Lysis of tubercle bacilli in fresh and stored sputum specimens: implications for diagnosing tuberculosis in stored and paucibacillary specimens by PCR

<p>Abstract</p> <p>Background</p> <p>Nucleic acid amplification techniques are being used increasingly in diagnosing tuberculosis. In developing countries clinical samples are often stored for subsequent analysis since molecular tests are conducted at only a limited number of laboratories. This study was conducted to assess the speed at which mycobacteria undergo autolysis and free DNA is detected in the supernatant during low-temperature storage.</p> <p>Results</p> <p>Eighty-seven smear positive sputa from tuberculosis patients were analysed immediately and after storage at -20°C. Timelines of 1 and 2 months were selected to assess the maximum extent of DNA loss that occurred during storage. All samples remained PCR- and smear-positive at 1 month and only 1 sample turned negative after 2 months. Bacterial lysis in the specimens was demonstrated by PCR analysis of supernatant fractions; 53% of the freshly analysed samples contained mycobacterial DNA in supernatants. PCR positivity increased significantly during storage (to 69% and 77% after 1 and 2 months of storage, respectively, P < 0.0001). Storage-associated bacterial lysis was accompanied by a decrease in smear grade status in 28 of 87 samples (P < 0.0001 after 2 months of storage) and a significant storage-associated reduction in bacterial numbers in the remaining samples.</p> <p>Conclusion</p> <p>We conclude that (i) freshly isolated sputum contains both intact and lysed mycobacteria, (ii) lysis increased during storage and (iii) supernatant fractions routinely discarded during sample processing contain mycobacterial DNA. We propose that supernatant is a valuable sample for PCR for both fresh and stored specimens, particularly those with a low bacterial load in addition to conventional sediment.</p

Experimental evaluation of anti-stripping additives on porous asphalt mixtures

The open structure of porous asphalt mix influences its strength and durability against air, water and clogging materials. These factors cause loss of adhesion between binder-aggregate interface and loss of cohesion within the binder film. This could lead to stripping problem which contribute to premature failures as well as deterioration in the performance and service life of porous asphalt. Therefore, this study is aimed to evaluate the potential of diatomite as anti-stripping additives in porous asphalt and compared with hydrated lime and Ordinary Portland Cement (OPC). Field Emission Scanning Electron Microscopy (SEM) test and Energy Dispersive X-ray Spectroscopy analysis (EDX) were conducted to investigate the microstructure and chemical composition of the anti-stripping additives. A number of gyratory compacted samples of porous asphalt mixture with Malaysian gradation were prepared. Each sample was incorporated with 2% of anti-stripping additives as filler then mixed with polymer modified bitumen of PG76. The samples were measured for air voids content, permeability rate, resilient modulus and abrasion loss. The results indicate that samples prepared with hydrated lime show higher permeability rate and lower abrasion loss compared to samples with OPC and diatomite. However, the samples prepared with diatomite show enhanced resilient modulus compared to those with hydrated lime and OPC

RAZNOLIKOST IHTIOFAUNE JUŽNIH OBALNIH VODA BANGLADEŠA: POSTOJEĆE STANJE, PRIJETNJE I MOGUĆNOSTI OČUVANJA

Despite the enormous anthropogenic and environmental hazards affecting wild fisheries resources, southern coastal waters are still considered one of the aquatic biodiversity hotspots in Bangladesh. Therefore, the present study was conducted to make a complete account of fishes and to assess their condition and conservation status in the rivers spread across four southern coastal districts of Bangladesh. During the study period from January to December 2014, a total of 98 species of fish were recorded belonging to 81 genera, 48 families and 13 orders. Perciforms were recorded as the most diverse fish group in terms of both number and individuals of species observed. Of the 98 species, 26.53% were listed as Locally Threatened in Bangladesh, including 11.22% species listed as Vulnerable, 10.20% as Endangered and 5.10% as Critically Endangered. Four population indices viz, Shannon–Wiener index (H), Simpson’s dominance index (D), Simpson’s index of diversity (1-D) and Margalef’s index (d) were applied to demonstrate the species diversity, richness and evenness of fish in sampling areas and their overall values were 3.54-3.70, 0.04-0.05, 0.95-0.96 and 7.48-8.67, respectively. To sustain the prospect of fisheries biodiversity in the southern coastal areas of Bangladesh, management and conservation strategies like restocking economically important fish species, establishing and maintaining fish sanctuaries, banning indiscriminate fishing and destructive fishing gears, identification and protection of the breeding and nursery grounds should be taken into consideration with utmost priority.Unatoč visokoj ugroženosti brojnim antropogenim i ekološkim faktorima koji utječu na ribolovne resurse, južne priobalne vode se još uvijek smatraju jednom od vodenih vrućih točki biološke raznolikosti u Bangladešu. Ova je studija provedena da bi se utvrdila brojnost riba, ocijenilo njihovo stanje i status zaštite u rijekama koje se prostiru preko četiri južne priobalne oblasti Bangladeša. Tijekom istraživanja, u razdoblju od siječnja do prosinca 2014. godine, zabilježeno je ukupno 98 vrsta riba koje pripadaju 81 rodu, 48 porodica i 13 rodova. Najveću raznolikost u broju jedinki i broju vrsta utvrđena je kod skupine Perciformes. Od 98 vrsta, 26,53% su navedene kao lokalno ugrožene u Bangladešu, uključujući 11,22% vrsta koje su navedene kao ranjive, 10,20% kao ugrožena i 5,10% kao kritično ugrožene. Pri istraživanju četiri populacije utvrđeni su Shannon–Wiener indeks (H), Simpsonov indeks dominacije (D), Simpson indeks raznolikosti (1-D) i Margalefov indeks (d) kako bi se utvrdila raznolikost i bogatstvo vrsta u području istraživanja, čija je ukupna vrijednost iznosila 3,54-3,70, 0,04-0,05, 0,95-0,96 7,48-8,67. Za održanje perspektive ribarske bioraznolikosti u južnim priobalnim područjima Bangladeša, treba uzeti u obzir s najvećim prioritetom strategiju upravljanja i očuvanja kao i poribljavanja gospodarski važnih vrsta riba, uz uspostavljanje i održavanje ribljih skloništa, te zabranu nekritičnog ribolova i destruktivnih ribolovnih alata, identifikaciju i zaštitu područja mrijesta i rastilištu

Effects of air voids content on the performance of porous asphalt mixtures

This study evaluates the effects of different air voids content on the resilient modulus, abrasion loss and permeability of porous asphalt mixture. One of the main issues with porous asphalt mixture is having an adequate amount of air voids content for its performance. High air voids content will increase the infiltration rate but reduces its durability and vice versa. Gyratory compacted samples were fabricated at various air void contents i.e. 17.5%, 20% and 22.5% using aggregate gradations adopted from Australian and Singaporean specifications. The samples were tested for permeability, resilient modulus and abrasion loss. From the analysis, it was found that the increase in the voids content improves the permeability but adversely affects the resilient modulus and the mixture's performance under abrasion. The resilient modulus and abrasion loss show similar pattern at low air voids content where no significant difference between both mixture types but at high voids content, finer compositions shows to be more durable. Therefore, it can be concluded that the air voids content influences the performance of porous asphalt mixtures

Air voids characterisation and permeability of porous asphalt gradations used in different countries

This paper presents the evaluation made on the properties of porous asphalt mixtures practiced in different countries. In order to fully understand the properties of porous asphalt mixtures, investigation should be conducted from different perspectives. Therefore this study was carried out to investigate the air voids properties and functional performance of porous asphalt simultaneously. An image analysis technique was conducted to analyse the air void properties within the gyratory compacted samples captured using a non-destructive scanning technique of X-ray Computed Tomography (CT). The results were then compared to the functional performance in terms of permeability. Four aggregate gradations of porous asphalt used in different countries i.e. Malaysia, Australia, Singapore and the United States were adopted for comparison. From the analysis, Australian mixture was found with the most homogeneous air voids distribution throughout the sample compared to other mixtures. The air void properties investigated have successfully described the air voids formation within the mixtures which reflects the result of permeability. This shows that air voids distribution within the sample plays an important role in determining the effectiveness of water transmission

The role of custom in managing child custody: a juridico-psychological analysis in local context

Child custody is one of most important matters in managing the after effects of divorce as far as their impact on the child is concerned. Guided by the general principles of the Qur‖an and Sunnah on parenting and parental role, classical jurists developed their own theory of managing such impacts in tandem with what was realistically work-ing for their time and environment. With the changes in the pattern of parenting and traditional family structure in societies like Malaysia, it is suggested the fiqh of child custody has to be relevantised so as to result in minimizing debilitating after effects of parental separation on the children. The Current practice of mostly awarding the custo-dy to the mother is not a full remedy, thus this study using juridico-psychological meth-ods of analysis argues for finding juridical basis for joint-custody. Data related to the research were collected from print and internet sources. The textual and content-analysis methods were used in interpreting the relevant data. The research findings highlighted that the solution to the problem with regard to child custody should be in line with the modern psychological needs of the child so long it is within the parameters set by the Shariah and brings greater benefit to the child. Moreover, if both the parents of the child are Islamic in their orientation of thinking, a joint-custody will be more re-warding towards the child‖s psychological needs and growth

Design of Nonlinear Backstepping Double-Integral Sliding Mode Controllers to Stabilize the DC-Bus Voltage for DC–DC Converters Feeding CPLs

This paper proposes a composite nonlinear controller combining backstepping and double-integral sliding mode controllers for DC–DC boost converter (DDBC) feeding by constant power loads (CPLs) to improve the DC-bus voltage stability under large disturbances in DC distribution systems. In this regard, an exact feedback linearization approach is first used to transform the nonlinear dynamical model into a simplified linear system with canonical form so that it becomes suitable for designing the proposed controller. Another important feature of applying the exact feedback linearization approach in this work is to utilize its capability to cancel nonlinearities appearing due to the incremental negative-impedance of CPLs and the non-minimum phase problem related to the DDBC. Second, the proposed backstepping double integral-sliding mode controller (BDI-SMC) is employed on the feedback linearized system to determine the control law. Afterwards, the Lyapunov stability theory is used to analyze the closed-loop stability of the overall system. Finally, a simulation study is conducted under various operating conditions of the system to validate the theoretical analysis of the proposed controller. The simulation results are also compared with existing sliding mode controller (ESMC) and proportional-integral (PI) control schemes to demonstrate the superiority of the proposed BDI-SMC

A nonlinear double‐integral sliding mode controller design for hybrid energy storage systems and solar photovoltaic units to enhance the power management in DC microgrids

In this paper, a nonlinear decentralized double‐integral sliding mode controller (DI‐SMC) is designed along with an energy management system (EMS) for the DC microgrid (DCMG). This DCMG includes having a hybrid energy storage system (HESS) that incorporates a battery energy storage system (BESS) and supercapacitor energy storage system (SCESS) while the load demand is met through the power generated from solar photovoltaic (SPV) units. First, dynamical models of each subsystem of DCMGs such as the SPV system, BESS, and SCESS are developed to capture highly nonlinear behaviors of DCMGs under various operating conditions. The proposed nonlinear DI‐SMC is then designed for each power unit in DCMGs to ensure the desired voltage level at the common DC‐bus and appropriate power dispatch of different components to fulfill the load requirement of the DCMG. On the other hand, an energy management system (EMS) is designed to determine the set point for the controller with an aim of ensuring the power balance within DCMGs under various operating conditions where the overall stability is assessed using the Lyapunov theory. Simulation studies along with the processor‐in‐loop validation, including a comparative study with a proportional‐integral (PI) controller, verify the applicability and effectiveness of the EMS‐based DI‐SMC under different operating conditions of the DCMG

Effect of Evotherm 3G on the performance of asphalt mixture

Temperature is the main element in producing asphalt mixture for asphalt pavement. The presence of Evotherm 3G in the asphalt can help to reduce the temperature of asphalt production and hence reduce energy usage. This study presents the bitumen properties with Evotherm 3G and the effect of this additive on asphalt mixture performance in reducing production temperature compared to hot mix asphalt. The bitumen tests were performed on the bitumen penetration grade of 60/70 using the penetration, softening point, and viscosity tests, while the Marshall samples were produced for the asphalt properties evaluation. The results showed that asphalt containing Evotherm 3G produced at a lower compaction temperature has comparable stability and flow to the conventional hot mix asphalt. The viscosity data of the bitumen added with Evotherm 3G does not give a significant difference compared to the penetration value. This justifies the applicability of Evotherm 3G as a surfactant in warm mix asphalt production

An Energy Management System-Based Control Strategy for DC Microgrids with Dual Energy Storage Systems

In this work, a control strategy is developed for different components in DC microgrids where set points for all controllers are determined from an energy management system (EMS). The proposed EMS-based control scheme is developed for DC microgrids with solar photovoltaic (PV) systems as the primary generation units along with energy storage systems. In this work, the concept of dual energy storage systems (DESSs) is used, which includes a battery energy storage system (BESS) and supercapacitor (SC). The main feature of this DESS is to improve the dynamic performance of DC microgrids during severe transients appearing from changes in load demands as well as in the output power from solar PV units. Furthermore, the proposed EMS-based control scheme aims to enhance the lifetime of the BESS in DC microgrids with DESSs and voltage stability as compared to the same without SCs. The proposed EMS-based control strategy uses proportional-integral (PI) controllers to regulate the switching control actions for different converters within the DC microgrid based on the decision obtained from the EMS in order to achieve the desired control objectives. The performance of the proposed scheme was analyzed through simulation results in terms of improving the voltage stability, maintaining the power balance, and enhancing the lifetime of BESSs within a DC microgrid framework incorporated with the DESS. The simulations are carried out in the MATLAB/SIMULINK simulation platform and compared with a similar approach having only a single energy storage system, i.e., the BESS