double “size-switch” mutant L121A/A129M. To make the interchange symmetrical, the combination of L121A with A129L to give L121A/A129L was also constructed. The single mutations were all destabilizing. Somewhat surprisingly, the small-to-large substitutions, which increase hydrophobic stabilization but can also introduce strain, were less deleterious than the large-to-small replacements. Both Ala129 → Leu and Ala129 → Met offset the destabiliza tion of L121A by about 50%. Also, in contrast to typical Leu → Ala core substitutions, which destabilize by 2 to 5 kcal/mol, Leu121 → Ala slightly stabilized A129L and A129M. Crystal structure analysis showed that a combination of side-chain and backbone adjustments partially accommo dated changes in side-chain volume, but only to a limited degree. For example, the cavity that was created by the Leu121 to Ala replacement actually became larger in L121A/A129L. The results demonstrate that the destabilization associated with a change in volume of one core residue can be specifically compensated by an offsetting volume change in an adjacent residue. It appears, however, that complete compensation is unlikely because it is difficult to reconstitute an equivalent set of interactions. The relatively slow evolution of core relative to surface residues appears, therefore, to be due to two factors. First, a mutation in a single core residue that results in a substantial change in size will normally lead to a significant loss in stability. Such mutations will presumably be selected against. Second, if a change in bulk does occur in a buried residue, it cannot normally be fully compensated by a mutation of an adjacent residue. Thus, the most probable response will tend to be reversion to the parent protein.