80 research outputs found
Identifying the pathological changes caused by familial Alzheimer’s disease-like mutations in zebrafish psen2
This project aimed to investigate the pathological changes caused by familial Alzheimer's
disease-related (fAD-related) mutations in the gene PSEN2 based on a zebrafish model system. The
CRISPR/Cas9 system was used to generate fAD-like mutations in the zebrafish genome. Although this
mutagenesis system failed to generate mutations directly equivalent to the fAD mutations Nl411 and
Vl481, (Nl40I and
Vl471 in zebrafishpsen2), a fAD-like mutation psen2T141_L142delinsMISLISV [T141_L142delinsMISLISV superscript], a truncation mutation psen2N140fs [N140fs superscript], and a putative null mutation psen2S4Ter [S4Ter superscript], were generated. Allele specific
expression tests using digital quantitative PCR were applied to all three mutations, and nonsense
mediated decay was found to occur for the psen2N140fs [N140fs superscript]
transcript. RNA-seq-based transcriptomic analysis was performed on brains from psen2S4Ter [S4Ter superscript]
heterozygous and wild type siblings from a single family and revealed a likely relationship between
psen2 and mitochondrial formation and function, which are thought to be associated with AD
pathology. A GFP-Lc3a-GFP construct was designed to assay changes in autophagic flux in zebrafish
larvae. By applying this assay to psen2S4Ter [S4Ter superscript]-carrying mutant larvae, as well as larvae possessing
mutations in psen1, the Psen2 protein was seen to play a role in autophagy, which is also thought
to be a process important in the development of AD pathology. Thus, the results of this project may
contribute to a better understanding of the pathological mechanisms underlying AD.Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Biological Sciences, 201
Recommended from our members
Ultra-Low-Power Sensors and Receivers for IoT Applications
The combination of ultra-low power analog front-ends and CMOS-compatible transducers enable new applications, such as environmental monitors, household appliances, health trackers, etc. that are seamlessly integrated into our daily lives. Furthermore, wireless connectivity allows many of these sensors to operate both independently and collectively. These techniques collectively fulfil the recent surge of internet-of-things (IoT) applications that have the potential to fundamentally change daily life for millions of people.In this dissertation, the circuit and system design of wireless receivers and sensors is presented that explores the challenges of implementing long lifespan, high accuracy, and large coverage range IoT sensor networks. The first is a wake-up receiver (WuRX), which continuously monitors the RF environment to wake up a higher-power radio upon detection of a predetermined RF signature. This work both improves sensitivity and reduces power over prior art through a multi-faceted design featuring an impedance transformation network with large passive voltage gain, an active envelope detector with high input impedance to facilitate large passive voltage gain, a low-power precision comparator, and a low-leakage digital baseband correlator.Although pushing the prior WuRX performance boundary by orders of magnitude, the first work shows moderate sensitivity, inferior temperature robustness, and large area with external lumped components. Thus, the second work shows a miniaturized WuRX that is temperature-compensated, yet still consumes only nano-watt power and millimeter area while operating at 9 GHz. To further reduce the area, a global common-mode feedback is utilized across the envelope detector and baseband amplifier that eliminates the need for off-chip ac-coupling components. Multiple temperature-compensation techniques are proposed to maintain constant bandwidth of the signal path and constant clock frequency. Both WuRXs operate at 0.4 V supply, consume near-zero power and achieve ~-70 dBm sensitivity.Lastly, the first reported CMOS 2-in-1 relative humidity and temperature sensor is presented. A unified analog front-end interfaces on-chip transducers and converts the inputs into a frequency vis a high-linearity frequency-locked loop. An incomplete-settling switched-capacitor-based Wheatstone bridge is proposed to sense the inputs in a power-efficient fashion
X-Mesh: Towards Fast and Accurate Text-driven 3D Stylization via Dynamic Textual Guidance
Text-driven 3D stylization is a complex and crucial task in the fields of
computer vision (CV) and computer graphics (CG), aimed at transforming a bare
mesh to fit a target text. Prior methods adopt text-independent multilayer
perceptrons (MLPs) to predict the attributes of the target mesh with the
supervision of CLIP loss. However, such text-independent architecture lacks
textual guidance during predicting attributes, thus leading to unsatisfactory
stylization and slow convergence. To address these limitations, we present
X-Mesh, an innovative text-driven 3D stylization framework that incorporates a
novel Text-guided Dynamic Attention Module (TDAM). The TDAM dynamically
integrates the guidance of the target text by utilizing text-relevant spatial
and channel-wise attentions during vertex feature extraction, resulting in more
accurate attribute prediction and faster convergence speed. Furthermore,
existing works lack standard benchmarks and automated metrics for evaluation,
often relying on subjective and non-reproducible user studies to assess the
quality of stylized 3D assets. To overcome this limitation, we introduce a new
standard text-mesh benchmark, namely MIT-30, and two automated metrics, which
will enable future research to achieve fair and objective comparisons. Our
extensive qualitative and quantitative experiments demonstrate that X-Mesh
outperforms previous state-of-the-art methods.Comment: Technical repor
Quasi-phase-matching with Spontaneous Domain Inversion in an Integrated Lithium Niobate Micro-racetrack Resonator
Quasi-phase-matching (QPM) technology is the most popular and significant
method to achieve efficient nonlinear frequency conversion. The realization of
periodically poling to achieve QPM in photonic integrated circuits (PICs) is a
challenging issue for the requirement of CMOS compatible and large-scale
fabrication. Here we realize a spontaneous periodical domain inversion without
poling but by dispersion engineering and designing the orientation of the
crystal due to the circular propagation of light waves in an integrated lithium
niobate micro-racetrack resonator (MRR). The QPM second harmonic generation
(SHG) with a normalized conversion efficiency of 2.25/W (169th-order QPM)
has been achieved in the high-quality factor resonator of with
the straight waveguide (TE mode) of ultra-low propagation loss of
0.0022dB/cm. The efficiency can be further enhanced by using a first-order QPM,
and the bandwidth can be made broader by employing a shorter interaction length
for photonics and quantum optics. The configurable spontaneous
quasi-phase-matching lithium niobate MRR on X-cut thin-film lithium niobate on
insulator (LNOI) provides a significant on-chip integrated platform for other
optical parametric processes
Minute-cadence Observations of the LAMOST Fields with the TMTS: III. Statistic Study of the Flare Stars from the First Two Years
Tsinghua University-Ma Huateng Telescopes for Survey (TMTS) aims to detect
fast-evolving transients in the Universe, which has led to the discovery of
thousands of short-period variables and eclipsing binaries since 2020. In this
paper, we present the observed properties of 125 flare stars identified by the
TMTS within the first two years, with an attempt to constrain their eruption
physics. As expected, most of these flares were recorded in late-type red stars
with > 2.0 mag, however, the flares associated with
bluer stars tend to be on average more energetic and have broader profiles. The
peak flux (F_peak) of the flare is found to depend strongly on the equivalent
duration (ED) of the energy release, i.e., , which is consistent with results derived from the Kepler
and Evryscope samples. This relation is likely related to the magnetic loop
emission, while -- for the more popular non-thermal electron heating model -- a
specific time evolution may be required to generate this relation. We notice
that flares produced by hotter stars have a flatter relation compared to that from cooler stars. This is related to the
statistical discrepancy in light-curve shape of flare events with different
colors. In spectra from LAMOST, we find that flare stars have apparently
stronger H alpha emission than inactive stars, especially at the low
temperature end, suggesting that chromospheric activity plays an important role
in producing flares. On the other hand, the subclass having frequent flares are
found to show H alpha emission of similar strength in their spectra to that
recorded with only a single flare but similar effective temperature, implying
that the chromospheric activity may not be the only trigger for eruptions.Comment: 17 pages, 15 figures, 2 tables, refereed version. For associated data
files, see https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/523/219
- …