Aplastic Anemia: Clinicohaematological Features, Treatment and Outcome Analysis

Objective: To determine the clinicohaematological features, treatment and outcome of children diagnosed with aplastic anemia at a single institution. Study Design: Observational study. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from January 1999 till December 2008. Methodology: Medical records of children aged less than 15 years of age diagnosed with aplastic anemia were reviewed. Clinicohaematological features, treatment and its response to therapy and outcome were recorded. Results were described in percentages. Results: Ninety patients were diagnosed to have aplastic anemia (AA); 65 were male during the study period. Age ranged from 1 to 15 years. Fever in 65 patients (72.2%), pallor in 53 (58.8%), skin bleeding in 49 (54.4%) and epistaxis in 31(34.4%) were the most common and frequent presenting features. Congenital (Fanconi’s) anemia was found in 15 (16.6%) and acquired idiopathic in 75 (83.4%) of patients. Very severe aplastic anemia (VSAA) was seen in 29 (32.2%), 26 (28.9%) had severe AA and 17 (18.9%) had moderate AA. Eight patients (8.9%) underwent haematopoietic stem cell transplantation (HSCT), 12 (13.3%) received immunosuppressive therapy (IST) and 70 patients (77.7%) received other and supportive therapy. Five (62.5%) patients showed complete response to HSCT and 3 (37.5%) failed to engraft. IST showed complete response in 3 (25%), partial response in 5 (41.6%) and no response in 4 (33.3%). Twenty two patients (24.4%) expired either due to infection in 16 (72.7%, fungal in 6, bacterial in 10) and intracranial haemorrhage in 6 (27.3%) cases. Conclusion: Majority of cases with AA were acquired and idiopathic in etiology. VSAA and SAA were frequent. Response to HSCT and IST was sub-optimal

Speech separation with dereverberation-based pre-processing incorporating visual cues

Humans are skilled in selectively extracting a single sound source in the presence of multiple simultaneous sounds. They (individuals with normal hearing) can also robustly adapt to changing acoustic environments with great ease. Need has arisen to incorporate such abilities in machines which would enable multiple application areas such as human-computer interaction, automatic speech recognition, hearing aids and hands-free telephony. This work addresses the problem of separating multiple speech sources in realistic reverberant rooms using two microphones. Different monaural and binaural cues have previously been modeled in order to enable separation. Binaural spatial cues i.e. the interaural level difference (ILD) and the inter- aural phase difference (IPD) have been modeled [1] in the time-frequency (TF) domain that exploit the differences in the intensity and the phase of the mixture signals (because of the different spatial locations) observed by two microphones (or ears). The method performs well with no or little rever- beration but as the amount of reverberation increases and the sources approach each other, the binaural cues are distorted and the interaural cues become indistinct, hence, degrading the separation performance. Thus, there is a demand for exploiting additional cues, and further signal processing is required at higher levels of reverberation

A new cascaded spectral subtraction approach for binaural speech dereverberation and its application in source separation

In this work we propose a new binaural spectral subtraction method for the suppression of late reverberation. The pro- posed approach is a cascade of three stages. The first two stages exploit distinct observations to model and suppress the late reverberation by deriving a gain function. The musical noise artifacts generated due to the processing at each stage are compensated by smoothing the spectral magnitudes of the weighting gains. The third stage linearly combines the gains obtained from the first two stages and further enhances the binaural signals. The binaural gains, obtained by indepen- dently processing the left and right channel signals are com- bined using a new method. Experiments on real data are per- formed in two contexts: dereverberation-only and joint dere- verberation and source separation. Objective results verify the suitability of the proposed cascaded approach in both the contexts

Development of Reaction Kinetics Model for the Production of Synthesis Gas from Dry Methane Reforming

The energy supply systems dependent on fossils and municipal solid waste (MSW) materials are primarily responsible for releasing greenhouse (GHG) gases and their related environmental hazards. The increasing amount of methane (CH4) and carbon dioxide (CO2) is the scientific community's main concern in this context. Reduction in the emission amount of both gases combined with the conversion technologies that would convert these total threat gases (CO2 and CH4) into valuable feedstocks will significantly lower their hazardous impact on climate change. The conversion technique known as dry methane reforming (DMR) utilizes CO2 and CH4 to produce a combustible gas mixture (CO+H2), popularly known as synthesis gas/or syngas. Therefore, this research study aims to explore and enlighten the characteristics of the DMR mechanism. The conversion behaviour of CO2 and CH4 was studied with modelling and simulation of the DMR process using MATLAB. The results showed that inlet gas flow has a significant impact on the reactions. In contrast, the inlet molar composition ratio of the reactions was found to have no substantial effect on the mechanism of DMR. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Terahertz time-gated spectral imaging for content extraction through layered structures

Spatial resolution, spectral contrast and occlusion are three major bottlenecks for non-invasive inspection of complex samples with current imaging technologies. We exploit the sub-picosecond time resolution along with spectral resolution provided by terahertz time-domain spectroscopy to computationally extract occluding content from layers whose thicknesses are wavelength comparable. The method uses the statistics of the reflected terahertz electric field at subwavelength gaps to lock into each layer position and then uses a time-gated spectral kurtosis to tune to highest spectral contrast of the content on that specific layer. To demonstrate, occluding textual content was successfully extracted from a packed stack of paper pages down to nine pages without human supervision. The method provides over an order of magnitude enhancement in the signal contrast and can impact inspection of structural defects in wooden objects, plastic components, composites, drugs and especially cultural artefacts with subwavelength or wavelength comparable layers

Potential of biomass for bioenergy in Pakistan based on present case and future perspectives

Authors have no conflict of interest and would like to acknowledge the National University of Sciences&Technology (NUST), Pakistan.Peer reviewedPostprin

Thermodynamic performance analysis of hydrofluoroolefins (HFO) refrigerants in commercial air-conditioning systems for sustainable environment

Global warming is one of most severe environmental concerns that our planet is facing today. One of its causes is the previous generation of refrigerants that, upon release, remain in the atmosphere for longer periods and contribute towards global warming. This issue could potentially be solved by replacing the previous generation's high global warming potential (GWP) refrigerants with environmentally friendly refrigerants. This scenario requires an analysis of new refrigerants for a comparison of the thermodynamic properties of the previously used refrigerants. In the present research, a numerical study was conducted to analyze the thermodynamic performance of specifically low GWP hydrofluoroolefens (HFO) refrigerants for an actual vapor compression refrigeration cycle (VCRC) with a constant degree of 3 K superheat. The output parameters included the refrigeration effect, compressor work input, the coefficient of performance (COP), and the volumetric refrigeration capacity (VRC), all of which were calculated by varying the condenser pressure from 6 to 12 bars and vapor pressure from 0.7 to 1.9 bars. Results showed that R1234ze(Z) clearly possessed the desired thermodynamic performance. The drop in refrigeration effect for R1234ze(Z) was merely 14.6% less than that of R134a at a 12 bar condenser pressure; this was minimum drop among candidate refrigerants. The drop in the COP was the minimum for R1234ze(Z)-5.1% less than that of R134a at a 9 bar condenser pressure and 4.7% less than that of R134a at a 1.9 bar evaporator pressure, whereas the COP values of the other refrigerants dropped more drastically at higher condenser pressures. R1234ze(Z) possessed favorable thermodynamic characteristics, with a GWP of 7, and it can serve as an alternative refrigerant for refrigeration systems for a sustainable environment