Engineered doping of organic semiconductors for enhanced thermoelectric efficiency

Significant improvements to the thermoelectric figure of merit ZT have emerged in recent years, primarily due to the engineering of material composition and nanostructure in inorganic semiconductors (ISCs). However, many present high-ZT materials are based on low-abundance elements that pose challenges for scale-up, as they entail high material costs in addition to brittleness and difficulty in large-area deposition. Here we demonstrate a strategy to improve ZT in conductive polymers and other organic semiconductors (OSCs) for which the base elements are earth-abundant. By minimizing total dopant volume, we show that all three parameters constituting ZT vary in a manner so that ZT increases; this stands in sharp contrast to ISCs, for which these parameters have trade-offs. Reducing dopant volume is found to be as important as optimizing carrier concentration when maximizing ZT in OSCs. Implementing this strategy with the dopant poly(styrenesulphonate) in poly(3,4-ethylenedioxythiophene), we achieve ZT  =  0.42 at room temperature.

Histological improvement of long-term antiviral therapy in chronic hepatitis B patients with persistently normal alanine aminotransferase levels

The aim of this study was to evaluate the histological outcomes of chronic hepatitis B (CHB) patients with persistently normal alanine aminotransferase (ALT) levels after long-term antiviral therapy. Paired liver biopsies before and after lamivudine (LAM) treatment in CHB patients with normal and elevated ALT levels were compared. Histological response was defined as a 1-point decrease according to the Scheuer scoring system, without worsening of fibrosis between pretreatment and posttreatment biopsies. Among the 48 patients who underwent paired liver biopsies, 17 had persistently normal baseline ALT level and 31 had elevated ALT level. The median age of the patients was 44 years and 72.9% of the patients were male. The median duration of antiviral treatment was 44.5 months (range 14-104). Long-term follow-up of liver biopsies revealed that 82.4% of patients in the normal ALT group and 61.3% in the elevated ALT group had a baseline fibrosis score of 4, which was reduced to 17.6% and 38.7% after long-term therapy, respectively, indicating reversal of cirrhosis in a large proportion of both groups, especially in patients with normal baseline ALT levels. Long-term antiviral treatment could achieve significant histological improvement in CHB patients with fibrosis or cirrhosis, regardless of ALT level.

Serum lactic dehydrogenase strongly predicts survival in metastatic nasopharyngeal carcinoma treated with palliative chemotherapy

BACKGROUND AND OBJECTIVE

The survival outcomes of patients with metastatic nasopharyngeal carcinoma (NPC) differ significantly between individuals. This study aimed to evaluate whether serum lactic dehydrogenase (S-LDH) level had a clinical value in predicting clinical response and survival outcome for patients with metastatic NPC.

METHODS

S-LDH level was measured at baseline and then before every cycle of treatment in 689 NPC patients with distant metastases. Correlations of pre-treatment and post-treatment S-LDH levels to response of treatment and survival were analysed retrospectively.

RESULTS

Patients with elevated values of pre-treatment S-LDH (>245 IU/L) had significantly worse survival than those with normal values of pre-treatment S-LDH (≤245 IU/L) (P<0.001). Patients with elevated values of post-treatment S-LDH had worse survival compared with those with normal values of post-treatment S-LDH (P<0.001). Patients with normal values of pre-treatment and post-treatment S-LDH showed the highest response rate and the most favourable prognosis.

CONCLUSION

S-LDH appears to be a significant independent prognostic index in patients with disseminated NPC that should be considered in the comparison of the results achieved with different therapies and in planning new randomised clinical therapeutic trials.

Pulsed ion beam measurement of defect diffusion lengths in irradiated solids

Radiation-generated point defects in solids often experience dynamic annealing-diffusion and interaction processes after the thermalization of collision cascades. The length scale of dynamic annealing can be described in terms of the characteristic defect diffusion length (Ld). Here, we propose to measure Ld by a pulsed beam method. Our approach is based on the observation of enhanced defect production when, for individual ion pulses, the average separation between adjacent damage regions is smaller than Ld. We obtain a value for Ld of ~30 nm for float-zone Si crystals bombarded at room temperature with 500 keV Ar ions.

Evaluation of the GenoType® MTBDRplus assay and identification of a rare mutation for improving MDR-TB detection

OBJECTIVE

To assess the new GenoType® MTBDRplus assay for the rapid detection of multidrug-resistant tuberculosis (MDR-TB) in comparison with DNA sequencing to identify drug resistance mutation profiles in China.

DESIGN

Using MTBDRplus, drug susceptibility testing (DST) and DNA sequencing, 237 Mycobacterium tuberculosis strains were tested.

RESULTS

The sensitivity of MTBDRplus was 75.0% (126/168) for isoniazid (INH) resistant strains, and 93.5% (157/168) for rifampicin (RMP) resistant strains. It correlated well with sequencing, with 94.9% and 99.6% agreement for each strain category and 100% specificity for all categories. The two most common rpoB mutations were S531L (53.6%, 90/168) and D516G (17.3%, 29/168) in RMP-resistant strains. INH resistance was dominated by the katG 315 locus (S to T, N, R, I) mutation (73.7%, 124/168), and a rare katG mutation, S315N (6.5%, 11/168), not covered by MTBDRplus was identified. The mutation combination inhA-15/inhA-8 and katG315 (34 strains) was characteristically displayed in MDR-TB strains (23.5%), but not in INH-monoresistant strains.

CONCLUSIONS

Although Genotype MTBDRplus is a rapid and reliable molecular test for detecting MDR-TB, a significant proportion of strains in China contain a rare katG S315N mutation that would be missed by the assay. Further improvements may be achieved by incorporating this mutation into the assay to increase sensitivity in detecting INH resistance in China.

Pulsed ion beam measurement of the time constant of dynamic annealing in Si

Under ion irradiation, all crystalline materials display some degree of dynamic annealing when defects experience evolution after the thermalization of collision cascades. The exact time scales of such defect relaxation processes are, however, unknown even for Si at room temperature. Here, we use a pulsed ion-beam method to measure a characteristic time constant of dominant dynamic annealing processes of about 6 ms in Si bombarded at room temperature with 500 keV Ar ions.

Interferometer-based structured-illumination microscopy utilizing complementary phase relationship through constructive and destructive image detection by two cameras

In an interferometer-based fluorescence microscope, a beam splitter is often used to combine two emission wavefronts interferometrically. There are two perpendicular paths along which the interference fringes can propagate and normally only one is used for imaging. However, the other path also contains useful information. Here we introduced a second camera to our interferometer-based three-dimensional structured-illumination microscope (I(5)S) to capture the fringes along the normally unused path, which are out of phase by π relative to the fringes along the other path. Based on this complementary phase relationship and the well-defined phase interrelationships among the I(5)S data components, we can deduce and then computationally eliminate the path length errors within the interferometer loop using the simultaneously recorded fringes along the two imaging paths. This self-correction capability can greatly relax the requirement for eliminating the path length differences before and maintaining that status during each imaging session, which are practically challenging tasks. Experimental data is shown to support the theory.

Design and performance evaluation of a whole-body Ingenuity TF PET-MRI system

The Ingenuity TF PET-MRI is a newly released whole-body hybrid PET-MR imaging system with a Philips time-of-flight GEMINI TF PET and Achieva 3T X-series MRI system. Compared to PET-CT, modifications to the positron emission tomography (PET) gantry were made to avoid mutual system interference and deliver uncompromising performance which is equivalent to the standalone systems. The PET gantry was redesigned to introduce magnetic shielding for the photomultiplier tubes (PMTs). Stringent electromagnetic noise requirements of the MR system necessitated the removal of PET gantry electronics to be housed in the PET-MR equipment room. We report the standard NEMA measurements for the PET scanner. PET imaging and performance measurements were done at Geneva University Hospital as described in the NEMA Standards NU 2-2007 manual. The scatter fraction (SF) and noise equivalent count rate (NECR) measurements with the NEMA cylinder (20 cm diameter) were repeated for two larger cylinders (27 cm and 35 cm diameter), which better represent average and heavy patients. A NEMA/IEC torso phantom was used for overall assessment of image quality. The transverse and axial resolution near the center was 4.7 mm. Timing and energy resolution of the PET-MR system were measured to be 525 ps and 12%, respectively. The results were comparable to PET-CT systems demonstrating that the effect of design modifications required on the PET system to remove the harmful effect of the magnetic field on the PMTs was negligible. The absolute sensitivity of this scanner was 7.0 cps kBq(-1), whereas SF was 26%. NECR measurements performed with cylinders having three different diameters, and image quality measurements performed with IEC phantom yielded excellent results. The Ingenuity TF PET-MRI represents the first commercial whole-body hybrid PET-MRI system. The performance of the PET subsystem was comparable to the GEMINI TF PET-CT system using phantom and patient studies. It is conceived that advantages of hybrid PET-MRI will become more evident in the near future.

Osteogenic Growth Peptide Accelerates Bone Healing during Distraction Osteogenesis in Rabbit Tibia

Distraction osteogenesis is a valuable treatment method that allows limb lengthening or reconstruction of large bone defects. However, its major disadvantage is the long period required for the consolidation of a distraction callus. Osteogenic growth peptide (OGP) stimulates endochondral bone formation in fracture callus, but its capacity to promote regenerate ossification during distraction osteogenesis has not been evaluated. This study investigated whether intravenously administered OGP accelerated bone healing during distraction osteogenesis in 36 male New Zealand White rabbits, randomized into two groups. The treatment group received OGP (200 ng/kg body weight) in phosphate-buffered saline (PBS), intravenously, each day; the control group received PBS alone. A 15-mm lengthening of the right lower leg was performed using the method of Ilizarov. Evidence from biomechanical, histological and radiographic evaluations demonstrated that systemic OGP treatment promoted optimal new bone formation during distraction osteogenesis in this rabbit model.

Local delivery of recombinant human bone morphogenetic protein-2 increases axonal regeneration and the expression of tau protein after facial nerve injury

This study explored the function and possible mechanism of bone morphogenetic protein-2 (BMP-2) in the healing of injured peripheral nerves in vivo. Rabbit facial nerves were injured by clamping and then treated with recombinant human BMP-2 (rhBMP-2) or phosphate-buffered saline (control) by injecting once during surgery and twice a day post-injury for 7 days. Facial nerve fragments within 5 mm of the clamping point were examined at different times post-surgery. Axon structures visualized by Bielschowsky staining were similar in experimental and control nerves 2 and 6 weeks post-injury. At 4 weeks post-injury, cross-section images of facial nerves showed that axons treated with rhBMP-2 were denser and thicker, and levels of tau protein were increased. It is concluded from these data that rhBMP-2 may affect injured facial nerve regeneration by inducing more neurons to return to embryonic patterns of tau gene expression.

The beneficial effect of n-3 polyunsaturated fatty acids on doxorubicin-induced chronic heart failure in rats

This study was designed to assess the effects of dietary supplementation with n-3 polyunsaturated fatty acids (PUFA) from fish oil on the response of doxorubicin-induced chronic heart failure in rats. Male Sprague-Dawley rats were treated daily for 8 weeks with normal saline or n-3 PUFA intragastrically after induction of myocardial injury by intraperitoneal injection of doxorubicin 2 mg/kg once weekly for 8 weeks. Cardiac function was assessed by echocardiography. The cytoprotective role of n-3 PUFA against doxorubicin-induced myocardial injury was demonstrated by light microscopy, and serum cytokines (tumour necrosis factor-alpha and interleukin-10) were analysed by enzyme-linked immunosorbent assay. Doxorubicin induced death, alterations in echocardiography parameters and histological damage, all of which are features that characterize heart failure. There were significant differences between the doxorubicin-induced heart failure group and the n-3 PUFA-treated group in terms of echocardiography parameters and cytokine changes. Thus, dietary supplementation with n-3 PUFA attenuated doxorubicin-induced cardiac dysfunction, an effect that might be associated with recovery from an imbalance of the cytokine network.

Effects of n-3 Polyunsaturated Fatty Acid Therapy on Plasma Inflammatory Markers and N-Terminal Pro-brain Natriuretic Peptide in Elderly Patients with Chronic Heart Failure

Several previous studies have suggested that n-3 polyunsaturated fatty acids ( n-3 PUFA) can exert favourable effects in patients with heart failure, but the mechanisms involved are not fully understood. This study was designed to investigate the effects of n-3 PUFA on circulating inflammatory markers and N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with heart failure. Seventy-six patients with heart failure were randomly assigned to receive 2 g/day of n-3 PUFA or placebo for 3 months. Treatment with n-3 PUFA significantly decreased plasma levels of tumour necrosis factor, interleukin-6, intercellular adhesion molecule 1 and NT-proBNP. Left ventricular ejection fraction showed a small, non-significant improvement. High-sensitivity C-reactive protein levels decreased significantly in smokers after n-3 PUFA treatment. Thus, n-3 PUFA can reduce levels of plasma inflammatory markers and NT-proBNP as biomarkers of risk stratification in patients with heart failure. n-3 PUFA may offer a novel therapy for heart failure.

Effect of tecarfarin, a novel vitamin K epoxide reductase inhibitor, on coagulation in beagle dogs

BACKGROUND AND PURPOSE

Tecarfarin (ATI-5923) is a novel vitamin K epoxide reductase inhibitor that is metabolized by esterase (mainly human carboxylesterase 2) to a single major metabolite, ATI-5900, in rats, dogs and humans. Tecarfarin is not significantly metabolized by CYP450 enzymes. The objective of this study was to test and compare the efficacy of tecarfarin with that of warfarin, when administered either intravenously or once a day orally, to produce stable anticoagulation in beagle dogs.

EXPERIMENTAL APPROACH

Effects on coagulation were assessed by measuring the activity levels of Factor VII and Factor X and thromboplastin-induced coagulation times, reported as prothrombin time (PT).

KEY RESULTS

Continuous intravenous infusions and oral administration of tecarfarin and warfarin caused a dose-dependent decrease in activity of Factor VII and Factor X, and associated increase in PT. Intravenous fresh frozen canine plasma or subcutaneous vitamin K(1) treatment reversed the anticoagulant effects of orally administered tecarfarin. Consistent with the inhibitory effects of amiodarone on CYP2C9, co-administration of amiodarone significantly increased the anticoagulation effect of warfarin and plasma warfarin concentrations. In contrast, amiodarone had no effect on the anticoagulation induced by tecarfarin or tecarfarin plasma concentrations in this model.

CONCLUSIONS AND IMPLICATIONS

Overall, the data presented herein indicate that tecarfarin, via a vitamin K-dependent mechanism, causes changes in key parameters of haemostasis in beagle dogs that are consistent with effective anticoagulation. Compared to warfarin it has a decreased potential to interact metabolically with drugs that inhibit CYP450 enzymes and, therefore, may offer an improved safety profile for patients.

Anti-Amyloid Effects of Small Molecule Aβ-Binding Agents in PS1/APP Mice

AIMS: One promising approach for treatment of Alzheimer's disease (AD) is use of anti-amyloid therapies, based on the hypothesis that increases in amyloid-beta (Aβ) deposits in brain are a major cause of AD. Several groups have focused on Aβ immunotherapy with some success. Small molecules derivatives of Congo red have been shown to inhibit Aβ aggregation and protect against Aβ neurotoxicity in vitro. The agents described here are all small molecule Aβ-binding agents (SMAβBA's) derivatives of Congo red. MAIN METHODS: Here, we have explored the anti-amyloid properties of these SMAβBA's in mice doubly transgenic for human prensenilin-1 (PS1) and APP gene mutations that cause early-onset AD. Mice were treated with either methoxy-X04, X:EE:B34 and X:034-3-OMe1. After treatment, brains were examined for Aβ-deposition, using histochemistry, and soluble and insoluble Aβ levels were determined using ELISA. KEY FINDINGS: A range of anti-amyloid activity was observed with these three compounds. PS1/APP mice treated with methoxy-X04 and X:EE:B34 showed decrease in total Aβ load, a decrease in Aβ fibril load, and a decrease in average plaque size. Treatment with methoxy-X04 also resulted in a decrease in insoluble Aβ levels. The structurally similar compound, X:034:3-OMe1, showed no significant effect on any of these measures. The effectiveness of the SMAβBA's may be related to a combination of binding affinity for Aβ and entry into brain, but other factors appear to apply as well. SIGNIFICANCE: These data suggest that SMAβBA's may significantly decrease amyloid burden in brain during the pathogenesis of AD and could be useful therapeutics alone, or in combination with immunotherapy.

[Studies on immunoprotection in mice after immunization with Schistosoma japonicum 22.6 kDa recombinant protein]

AIM

To evaluate the immunoprotective effect of Schistosoma japonicum recombinant 22.6 kDa (rSj22.6) and Sj22.6/Sj26 GST fusion protein.

METHODS

The Sj22.6/Sj26 GST fusion protein was prepared by affinity chromatography using glutathione Sepharose 4B. The purified rSj22.6 could be cleaved easily from the fusion protein with Thrombin. 17 and 12 mice immunized with rSj22.6 and Sj22.6/Sj26 GST separately were each challenged with 40 +/- 1 S. japonicum cercariae.

RESULTS

In BALB/c mice, the rSj22.6 and Sj22.6/Sj26 GST could induce 32.1 (P < 0.005) and 34.9% (P < 0.02) worm reduction, respectively, as well as 28.4% (P < 0.02) and 45.1% (P < 0.005) total egg reduction, respectively.

CONCLUSION

Bpth rSj22.6 and Sj22.6/Sj26 GST fusion protein are partially effective against S. japonicum.

Variants in the gene encoding C3 are associated with asthma and related phenotypes among African Caribbean families

Proinflammatory and immunoregulatory products from C3 play a major role in phagocytosis, respiratory burst, and airways inflammation. C3 is critical in adaptive immunity; studies in mice deficient in C3 demonstrate that features of asthma are significantly attenuated in the absence of C3. To test the hypothesis that the C3 gene on chromosome 19p13.3-p13.2 contains variants associated with asthma and related phenotypes, we genotyped 25 single nucleotide polymorphism (SNP) markers distributed at intervals of approximately 1.9 kb within the C3 gene in 852 African Caribbean subjects from 125 nuclear and extended pedigrees. We used the multiallelic test in the family-based association test program to examine sliding windows comprised of 2-6 SNPs. A five-SNP window between markers rs10402876 and rs366510 provided strongest evidence for linkage in the presence of linkage disequilibrium for asthma, high log[total IgE], and high log[IL-13]/[log[IFN-gamma] in terms of global P-values (P = 0.00027, 0.00013, and 0.003, respectively). A three-SNP haplotype GGC for the first three of these markers showed best overall significance for the three phenotypes (P = 0.003, 0.007, 0.018, respectively) considering haplotype-specific tests. Taken together, these results implicate the C3 gene as a priority candidate controlling risk for asthma and allergic disease in this population of African descent.