Tailoring the reducibility and catalytic activity of CuO nanoparticles for low temperature CO oxidation

Copper oxide (CuO) nanoparticles have received considerable interest as active and inexpensive catalysts for various gas–solid reactions. The CuO reducibility and surface reactivity are of crucial importance for the high catalytic activity. Herein, we demonstrate that the reducibility and stability of CuO nanoparticles can be controlled and tailored for the high catalytic activity of CO oxidation. The synthesized CuO nanoparticles possessed enhanced reducibility in CO atmosphere at lower reduction temperature of 126 °C compared to 284 °C for that of reference CuO particles. Moreover, the CuO catalysts with tailored reducibility demonstrated a reaction rate of 35 μmol s⁻¹ g⁻¹ and an apparent activation energy of 75 kJ mol⁻¹. Furthermore, the tailored catalysts exhibited excellent long-term stability for CO oxidation for up to 48 h on stream. These readily-reducible CuO nanoparticles could serve as efficient, inexpensive and durable catalysts for CO oxidation at low temperatures.

Copper oxide (CuO) nanoparticles of tailored reducibility could be used as inexpensive, efficient and durable catalysts for CO oxidation at low temperature.     

Effect of shoulder girdle strengthening on trunk alignment in patients with stroke

[Purpose] This study investigated the effect of shoulder girdle strengthening, particularly the scapular muscles, on poststroke trunk alignment. [Subjects and Methods] The study involved 30 patients with residual hemiparesis following cerebrovascular stroke. Patient assessment included measuring shoulder muscle peak torque, scapular muscles peak force, spinal lateral deviation angle, and motor functional performance. Patients were randomly allocated either to the control group or the study group and received an 18-session strengthening program including active resisted exercises for shoulder abductors and external rotators in addition to trunk control exercises. The study group received additional strengthening exercises for the scapular muscles. [Results] The two groups showed significant improvement in strength of all shoulder and scapular muscles, with higher improvement in the study group. Similarly, the lateral spinal deviation angles significantly improved in both groups, with significantly higher improvement in the study group. Transfer activity, sitting balance, upper limb functions, and hand movements significantly improved in the two groups, with higher improvement in the latter two functions in the study group. [Conclusion] Strengthening of shoulder girdle muscles, particularly scapular muscles, can significantly contribute to improving the postural alignment of the trunk in patients with poststroke hemiparesis.Key words: Stroke, Scapular muscles strengthening, Lateral trunk alignment     

Ex vivo immunomodulatory effect of all-trans-retinoic acid during Behçet’s disease: a study in Algerian patients

Uveitis, recurrent oral and genital ulcerations associated with skin lesions are the major symptoms of a chronic multisystemic inflammatory disorder known as Behçet’s disease (BD). High prevalence of this dreaded disease has been observed in the Mediterranean basin, including Algeria and along the Silk Road. Although the etiologic agent of this disease remains uncertain, many hypotheses have been advanced in its pathogenesis. Our team has previously reported high levels of nitric oxide (NO) in sera of BD patients, suggesting its deleterious effect during chronic inflammation. In our current study, the aim is to investigate the ex vivo immunomodulatory effect of all-trans-retinoic acid (ATRA) on NO pathway in Algerian BD patients. First, peripheral blood mononuclear cells isolated from active and inactive BD patients and healthy controls were cultured with different concentrations of ATRA. NO production was estimated with the Griess method. To elucidate the underlying mechanisms of ATRA effect on NO production, we analyze inducible nitric oxide synthase expression and nuclear factor-κB (NF-κB) activity by immunofluorescence test. Our results revealed a higher production of NO in active BD compared with the inactive stage and healthy controls. We observed that ATRA inhibits NO production in BD both in active and inactive stages and inhibits NF-κB translocation. In conclusion, we report a relationship between NO production and the disease activity. ATRA down-regulates NO production in BD patients. This immunomodulatory effect seems to be mediated through NF-κB pathway. All these findings suggest that ATRA could be considered as a promising therapy for BD.     

Attachment and psychological well-being among adolescents with and without disabilities in Kenya: The mediating role of identity formation

The current study is aimed at evaluating the relationship between attachment and identity development, and their influence on psychological well-being in adolescents with and without disabilities in Kenya. The sample was composed of 296 adolescents (151 with disabilities and 145 without any disability). The mean age in our sample was 16.84 years (SD = 1.75). Adolescents with disabilities had significantly lower scores in identity formation, paternal attachment, and life satisfaction. A path model indicated that identity formation partially mediated the relationship between secure attachment and psychological well-being. Our findings indicate that both parent and peer attachment play an important role in the identity formation and psychological well-being of adolescents in Kenya, irrespective of a disabling condition. A multigroup analysis indicated that while the structure of the relationship between variables held for groups, the pattern and strength of the relationships differed. Implications for practice, especially the guidance and counseling services in schools, are discussed.     

Use of Cyclodextrin as a Novel Agent in the SEC-HPLC Mobile Phase to Mitigate the Interactions of Proteins or Peptide or their Impurities with the Residual Silanols of Commercial SEC-HPLC Columns with Improved Separation and Resolution

Purpose

Accurate quantification of the intact proteins, antibodies or peptides and their impurities without interaction to silanols of HPLC column.

Methods

Hydroxypropyl ß Cyclodextrin (HPCD) is added in the mobile phase at different concentrations. Different commercial SEC-HPLC columns and biologics with a molecular weight ranging from 5.8 kDa to 150kDa were assessed with and without cyclodextrin.

Results

Addition of non-ionic sugars such as Hydroxypropyl ß Cyclodextrin in the mobile phase, resulted improved peak performance such as theoretical plates, peak resolution, peak width, peak height, and improved quantification of aggregates in biologics such as antibodies Humira and Actemra, and peptides such as insulin. There is an increase in peak height, reduced retention time, increased plate and reduced peak width with increasing concentration of cyclodextrin studied.

Discussion

High ionic strength, basic amino acids such as arginine, organic solvents (with a concentration low enough not to precipitate protein), sodium perchlorate and ion pairing agents in the mobile phase used for separation of peptides, proteins and antibodies to prevent silanol interaction. These commonly used solutions are not always successful, as they not only interact with the biologic, but are sometimes, not compatible. The non-ionic cyclodextrin itself does not cause protein aggregation but prevents the nonspecific binding or interaction of protein itself and thereby allowing for improved resolution, and accurate quantification of aggregates in antibodies, and peptides. The data on the separation in presence of cyclodextrin in the mobile phase showed higher peak resolution, improved peak shape, accurate apparent molecular weight, improved efficiency, and less peak tailing for biological products.

Conclusion

Hydroxypropyl ß Cyclodextrin in the mobile phase, resulted improved SEC-HPLC resolution, and quantitation of aggregates in biologics by preventing the interaction of biologics to silanol of the commercial SEC-HPLC columns.