Open Access Original Research Article

Phosphate-buffered Formalin Fixative Under Controlled Fixation Temperature Yielded Excellently Preserved Histomorphology

Kenneth C. Onyegbula, Gideon T. Oluwaloye

Current Journal of Applied Science and Technology, Page 42-49
DOI: 10.9734/cjast/2021/v40i4031601

Aim: Using mouse liver as experimental model, this study attempts to identify a formalin-based fixative and fixation temperature that jointly provides the best balance of preservation of tissue morphology.

Methodology: Liver samples from fifty (50) albino mice aged between of 6 to 8 weeks consisting of both male and female was harvested following cervical dislocation and randomly distributed into control and experimental groups. Control samples were fixed in 10mL of 10% formalin at 25oC, 30oC, 35oC, 40oC, 45oC, 50oC, 55oC and 60oC respectively for 24 hours, while experimental samples were each fixed in equal volume of phosphate-buffered 10% formalin (pH 7.2, 7.4, 7.6 and 7.8) at the same temperature and time duration regimen and processed for general tissue morphology. Nuclear, cytoplasm and cell membrane morphology were assessed as evidence of the combined effectiveness of fixative and fixation temperature. Morphology was scored using a four-point grading scale with 1 being poor and 4 being excellent.

Results: Nuclear, cytoplasm and cell membrane morphology were excellently preserved in tissue fixed with phosphate-buffered 10% formalin (pH 7.2) at 45oC. Tissue fixed with 10% formalin at 35oC exhibited excellent nuclear and cell membrane morphology, while excellent preservation of cell membrane morphology were observed in tissues fixed with 10% formalin at 40oC, phosphate-buffered 10% formalin (pH 7.4) at 55oC and 60oC, (pH 7.6) at 50oC and 55oC and (pH 7.8) at 55oC respectively. Furthermore, excellent preservation of nuclear morphology was observed in tissue fixed with phosphate-buffered 10% formalin (pH 7.8) at 60oC.

Conclusion: Phosphate-buffered 10% formalin at a temperature of 45oC and pH 7.2 provide an excellent formalin-based fixative and fixation temperature that adequately preserves the microanatomy of tissue for histopathology examination.

Open Access Original Research Article

Ascertaining Optimum Pyrolysis Conditions for Biochar Production from Maple Sawdust

A. Bello, A. Mohammed, A. Manase, A. Abdullahi

Current Journal of Applied Science and Technology, Page 1-6
DOI: 10.9734/cjast/2021/v40i4031597

Sawdust is a bi-product from wood processing industries. In the recent time, pyrolysis of organic waste is an emerging technology where biochar can be produced and used for carbon sequestration. In that respect, the aim of the present work was to ascertaining optimum pyrolysis conditions in producing sawdust biochar (SBC) for the said uses. The raw material was collected from Belad furniture industry because of their specialization in furniture work and large volume availability. The proximate and ultimate analysis of 3.56% moisture, 1.49% ash content, 72.32% carbon and 0.19% surphur confirmed its good candidature for biochar production. The pyrolysis experiment was carried out by using six combination each of temperature (400, 450, 500, 550, 600 and 650°C), nitrogen flow rates (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0L/mins) and residence times (10, 20, 30, 40, 50 and 60mins). Analysis of resulted biochar was done according to IBI standard. Results showed that the three factors decrease the yield of biochar at their increasing values. SBC yield being optimum at temperature of 400°C, 10 min residence time and 1.0L/min nitrogen flow rate.

Open Access Original Research Article

Development of an Automatic Solar-driven Hand Sanitizing System (AHSS) using Proximity Sensors

Adegoke B. O., Olokun M. S., Agboola S.

Current Journal of Applied Science and Technology, Page 7-16
DOI: 10.9734/cjast/2021/v40i4031598

Inception of COVID ’19 has brought new normal globally. Contagious nature of various infectious diseases necessitated frequent hand washing in order to reduce rate of contamination and community transmission. The need to contain the spread of COVID-19 necessitated the development of an Automatic Hand Sanitizing System (AHSS). The AHSS employed proximity sensor (IR) to sense the hand and actuate the 5V DC submersible pumps in charge of both water and sanitizer units of the AHSS. The DC voltage that powered the system was harvested from the Sun with the help of 5v Photovoltaic cell connected to a controlled charging circuit. The system responded to presence of user object within the active zone of the IR proximity sensors. This presence sends signal to the pumps to release either the Sanitizer/water. Evaluation based on Delay Time (DT), Average DT (ADT), True Positive (TP), False Positive (FP), Unable to Detect (UTD) and Accuracy (A) was conducted. The system was tested 180 times among students of School of Engineering, Federal Polytechnic, Ile-Oluji (FEDPOLEL). Results of evaluation indicate 12s, 180, 0.00, 0.00 and 100% for ADT, TP, FP, UTD and Accuracy, respectively. Accuracy of the designed AHSS was encouraging. An AHSS that can notify user about level of water and sanitizer, also test for presence of COVID-19 infection can also be designed and constructed.

Open Access Original Research Article

Geoscience Assessment of Declined Production Rate and Recovery from a Reservoir in “ANDA” Field, Onshore Southwestern Niger Delta

Udoinyang, I. E., Ekere, Udo Akpan, George, N. J.

Current Journal of Applied Science and Technology, Page 17-29
DOI: 10.9734/cjast/2021/v40i4031599

Declined production rates in wells producing from common reservoirs are enigmatic and generally viewed as phenomenal in some fields worldwide. The challenge posed by such discordant production trends forecloses the preponderance of totally and partially abandoned production, especially in aging fields. This study assesses possible factors associated with varying well production trends from a common reservoir in a field in the onshore western Niger Delta, by integrating multi-geoscience parameters including formation evaluation, 3D quantitative seismic analyses, paleoenvironmental diagnoses, paleobathymetric studies, and reservoir petrophysics to unravel the complexity of the reservoir. Composite well logs were collected from five wells selected for the study. Gamma-ray and SP logs were combined to delineate the depositional environment of "Heri sand" based on Schlumberger's (1985) log motif classification. The results were applied and found useful to develop an optimum recovery production plan for the study field.  It has been revealed from this study that declined production performances of the Heri sand reservoir are attributed to the deposition of the reservoir in three distinct paleoenvironments under different bathymetric settings within a coeval period. These factors constitute strong influences on the petrophysics of the reservoir which invariably influences’ the production performance of the reservoir.   Having realized the cause of the declined rate of the reservoir in the Anda field, the reservoir can be revitalized by well injection and fracturing.

Open Access Original Research Article

Investigations on Biosuppression of Wilt Disease in Tomato Using Cell-Free Culture Filtrate of Phytopathogenic Fusarium oxysporum f.sp. lycopersici

Borisade Omotoso Abiodun, Olofin Adeola Rosemary, M. J. Falade

Current Journal of Applied Science and Technology, Page 30-41
DOI: 10.9734/cjast/2021/v40i4031600

Potency of cell-free culture filtrate of pathogenic Fusarium oxysporum f.sp. lycopersici as systemic defense inducer against wilt disease in tomato was tested by treating seedlings with the filtrate before pathogen challenge. Infective conidia and the cell-free culture filtrate were prepared from F. oxysporum (Sensu lato) previously isolated from wilt diseased affected plants. Growth relations of the isolates were characterized under ambient temperature (25 ± 2°C) and viability of the infective conidia of the two isolates were evaluated. Treatments were done as follows: (a) treatment of seedlings with infective conidia only (Treatment-A) (b) culture filtrate treatment only (Treatment-B) (c) treatment with culture filtrate followed by inoculation with infective conidia (Treatment-C) and (d) the control which consisted of plants sprayed with sterile distilled water only (Treatment-D). Effects of fungal conidia on tomato seed germination as well as some agronomic characters of the tomato plants and disease incidence under treatments A, B, C and D were evaluated. The growth and sporulation rates of the F. oxysporum F-isolate-1 were 12.1 mm day-1 and 6.5 x 104 conidia cm-2 colony area respectively and the values for the second isolate, F-Isolate 2 were 6.1 mm day-1 and 5.4 x 104 conidia cm-2 colony area. The germination rates of the infective conidia of F-isolate 1 and F-Isolate 2 after 24 hours incubation period at ambient temperature were 70% and 85% respectively. Treatment of tomato seeds with conidia suspension containing 1.0 x 106 had no statistically significant effects on seed germination [F(2,12)=0.148, P=0.64]; the mean percentage germination of the seeds treated with F-Isolate 1, F-Isolate 2 conidia and the control were 52%,46% and 52% respectively after five days. In the Treatment-A (Infective conidia only), F-Isolate 1 and F-isolate 2 caused 100% and 80% wilt of the plant populations at 7 weeks post-inoculation, when the tomato plants were 9 weeks old and no wilt was recorded in the control. There was no wilt recorded under Treatment-B and Treatment-C also, but there was reduced flowering and the mean percentage number of leaves showing chlorosis were significantly higher than the control [F (4, 192) =6.641, P=0.001]. When the plants were 10 weeks old, withered branches at the lower vegetal strata and the senescent leaves in the control were comparable with that recorded under Treatment-B and Treatment-C (F (4, 159) =3.563, P=0.08].