The labial gene is required to terminate proliferation of identified neuroblasts in postembryonic development of the Drosophila brain

The developing brain of Drosophila has become a useful model for studying the molecular genetic mechanisms that give rise to the complex neuronal arrays that characterize higher brains in other animals including mammals. Brain development in Drosophila begins during embryogenesis and continues during a subsequent postembryonic phase. During embryogenesis, the Hox gene labial is expressed in the developing tritocerebrum, and labial loss-of-function has been shown to be associated with a loss of regional neuronal identity and severe patterning defects in this part of the brain. However nothing is known about the expression and function of labial, or any other Hox gene, during the postembryonic phase of brain development, when the majority of the neurons in the adult brain are generated. Here we report the first analysis of Hox gene action during postembryonic brain development in Drosophila. We show that labial is initially expressed in six larval brain neuroblasts, of which only four give rise to the labial expressing neuroblast lineages present in the late larval brain. Although MARCM-based clonal mutation of labial in these four neuroblast lineages does not result in an obvious phenotype, a striking and unexpected effect of clonal labial loss-of-function does occur during postembryonic brain development, namely the formation of two ectopic neuroblast lineages that are not present in wild-type brains. The same two ectopic neuroblast lineages are also observed following cell death blockage and, significantly, in this case the resulting ectopic lineages are Labial-positive. These findings imply that labial is required in two specific neuroblast lineages of the wildtype brain for the appropriate termination of proliferation through programmed cell death. Our analysis of labial function reveals a novel cell autonomous role of this Hox gene in shaping the lineage architecture of the brain during postembryonic development

Towards a single-photon energy-sensitive pixel readout chip: pixel level ADCs and digital readout circuitry

Unlike conventional CMOS imaging, a single\ud photon imager detects each individual photon impinging on\ud a detector, accumulating the number of photons during a\ud certain time window and not the charge generated by the all\ud the photons hitting the detector during said time window.\ud The latest developments in the semiconductor industry\ud are allowing faster and more complex chips to be designed\ud and manufactured. With these developments in mind we are\ud working towards the next step in single photon X-ray imaging:\ud energy sensitive pixel readout chips. The goal is not only\ud to detect and count individual photons, but also to measure\ud the charge deposited in the detector by each photon, and\ud consequently determine its energy. Basically, we are aiming\ud at a spectrometer-in-a-pixel, or a “color X-ray camera”.\ud The approach we have followed towards this goal is the\ud design of small analog-to-digital-converters at the pixel level,\ud together with a very fast digital readout from the pixels to\ud the periphery of the chip, where the data will be transmitted\ud off-chip.\ud We will present here the design and measurement on prototype\ud chips of two different 4-bit pixel level ADCs. The\ud ADCs are optimized for very small area and low power, with\ud a resolution of 4-bits and a sample rate of 1 Msample/s. The\ud readout architecture is based around current-mode sense\ud amplifiers and asynchronous token-passing between the pixels.\ud This is done in order to achieve event-by-event readout\ud and, consequently, on-line imaging. We need to read eventby-\ud event (photon-by-photon), because we cannot have memory\ud on the pixels due to obvious size constraints. We use\ud current-mode sense amplifiers because they perform very\ud well in similar applications as very fast static-RAM readout

Anomalously large capacitance of a plane capacitor with a two-dimensional electron gas

In electronic devices where a two-dimensional electron gas (2DEG) comprises one or both sides of a plane capacitor, the resulting capacitance $C$ can be larger than the "geometric capacitance" $C_g$ determined by the physical separation $d$ between electrodes. This larger capacitance is known to result from the Coulomb correlations between individual electrons within the low density 2DEG, which lead to a negative thermodynamic density of states (negative compressibility). Experiments on such systems generally operate in the regime where the average spacing between electrons $n^{-1/2}$ in the 2DEG is smaller than $d$, and these experiments observe $C > C_g$ by only a few percent. A recent experiment [1], however, has observed $C$ larger than $C_g$ by almost 40% while operating in the regime $nd^2 << 1$. In this paper we argue that at $nd^2 << 1$ correlations between the electronic charge of opposite electrodes become important. We develop a theory of the capacitance for the full range of $nd^2$. We show that, in the absence of disorder, the capacitance can be $4d/a$ times larger than the geometric value, where $a << d$ is the electron Bohr radius. Our results compare favorably with the experiment of Ref. [1] without the use of adjustable parameters.Comment: 8 pages, 6 figures; revised discussion of the zero density limit; some typos fixe

Hydroprocessing Microalgae Derived Hydrothermal Liquefaction Bio-Crude for Middle Distillate Fuels Production – A Review

Bio-crude, a biomass derived oil similar to petroleum crude in properties, can be produced from microalgae via hydrothermal liquefaction (HTL) and upgraded to middle distillates fuels by hydroprocessing which is a very common refinery technology. This paper reviews available literature on HTL of microalgae and the subsequent upgrade of the bio-crude into middle distillate fuels via hydroprocessing. Experimental and process simulation results from different studies were used to explore the differences and similarities between the bio-crude and conventional crude; the methods and process conditions for hydroprocessing the bio-crude; the products obtainable, their compositions &amp; properties; as well as the inputs required for modelling and simulation of the process. The review illustrates that the same fuels (of almost the same properties) can be produced from the bio-crude as from petroleum crude; the process conditions depend on the required product distribution (maximum diesel or kerosene/jet range fuels); and the process is characterized by much higher hydrogen consumption than hydro processing conventional crude.http://dx.doi.org/10.4314/njt.v34i4.1

Torsion of an Ovarian Cyst in Pregnancy

Torsion of the ovary is the partial or total rotation of the ovary over its pedicle. It is unusual for it to occur in the second trimester. We report a case&nbsp; of a 35year old G10P9+0A7 at 17weeks gestation who presented with acute severe abdominal pain. She was found to have an ovarian cyst in pregnancy. She had Exploratory Laparotomy where a huge gangrenous cyst was found and Salpingoophorectomy was performed. The pregnancy continued without any problems. The histology report showed a Simple Cyst. Key words: Torsion, Ovarian Cyst, Pregnanc

Experimental investigation of sand minimum transport velocity in multiphase fluid flow in pipes.

The production of reservoir fluid through long tiebacks/pipelines has emerged as one of the cost effective alternative especially for many marginal fields which can now be produced as clusters into a common processing facility. However, sand is often co-produced with the reservoir fluid especially when produced from unconsolidated formations. The sand will settle to form beds along the bottom of the pipe if the fluid velocity is below the minimum transport velocity required (MTV). In order to prevent solid deposition and ensure flow assurance, it is therefore critical to identify and measure the MTV. Two approaches are generally recognised for development of solid minimum transport velocity models in pipelines, the analytical and empirical methods. Because of the complexities of multiphase flow, the analytical approach will often require some assumptions and inputs from empirical measurement. This study presents the results of the experimental investigation for minimum transport velocity (MTV) both in suspension and rolling. The minimum transport velocity was found to be greatly influenced by the flow patterns and pipe inclinations. It was observed that the slug flow provides better solid carrying capacity in pipes when compared with other observed flow patterns. It was also observed that the influence of pipe inclination diminishes beyond 20{deg}. The acquired experimental data will ultimately provide a comprehensive data base for testing and validations of analytical models for improved accuracy. The justification for experimental work was evident from the inconsistent and inaccurate results obtained using existing analytical models for MTV predictions

Knowledge and Utilization of Red Flags by Physiotherapists in the Assessment and Management of Patients with Low Back Pain

Proper diagnosis and effective treatment of low back pain (LBP) by physiotherapists are believed to be enhanced by knowledge and utilization of red flags. This cross-sectional study assessed knowledge and utilization of red flags by physiotherapists in the management of patients with LBP. A total of 50 physiotherapists in Kano State were involved in the study. A modified version of a questionnaire from the Royal College of General Practitioners (1999) was used as a tool for data collection. Data retrieved were analysed using descriptive statistics of frequency and percentage. Themajority of the physiotherapists 44 (88%) had knowledge of red flags but only 14 (28%) were putting it to good use. A few red flags, such as age of the patient 9 (18%), and history of trauma 8(12%), were more oftendocumented, while medical history of cancer, HIV status, as well as history of fever were the least documented and by only 1 (2%) physiotherapist.It was concluded that physiotherapists have adequate knowledge but poor utilization of red flags in their clinical practice.KEYWORDS: red flags, physiotherapist, low back pai

Production and Characterization of Biosurfactants from Abattoir Wastewater

Five genera of bacteria were isolated from abattoir waste water and identified as Bacillus licheniforms, Bacillus alvei, Pseudomonas paucimobilis, Vibrio metschnikovii and Yersinia enterocolitica. The isolates were screened for biosurfactant production using blood haemolysis test, emulsification test, oil spreading methods. The biosurfactants were characterized using GC-MS analysis. The isolates showed haemolytic activity and the highest emulsification index of 71% was observed from Pseudomonas paucimobilis followed by Bacillus alvei with emulsification index of 67% whereas Bacillus licheniformis has the lowest emulsification index of 11%. Also Bacillus alvei showed a high oil displacement of 20mm followed by Bacillus licheniformis with 18ml oil displacement whereas Pseudomonas paucimobilis has the lowest oil displacement of 15mm. The biosurfactant could be employed to enhance oil recovery bioremediation. Keywords: Abattoir, Bacillus, Pseudomonas, Biosurfactants, Wastewate