Human resource management practices and organizational performance: The mediation of knowledge management and the moderation of competitive strategies in Jordanian service organizations

This study examined the mediating influence of knowledge management on human resource management (HRM) practices and organizational performance (OP), and the moderating role of competitive strategies on the relationship between knowledge management (KM) and organizational performance. Two-hundred and sixty service organizations in Jordan participated in the survey. Multiple regression and hierarchical multiple regressions were used to test the hypotheses. Results indicated that only three dimensions of HRM practices (i.e. staffing, training and development, and job security) had positive influence on OP. Factor analysis revealed three dimensions of KM: technical, cultural, and human. The results further showed that specific HRM practices were significantly associated with different KM dimensions. Performance appraisal had a positive influence on technical KM, while staffing, performance appraisal, and job security were positively associated with cultural KM. Staffing, training and development, and employee participation and involvement were found to enhance human KM. In addition, different dimensions of KM were found to mediate between different types of HRM practices and OP. Technical KM mediated the relationship between staffing, and training and development and OP, while cultural KM mediated the relationship between staffing and job security, and OP. On the other hand, human KM mediated the relationship between staffing, training and development, and job security, and OP. Finally, competitive strategies interacted with human KM in predicting OP. This study offers several recommendations on how to improve the performance of the service sector in Jordan, discusses limitations of the study, and outlines suggestions for future research

Purification, Characterization and Molecular Studies of Fructose-6-Phosphate Phosphoketolase (F6PPK) from Bifidobacteria

Fructose-6-phosphate phosphoketolase (F6PPK; EC 4.1.2.22) is the key enzyme in the fructose-6-phosphate shunt pathway of glucose metabolism which is apparently restricted to bifidobacteria. Despite the biological importance of this bacterial group and the heterogeneity of the enzyme from different species, F6PPK in itself has not been characterized in detail with respect to size, subunit number, steady kinetics and N-terminal sequence. F6PPK was extracted and characterized for the first time from Bifidobacterium asteroides (isolated from the intestine of honeybees; ATTC 25909). The enzyme was purified to homogeneity using acetone fractionation at 40-70% saturation followed by fast protein liquid chromatography (FPLC) on Mono-Q anion exchange and Superose 12 gel filtration columns. The intact enzyme has a relative molecular mass of 110 ± 5 kDa as estimated by gel filtration chromatography (Sephadex G-200), and a single band was obtained on nondenaturingP AGE. It was then shown to be that of F6PPK following elution from preparative polyacrylamid gel. Sodium dodecyl sulphate (SDS)-PAGE under nonreducing conditions revealed the presence of a single polypeptide of 110 ± 2 kDa. SDS-PAGE of F6PPK reacted with 2-mecaptoethanol revealed the presence of two polypeptides of 59 ± 1 and 53 ± 0.5 kDa, indicating a dimeric structure (α₁ β₁) with disulfide-linked subunits. The NH2-terminal amino acid of the a. chain was found to be methionine. The enzyme was stable at pH 4.5-8.0 with an optimum activity at pH 6.0. The enzyme was stable below 42°C and the optimum temperature was 30°C. The apparent Km value of the enzyme for fructose-6-phosphate was 14.1 mM. The purified enzyme has no apparent requirement for thiamine pyrophosphate as cofactors. The enzyme was inactivated by Hg2+ and recovered after addition of dithiothretol, indicating that sulfhydryl group was probably involved in the enzyme activity. The features of B. asteroides F6PPK showed marked differences from those previously reported from animal and human strains. F6PPK from Bifidobacterium longum (probiotic grade; BB536) was also purified to electrophoretic homogeneity using the same purification steps above. The purified enzyme had a molecular mass of about 300 kDa as determined by gel filtration on Superose 12. F6PPK migrated as a single electrophoretic band in nondenaturing polyacrylamide gel electrophoresis (PAGE). It is probably a tetramer containing two different subunits with molecular masses of about 93 ± 1 kDa and 59 ± 0.5 kDa, as determined by SDS-PAGE. The N-terminal amino acid sequences of the subunits were determined, and no significant similarity was found between the deduced amino acid sequences and those in the databases of EMBL and SWISSPORT, indicating that we may be reporting for the first time the partial sequence of F6PPK from two type strains of Bifidobacterium species. However, the Mr 59000 subunit of B. asteroides F6PPK showed a significant similarity (70%) with the corresponding subunit from B. longum species. Oligonucleotide probes which were designed based on the deduced N-terminal amino acids sequences were unable to detect the presence of F6PPK gene using dot blot and Southern blot of the total genomic DNA from different species of bifidobacteria and other bacterial strains. In addition, the genomic library of B. asteroides was constructed in BamHI-digested pUCI9 by using about 2 to 6-kb DNA fragments obtained by partial digestion of the total genomic DNA with BamHI. The transformed cells efficiency of E. coli XLI- blue carrying plasmids with genomic inserts was 1.1 x 104 cfu mrl, and this library may be a useful tool for fishing the gene encoding for F6PPK

Assessment of the immunogenicity and protective efficacy of leishmania donovani superoxide dimutase and peroxidoxins and the role of peroxidoxin gene cluster in parasite survival

Bibliography: p. 240-258Many pages are in colour

Effect of ultrasound application during setting on the mechanical properties of high viscous glass-ionomers used for ART restorations

This study was conducted to evaluate the effect of ultrasound application on the surface microhardness (VHN) and diametral tensile strength (DTS) of three high viscous glass-ionomer restorative materials (HVGIRMs). For each test (VHN and DTS), a total of 180 specimens were prepared from three HVGIRMs (Ketac-Molar Aplicap, Fuji IX GP Fast, and ChemFil Rock). Specimens of each material (n = 60) were further subdivided into three subgroups (n = 20) according to the setting modality whether ultrasound (20 or 40 s) was applied during setting or not (control). Specimens within each subgroup were then equally divided (n = 10) and tested at 24 h or 28 days. For the VHN measurement, five indentations, with a 200 g load and a dwell time for 20 s, were made on the top surface of each specimen. The DTS test was done using Lloyd Testing machine at a cross-head speed of 0.5 mm/min. Ultrasound application had no significant effect on the VHN. Fuji IX GP Fast revealed the highest VHN value, followed by Ketac-Molar Aplicap, and the least was recorded for ChemFil Rock. Fuji IX GP Fast and Ketac-Molar Aplicap VHN values were significantly increased by time. ChemFil Rock recorded the highest DTS value at 24 h and was the only material that showed significant improvement with both US application times. However, this improvement did not sustain till 28 days. The ultrasound did not enhance the surface microhardness, but its positive effect on the diametral tensile strength values was material and time dependent

Differential Immune Response against Recombinant Leishmania donovani Peroxidoxin 1 and Peroxidoxin 2 Proteins in BALB/c Mice

We assessed the immune response against recombinant proteins of two related, albeit functionally different, peroxidoxins from Leishmania donovani: peroxidoxin 1 (LdPxn1) and peroxidoxin 2 (LdPxn2) in BALB/c mice. We also evaluated the effect of coadministration of TLR agonists (CpG ODN and GLA-SE) on the antigen-specific immune response. Immunization with recombinant LdPxn1 alone induced a predominantly Th2 type immune response that is associated with the production of high level of IgG1 and no IgG2a isotype while rLdPxn2 resulted in a mixed Th1/Th2 response characterized by the production of antigen-specific IgG2a in addition to IgG1 isotype. Antigen-stimulated spleen cells from mice that were immunized with rLdPxn1 produced low level of IL-10 and IL-4 and no IFN-γ, whereas cells from mice immunized with rLdPxn2 secreted high level of IFN-γ, low IL-4, and no IL-10. Coadministration of CpG ODN or GLA-SE with rLdPxn1 skewed the immune response towards a Th 1 type as indicated by robust production of IgG2a isotype. Furthermore, the presence of TLR agonists together with rLdPxn1 antigen enhanced the production of IFN-γ and to a lesser extent of IL-10. TLR agonists also enhanced a more polarized Th 1 type immune response against rLdPxn2.Peer Reviewe

Evaluation of femtosecond laser in flap and cap creation in corneal refractive surgery for myopia: a 3-year follow-up

Mohamed Nagy Elmohamady, Walid Abdelghaffar, Ahmed Daifalla, Tamer Salem Ophthalmology Department, Benha University, Banha, Egypt Purpose: To evaluate femtosecond laser in flap and cap creation, detect some corneal biomechanical changes, and evaluate dry eye after laser in situ keratomileusis (LASIK), FemtoLASIK, and small incision lenticule extraction (SMILE) with 3-year follow-up. Patients and methods: Preoperative evaluation taken: full ophthalmic examination, Pentacam, ocular response analyzer, ocular surface disease index (OSDI), and tear breakup time (TBUT). LASIK flap was created using Moria microkeratome in 30 eyes (LASIK group) and using VisuMax femtosecond laser in 38 eyes (FS-LASIK group) and SMILE was done by VisuMax in 35 eyes (SMILE group). Postoperative evaluation: anterior segment optical coherence tomography to measure flap and cap thickness, ocular response analyzer to measure corneal hysteresis (CH) and corneal resistance factor (CRF), OSDI, and TBUT at 1, 3, 6, 12, 24, and 36 months after surgery. Results: This study included 103 eyes of 103 patients. The mean deviation of central cap or flap thickness from intended was statistically higher in the LASIK group (P<0.001). Both CH and CRF showed significant reduction postoperatively but were significantly higher in the SMILE group during follow up (P<0.05). The mean OSDI scores were significantly elevated in all groups postoperatively (P<0.01) but were significantly lower in the SMILE group 3 months postoperatively (P<0.05). The mean TBUT was significantly decreased in all groups postoperatively (P<0.01) but was significantly higher in the SMILE group 6 months postoperatively (P<0.05). Conclusion: Femtosecond laser is more accurate than microkeratomes. CH and CRF changes were least after SMILE. The three procedures led to significant dryness but for shorter duration with SMILE. Keywords: LASIK, femtosecond laser, SMILE, dry eye, corneal biomechanics, myopi

Immune Response and Protective Efficacy of a Heterologous DNA-Protein Immunization with Leishmania Superoxide Dismutase B1

Growing evidence shows that antioxidant proteins of Leishmania could be used as vaccine candidates. In this study, we report the efficacy of Leishmania donovani iron superoxide dismutase B1 (LdFeSODB1) as a vaccine antigen in BALB/c mice in a DNA-protein prime-boost immunization regimen in the presence or absence of murine granulocyte macrophage colony stimulating factor (mGMCSF) DNA adjuvant. The expression study confirmed that LdFeSODB1 is expressed in mammalian cells and mGMCSF fusion mediates the secretion of the recombinant protein. Heterologous immunization with LdFeSODB1 induced a strong antibody- and cell-mediated immune response in mice. Immunization triggered a mixed Th1/Th2 response as evidenced by the ratio of IgG2a to IgG1. Antigen-stimulated spleen cells from the immunized mice produced high level IFN-γ. Multiparametric flow cytometry data showed that immunization with LdFeSODB1 induced significantly higher expression of TNF-α or IL-2 by antigen-stimulated T cells. Eight weeks after L. major infection, immunization with the antigen shifted the immune response to a more Th1 type than the controls as demonstrated by IgG2a/IgG1 ratio. Moreover, IFN-γ production by antigen-stimulated spleen cells from immunized mice remained high. The footpad swelling experiment showed that immunization with LdFeSODB1 resulted in partial protection of mice from a high dose L. major infection

Differential Immune Response against Recombinant Leishmania donovani Peroxidoxin 1 and Peroxidoxin 2 Proteins in BALB/c Mice

We assessed the immune response against recombinant proteins of two related, albeit functionally different, peroxidoxins from Leishmania donovani: peroxidoxin 1 (LdPxn1) and peroxidoxin 2 (LdPxn2) in BALB/c mice. We also evaluated the effect of coadministration of TLR agonists (CpG ODN and GLA-SE) on the antigen-specific immune response. Immunization with recombinant LdPxn1 alone induced a predominantly Th2 type immune response that is associated with the production of high level of IgG1 and no IgG2a isotype while rLdPxn2 resulted in a mixed Th1/Th2 response characterized by the production of antigen-specific IgG2a in addition to IgG1 isotype. Antigen-stimulated spleen cells from mice that were immunized with rLdPxn1 produced low level of IL-10 and IL-4 and no IFN-γ, whereas cells from mice immunized with rLdPxn2 secreted high level of IFN-γ, low IL-4, and no IL-10. Coadministration of CpG ODN or GLA-SE with rLdPxn1 skewed the immune response towards a Th 1 type as indicated by robust production of IgG2a isotype. Furthermore, the presence of TLR agonists together with rLdPxn1 antigen enhanced the production of IFN-γ and to a lesser extent of IL-10. TLR agonists also enhanced a more polarized Th 1 type immune response against rLdPxn2

L-methionine protects against nephrotoxicity induced by methotrexate through modulation of redox status and inflammation

ABSTRACTObjective: Methotrexate (MTX) is a drug used in the treatment of cancer and autoimmune disorders; however, its clinical use is limited because of serious side effects including renal toxicity. This study aimed to investigate the protective effect of Lmethionine (L-Met) on MTX toxicity in the kidneys of rats.Methods: Thirty male rats were divided equally into five groups: control (saline), Met400 (400 mg/kg L-Met), MTX (20 mg/kg MTX), MTX-Met300 (300 mg/kg L-Met and 20 mg/kg MTX), and MTX-Met400 (400 mg/kg L-Met and 20 mg/kg MTX). Rats were euthanized one day after the last dose administration (day 16) and serum and renal tissue samples were collected. Renal function and injury indices, oxidative stress/antioxidant indices and proinflammatory cytokines were evaluated.Results: The results showed that L-Met could effectively counteract the nephrotoxic effects of MTX, in a dose-related manner, by improving most of the tested parameters. Furthermore, the higher dose of L-Met was able to restore several parameters to normal levels. In addition, investigation of MTX-induced hematological changes revealed a corrective potential of L-Met.Conclusion: L-Met can be an effective adjuvant therapy to modulate renal toxicity associated with MTX because of its antioxidant and antiinflammatory effects