A linear piezoelectric micromachined ultrasound transducer (PMUT) array was fabricated and integrated into a device for photoacoustic imaging (PAI) of tissue phantoms. The PMUT contained 65 array ...elements, with each element having 60 diaphragms of 60 μm diameter and 75 μm pitch. A lead zirconate titanate (PZT) thin film was used as the piezoelectric layer. The in-air vibration response of the PMUT array elements showed a first mode resonance between 6 and 8 MHz. Hydrophone measurements showed 16.2 kPa average peak ultrasound pressure output at 7.5 mm from one element excited with 5 Vpp input. A receive sensitivity of ~0.48 mV/kPa was observed for a PMUT array element with 0 dB gain. The PMUT array was bonded to a custom-printed circuit board to enable compact integration with an optical fiber bundle for PAI. A broad photoacoustic bandwidth of ~89% was observed for the photoacoustic response captured from absorbing pencil lead targets. Linear scanning of a single element of a PMUT array was performed on different tissue phantoms embedded with light-absorbing targets to successfully demonstrate B-mode PAI using PMUTs.
Few studies have quantified aerosol concentrations of SARS-CoV-2 in hospitals and long-term care homes, and fewer still have examined samples for viability. This information is needed to clarify ...transmission risks beyond close contact.
We deployed particulate air samplers in rooms with COVID-19 positive patients in hospital ward and ICU rooms, rooms in long-term care homes experiencing outbreaks, and a correctional facility experiencing an outbreak. Samplers were placed between 2 and 3 meters from the patient. Aerosol (small liquid particles suspended in air) samples were collected onto gelatin filters by Ultrasonic Personal Air Samplers (UPAS) fitted with <2.5μm (micrometer) and <10 μm size-selective inlets operated for 16 hours (total 1.92m3), and with a Coriolis Biosampler over 10 minutes (total 1.5m3). Samples were assayed for viable SARS-CoV-2 virus and for the viral genome by multiplex PCR using the E and N protein target sequences. We validated the sampling methods by inoculating gelatin filters with viable vesicular stomatitis virus (VSV), and with three concentrations of viable SARS-CoV-2, operating personal samplers for 16hrs, and quantifying viable virus recovery by TCID50 assay.
In total, 138 samples were collected from 99 rooms. RNA samples were positive in 9.1% (6/66) of samples obtained with the UPAS 2.5μm samplers, 13.5% (7/52) with the UPAS 10μm samplers, and 10.0% (2/20) samples obtained with the Coriolis samplers. Culturable virus was not recovered in any samples. Viral RNA was detected in 15.1% of the rooms sampled. There was no significant difference in viral RNA recovery between the different room locations or samplers. Method development experiments indicated minimal loss of SARS-CoV-2 viability via the personal air sampler operation.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Bone morphogenetic proteins (BMPs) are multifunctional growth factors belonging to the transforming growth factor beta (TGFβ) multigene family. Current evidence indicates that they may play different ...and even antagonistic roles at different stages of limb development. Refined studies of their function in these processes have been impeded in the mouse due to the early lethality of null mutants for several BMP ligands and their receptors. Recently, however, these questions have benefited from the very powerful Cre-loxP technology. In this review, I intend to summarize what has been learned from this conditional mutagenesis approach in the mouse limb, focusing on Bmp2, Bmp4 and Bmp7 while restricting my analysis to the initial phases of limb formation and patterning. Two major aspects are discussed, the role of BMPs in dorsal-ventral polarization of the limb bud, together with their relation to apical ectodermal ridge (AER) induction, and their role in controlling digit number and identity. Particular attention is paid to the methodology, its power and its limits.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Frailty is a complex condition that primary care providers (PCPs) are managing in increasing numbers, yet there is no clear guidance or training for frailty care.
The present study examined eConsult ...questions PCPs asked specialists about patients with frailty, the specialists' responses, and the impact of eConsult on the care of these patients.
Cross-sectional observational study.
ChamplainBASE™ eConsult located in Eastern Ontario, Canada.
Sixty one eConsult cases closed by PCPs in 2019 that use the terms "frail" or "frailty" to describe patients 65 years of age or older.
The Taxonomy of Generic Clinical Questions (TGCQ) was used to classify PCP questions and the International Classification for Primary Care 3 (ICPC-3) was used to classify the clinical content of each eConsult. The impact of eConsult on patient care was measured by PCP responses to a mandatory survey.
PCPs most frequently directed their questions to cardiology (n = 7; 11%), gastroenterology (n = 7; 11%), and endocrinology (n = 6; 10%). Specialist answers most often pertained to medications (n = 63, 46%), recommendations for clinical investigation (n = 24, 17%), and diagnoses (n = 22, 16%). Specialist responses resulted in PCPs avoiding referral in 57% (n = 35) of cases whereas referrals were still required in 15% (n = 9) of cases. Specialists responded to eConsults in a median 1.11 days (IQR = 0.3-4.7), and 95% (n = 58) of cases received a response within 7 days. Specialists recorded a median of 15 min to respond (IQR = 10-20), with a median cost of $50.00 CAD (IQR = 33.33 - 66.66) per eConsult.
Through the analysis of questions and responses submitted to eConsult, this study provides novel information on PCP knowledge gaps and approaches to care for patients living with frailty. Furthermore, these analyses provide evidence that eConsult is a feasible and valuable tool for improving care for patients with frailty in primary care settings.
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CEKLJ, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper reports the development of piezoelectrically actuated radio frequency (RF) micro-electromechanical systems (MEMS) switches on Si-on-sapphire substrates using a novel greyscale lithography ...fabrication technique. Lead zirconium titanate (PZT) thin-film actuators are used to close a series ohmic contact single-pole single-throw (SPST) switch implemented in co-planar waveguide (CPW). The switch design on a Si substrate has maximum insertion loss of 2.6 dB from DC - 67 GHz. While over the same frequency span, the switch on a sapphire substrate exhibits insertion loss better than 1.4 dB and isolation better than 15 dB. 2020-0071
The prospect of using cell replacement therapies has raised the key issue of whether elucidation of developmental pathways can facilitate the generation of therapeutically important cell types from ...stem cells. Here we show that the homeodomain proteins Lmx1a and Msx1 function as determinants of midbrain dopamine neurons, cells that degenerate in patients with Parkinson's disease. Lmx1a is sufficient and required to trigger dopamine cell differentiation. An early activity of Lmx1a is to induce the expression of Msx1, which complements Lmx1a by inducing the proneural protein Ngn2 and neuronal differentiation. Importantly, expression of Lmx1a in embryonic stem cells results in a robust generation of dopamine neurons with a “correct” midbrain identity. These data establish that Lmx1a and Msx1 are critical intrinsic dopamine-neuron determinants in vivo and suggest that they may be essential tools in cell replacement strategies in Parkinson's disease.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Lead zirconate titanate (PZT)-based piezoelectric micromachined ultrasonic transducers (PMUTs) for particle manipulation applications were designed, fabricated, characterized, and tested. The PMUTs ...had a diaphragm diameter of 60 μm, a resonant frequency of ~8 MHz, and an operational bandwidth (BW) of 62.5%. Acoustic pressure output in water was 9.5 kPa at 7.5 mm distance from a PMUT element excited with a unipolar waveform at 5 V pp. The element consisted of 20 diaphragms connected electrically in parallel. Particle trapping of 4 μm silica beads was shown to be possible with 5 V pp unipolar excitation. Trapping of multiple beads by a single element and deterministic control of particles via acoustophoresis without the assistance of microfluidic flow were demonstrated. It was found that the particles move toward diaphragm areas of highest pressure, in agreement with literature and simulations. Unique bead patterns were generated at different driving frequencies and were formed at frequencies up to 60 MHz, much higher than the operational BW. Levitation planes were generated above the 30 MHz driving frequency.
Msx1 and Msx2 promote meiosis initiation Le Bouffant, Ronan; Souquet, Benoit; Duval, Nathalie ...
Development (Cambridge),
12/2011, Volume:
138, Issue:
24
Journal Article
Peer reviewed
The mechanisms regulating germ line sex determination and meiosis initiation are poorly understood. Here, we provide evidence for the involvement of homeobox Msx transcription factors in foetal ...meiosis initiation in mammalian germ cells. Upon meiosis initiation, Msx1 and Msx2 genes are strongly expressed in the foetal ovary, possibly stimulated by soluble factors found there: bone morphogenetic proteins Bmp2 and Bmp4, and retinoic acid. Analysis of Msx1/Msx2 double mutant embryos revealed a majority of undifferentiated germ cells remaining in the ovary and, importantly, a decrease in the number of meiotic cells. In vivo, the Msx1/Msx2 double-null mutation prevented full activation of Stra8, a gene required for meiosis. In F9 cells, Msx1 can bind to Stra8 regulatory sequences and Msx1 overexpression stimulates Stra8 transcription. Collectively, our data demonstrate for the first time that some homeobox genes are required for meiosis initiation in the female germ line.
The phase behaviour of drug molecules is important for the control over the desired polymorph in drug formulations, whether it is to ensure better stability or better solubility. In the case of ...pyrazinamide, a drug against tuberculosis, stability studies have been complicated due to the very slow transition kinetics observed in DSC measurements. Using vapour pressure measurements, in which the reluctance of phase transformation is in fact an advantage, all solid-solid phase transformation temperatures have been determined. This method has been key to map the phase behaviour of pyrazinamide. The use of high-pressure measurements with synchrotron X-ray diffraction has allowed the construction of the pressure-temperature phase diagram of the four solid phases of pyrazinamide and the liquid phase. The
α
form was found to be the stable form at room temperature. One striking feature of pyrazinamide is that one polymorph, the
δ
form, has a very large thermal expansion and extreme compressibility not found in the other three forms. This gives rise to curved solid-solid transition equilibria in the pressure-temperature phase diagram, which is not commonly observed in the pressure range of 0 to 1 GPa. Using the phase diagram, polymorph
β
could be obtained in its stable temperature domain.
All four pyrazinamide polymorphs possess a stable domain under ordinary pressure;
α
is the stable form at room temperature.
The involvement of
Msx homeobox genes in skull and tooth formation has received a great deal of attention. Recent studies also indicate a role for the
msh/Msx gene family in development of the ...nervous system. In this article, we discuss the functions of these transcription factors in neural-tissue organogenesis. We will deal mainly with the interactions of the
Drosophila muscle segment homeobox (
msh) gene with other homeobox genes and the repressive cascade that leads to neuroectoderm patterning; the role of
Msx genes in neural-crest induction, focusing especially on the differences between lower and higher vertebrates; their implication in patterning of the vertebrate neural tube, particularly in diencephalon midline formation. Finally, we will examine the distinct activities of
Msx1,
Msx2 and
Msx3 genes during neurogenesis, taking into account their relationships with signalling molecules such as BMP.
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