To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Using panel data on top management characteristics and a management quality factor constructed using common factor analysis on individual management quality measures, we analyze the relation between top firm management quality and corporate innovation input and output. We show that top management quality is an important determinant of corporate innovation, with individual aspects of management quality affecting innovation in younger and older firms differently. Further, firms with higher top management quality engage in more risky (“explorative”) innovation strategies. Finally, hiring more and higher-quality inventors is an important channel through which firms with higher management quality achieve greater innovation output.
Hand-foot-mouth disease (HFMD) is an acute infectious disease caused by serotypes of the enterovirus (EV) family. HFMD reinfection occurs commonly in lack of cross-protection between different EV serotypes. In this study, we investigated the hazards of HFMD reinfection using Cox-proportional hazard model. Retrospective data of 95 209 HFMD cases in Wuhan during 2008–2015 was used. Kaplan–Meier survival methods and Cox-proportional hazard model were used to estimate the hazard probabilities. Of the all HFMD cases, about 2% experienced reinfection (1842/95 209). Kaplan–Meier curves revealed the reinfection risk sharply increased before 40 months from first infection. Higher hazards of reinfection were detected among those who were males, aged 3 years and below, scattered children, belonging to urban areas and first infected with coxsackievirus (CV)-A16 compared with their respective counterparts. Cox-proportional hazard model suggested that gender, age, group, living area and serotypes of first infection had significant effect on reinfection even after adjusting for potential confounding effects of other selected factors considered in the study. These results indicate that boys aged 3 years and below, especially those living in urban areas and first infected with CV-A16 are more prone to reinfection. Interventions should be imposed on these high-risk populations.
Previously known to form only under high pressure synthetic conditions, here we report that the T′-type 214-structure cuprate based on the rare earth atom Tb is stabilized for ambient pressure synthesis through partial substitution of Pd for Cu. The new material is obtained in purest form for mixtures of nominal composition Tb1.96Cu0.8Pd0.2O4. The refined formula, in orthorhombic space group Pbca, with a = 5.5117(1) Å, b = 5.5088(1) Å, and c = 11.8818(1) Å, is Tb2Cu0.83Pd0.17O4. An incommensurate structural modulation is seen along the a axis by electron diffraction and high resolution imaging. Magnetic susceptibility measurements reveal long-range antiferromagnetic ordering at 7.9 K, with a less pronounced feature at 95 K; a magnetic moment reorientation transition is observed to onset at a field of approximately 1.1 T at 3 K. The material is an n-type semiconductor.
We investigated the first presence of qnrA among Shigella sonnei clinical isolates in Jiangsu Province, China. The qnrA-positive isolates coexisted with the mutation in gyrA at codon 83, these isolates were resistant to nalidixic acid and 22·2% (2 of 9) of them were resistant to norfloxacin.
Chronic rhinosinusitis is a common nasal disorder in children that is prone to recurrence. This study investigated the prevention of chronic rhinosinusitis recurrence with bacteria lysate in children.
Bacteria lysate was administered 10 days per month for 3 months to children with chronic rhinosinusitis, who had just entered a remission phase. Visual analogue score, nasal symptoms scores, rhinitis attack frequency and antibiotic use were assessed at three months and one year.
At one year of follow up, the visual analogue score, nasal discharge and obstruction scores, number of days with rhinitis attacks per month and number of days with antibiotic use per month were significantly decreased in the prevention group versus the control group (p < 0.05).
Bacterial lysate used in the remission period of rhinosinusitis in children was shown to provide long-term prophylaxis. Bacterial lysate can effectively reduce the frequency of rhinosinusitis attacks and ameliorate attack symptoms.
Efforts to extract weak geomagnetic excursion signals from Chinese loess-paleosol 10Be have generally been unsuccessful due to the complexities of its accumulation, because the geomagnetic and climate (precipitation and dust) signals contained in loess-paleosol sequence are tightly overprinted. Here, we present a reconstruction of geomagnetic relative paleointensities for the past 130 kyr from 10Be records in 2 Chinese loess-paleosol sections using a correction based on the correlation of 10Be with magnetic susceptibility (SUS) to remove the climatic contamination. Both these records reveal the Laschamp and Blake events, which lie in the loess and paleosol (L1SS1 and S1SS3) horizons corresponding to mid-MIS 3 and 5e, respectively. The good agreement between our results and other geomagnetic intensities reconstructions from Atlantic and Pacific sediments indicates that our method is robust. Our study suggests the potential application of loess-paleosol 10Be for reconstructing geomagnetic intensity variations spanning the whole Quaternary.
Repeat rectal chlamydia infection is common in men who have sex with men (MSM) following treatment with 1 g azithromycin. This study describes the association between organism load and repeat rectal chlamydia infection, genovar distribution, and efficacy of azithromycin in asymptomatic MSM. Stored rectal chlamydia-positive samples from MSM were analysed for organism load and genotyped to assist differentiation between reinfection and treatment failure. Included men had follow-up tests within 100 days of index infection. Lymphogranuloma venereum and proctitis diagnosed symptomatically were excluded. Factors associated with repeat infection, treatment failure and reinfection were investigated. In total, 227 MSM were included – 64 with repeat infections [28·2%, 95% confidence interval (CI) 22·4–34·5]. Repeat positivity was associated with increased pre-treatment organism load [odds ratio (OR) 1·7, 95% CI 1·4–2·2]. Of 64 repeat infections, 29 (12·8%, 95% CI 8·7–17·8) were treatment failures and 35 (15·4%, 95% CI 11·0–20·8) were reinfections, 11 (17·2%, 95% CI 8·9–28·7) of which were definite reinfections. Treatment failure and reinfection were both associated with increased load (OR 2·0, 95% CI 1·4–2·7 and 1·6, 95% CI 1·2–2·2, respectively). The most prevalent genovars were G, D and J. Treatment efficacy for 1 g azithromycin was 83·6% (95% CI 77·2–88·8). Repeat positivity was associated with high pre-treatment organism load. Randomized controlled trials are urgently needed to evaluate azithromycin's efficacy and whether extended doses can overcome rectal infections with high organism load.
We derive zphot for sources in the entire (~0.4 deg2) H-HDF-N field with the EAzY code, based on PSF-matched broad-band (U band to IRAC 4.5 μm) photometry. Our catalog consists of a total of 131,678 sources. We find σNMAD = 0.029 for non-X-ray sources. We also classify each object as a star or galaxy through SED fitting. Furthermore, we match our catalog with the 2 Ms CDF-N main X-ray catalog. For the 462 matched non-stellar X-ray sources, we improve their zphot quality (σNMAD = 0.035) by adding three additional AGN templates. We make our photometry and zphot catalog publicly available.
The paper studied the effect of an array of hemispherical substance-units (HSUs) immersed in inviscid and incompressible liquid on resonance frequency of a quartz crystal resonator (QCR) under the thickness-shear mode (TSM) vibrations. A dynamic model of the compound QCR system, consisting of a QCR and HSUs, was established in advance. The frequency equation of the compound QCR system including the liquid-solid coupling was derived subsequently. Numerical results showed the frequency-shift characteristics of the compound system. The obtained results are useful in resonator design and applications.
The shoot beetles Tomicus minor, Tomicus yunnanensis, and Tomicus brevipilosus have been decimating Pinus yunnanensis trees for more than 30 years in Southwestern China. To understand the chemical ecological relationship between pines and Tomicus, and among the three beetle species, we compared the attraction of these beetles to damaged shoots, extracts from damaged shoots, and volatiles from damaged shoots collected by the dynamic headspace sampling method. Experiments were performed using a modified open-arena olfactometer. The male T. minor and both sexes of T. brevipilosus were more strongly attracted to damaged shoots than to undamaged shoots and they showed attraction to shoots damaged by the same species. Female T. minor and both sexes of T. yunnanensis were attracted to shoots damaged by female T. brevipilosus. The three beetle species were attracted to shoot extracts and dynamic headspace volatiles from shoots damaged by the same species and sex. Female T. minor and male T. yunnanensis were also attracted to dynamic headspace volatiles from shoots damaged by both sexes of T. brevipilosus. The results suggested that specific semiochemicals that are induced or produced by T. brevipilosus also attract T. minor and T. yunnanensis. The semiochemicals in damaged shoots affect the attraction of the three beetle species and play an important chemical communication role in weakening the host trees during the beetles’ shoot-feeding phase.
Trematode tyrosinases (TYRs) play a major role in the tanning process during eggshell formation. We investigated the molecular and biochemical features of Paragonimus westermani TYR (PwTYR). The PwTYR cDNA was composed of 1568-bp encompassing a 1422-bp-long open reading frame (474-amino acid polypeptide). A strong phylogenetic relationship with Platyhelminthes and Deuterostomian orthologues was evident. The recombinant PwTYR expressed in prokaryotic cells promptly oxidized diphenol substrates, with a preferential affinity toward ortho-positioned hydroxyl groups. It demonstrated fairly weak activity for monophenol compounds. Diphenol oxidase activity was augmented with an increase of pH from 5·0 to 8·0, while monophenol oxidase activity was highest at an acidic pH and gradually decreased as pH increased. Transcription profile of PwTYR was temporally upregulated along with worm development. PwTYR was specifically localized in vitellocytes and eggs. The results suggested that conversion of tyrosine to L-dihydroxyphenylalanine by PwTYR monophenol oxidase activity might be rate-limiting step during the sclerotization process of P. westermani eggs. The pH-dependent pattern of monophenol and diphenol oxidase activity further proposes that the initial hydroxylation might slowly but steadily progress in acidic secreted vesicles of vitellocytes and the second oxidation process might be rapidly accelerated by neural or weak alkaline pH environments within the ootype.
Multidrug-resistant bacteria are major causes of nosocomial infections and are associated with considerable morbidity, mortality, and healthcare costs. Preventive strategies have therefore become increasingly important. Mathematical modeling has been widely used to understand the transmission dynamics of nosocomial infections and the quantitative effects of infection control measures. This review will explore the principles of mathematical modeling used in nosocomial infections and discuss the effectiveness of infection control measures investigated using mathematical modeling.
Infect Control Hosp Epidemiol 2014;35(12):1521–1530
Introduction: stem/progenitor cell recruitment vs. transplantation
The utilization of transplanted stem cells in regenerative medicine has been studied extensively as a potential therapy to repair or replace tissues that are lost due to trauma, congenital deformities, tumor resections, or infectious diseases [1–3]. The current cell transplantation model in regenerative medicine is founded on the principle that the application of transplanted stem cells could repopulate and regenerate damaged or diseased tissues, with restored tissue functions and homeostasis. However, cell transplantation is faced with a multitude of clinical and cell culture complications including the complexity of the multistep surgical procedures, donor-site trauma, immune rejection for allogeneic and xenogeneic cells, cell phenotypic variations due to in-vitro culture techniques, potential tumorigenesis associated with long-term cell expansion, failure of exogenous cell engraftment, and uncertainties and difficulties in the regulatory approval process [4–8]. The difficulties in the clinical application of stem cell transplantation are in strong contrast to the results of multiple experimental studies that demonstrate different levels of efficacy of cell delivery in a number of disease models such as Parkinson’s disease [9, 10], blood cancers and diseases [11, 12], and muscle and spinal disorders/injuries [13, 14].
For a number of regenerative medicine applications, the use of stem cell transplantation might not be competitive with the cost-effectiveness of current clinical treatment modalities in the dental and musculoskeletal fields, including titanium joint replacements, dental implants, and operative dental procedures [15–17]. Alternatively, the concept of endogenous stem/progenitor cell recruitment in regenerative medicine is based on the idea that native stem/progenitor cells that already reside within mature tissue can be stimulated and functionally enhanced to repopulate, repair, and/or regenerate damaged tissues . Relative to stem cell transplantation, the application of endogenous stem cell recruitment in regenerative medicine is still in its infancy. The combination of the use of biological factors, release technology, biomaterials, and bioengineered scaffolds to enhance endogenous stem cell recruitment seems very promising for potential use in translational regenerative medicine. However, further scientific experimentation is warranted, since many scientific questions concerning the mechanistic details remain unresolved and it will be necessary to validate the efficacy of this approach for clinical application.
The epitaxial lateral overgrowth (ELO) process for GaN has been studied using SiC and sapphire substrates. Both MBE and MOVPE growth processes were employed in the study. The use of SiO2 versus SiNx insulator stripes was investigated using window/stripe widths ranging from 20 μm/4 μm to 3 μm/15 μm. GaN film depositions were completed at temperatures ranging from 800 °C to 1120 °C. Characterization experiments included RHEED, TEM, SEM and cathodolumenescence studies. The MBE growth experiments produced polycrystalline GaN over the insulator stripes even at deposition temperatures as high as 990 °C. In contrast, MOVPE growth produced single-crystal GaN stripes with no observable threading dislocations.
We report on an experimental study of microstructure-based lasing in an optically pumped GaN/AlGaN separate confinement heterostructure (SCH). We achieved low-threshold ultra-violet lasing in optically pumped GaN/AlGaN separate confinement heterostructures over a wide temperature range. The spacing, directionality, and far-field patterns of the lasing modes are shown to be the result of microcavities that were naturally formed in the structures due to strain relaxation. The temperature sensitivity of the lasing wavelength was found to be twice as low as that of bulk-like GaN films. Based on these results, we discuss possibilities for the development of ultra-violet laser diodes with increased temperature stability of the emission wavelength.
The establishment of standardised methods for monitoring the oriental fruit moth Grapholitha molesta (Busck) (Lepidoptera: Tortricidae) requires the identification of factors that significantly affect trap catch efficacy. We examined the effects of trap height, trap location, and inter-trap spacing on trap catches in a conventional peach orchard. Traps were placed at heights of up to 3.0 m above the ground and sets of nine traps were positioned in grids with inter-trap distances of 10–50 m to determine the optimum trap height, location, and spacing. Traps were checked daily over 10 days for males during four periods corresponding to peak moth flight. Moth catches were higher when traps were placed toward the tops (2.5 m) and outside the canopy (3.0 m). Moth catches in traps located upwind and outside tended to be higher than in the central trap for all inter-trap distances. When inter-trap distances were shorter than 30 m, interference between traps occurred. Our results provide an efficient trap distribution for monitoring G. molesta in peach orchards.
We investigated the seasonality of tuberculosis (TB) in Wuhan, China, to evaluate the increased risk of disease transmission during each season and to develop an effective TB control strategy. We applied spectral analysis to the weekly prevalence data of sputum smear positive (SSP) and sputum smear negative (SSN) pulmonary TB reported from 2006 to 2010. Cases of both SSP and SSN feature 1·0- and 0·5-year periodic modes. The least squares method was used to fit curves to the two periodic modes for SSP and SSN data. The curves demonstrated dominant peaks in spring similar to cases reported previously for other locations. Notably for SSP, dominant peaks were also observed in summer. The spring peaks of SSP and SSN were explained in terms of poorly ventilated and humid rooms and vitamin D deficiency. For the summer peaks of SSP, summer influenza epidemics in Wuhan may contribute to the increase in TB prevalence.
The present study assessed the impact of the 2009 food packages mandated by the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) on dietary intake and home food availability in low-income African-American and Hispanic parent/child dyads.
A natural experiment was conducted to assess if the revised WIC food package altered dietary intake, home food availability, weight and various lifestyle measures immediately (6 months) following policy implementation.
Twelve WIC clinics in Chicago, IL, USA.
Two hundred and seventy-three Hispanic and African-American children aged 2–3 years, enrolled in WIC, and their mothers.
Six months after the WIC food package revisions were implemented, we observed modest changes in dietary intake. Fruit consumption increased among Hispanic mothers (mean = 0·33 servings/d, P = 0·04) and low-fat dairy intake increased among Hispanic mothers (0·21 servings/d, P = 0·02), Hispanic children (0·34 servings/d, P < 0·001) and African-American children (0·24 servings/d, P = 0·02). Home food availability of low-fat dairy and whole grains also increased. Dietary changes, however, varied by racial/ethnic group. Changes in home food availability were not significantly correlated with changes in diet.
The WIC food package revisions are one of the first efforts to modify the nutrition guidelines that govern foods provided in a federal food and nutrition assistance programme. It will be important to examine the longer-term impact of these changes on dietary intake and weight status.