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Laser interaction with an ultra-thin pre-structured target is investigated with the help of both two-dimensional and three-dimensional particle-in-cell simulations. With the existence of a periodic structure on the target surface, the laser seems to penetrate through the target at its fundamental frequency even if the plasma density of the target is much higher than the laser’s relativistically critical density. The particle-in-cell simulations show that the transmitted laser energy behind the pre-structured target is increased by about two orders of magnitude compared to that behind the flat target. Theoretical analyses show that the transmitted energy behind the pre-structured target is actually re-emitted by electron ‘islands’ formed by the surface plasma waves on the target surfaces. In other words, the radiation with the fundamental frequency is actually ‘surface emission’ on the target rear surface. Besides the intensity of the component with the fundamental frequency, the intensity of the high-order harmonics behind the pre-structured target is also much enhanced compared to that behind the flat target. The enhancement of the high-order harmonics is also related to the surface plasma waves generated on the target surfaces.
Triploid and pentaploid breeding is of great importance in agricultural production, but it is not always easy to obtain double ploidy parents. However, in fishes, chromosome ploidy is diversiform, which may provide natural parental resources for triploid and pentaploid breeding. Both tetraploid and hexaploid exist in Schizothorax fishes, which were thought to belong to different subfamilies with tetraploid Percocypris fishes in morphology, but they are sister genera in molecule. Fortunately, the pentaploid hybrid fishes have been successfully obtained by hybridization of Schizothorax wangchiachii (♀, 2n = 6X = 148) × Percocypris pingi (♂, 2n = 4X = 98). To understand the genetic and morphological difference among the hybrid fishes and their parents, four methods were used in this study: morphology, karyotype, red blood cell (RBC) DNA content determination and inter-simple sequence repeat (ISSR). In morphology, the hybrid fishes were steady, and between their parents with no obvious preference. The chromosome numbers of P. pingi have been reported as 2n = 4X = 98. In this study, the karyotype of S. wangchiachii was 2n = 6X = 148 = 36m + 34sm + 12st + 66t, while that the hybrid fishes was 2n = 5X = 123 = 39m + 28sm + 5st + 51t. Similarly, the RBC DNA content of the hybrid fishes was intermediate among their parents. In ISSR, the within-group genetic diversity of hybrid fishes was higher than that of their parents. Moreover, the genetic distance of hybrid fishes between P. pingi and S.wangchiachii was closely related to that of their parental ploidy, suggesting that parental genetic material stably coexisted in the hybrid fishes. This is the first report to show a stable pentaploid F1 hybrids produced by hybridization of a hexaploid and a tetraploid in aquaculture.
The seasonality of individual influenza subtypes/lineages and the association of influenza epidemics with meteorological factors in the tropics/subtropics have not been well understood. The impact of the 2009 H1N1 pandemic on the prevalence of seasonal influenza virus remains to be explored. Using wavelet analysis, the periodicities of A/H3N2, seasonal A/H1N1, A/H1N1pdm09, Victoria and Yamagata were identified, respectively, in Panzhihua during 2006–2015. As a subtropical city in southwestern China, Panzhihua is the first industrial city in the upper reaches of the Yangtze River. The relationship between influenza epidemics and local climatic variables was examined based on regression models. The temporal distribution of influenza subtypes/lineages during the pre-pandemic (2006–2009), pandemic (2009) and post-pandemic (2010–2015) years was described and compared. A total of 6892 respiratory specimens were collected and 737 influenza viruses were isolated. A/H3N2 showed an annual cycle with a peak in summer–autumn, while A/H1N1pdm09, Victoria and Yamagata exhibited an annual cycle with a peak in winter–spring. Regression analyses demonstrated that relative humidity was positively associated with A/H3N2 activity while negatively associated with Victoria activity. Higher prevalence of A/H1N1pdm09 and Yamagata was driven by lower absolute humidity. The role of weather conditions in regulating influenza epidemics could be complicated since the diverse viral transmission modes and mechanism. Differences in seasonality and different associations with meteorological factors by influenza subtypes/lineages should be considered in epidemiological studies in the tropics/subtropics. The development of subtype- and lineage-specific prevention and control measures is of significant importance.
Hypoimmunity and numerous stresses are two major challenges in broiler industry. Nutrient intervention at the specific time of embryonic stage is a feasible way to improve animal performance. This study was conducted to investigate the possible effects of in ovo feeding (IOF) of vitamin C at embryonic age 15th day (E15) on growth performance, antioxidation and immune function of broilers. A total of 240 broiler fertile eggs were randomly divided into two groups (0 and 3 mg injected dose of vitamin C at E15), and new-hatched chicks from each treatment were randomly allocated into six replicates with 10 chicks per replicate after incubation. The results indicated that in ovo vitamin C injection improved the hatchability (P < 0.05) and increased immunoglobulin M (IgM) (at the broiler’s age 1st day, D1), IgG and IgM concentrations (D21), as well as lysozyme activity (D21, P < 0.05) and total antioxidant capacity (D42, P < 0.01) in plasma of broilers. On D21, the splenic expression level of DNA methyltransferase 1 (DNMT1) was up-regulated in vitamin C (VC) group, whereas interleukin (IL)-6, interferon-γ, ten-eleven translocation protein 1 and thymine-DNA glycosylase were down-regulated (P < 0.05). On D42, in ovo vitamin C injection up-regulated splenic expression levels of DNMT1, DNA methyltransferase 3B (DNMT3B) and growth arrest and DNA-damage-inducible protein beta (P < 0.05), whereas down-regulated splenic expression levels of IL-6, tumour necrosis factor-α and methyl-CpG-binding domain protein 4 (P < 0.05). Our findings suggested that IOF of 3 mg vitamin C at E15 could improve, to some extent, the antioxidant activity and immune function in plasma, corresponding with the lower expression of pro-inflammatory cytokines in spleen. However, IOF of vitamin C leading to the changes in the expression of DNA methyltransferases and demethylases may suggest an increased trend of DNA methylation level in spleen and whether DNA methylation variation is associated with the lower expression of pro-inflammatory cytokines in spleen warrants future study.
Muons produced by the Bethe–Heitler process from laser wakefield accelerated electrons interacting with high
materials have velocities close to the laser wakefield. It is possible to accelerate those muons with laser wakefield directly. Therefore for the first time we propose an all-optical ‘Generator and Booster’ scheme to accelerate the produced muons by another laser wakefield to supply a prompt, compact, low cost and controllable muon source in laser laboratories. The trapping and acceleration of muons are analyzed by one-dimensional analytic model and verified by two-dimensional particle-in-cell (PIC) simulation. It is shown that muons can be trapped in a broad energy range and accelerated to higher energy than that of electrons for longer dephasing length. We further extrapolate the dependence of the maximum acceleration energy of muons with the laser wakefield relativistic factor
and the relevant initial energy
. It is shown that a maximum energy up to 15.2 GeV is promising with
on the existing short pulse laser facilities.
Good canopy structure is essential for optimal maize (Zea mays L.) production. However, creating appropriate maize canopy structure can be difficult, because the characteristics of individual plants are altered by changes in plant age, density and interactions with neighbouring plants. The objective of the current study was to find a reliable method for building good maize canopy structure by analysing changes in canopy structure, light distribution and grain yield (GY). A modern maize cultivar (ZhengDan958) was planted at 12 densities ranging from 1.5 to 18 plants/m2 at two field locations in Xinjiang, China. At the silking stage (R1), plant and ear height increased with plant density as well as leaf area index (LAI), whereas leaf area per plant decreased logarithmically. The fraction of light intercepted by the plant (F) increased with increasing plant density, but the light extinction coefficient (K) decreased linearly from 0.61 to 0.39. Taking the optimum value of F (95%) as an example, and using measured values of K for each plant density at R1 and the equation from Beer's law, the corresponding (theoretical) LAI for each plant density was calculated and optimum plant density (9.72 plants/m2) obtained by calculating the difference between theoretical LAIs and actual observations. Further analysis showed that plant density ranging from 10.64 to 11.55 plants/m2 yielded a stable GY range. Therefore, taking into account the persistence time for maximum LAI, the plant density required to obtain an ideal GY maize canopy structure should be increased by 10–18% from 9.72 plants/m2.
The gastrointestinal tract (GIT) of animals is capable of sensing various kinds of nutrients via G-protein coupled receptor-mediated signaling transduction pathways, and the process is known as ‘gut nutrient chemosensing’. GPR40, GPR41, GPR43 and GPR119 are chemoreceptors for free fatty acids (FFAs) and lipid derivatives, but they are not well studied in small ruminants. The objective of this study is to determine the expression of GPR40, GPR41, GPR43 and GPR119 along the GIT of kid goats under supplemental feeding (S) v. grazing (G) during early development. In total, 44 kid goats (initial weight 1.35±0.12 kg) were slaughtered for sampling (rumen, abomasum, duodenum, jejunum, ileum, cecum, colon and rectum) between days 0 and 70. The expression of GPR41 and GPR43 were measured at both mRNA and protein levels, whereas GPR40 and GPR119 were assayed at protein level only. The effects of age and feeding system on their expression were variable depending upon GIT segments, chemoreceptors and expression level (mRNA or protein), and sometimes feeding system × age interactions (P<0.05) were observed. Supplemental feeding enhanced expression of GPR40, GPR41 and GPR43 in most segments of the GIT of goats, whereas G enhanced expression of GPR119. GPR41 and GPR43 were mainly expressed in rumen, abomasum and cecum, with different responses to age and feeding system. GPR41 and GPR43 expression in abomasum at mRNA level was greatly (P<0.01) affected by both age and feeding system; whereas their expression in rumen and abomasum at protein level were different, feeding system greatly (P<0.05) affected GPR41 expression, but had no effect (P>0.05) on GPR43 expression; and there were no feeding system×age interactions (P>0.05) on GPR41 and GPR43 protein expression. The expression of GPR41 and GPR43 in rumen and abomasum linearly (P<0.01) increased with increasing age (from days 0 to 70). Meanwhile, age was the main factor affecting GPR40 expression throughout the GIT. These outcomes indicate that age and feeding system are the two factors affecting chemoreceptors for FFAs and lipid derivatives expression in the GIT of kids goats, and S enhanced the expression of chemoreceptors for FFAs, whereas G gave rise to greater expression of chemoreceptors for lipid derivatives. Our results suggest that enhanced expression of chemoreceptors for FFAs might be one of the benefits of early supplemental feeding offered to young ruminants during early development.
Compensatory gain describes an accelerated growth seen in animals following a period of nutrient restriction. Methionine (Met) is the second limiting amino acid in typical swine diets and is essential for muscle growth. This study was conducted to determine (1) if a Met-deficient diet can cause growth retardation in growing pigs, (2) if returning to a normal feeding can yield compensatory gain in the pigs previously fed the Met-deficient diet, and (3) if this Met-deficiency followed by the normal feeding program affects carcass characteristics. Twenty individually-penned crossbred young barrows were randomly allotted to two dietary treatments (n = 10). One Met-deficient (D1) and one Met-adequate (D2) diets were formulated based on corn and soybean meal and fed to respective pigs for 31 days. After that, all pigs were fed the same commercial grower-finisher diet until market weight (around 125 kg), then slaughtered, and carcass characteristics measured. The D1 and D2 pigs began with similar body weights (23.5 vs. 23.6 kg; P = 0.935), but after 31-days on the dietary treatments, D1 pigs were lighter than D2 pigs (51.6 vs. 55.0 kg; P = 0.102). After feeding the normal diet for 55 days, D1 and D2 pigs had similar body weights (122.7 vs. 122.6 kg; P = 0.989). In terms of carcass characteristics, however, D1 pigs had thicker back-fat (at 10th rib; 2.95 vs. 2.51 cm; P = 0.015), heavier belly weight (11.0 vs. 9.6 kg; P = 0.005), lighter ham weights (untrimmed: 20.8 vs. 21.6 kg; P = 0.043; trimmed: 19.6 vs. 20.6 kg; P = 0.016), lighter picnic shoulder weight (8.72 vs. 9.80 kg; P = 0.041), lighter total lean cut weight (51.8 vs. 53.8 kg; P = 0.055), and lower lean cut percentage (56.4 vs. 59.0%; P = 0.012). These results indicate that the Met-deficient diet produced growth-retarded pigs, which showed compensatory gain after the normal feeding. At slaughter, the pigs previously fed the Met-deficient diet had more fat and less lean tissue than their non-deficient counterparts.
In vivo and in vitro trials were conducted to assess the effects of tributyrin (TB) supplementation on short-chain fatty acid (SFCA) concentrations, fibrolytic enzyme activity, nutrient digestibility and methanogenesis in adult sheep. Nine 12-month-old ruminally cannulated Small Tail ewes (initial body weight 55 ± 5.0 kg) without pregnancy were used for the in vitro trial. In vitro substrate made to offer TB at 0, 2, 4, 6 and 8 g/kg on a dry matter (DM) basis was incubated by ruminal microbes for 72 h at 39°C. Forty-five adult Small Tail ewes used for the in vivo trial were randomly assigned to five treatments with nine animals each for an 18-d period according to body weight (55 ± 5.0 kg). Total mixed ration fed to ewes was also used to offer TB at 0, 2, 4, 6 and 8 g/kg on a DM basis. The in vitro trial showed that TB supplementation linearly increased apparent digestibility of DM, crude protein, neutral detergent fibre and acid detergent fibre, and enhanced gas production and methane emissions. The in vivo trial showed that TB supplementation decreased DM intake, but enhanced ruminal fermentation efficiency. Both in vitro and in vivo trials showed that TB supplementation enhanced total SFCA concentrations and carboxymethyl cellulase activity. The results indicate that TB supplementation might exert advantage effects on rumen microbial metabolism, despite having an enhancing effect on methanogenesis.
The present study evaluated the effects of isovalerate supplementation on the development of the small intestinal mucosa in dairy calves. Forty-eight Chinese Holstein bull calves at 15 days of age and 45.1 ± 0.36 kg of body weight were assigned randomly to four groups. The treatments were control, low-isovalerate, moderate-isovalerate and high-isovalerate with 0, 3, 6 and 9 g isovalerate per calf per day, respectively. The study comprised 75 days with a 15-day adaptation period followed by a 60-day sampling period. Calves were weaned at 60 days of age. Six calves were chosen from each treatment at random and slaughtered at 30 and 90 days of age. The small intestine morphology and activities of amylase and trypsin improved significantly with increasing age. No interaction between treatments and age was observed. The small intestine length, mucosa layer thickness, villus height and crypt depth increased linearly with increasing isovalerate supplementation. However, the ratio of villus height to crypt depth was not affected by treatment. Activities of amylase and trypsin increased linearly. The lactase activity increased linearly during the 75-day period and for pre-weaned calves but was unaltered for post-weaned calves. The relative mRNA expressions of growth hormone receptor, insulin-like growth factor-1 receptor and sodium-glucose co-transporter-1 in the small intestine mucosa increased linearly, and a similar pattern was observed for the expression of peptide transporter-1 in the duodenum and proximal jejunum. The results suggested that small intestine development was promoted by isovalerate in a dose-dependent manner.
The study investigated whether different dietary energy and protein sources affect laying performance, antioxidant status, fresh yolk fatty acid profile and quality of salted yolks in laying ducks. In all, 360 19-week-old Longyan ducks were randomly assigned to four diets in a factorial arrangement (2×2). The four diets consisted of two energy sources, corn (CO) or sorghum (SO) and two protein sources, soybean meal (SM) and rapeseed meal with corn distillers dried grains with solubles (RMD), and each treatment contained six replicates of 15 birds each. The experimental diets were isocaloric (metabolizable energy, 10.84 MJ/kg) and isonitrogenous (CP, 17%). The results showed that egg production, average egg weight, egg mass and feed conversion ratio were not affected by diets (P>0.05). Plasma contents of reduced glutathione (GSH), GSH/oxidized glutathione and total antioxidant capacity were lower (P<0.05) in ducks fed the RMD diets compared with those fed SM diets with a substantial increase (P=0.006) in plasma content of malondialdehyde (MDA). Egg yolks from ducks fed SO diets had higher proportions of polyunsaturated fatty acids (PUFA) and lower saturated and monounsaturated fatty acids compared with CO diets (P<0.001). Similarly, ducks fed RMD diets had a higher content of PUFA and n-6/n-3 ratio in fresh yolks (P<0.001), and increased salted yolk MDA, carbonylated proteins content and incidence of hard salted yolks (P<0.05) compared with SM diets. Scanning electron microscopy showed that salted yolks contained rougher polyhedral granules and fewer fat droplets, and were surrounded with a layer of bunchy fibers in ducks fed SO+RMD than those fed CO+SM diet. In conclusion, the current study showed that feeding laying ducks with diets containing SO or RMD reduced antioxidant capacity and increased egg yolk concentrations of PUFA. It appeared that egg yolks from ducks fed these diets were more sensitive to lipid peroxidation and protein oxidation during salting, and reduced the quality of salted yolks.
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
Diarrhea is a common cause of morbidity and mortality and the incidence of diarrhea in the world has changed little over the past four decades. To assess the prevalence of and healthcare practices for diarrhea, a cross-sectional study was conducted in Pudong, Shanghai, China. In October 2014, a total of 5324 community residents were interviewed. Respondents were asked if they had experienced diarrhea (defined as ⩾3 passages of watery, loose, bloody, or mucoid stools within a 24-h period) in the previous month prior to the interview. The monthly prevalence of diarrhea was 4·1% (95% CI: 3·3–4·8), corresponding to an incidence rate of 0·54 episodes per person-year. The proportion of individuals with diarrhea who sought healthcare was 21·2% (95% CI: 13·4–29·0). Diarrhea continues to impose a considerable burden on the community and healthcare system in Pudong. Young age and travel were identified as predictors of increased diarrhea occurrence.
The current experiment was conducted to evaluate the effects of different dietary protein levels and rumen-protected folic acid (RPFA) supplementation on ruminal fermentation, microbial enzyme activity, bacterial populations and urinary excretion of purine derivatives (PD) in growing beef steers. Low-protein (LP) or high-protein (HP) diets were fed to eight ruminally cannulated first-generation cross-bred (Blonde d'Aquitaine × Simmental) beef steers with or without RPFA supplementation. Steers were fed a total mixed ration, and dietary concentrate to maize silage ratio was 50 : 50 (dry matter (DM) basis). No interaction between dietary crude protein (CP) levels and RPFA supplementation was observed during the experiment. Ruminal pH was unaffected by RPFA supplementation, but decreased with increasing dietary CP levels. Ruminal total volatile fatty acid concentration increased with increasing dietary CP levels or RPFA supplementation. Molar proportion of acetate increased with RPFA supplementation, but tended to decrease with increasing dietary CP levels. The proportion of propionate decreased with RPFA supplementation, but was unaffected by dietary CP levels. As a result, the acetate to propionate ratio increased with RPFA supplementation, but tended to be lower for the HP diets than the LP diets. Ammonia-nitrogen content decreased with RPFA supplementation, but increased with increasing dietary CP levels. In situ ruminal degradability of maize straw and concentrate increased with increasing dietary CP levels or RPFA supplementation. Microbial enzyme (carboxymethyl-cellulase, cellobiase, xylanase, pectinase, α-amylase and protease) activity, bacterial populations (Ruminococcus albus, Ruminococcus flavefaciens, Butyrivibrio fibrisolvens, Prevotella ruminicola, Fibrobacter succinogenes and Ruminobacter amylophilus) and urinary PD excretion increased with increasing dietary CP levels or RPFA supplementation. The current study showed that increasing dietary CP levels from 109·1 to 130·7 g/kg DM or supplementing 75 mg RPFA improved ruminal fermentation and microbial protein synthesis by increasing bacterial population and microbial enzyme activity.
Winter wheat (Triticum aestivum L.) production on the Loess Plateau in China has been threatened by water scarcity and climate change during the last decade. Sustainable crop production in this region requires managerial practices that can provide high yield and high water productivity (WP). A 7-year (2001–2008) study at the Loess Plateau Research Station of Lanzhou University investigated the effects of various conservation tillage practices on grain yield, soil water content (SWC), WP and economic return of winter wheat production. Tillage treatments included: conventional tillage (T), conventional tillage followed by stubble retention (TS), no-till (NT) and no-till followed by stubble retention (NTS). Over the entire experimental period, grain yield and WP of winter wheat ranged from 1279 to 4894 kg/ha and 0·32 to 2·41 kg/m3, respectively. Both were significantly affected by tillage treatment and year, while SWC was only affected by year. Grain yield and WP in TS was increased by 4·9, 12·1, 0·9% and 13·7, 20·4 and 3·9% compared with NTS, NT and T, respectively, over seven growing seasons. Additionally, a multiple linear regression analysis indicated that grain yield is mainly limited by SWC during planting. Despite its lower grain yield, the NTS treatment increased economic benefit by US$ 328, US$ 23 and US$ 87/ha compared with TS, NT and T, respectively. Therefore, it is suggested that increasing soil water storage at wheat sowing time and encouraging the use of NTS could improve economic returns in this region.
The effects of high-Z dopant on the laser-driven ablative Richtmyer–Meshkov instability (RMI) are investigated by theoretical analysis and radiation hydrodynamics simulations. It is found that the oscillation amplitude of ablative RMI depends on the ablation velocity, the blow-off plasma velocity and the post-shock sound speed. Owing to enhancing the radiation at the plasma corona and increasing the radiation temperature at the ablation front, the high-Z dopant in plastic target can significantly increase the ablation velocity and the blow-off plasma velocity, leading to an increase in oscillation frequency and a reduction in oscillation amplitude of the ablative RMI. The high-Z dopant in plastic target is beneficial to reduce the seed of ablative Rayleigh–Taylor instability. These results are helpful for the design of direct drive inertial confinement fusion capsules.
Bacillary dysentery continues to be a major health issue in developing countries and ambient temperature is a possible environmental determinant. However, evidence about the risk of bacillary dysentery attributable to ambient temperature under climate change scenarios is scarce. We examined the attributable fraction (AF) of temperature-related bacillary dysentery in urban and rural Hefei, China during 2006–2012 and projected its shifting pattern under climate change scenarios using a distributed lag non-linear model. The risk of bacillary dysentery increased with the temperature rise above a threshold (18·4 °C), and the temperature effects appeared to be acute. The proportion of bacillary dysentery attributable to hot temperatures was 18·74% (95 empirical confidence interval (eCI): 8·36–27·44%). Apparent difference of AF was observed between urban and rural areas, with AF varying from 26·87% (95% eCI 16·21–36·68%) in urban area to −1·90% (95 eCI −25·03 to 16·05%) in rural area. Under the climate change scenarios alone (1–4 °C rise), the AF from extreme hot temperatures (>31·2 °C) would rise greatly accompanied by the relatively stable AF from moderate hot temperatures (18·4–31·2 °C). If climate change proceeds, urban area may be more likely to suffer from rapidly increasing burden of disease from extreme hot temperatures in the absence of effective mitigation and adaptation strategies.
This study aimed to estimate the disease burden of hepatitis E in a rural region in China. A total of 489 hepatitis E cases were reported according to a community-based survey in an active hepatitis surveillance system between 2008 and 2015, the questionnaire and record-review methods were constructed to evaluate the economic and health burden of hepatitis E virus infections from societal perspectives. All costs were converted to US$ in 2015. The age-standardized cumulative incidence rate was 107·9/100 000, and the median age-standardized annual incidence rate was 16·5/100 000. The median direct, indirect, and intangible cost were $1046·0, $49·1, and $77·3/patient, respectively, and the median economic burden per patient was $1836·5, which accounted for 51·2% of per capita disposable income. Moreover, the median quality-adjusted life year and visual analogue scale score were 0·7 and 70·0/case, respectively. Both economic burden and health burden of inpatients was more serious than that of outpatients (P < 0·001). Disease burden of hepatitis E is heavy on patients, their families, and society. More studies on the disease burden of hepatitis E are necessary to increase social awareness of the disease and confirm reasonable disease-control measures.
Longan County is considered a highly endemic area for hepatitis B virus (HBV). The plasma-derived vaccine has been used in newborns in this area since 1987. A cross-sectional survey was conducted to evaluate the long-term effectiveness of this vaccine. In total, 1634 participants born during 1987–1993 and who had received a series of plasma-derived HB vaccinations at ages 0, 1, and 6 months were enrolled. Serological HBV markers were detected and compared with previous survey data. Overall the prevalence of hepatitis B surface antigen (HBsAg) in all participants was 3·79%; 3·47% of subjects who had received the first dose within 24 h were HBsAg positive, and 8·41% of subjects who had received a delayed first dose were also HBsAg positive. There were 1527 subjects identified who had received the first dose within 24 h and whose HBsAg and anti-HBc prevalence increased yearly after immunization, while the anti-HBs-positive rate and vaccine effectiveness declined. The geometric mean concentration of antibody in the anti-HB-positive participants was 55·13 mIU/ml and this declined after immunization. Fewer than 2·0% of participants had anti-HB levels ⩾1000 mIU/ml. The data show that the protective efficacy of the plasma-derived vaccinations declined and administration of HB vaccine within 24 h of birth was very important. To reduce the risk of HBV infection in this highly endemic area, a booster dose might be necessary if anti-HBs levels fall below 10 mIU/ml after age 18 years. Furthermore, studies on the immune memory induced by plasma-derived HB vaccine are needed.
Isobutyrate supplements could improve rumen development by increasing ruminal fermentation products, especially butyrate, and then promote the growth performance of calves. The objective of this study was to evaluate the effects of isobutyrate supplementation on growth performance, rumen development, blood metabolites and hormone secretion in pre- and post-weaned dairy calves. In total, 56 Chinese Holstein male calves with 30 days of age and 72.9±1.43 kg of BW, blocked by days of age and BW, were assigned to four groups in a randomized block design. The treatments were as follows: control, low-isobutyrate, moderate-isobutyrate and high-isobutyrate with 0, 0.03, 0.06 and 0.09 g isobutyrate/kg BW per calf per day, respectively. Supplemental isobutyrate was hand-mixed into milk of pre-weaned calves and the concentrate portion of post-weaned calves. The study consisted of 10 days of an adaptation period and a 50-day sampling period. Calves were weaned at 60 days of age. Seven calves were chosen from each treatment at random and slaughtered at 45 and 90 days of age. BW, dry matter (DM) intake and stomach weight were measured, samples of ruminal tissues and blood were determined. For pre- and post-weaned calves, DM intake and average daily gain increased linearly (P<0.05), but feed conversion ratio decreased linearly (P<0.05) with increasing isobutyrate supplementation. Total stomach weight and the ratio of rumen weight to total stomach weight tended to increase (P=0.073) for pre-weaned calves and increased linearly (P=0.021) for post-weaned calves, whereas the ratio of abomasum weight to total stomach weight was not affected for pre-weaned calves and decreased linearly (P<0.05) for post-weaned calves with increasing isobutyrate supplementation. Both length and width of rumen papillae tended to increase linearly for pre-weaned calves, but increased linearly (P<0.05) for post-weaned calves with increasing isobutyrate supplementation. The relative expression of messenger RNA for growth hormone (GH) receptor and 3-hydroxy-3-methylglutaryl-CoA synthase 1 in rumen mucosa increased linearly (P<0.05) for pre- and post-weaned calves with increasing isobutyrate supplementation. Blood concentrations of glucose, acetoacetate, β-hydroxybutyrate, GH and IGF-1 increased linearly (P<0.05) for pre- and post-weaned calves, whereas blood concentration of insulin decreased linearly with increasing isobutyrate supplementation. The present results indicated that isobutyrate promoted growth of calves by improving rumen development and its ketogenesis in a dose-dependent manner.