Characterization of a heat-tolerant Chlorella sp. GD mutant with enhanced photosynthetic CO2 fixation efficiency and its implication as lactic acid fermentation feedstock

BACKGROUND

Fermentative production of lactic acid from algae-based carbohydrates devoid of lignin has attracted great attention for its potential as a suitable alternative substrate compared to lignocellulosic biomass.

RESULTS

A Chlorella sp. GD mutant with enhanced thermo-tolerance was obtained by mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine to overcome outdoor high-temperature inhibition and it was used as a feedstock for fermentative lactic acid production. The indoor experiments showed that biomass, reducing sugar content, photosynthetic O₂ evolution rate, photosystem II activity (F_v/F_m and F_v'/F_m'), and chlorophyll content increased as temperature, light intensity, and CO₂ concentration increased. The mutant showed similar DIC affinity and initial slope of photosynthetic light response curve (α) as that of the wild type but had higher dissolved inorganic carbon (DIC) utilization capacity and maximum photosynthesis rate (P_max). Moreover, the PSII activity (F_v'/F_m') in the mutant remained normal without acclimation process after being transferred to photobioreactor. This suggests that efficient utilization of incident high light and enhanced carbon fixation with its subsequent flux to carbohydrates accumulation in the mutant contributes to higher sugar and biomass productivity under enriched CO₂ condition. The mutant was cultured outdoors in a photobioreactor with 6% CO₂ aeration in hot summer season in southern Taiwan. The harvested biomass was subjected to separate hydrolysis and fermentation (SHF) for lactic acid production with carbohydrate concentration equivalent to 20 g/L glucose using the lactic acid-producing bacterium Lactobacillus plantarum 23. The conversion rate and yield of lactic acid were 80% and 0.43 g/g Chlorella biomass, respectively.

CONCLUSIONS

These results demonstrated that the thermo-tolerant Chlorella mutant with high photosynthetic efficiency and biomass productivity under hot outdoor condition is an efficient fermentative feedstock for large-scale lactic acid production.

The Growth Hormone Receptor Gene is Associated with Mandibular Height in a Chinese Population

Genetic influences are important in the determination of mandibular morphology, and growth hormone receptor ( GHR) is believed to have an important influence on the growth of craniofacial bone. In this study, we used quantitative trait locus methods to evaluate the relationship between craniofacial morphology and single-nucleotide polymorphisms (SNPs) in GHR in an unselected healthy Chinese population. We systematically screened the 10 exons and nearby introns of GHR and identified 6 SNPs. Using 4 SNPs as markers, we studied the relationships between genotypes and craniofacial linear measurements. Individuals with the genotype CC of polymorphism I526L had a significantly greater mandibular ramus length (condylion-gonion/ articulare-gonion) than those with genotype AC or AA. Haplotype analysis showed that there were also significant differences between the long and short mandibular height groups in an extreme population. Our results indicate that the GHR gene polymorphism I526L is associated with mandibular height in the Chinese population.

Foxp2 controls synaptic wiring of corticostriatal circuits and vocal communication by opposing Mef2c

Cortico-basal ganglia circuits are critical for speech and language and are implicated in autism spectrum disorder (ASD), in which language function can be severely affected. We demonstrate that in the striatum, the gene, Foxp2, negatively interacts with the synapse suppressor, Mef2C. We present causal evidence that Mef2C inhibition by Foxp2 in neonatal mouse striatum controls synaptogenesis of corticostriatal inputs and vocalization in neonates. Mef2C suppresses corticostriatal synapse formation and striatal spinogenesis, but can, itself, be repressed by Foxp2 through direct DNA binding. Foxp2 deletion de-represses Mef2C, and both intrastriatal and global decrease of Mef2C rescue vocalization and striatal spinogenesis defects of Foxp2-deletion mutants. These findings suggest that Foxp2-Mef2C signaling is critical to corticostriatal circuit formation. If found in humans, such signaling defects could contribute to a range of neurologic and neuropsychiatric disorders.

[Analysis of long-term compliance to continuous positive airway pressure in patients with obstructive sleep apnea]

OBJECTIVE

To explore the continuous positive airway pressure (CPAP) therapy compliance in patients with obstructive sleep apnea (OSA).

METHODS

This prospective study recruited a group of subjects from May 2009 to December 2013 who were diagnosed and had accepted CPAP treatment in Sleep Center of Guangdong General Hospital, and the patients were followed-up regularly for long-term and assessed the CPAP treatment compliance. The patients were diagnosed, had pressure titration and CPAP treatment through out of center sleep test. The subjects were followed-up for 1 st, 3rd, 6th, 12th month, and each year regularly after accepting the CPAP treatment in Sleep Center by face to face follow-up with specialist physicians. Physicians followed-up the patients' subjective symptoms, CPAP adherence, patient education and side effect solutions. The patients were classified into good and poor compliance groups, and statistical analysis was done between the two groups.

RESULTS

There were 77 cases enrolled until December 2015, only 73 patients completed the study. The patients were followed-up about 2-6 years, the average was (3.93±1.29) years, the compliance accounted for 54.8% (40/73), and the average compliance was (4.02±1.87) hours/night. The trend of the long-term compliance showed that there was a gradual increase within the first 3 months of CPAP treatment and then the compliance decreased; it then increased gradually after the first two years. The good compliance group showed that the compliance increased gradually in the initial 3 months, and then fell; from the first year to the 3rd year, the compliance was stable; after the 3rd year there was a drop and the compliance tended to increase again after the 4th year. The poor compliance group showed the compliance had a downward trend from the beginning of the first two years, then after a brief rise, the compliance decreased linearly. Multivariate analysis showed that long-term compliance was not associated with age, daytime sleepiness (ESS), oxygen desaturation index (ODI), anxiety, depression (P>0.05), etc. However, it was associated with the time of the titration treatment (P<0.001), the time of the flow monitored (P<0.01) and the number of the pressure titration within one week (P<0.05).

CONCLUSIONS

Long-term compliance shows a curve change, the increased compliance is related with the regular follow-up. Long-term compliance can be predicted by the degree of cooperation with the initial diagnosis and treatment.

Clinical outcomes after spontaneous and nucleos(t)ide analogue-treated HBsAg seroclearance in chronic HBV infection

BACKGROUND

Both spontaneous and nucleos(t)ide analogue (Nuc)-treated hepatitis B surface antigen (HBsAg) seroclearance are associated with excellent clinical outcomes.

AIM

To conduct a case-control study to explore whether there is difference of clinical outcomes between these two groups.

METHODS

A total of 312 chronic hepatitis B patients with spontaneous HBsAg seroclearance and 110 patients with Nuc-treated HBsAg seroclearance were recruited retrospectively. Propensity score (PS) matching method produced 98 patients in each group for comparison. The development of hepatocellular carcinoma (HCC), hepatic complications and cumulative incidence of antibody to HBsAg (anti-HBs) was compared.

RESULTS

During a mean follow-up period of 107 months after HBsAg seroclearance, five patients developed HCC after a mean period of 75.3 months (four and one patients with spontaneous and Nuc-treated HBsAg seroclearance, respectively) in overall population. One died of pneumonia with sepsis and one experienced variceal bleeding in Nuc-treated patients but none in spontaneous group. The incidence of anti-HBs seroconversion was comparable between spontaneous and Nuc-treated HBsAg seroclearance (69.6% vs. 66.4%, respectively, P = 0.617). There were no significant differences in HCC development (2% vs. 1.1%), overall mortality (0% vs. 1%), variceal bleeding (0% vs. 4.2%) and 6-year cumulative incidence of anti-HBs seroconversion (62.3% vs. 61.5%) among PS-matched patients with spontaneous and Nuc-treated HBsAg seroclearance.

CONCLUSIONS

The clinical outcomes between patients with spontaneous and Nuc-treated HBsAg seroclearance are comparable. HCC can develop at a low rate during long-term follow-up and periodic surveillance after HBsAg seroclearance is still mandatory.

When "Bouba" equals "Kiki": Cultural commonalities and cultural differences in sound-shape correspondences

It has been suggested that the Bouba/Kiki effect, in which meaningless speech sounds are systematically mapped onto rounded or angular shapes, reflects a universal crossmodal correspondence between audition and vision. Here, radial frequency (RF) patterns were adapted in order to compare the Bouba/Kiki effect in Eastern and Western participants demonstrating different perceptual styles. Three attributes of the RF patterns were manipulated: The frequency, amplitude, and spikiness of the sinusoidal modulations along the circumference of a circle. By testing participants in the US and Taiwan, both cultural commonalities and differences in sound-shape correspondence were revealed. RF patterns were more likely to be matched with “Kiki” than with “Bouba” when the frequency, amplitude, and spikiness increased. The responses from both groups of participants had a similar weighting on frequency; nevertheless, the North Americans had a higher weighting on amplitude, but a lower weighting on spikiness, than their Taiwanese counterparts. These novel results regarding cultural differences suggest that the Bouba/Kiki effect is partly tuned by differing perceptual experience. In addition, using the RF patterns in the Bouba/Kiki effect provides a “mid-level” linkage between visual and auditory processing, and a future understanding of sound-shape correspondences based on the mechanism of visual pattern processing.

Hyperleptinemia Is a Risk Factor for the Development of Central Arterial Stiffness in Kidney Transplant Patients

BACKGROUND

Arterial stiffness could cause adverse outcomes in kidney transplant (KT) patients. Leptin has a role in influencing vascular smooth muscle that may contribute to atherosclerosis. The aim of this study was to evaluate the relationship between fasting serum leptin concentration and carotid-femoral pulse wave velocity (cfPWV) in KT patients.

MATERIALS AND METHODS

Fasting blood samples were obtained from 55 KT patients and 65 subjects from the outpatient department were enrolled as the control group. The cfPWV values of >10 m/s were used to define as the high arterial stiffness group and <10 m/s as the low arterial stiffness group. The predictive ability of leptin for arterial stiffness of KT was assessed using receiver operating characteristic (ROC) curve and multivariate logistic regression analyses.

RESULTS

Kidney transplant patients had lower hemoglobin, but higher blood urea nitrogen, creatinine, total cholesterol, diastolic blood pressure, intact parathyroid hormone levels, and leptin levels than controls. Although cfPWV levels were higher in KT patients, there is no difference of cfPWV levels between KT patients and control (P = .595). Fifteen KT patients (27.3%) were defined in the high arterial stiffness group, and serum leptin level was higher in the high arterial stiffness group compared with the low arterial stiffness group in KT patients (P < .001). Multivariate logistic regression analysis showed that leptin (odds ratio: 1.044, 95% confidence interval [CI]: 1.016-1.072, P = .002) was an independent predictor of arterial stiffness in KT patients. The sensitivity, specificity, positive predictive value, negative predictive value, and area under the ROC curve predicting arterial stiffness in KT patients were 73.33%, 87.5%, 68.7%, 89.7%, and 0.828 (95% CI: 0.703-0.917, P < .001), and the leptin cut-off value was 74.14 ng/mL.

CONCLUSION

Serum fasting leptin level could predict the development of central arterial stiffness of KT patients.

Measurement of body joint angles for physical therapy based on mean shift tracking using two low cost Kinect images

Range of motion (ROM) is commonly used to assess a patient's joint function in physical therapy. Because motion capture systems are generally very expensive, physical therapists mostly use simple rulers to measure patients' joint angles in clinical diagnosis, which will suffer from low accuracy, low reliability, and subjective. In this study we used color and depth image feature from two sets of low-cost Microsoft Kinect to reconstruct 3D joint positions, and then calculate moveable joint angles to assess the ROM. A Gaussian background model is first used to segment the human body from the depth images. The 3D coordinates of the joints are reconstructed from both color and depth images. To track the location of joints throughout the sequence more precisely, we adopt the mean shift algorithm to find out the center of voxels upon the joints. The two sets of Kinect are placed three meters away from each other and facing to the subject. The joint moveable angles and the motion data are calculated from the position of joints frame by frame. To verify the results of our system, we take the results from a motion capture system called VICON as golden standard. Our 150 test results showed that the deviation of joint moveable angles between those obtained by VICON and our system is about 4 to 8 degree in six different upper limb exercises, which are acceptable in clinical environment.

Clinical outcomes after interruption of entecavir therapy in HBeAg-negative chronic hepatitis B patients with compensated cirrhosis

BACKGROUND

Long-term nucleos(t)ide analogues therapy may reduce hepatocellular carcinoma (HCC) in chronic hepatitis B patients with advanced fibrosis or cirrhosis.

AIM

To investigate in a retrospective-prospective study whether this beneficial effect would be reduced in cirrhotic patients who discontinued a successful course of entecavir (ETV) therapy.

METHODS

The study included 586 hepatitis B e antigen (HBeAg)-negative patients with compensated cirrhosis, mean age of 53.8 ± 10 years and 81% males, treated with ETV for at least 12 months. After ETV therapy for 46.5 ± 22.9 months, 205 patients who achieved hepatitis B virus (HBV) DNA suppression discontinued therapy. The clinical outcomes were assessed and HCC incidence was compared between propensity score (PS)-matched patients who continued and patients who discontinued ETV therapy by Asian Pacific Association for the Study of Liver stopping rule.

RESULTS

During a mean duration of 59.3 ± 19 months after start of ETV therapy, nine and six HCC developed in an estimated annual incidence of 2.3% and 1.6% in 154 PS-matched patients who continued and who discontinued ETV therapy, respectively (P = 0.587). Multivariate Cox proportional hazards regression analyses showed that age (HR 1.065, P < 0.001) and HBV DNA (HR 1.216, P = 0.048) were the significant factors for HCC development. The rates of adverse clinical outcomes were comparable.

CONCLUSIONS

The clinical outcomes, including HCC, after cessation of a successful course of entecavir therapy in patients with compensated cirrhosis were comparable to those who continued therapy. The results suggest that this strategy of finite therapy is safe and a feasible alternative to indefinite therapy, especially in a low resources setting.

Tevatron Combination of Single-Top-Quark Cross Sections and Determination of the Magnitude of the Cabibbo-Kobayashi-Maskawa Matrix Element V_{tb}

We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb^{-1} per experiment. The t-channel cross section is measured to be σ_{t}=2.25_{-0.31}^{+0.29} pb. We also present the combinations of the two-dimensional measurements of the s- vs t-channel cross section. In addition, we give the combination of the s+t channel cross section measurement resulting in σ_{s+t}=3.30_{-0.40}^{+0.52} pb, without assuming the standard model value for the ratio σ_{s}/σ_{t}. The resulting value of the magnitude of the top-to-bottom quark coupling is |V_{tb}|=1.02_{-0.05}^{+0.06}, corresponding to |V_{tb}|>0.92 at the 95% C.L.

Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment

We report on a search for charged massive resonances decaying to top (t) and bottom (b) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √[s]=1.96  TeV collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5  fb(-1). No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to tb. Using a standard model extension with a W'→tb and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300-900  GeV/c(2) range. The limits presented here are the most stringent for a charged resonance with mass in the range 300-600  GeV/c(2) decaying to top and bottom quarks.

Establishment of a prediction model for the miRNA-based heading date characteristics of rice in the booting stage

Rice (Oryza sativa L.) is one of the most important food crops in the world. In Taiwan, due to the warm climate, there are two harvests annually. However, the yield and quality of rice can vary between each crop season in any given year. Previous reports have shown that microRNAs (miRNAs) play a crucial role in many developmental and physiological processes in plants. In this study, the heading date characteristics of 167 rice cultivars from the second crop season were recorded, and 27 rice cultivars were selected for preliminary microarray analysis. A total of 14 miRNAs from different heading date characteristics in 21 cultivars were selected based on significant differences in their expression profiles. Using a correlation analysis between the heading date and selected miRNA expression obtained from real-time polymerase chain reaction (PCR) assays, we developed a heading date prediction model. The model includes nine miRNA genes with corresponding R2 values of 0.8. To confirm the model, a real-time PCR analysis was performed on an additional 27 rice cultivars and we found the model predicted the heading date with accuracy. Therefore, the developed prediction may be useful in further studies aimed at confirming the reliability of the use of miRNA in molecular breeding and to increase the selection efficiency of rice cultivars and breeding.

Tevatron constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quark pairs

Combined constraints from the CDF and D0 Collaborations on models of the Higgs boson with exotic spin J and parity P are presented and compared with results obtained assuming the standard model value JP=0+. Both collaborations analyzed approximately 10  fb(-) of proton-antiproton collisions with a center-of-mass energy of 1.96 TeV collected at the Fermilab Tevatron. Two models predicting exotic Higgs bosons with JP=0- and JP=2+ are tested. The kinematic properties of exotic Higgs boson production in association with a vector boson differ from those predicted for the standard model Higgs boson. Upper limits at the 95% credibility level on the production rates of the exotic Higgs bosons, expressed as fractions of the standard model Higgs boson production rate, are set at 0.36 for both the JP=0- hypothesis and the JP=2+ hypothesis. If the production rate times the branching ratio to a bottom-antibottom pair is the same as that predicted for the standard model Higgs boson, then the exotic bosons are excluded with significances of 5.0 standard deviations and 4.9 standard deviations for the JP=0- and JP=2+ hypotheses, respectively.

Constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quarks in the full CDF data set

A search for particles with the same mass and couplings as those of the standard model Higgs boson but different spin and parity quantum numbers is presented. We test two specific alternative Higgs boson hypotheses: a pseudoscalar Higgs boson with spin-parity J^{P}=0^{-} and a gravitonlike Higgs boson with J^{P}=2^{+}, assuming for both a mass of 125  GeV/c^{2}. We search for these exotic states produced in association with a vector boson and decaying into a bottom-antibottom quark pair. The vector boson is reconstructed through its decay into an electron or muon pair, or an electron or muon and a neutrino, or it is inferred from an imbalance in total transverse momentum. We use expected kinematic differences between events containing exotic Higgs bosons and those containing standard model Higgs bosons. The data were collected by the CDF experiment at the Tevatron proton-antiproton collider, operating at a center-of-mass energy of sqrt[s]=1.96  TeV, and correspond to an integrated luminosity of 9.45  fb^{-1}. We exclude deviations from the predictions of the standard model with a Higgs boson of mass 125  GeV/c^{2} at the level of 5 standard deviations, assuming signal strengths for exotic boson production equal to the prediction for the standard model Higgs boson, and set upper limits of approximately 30% relative to the standard model rate on the possible rate of production of each exotic state.

Designer germanium quantum dot phototransistor for near infrared optical detection and amplification

We demonstrated a unique CMOS approach for the production of a high-performance germanium (Ge) quantum dot (QD) metal-oxide-semiconductor phototransistor. In the darkness, low off-state leakage (Ioff ∼ 0.27 pA μm(-2)), a high on-off current ratio (Ion/Ioff ∼ 10(6)), and good switching behaviors (subthreshold swing of 175 mV/dec) were measured on our Ge-QD phototransistor at 300 K, indicating good hetero-interfacial quality of the Ge-on-Si. Illumination makes a significant enhancement in the drain current of Ge QD phototransistors when biased at both the on- and off-states, which is a great benefit from Ge QD-mediated photoconductive and photovoltaic effects. The measured photocurrent-to-dark-current ratio (Iphoto/Idark) and the photoresponsivities from the Ge QD phototransistor are as high as 4.1 × 10(6) and 1.7 A W(-1), respectively, under an incident power of 0.9 mW at 850 nm illumination. A superior external quantum efficiency of 240% and a very fast temporal response time of 1.4 ns suggest that our Ge QD MOS phototransistor offers great promise as optical switches and transducers for Si-based optical interconnects.