58 research outputs found

    Pneumococcal conjugate vaccine given shortly after birth stimulates effective antibody concentrations and primes immunological memory for sustained infant protection.

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    BACKGROUND: In developing countries, newborn immunization with pneumococcal conjugate vaccines (PCVs) could protect young infants who are at high risk of invasive pneumococcal disease (IPD) but might lead to immune tolerance. METHODS: In a randomized trial, young infants received 7-valent PCV at 6, 10, and 14 weeks (Expanded Programme on Immunization [EPI] group) or 0, 10, and 14 weeks (newborn group). Safety was monitored actively at 2-7 days and then passively. Serum samples obtained at birth and 6, 10, 14, 18, 36, and 37 weeks were assayed by enzyme-linked immunosorbent assay for anticapsular immunoglobulin G concentration and avidity. Infants were boosted with either 7-valent PCV or one-fifth dose of pneumococcal polysaccharide vaccine at 36 weeks. Nasopharyngeal swab samples were obtained at 18 and 36 weeks. RESULTS: Three-hundred neonates and young infants were enrolled. Newborn vaccination was well tolerated. Adverse events occurred equally in each group; none was related to immunization. One infant, immunized at birth, died of unrelated neonatal sepsis. At 18 weeks, protective concentrations (ā‰„0.35 Ī¼g/mL) were achieved against each serotype by ā‰„87% of infants with no significant differences between groups. Geometric mean concentrations were higher in the EPI group for serotypes 4, 9V, 18C, and 19F at 18 weeks and for serotype 4 at 36 weeks. Avidity was greater in the newborn group for serotypes 4, 6B, and 19F at 18 weeks and for serotype 19F at 36 weeks. Booster responses and vaccine-type/nonvaccine-type carriage prevalence did not differ between groups. CONCLUSIONS: PCV was safe, immunogenic, and primed for memory when given at birth. There was no evidence of immune tolerance. Vaccination beginning at birth offers an alternative to control IPD in vulnerable young infants

    Lewis Base Mediated Ī²-Elimination and Lewis Acid Mediated Insertion Reactions of Disilazido Zirconium Compounds

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    The reactivity of a series of disilazido zirconocene complexes is dominated by the migration of anionic groups (hydrogen, alkyl, halide, OTf) between the zirconium and silicon centers. The direction of these migrations is controlled by the addition of two-electron donors (Lewis bases) or two-electron acceptors (Lewis acids). The cationic nonclassical [Cp2ZrN(SiHMe2)2]+ ([2]+) is prepared from Cp2Zr{N(SiHMe2)2}H (1) and B(C6F5)3 or [Ph3C][B(C6F5)4], while reactions of B(C6F5)3 and Cp2Zr{N(SiHMe2)2}R (R = Me (3), Et (5), n-C3H7 (7), CHā•CHSiMe3 (9)) provide a mixture of [2]+ and [Cp2ZrN(SiHMe2)(SiRMe2)]+. The latter products are formed through B(C6F5)3 abstraction of a Ī²-H and R group migration from Zr to the Ī²-Si center. Related Ī²-hydrogen abstraction and X group migration reactions are observed for Cp2Zr{N(SiHMe2)2}X (X = OTf (11), Cl (13), OMe (15), O-i-C3H7 (16)). Alternatively, addition of DMAP (DMAP = 4-(dimethylamino)pyridine) to [2]+ results in coordination to a Si center and hydrogen migration to zirconium, giving the cationic complex [Cp2Zr{N(SiHMe2)(SiMe2DMAP)}H]+ ([19]+). Related hydrogen migration occurs from [Cp2ZrN(SiHMe2)(SiMe2OCHMe2)]+ ([18]+) to give [Cp2Zr{N(SiMe2DMAP)(SiMe2OCHMe2)}H]+ ([22]+), whereas X group migration is observed upon addition of DMAP to [Cp2ZrN(SiHMe2)(SiMe2X)]+ (X = OTf ([12]+), Cl ([14]+)) to give [Cp2Zr{N(SiHMe2)(SiMe2DMAP)}X]+ (X = OTf ([26]+), Cl ([20]+)). The species involved in these transformations are described by resonance structures that suggest Ī²-elimination. Notably, such pathways are previously unknown in early metal amide chemistry. Finally, these migrations facilitate direct Siā€“H addition to carbonyls, which is proposed to occur through a pathway that previously had been reserved for later transition metal compounds

    Effect of Integrated Employee Training on Sustainable Mobility of Matatu Saccos in Public Transport Sector in Nairobi County, Kenya

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    This study was carried out to assess the effect of integrated employee training on sustainable mobility of Matatu Sacco in public transport sector in Nairobi County. Training in transport sector is of paramount importance as it makes the drivers more responsible which in turn reduces road accident, vehicle maintenance and enhances proper handling of passengers and creates an improved public image for the sector. The study comprised of 177 Sacco Managers representing all the Matatu Sacco registered by NTSA in Nairobi County in 2015.NTSA, 2015. The study was guided by positivism philosophy where census was applied and adopted mixed method research design. Data from the Sacco Managers was collected using a structured questionnaire, while an interview schedule was used for the representatives from both the MoT and VOA. Data was analyzed using descriptive and inferential statistics, and the results revealed that influence of integrated employee training, had significant influence on sustainable mobility of Matatu Saccos in public transport sector in Nairobi County, Kenya. The results also revealed that there has been training of simple technical skills, such as, maintenance of vehicles and first aid to the drivers. It can be concluded that training drivers on safety improves public image in Matatu Saccos. Recommendations can be made that it is important to conduct training needs assessment before training employees to ensure missing gaps or mismatch on the skills are well filled or captured to ensure training objectives are achieved effectively. This would enable both the ministry of transport and Sacco management to develop competent training programs for its employees

    Outcome of delivery and cause-specific mortality and severe morbidity in early infancy: a Kenyan District Hospital birth cohort.

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    It has proven very difficult to determine the causes of early infant mortality and morbidity in Africa. We undertook a two-year, prospective birth cohort study in a rural Kenyan District Hospital to estimate cause-specific mortality and severe morbidity in infants too young to gain benefit from routine immunization approaches. A total of 2,359 infants eligible for the cohort were delivered. Of these, 136 (6%) were stillborn and 77 (3.5%) subsequently died. Prematurity (34%), birth asphyxia (27%), and infection (18.5%) were the predominant causes of death in the first 98 days of life, although infection accounted for 36% of all life-threatening illness episodes in the same period. The data suggest that health system constraints are likely to impede programmatic efforts to reduce early infant mortality and morbidity, and that infection prevention measures offer some promise for mortality reduction. Assessing the cost effectiveness of the latter, particularly for very specific interventions such as further maternal vaccination, will require very large trials

    Titanocene(II)-Catalyzed Hydroboration of Carbonyl Compounds

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    Titanocene bisĀ­(catecholborane), [Cp<sub>2</sub>TiĀ­(HBcat)<sub>2</sub>] (<b>1</b>), catalyzes the room-temperature hydroboration of carbonyl compounds by pinacolborane (HBpin) rapidly, cleanly, and chemoselectively. Aryl aldehydes and ketones produced alkoxypinacolboronate esters in moderate to high yields in 2 h, and facile hydrolysis of alkoxypinacolboronate esters over silica occurred cleanly to afford alcohols in good yields. Complex <b>1</b> demonstrated a preference for Cī—»O bonds over Cī—»C bonds in both conjugated and nonconjugated enones. Kinetic studies of the catalytic hydroboration of a series of acetophenones showed that electron-poor substrates undergo the reaction more quickly than electron-rich substrates. This result is consistent with the proposed mechanism, in which stronger Ļ€-acids should undergo Cī—»O bond cleavage more readily. Computational studies using benzophenone and benzaldehyde showed that the hydroboration is spontaneous and likely proceeds via intermediates that are best described as Ti metallacycles whose structures are not significantly altered by substrate steric differences. This result indicates that similarities in the electronic properties of benzophenone and benzaldehyde supersede their steric differences in determining reaction outcomes
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