iPS cell therapy for Parkinson’s disease

De ziekte van Parkinson wordt veroorzaakt door het afsterven van dopaminerge neuronen in een specifiek deel van het brein. Vervanging van die verloren neuronen via celtransplantatie is eerder gesuggereerd als een mogelijke therapie. In de 80- en 90-er jaren kregen wereldwijd ±400 Parkinsonpatiënten een hersenimplantaat met nieuwe dopaminerge neuronen geïsoleerd uit geaborteerde foetussen. Helaas maakten ethische bezwaren en praktische beperkingen standaard klinische toepassing onmogelijk. De ontdekking dat gewone lichaamscellen geherprogrammeerd konden worden tot (induced) pluripotente stamcellen (iPS-cellen) heeft een onuitputtelijk bron voor transplanteerbare patiënt-eigen nieuwe dopaminerge neuronen opgeleverd. Belangrijke vraag daarbij is of deze uit iPS-cellen verkregen dopaminerge neuronen net zo efficiënt zijn als foetale dopaminerge neuronen. Uit analyses van transplantatie-studies met beide dopaminerge neurontypes in een ratmodel voor Parkinson, vonden wij dat de uit iPS-cellen verkregen dopaminerge neuronen minder goed uitgroeiden na implantatie. Door de gen-expressie te vergelijken in beide dopaminerge neurontypes, ontdekten wij dat de uit iPS-cellen verkregen dopaminerge neuronen enkele afwijkingen vertoonden met name in de expressie van genen die betrokken zijn bij de uitgroei van neuronen. Wij lieten zien dat de uitgroei van deze dopaminerge neuronen weer gestimuleerd zou kunnen worden door specifieke cel-adhesiemoleculen geforceerd tot expressie te brengen. Als conclusie: Voordat uit iPS-cellen verkregen dopaminerge neuronen in de kliniek toegepast zouden kunnen worden, de protocollen voor de herprogrammering van somatische cellen tot iPS-cellen en voor hun differentiatie tot dopaminerg neuron verder geoptimaliseerd dienen te worden, zodat zij na implantatie net zo efficiënt zijn in de reductie van Parkinson symptomen als de foetale dopaminerge neuronen

Laboratory study of acoustic velocity in different types of rocks at seismic frequency band

In order to understand the characteristics of acoustic wave propagation in rocks within seismic frequency band (<100 Hz), the velocities of longitudinal and transverse waves of four different types of rocks were tested using low-frequency stress-strain method by means of the physical testing system of rock at low frequency and the experimental data of acoustic velocities of four different types of rocks at this frequency band were obtained. The experimental results showed that the acoustic velocities of four different types of rocks increased with the increase of temperature and pressure within the temperature and pressure ranges set by the experiment. The acoustic velocity of fine sandstone at 50% water saturation was smaller than that of dry sample. The acoustic velocities of four different types of rocks were different and the velocities of longitudinal waves of gritstone, fine sandstone, argillaceous siltstone and mudstone increased in turn under similar conditions and were smaller than those at ultrasonic frequency. Few of existing studies focus on the acoustic velocity at seismic frequency band, thus, further understanding of the acoustic characteristics at this seismic frequency band still requires more experimental data

International Metropolis Soft Power Evaluation and Empirical Studies from Shanghai

The AHP analysis method is used to determine various factors affecting soft power of international metropolis, and these factors are listed in order. The research finds that the important indices include share of cultural industry in GDP, urban green coverage, number of highly educated personnel, and qualified personnel who have studied abroad choose to stay in the city, etc. The 2009 empirical data analysis from Shanghai showed that indices such as urban environment, urban culture, and urban mobility have increased 85.7%, 91.6% and 128.1% upon those of the year 2000, respectively. While urban mobility is higher than the value of other factors, the index is still low, this may be more due to the lack of openness of the existing residence registration and social security system in Shanghai. In the mean time, education development and urban innovation effects are not significant as well. Therefore, the city should strengthen efforts to attract talents, improve quality of urban culture and urban image, and enhance cohesion of modern metropolis and cultural soft power, to improve the city's soft environment.Key words: AHP analysis; Soft power; International metropolis; Weight of inde

A Miniaturized Dual-Mode Bandpass Filter Using Slot Spurline Technique

A miniaturized dual-mode bandpass filter (BPF) with elliptic function response using slot spurline is designed in this paper. The slot spurline can not only splits the degenerate modes but also determine the type of filter characteristic (Chebyshev or elliptic). To miniaturize the resonator, four sagittate stubs are proposed. For demonstration purpose, a BPF operating at 5.75 GHz for WLAN application was designed, fabricated, and measured. The measured results are in good agreement with the full-wave simulation results

Harmonic-Rejection Compact Bandpass Filter Using Defected Ground Structure for GPS Application

A miniaturized bandpass filter (BPF) using defected ground structure (DGS) resonator with the characteristic of harmonic rejection is developed in this paper. The second and third harmonics of the proposed BPF are rejected by the characteristic of stepped-impedance DGS resonator. Moreover, open stubs are established so that two adjustable transmission zeros can independently be created to extend the stopband and improve the rejection level. Finally, a second-order BPF, centered at 1.62 GHz with a stopband extended up to 5.6 GHz and a rejection level better than 20 dB, is designed and implemented for GPS application. A good agreement between simulation and measurement verifies the validity of this design methodology

Assessment of fetal left atrial volume and function using a novel left atrial volume tracking method

BACKGROUND: A number of fetal cardiovascular structural defects may alter the hemodynamics of the cardiac chambers resulting in changes in chamber sizes. Quantitative measurements of the sizes of cardiac chambers can augment the diagnostic power of fetal echocardiography. AIMS: Using a new left atrial volume tracking (LAVT) method, time-left atrial volume curves (TLAVCs) can be automatically obtained. The goal of this study was to examine whether this method can be used to evaluate left atrial volume (LAV) and provide reference values for LAV, and indices of left atrial function in normal human fetuses. METHODS: 204 normal human fetuses were enrolled. Using LAVT, the maximal left atrial volume (LAVmax) and minimal left atrial volume (LAVmin) were measured from TLAVCs. Left atrial ejection fraction (EF) was calculated. The maximal left atrial area (LAAmax) and minimal left atrial area (LAAmin) were measured using manual method tracing. RESULTS: From 21-40 weeks, mean LAVmax increased from 0.27 ml to 4.15 ml and mean LAVmin increased from 0.13ml to 2.26ml, respectively. While the EF remained stable at around 0.43. From 21-40 weeks, mean LAAmax increased from 0.61 cm2 to 2.64 cm2 and mean LAAmin increased from 0.34 cm2 to 1.53 cm2. CONCLUSIONS: This study establishes reference values for fetal LAV during the second half of gestation. LAVT method has proven to be a feasible method to estimate fetal LAV, suggesting the potential value in assessing left atrial function