Aqueous zinc-ion batteries(AZIBs)are an appealing battery system due to their low cost,intrinsic safety,and environmental-friendliness,while their application is plagued by the obstacles from the cathode,electrolyte,a...Aqueous zinc-ion batteries(AZIBs)are an appealing battery system due to their low cost,intrinsic safety,and environmental-friendliness,while their application is plagued by the obstacles from the cathode,electrolyte,and zinc anode.Summarizing the design principles and strategies toward the optimization of cathode,electrolyte,and zinc anode is crucial for the development of AZIBs.Herein,we present a comprehensive analysis of the design principles and promising strategies toward the improvement of AZIBs.Firstly,the various reaction mechanisms are summarized and the existing issues associated with the cathode,electrolyte,and zinc anode are discussed to guide the rational design of AZIBs.Subsequently,we provide an in-depth and comprehensive discussion on the design principles and strategies for the electrodes/electrolyte/separator optimization,and analyze the advantages and disadvantages of various strategies.Importantly,the design principles and strategies of the newly appeared conversion-type AZIBs,such as Zn-S battery and Zn-Se battery,are also discussed and analyzed.The effect of design strategies on the electrochemical performance and the relationship between the current issues and strategies are also unveiled in detail.Finally,some research trends and perspectives are provided for designing better AZIBs.展开更多
The present study enhances the knowledge on the diversity, abundance and depth distribution of larger benthic foraminifera (LBF) from six different islands in Mahatma Gandhi Marine National Park (MGMNP), where meagre ...The present study enhances the knowledge on the diversity, abundance and depth distribution of larger benthic foraminifera (LBF) from six different islands in Mahatma Gandhi Marine National Park (MGMNP), where meagre anthropogenic impact existed. Very few works have been reported on the Larger Benthic Foraminifera (LBF) on this Island environment, as this region also falls under Marine Protected Area (MPA). Development of database on this study has a validity for pristine nature of LBF environment. Modern LBF hotspot diversity is often overlooked and no data are available to date on tropical regions. Out of 105 MPA’s existed in this Island, MGMNP encompasses about 15 islands, out of which six islands were considered for the study. These six islands are Snob Island, Grub Island, Boat Island, Hobday Island, Belle Island and Jolly Buoy Island. The study revealed presence of 22 taxa of modern LBF and the most common families are the Amphisteginidae, Calcarinidae, Nummulitidae, Peneroplidae and Soritidae. The purpose of this study was to document the distribution of LBF species prevailing in this area, as well as develop the baseline environmental information of its existences to facilitate further continuous monitoring the changes occurring in this island environment. The environment suggested that the presence of major LBF species studied are Calcarina calcarinoides, Calcarina defrancei, Calcarina hispida, Calcarina spengleri, Neorotalia calcar and Neorotalia gaimardi exhibited the availability of good coral cover with commendable macro algal coverage or sparsely sea grasses, as they prefer such substratum for their epiphytic association.展开更多
Evaluating the clinical performance of nursing students effectively and fairly is a challenge which continues to confront nurse education and there is evidence of both faculty and student concerns. This paper reports ...Evaluating the clinical performance of nursing students effectively and fairly is a challenge which continues to confront nurse education and there is evidence of both faculty and student concerns. This paper reports part findings of a hermeneutic phenomenological study which explored the clinical learning experience of Malawian undergraduate student nurses. The study took place at a University Nursing College in Malawi, using a purposive sample of thirty student nurse participants. Conversational interviews were conducted to obtain participants’ accounts of their clinical learning experience and a framework developed by modifying Colaizzi’s procedural steps guided the phenomenological analysis. Several issues emerged from this study, but for this paper the assessment issues which the study revealed were discussed. It revealed concerns of unfairness and lack of objectivity during the evaluation of the clinical performance of nursing students. It also revealed that interpersonal relationships significantly influenced the evaluation process. Consequently, nursing students become preoccupied with building relationships with qualified nurses knowing the impact of such relationships on the clinical grade. The findings reveal that students employ various strategies in order to obtain good grades and this illustrates students’ overall preoccupation with “making the grade”. It is argued that the evaluation of the clinical performance of nursing students is a vital component of nursing education and it must be conducted in a manner that enables nurse educators to effectively determine the clinical proficiency of nursing students.展开更多
Improving the cycling stability of metal sulfide-based anode materials at high rate is of great significance for advanced sodium ion batteries.However,the sluggish reaction kinetics is a big obstacle for the developme...Improving the cycling stability of metal sulfide-based anode materials at high rate is of great significance for advanced sodium ion batteries.However,the sluggish reaction kinetics is a big obstacle for the development of high-performance sodium storage electrodes.Herein,we have rationally engineered the heterointerface by designing the Fe1?xS/MoS2 heterostructure with abundant“ion reservoir”to endow the electrode with excellent cycling stability and rate capability,which is proved by a series of in and ex situ electrochemical investigations.Density functional theory calculations further reveal that the heterointerface greatly decreases sodium ion diffusion barrier and facilitates charge-transfer kinetics.Our present findings not only provide a deep analysis on the correlation between the structure and performance,but also draw inspiration for rational heterointerface engineering toward the next-generation high-performance energy storage devices.展开更多
It is common knowledge that the end user of stream flow data may necessarily not have any prior knowledge of the quality control measures applied in their generation, therefore, conclusions drawn most often times may ...It is common knowledge that the end user of stream flow data may necessarily not have any prior knowledge of the quality control measures applied in their generation, therefore, conclusions drawn most often times may not be effective as desired. Thus, this study is an attempt at providing an independent quality construct to boost the confidence in the use of stream flow data by developing regional flow duration curves for selected ungauged stations of the upper Niger River Basin, Nigeria. Toward this end, stream flow data for seven gauging stations cover some sub basins in the Basin were obtained;precisely, monthly stream flow data covering a range of eleven to fifty-three years period. The flow duration curves from the gauging stations were fitted with three probability distribution models;i.e., logarithmic, power and exponential regression models. For the regionalisation, parameterisation was carried out in terms of the drainage area alone to allow for simplicity of models. Results obtained showed that the exponential regression model, in terms of Coefficient of Determination (R<sup>2</sup>) had the best fit. Though the regionalised model was simple, measurable agreement was obtained during the calibration and validation phases. However, considering the length of data used and probable variability in the stream flow regime, it is not possible to objectively generalise on the quality of the results. Against this backdrop, it suffices to take into cognisance the need to use an ensemble of catchment characteristics in the development of the flow duration curves and the overall regional models;this is important considering the implications of anthropogenic activities and hydro-climatic variations.展开更多
The choice of a particular Artificial Neural Network (ANN) structure is a seemingly difficult task;worthy of relevance is that there is no systematic way for establishing a suitable architecture. In view of this, the ...The choice of a particular Artificial Neural Network (ANN) structure is a seemingly difficult task;worthy of relevance is that there is no systematic way for establishing a suitable architecture. In view of this, the study looked at the effects of ANN structural complexity and data pre-processing regime on its forecast performance. To address this aim, two ANN structural configurations: </span><b><span style="font-family:Verdana;font-size:12px;">1) Single-hidden layer, </span></b><span style="font-family:Verdana;font-size:12px;">and</span><b><span style="font-family:Verdana;font-size:12px;"> 2) Double-hidden layer</span></b><span style="font-family:Verdana;font-size:12px;"> feed</span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">forward back</span><span style="font-size:10pt;font-family:""> </span><span style="font-size:10pt;font-family:""><span style="font-family:Verdana;font-size:12px;">propagation network were employed. Results obtained revealed generally that: a) ANN comprised of double hidden layers tends to be less robust and converges with less accuracy than its single-hidden layer counterpart under identical situations;b) for a univariate time series, phase-space reconstruction using embedding dimension which is based on dynamical systems theory is an effective way for determining the appropriate number of ANN input neurons, and c) data pre-processing via the scaling approach excessively limits the output range of the transfer function. In specific terms considering extreme flow prediction capability on the basis of effective correlation: Percent maximum and minimum correlation coefficient (</span><b><span style="font-family:Verdana;font-size:12px;">R</span><sub><span style="font-family:Verdana;font-size:12px;">max</span></sub><span style="font-family:Verdana;font-size:12px;">%</span></b><span style="font-family:Verdana;font-size:12px;"> and </span><b><span style="font-family:Verdana;font-size:12px;">R</span><sub><span style="font-family:Verdana;font-size:12px;">min展开更多
Anopheles gambiae is a vector that is responsible for the transmission of malaria parasites which causes high morbidity and mortality in Nigeria and the world at large.Human-vector contact can be reduced by the use of...Anopheles gambiae is a vector that is responsible for the transmission of malaria parasites which causes high morbidity and mortality in Nigeria and the world at large.Human-vector contact can be reduced by the use of conventional repellents being sold in the market,though some of these repellent are not environmentally friendly and An.gambiae have developed resistance to some of these repellents.To this end,the phytochemical constituents and insecticidal activity of crude extracts of Hyptis suaveolens(bush mint)was determined on adult An.gambiae mosquitoes collected from Lafia,Nasarawa State,Nigeria to evaluate its effect in controlling them.Here,70%ethanolic and diethyl ether fat crude extracts were made from H.suaveolens dried leaves and used to carry out the experiment.The phytochemical screening of the ethanol extract revealed the presence of alkaloids,flavonoid,saponins,tannins,steroids and reducing sugar.Glycoside was not detected in the ethanol extract.Only steroids was detected in diethyl ether extract the rest of the phytochemical tested were absent.An.gambiae larvae were collected from the field and were raised to F1 progeny adults that were used for the study.WHO protocol for carrying out human bait repellency cage test was used.Human hand treated with the extracts was exposed to a cage containing 30 female mosquitoes for each of the extracts respectively.The ethanolic crude extract treatment proved to be more effective in repelling mosquitoes with 0%(0/30)mosquito landing than diethyl ether extract which had 40%(12/30)mosquitoes landing and the control hand(untreated left hand)had the highest landing rate 63.3%(19/30)which showed very high significant difference(χ^(2)=27.2619,df=2,P<0.00001)in relation to the treatments.After 24 hours holding period,the mortality rate of exposed mosquitoes was observed to be highest in the ethanolic treatment 73.3%(22/30).In conclusion,H.suaveolens extracts have repellency potential in controlling adult An.gambiae.展开更多
Vector surveillance is very key in solving mosquito-borne health problems in Nigeria.To this end,the composition and distribution of mosquito vectors in a peri-urban community surrounding an institution of learning in...Vector surveillance is very key in solving mosquito-borne health problems in Nigeria.To this end,the composition and distribution of mosquito vectors in a peri-urban community surrounding an institution of learning in Lafia metropolis,Nasarawa State,Central Nigeria was carried out between December 2016 and June 2017.The Prokopack Aspirator was used to collect indoor resting mosquitoes between 6:00 a.m.and 9:00 a.m.from 30 randomly selected houses.Mosquitoes collected were knocked down and transferred into a well labelled petri-dish and taken to the laboratory for processing.A total of 664 mosquitoes were collected which spread across Culex quinquefasciatus 572(86.14%),Anopheles gambiae 88(13.25%)and Aedes aegypti 4(0.60%).The abundance of mosquitoes in relation to seasons,species,sex,abdominal conditions as well as transmission indices across seasons significantly varied(P<0.05).But,the distribution of mosquito in relation to house types showed no significant difference(P>0.05).The inhabitants of the area should ensure that all drainages flow through so as to reduce mosquito breeding grounds.Also,members of the community should always protect themselves by sleeping under insecticide treated bed nets.展开更多
Trypanosomiasis afflicts about 6~7 million people globally and to a large extent impedes livestock production in Africa.Naturally,trypanosomal parasites undergo genetic mutation and have developed resistance over a wi...Trypanosomiasis afflicts about 6~7 million people globally and to a large extent impedes livestock production in Africa.Naturally,trypanosomal parasites undergo genetic mutation and have developed resistance over a wide range of therapies.The utilization of animals and plants products has presented therapeutic potential for identifying novel anti-trypanosomal drugs.This study evaluated toad venom for anti-trypanosomal potency in-vivo in Swiss mice.Toads were collected from July to August 2019.The acute oral toxicity and biochemical characterization of the toad venom were determined.The experimental mice were administered various doses(130 mg/kg,173 mg/kg and 217 mg/kg)of the toad venom crude extract and 0.75 mg/mL of Diamizan Plus standard drug for the treatment of trypanosomiasis,once daily for 3 days.The in-vivo anti-trypanosomal activity was evaluated by a curative test,after infecting the mice with Trypanosoma brucei brucei.The pre-patent period was 72 hours before treatment commenced.The overall results showed that trypanosomal load was highest in the control group while the group treated with Diamizan drug had the least trypanosomal load.As such,the mean trypanosomal load in relation to treatments showed a very high significant difference(P<0.05).Also,the mean trypanosomal load in Swiss mice in relation to the highest dosage of toad venom versus Diamizan drug showed a very high significant difference(P<0.05).The mean change in relation to the haematological parameters across treatments groups varied significantly(P<0.05)with the exception of Hb which showed no significant difference(P>0.05)across treatment groups.The over 50%reduction in the trypanosomal load in the 130 mg/kg group in comparison with the control group brings to bare the anti-trypanosomal potency of the toad venom.The anti-trypanosomal activity demonstrated by the toad venom has provided basis for development of new therapeutic agents from different toad species.The study recommends further studies(both in-vivo and in-vitro)followed by the c展开更多
Multiple endocrine neoplasia 2B(MEN2B) is a rare syndrome caused by an activating mutation of the RET gene, leading to enteric gangliomatosis. This child presented with constipation at 1-mo old, was diagnosed with MEN...Multiple endocrine neoplasia 2B(MEN2B) is a rare syndrome caused by an activating mutation of the RET gene, leading to enteric gangliomatosis. This child presented with constipation at 1-mo old, was diagnosed with MEN2 B by rectal biopsy at 4 mo, had thyroidectomy at 9 mo and a colectomy at 4 years. We studied the extent of neuronal and nerve fibre proliferation and which classes of enteric nerves are affected by examining the colon with multiple neuronal antibodies. Resected transverse colon was fixed, frozen, sectioned and processed for fluorescence immunohistochemistry labelling with antibodies against TUJ1, Hu, ChAT, NOS, VIP, SP and CGRP and cKit. Control transverse colon was from the normal margin of Hirschsprung(HSCR) colon(4-year-old) and a child with familial adenomatous polyposis(FAP, 12 year). Myenteric ganglia were increased in size to as wide as the circular muscle. There was a large increase in nerve cells and nerve fibres. ChAT-, NOS-, VIP-and SP-immunoreactive nerve fibres all increased in the myenteric ganglia. NOS-IR nerves preferentially increased in the muscle, while VIP and SP increased in submucosal ganglia and mucosal nerve fibres. The density of ICC was normal. RET overactivation in MEN2B lead to a large increase in intrinsic nerve fibres in the myenteric and submucosal ganglia, with a relative increase in NOS-IR nerve fibres in the circular muscle and VIP and SP in the submucosal ganglia and mucosa. The changes were associated with severe constipation resulting in colectomy at 4 years.展开更多
基金supported by the research funds from South-Central University for Nationalities(Grant No.YZZ19001)financial support from the National Natural Science Foundation of China(51873233)the Hubei Provincial Natural Science Foundation(2018CFA023)。
文摘Aqueous zinc-ion batteries(AZIBs)are an appealing battery system due to their low cost,intrinsic safety,and environmental-friendliness,while their application is plagued by the obstacles from the cathode,electrolyte,and zinc anode.Summarizing the design principles and strategies toward the optimization of cathode,electrolyte,and zinc anode is crucial for the development of AZIBs.Herein,we present a comprehensive analysis of the design principles and promising strategies toward the improvement of AZIBs.Firstly,the various reaction mechanisms are summarized and the existing issues associated with the cathode,electrolyte,and zinc anode are discussed to guide the rational design of AZIBs.Subsequently,we provide an in-depth and comprehensive discussion on the design principles and strategies for the electrodes/electrolyte/separator optimization,and analyze the advantages and disadvantages of various strategies.Importantly,the design principles and strategies of the newly appeared conversion-type AZIBs,such as Zn-S battery and Zn-Se battery,are also discussed and analyzed.The effect of design strategies on the electrochemical performance and the relationship between the current issues and strategies are also unveiled in detail.Finally,some research trends and perspectives are provided for designing better AZIBs.
文摘The present study enhances the knowledge on the diversity, abundance and depth distribution of larger benthic foraminifera (LBF) from six different islands in Mahatma Gandhi Marine National Park (MGMNP), where meagre anthropogenic impact existed. Very few works have been reported on the Larger Benthic Foraminifera (LBF) on this Island environment, as this region also falls under Marine Protected Area (MPA). Development of database on this study has a validity for pristine nature of LBF environment. Modern LBF hotspot diversity is often overlooked and no data are available to date on tropical regions. Out of 105 MPA’s existed in this Island, MGMNP encompasses about 15 islands, out of which six islands were considered for the study. These six islands are Snob Island, Grub Island, Boat Island, Hobday Island, Belle Island and Jolly Buoy Island. The study revealed presence of 22 taxa of modern LBF and the most common families are the Amphisteginidae, Calcarinidae, Nummulitidae, Peneroplidae and Soritidae. The purpose of this study was to document the distribution of LBF species prevailing in this area, as well as develop the baseline environmental information of its existences to facilitate further continuous monitoring the changes occurring in this island environment. The environment suggested that the presence of major LBF species studied are Calcarina calcarinoides, Calcarina defrancei, Calcarina hispida, Calcarina spengleri, Neorotalia calcar and Neorotalia gaimardi exhibited the availability of good coral cover with commendable macro algal coverage or sparsely sea grasses, as they prefer such substratum for their epiphytic association.
文摘Evaluating the clinical performance of nursing students effectively and fairly is a challenge which continues to confront nurse education and there is evidence of both faculty and student concerns. This paper reports part findings of a hermeneutic phenomenological study which explored the clinical learning experience of Malawian undergraduate student nurses. The study took place at a University Nursing College in Malawi, using a purposive sample of thirty student nurse participants. Conversational interviews were conducted to obtain participants’ accounts of their clinical learning experience and a framework developed by modifying Colaizzi’s procedural steps guided the phenomenological analysis. Several issues emerged from this study, but for this paper the assessment issues which the study revealed were discussed. It revealed concerns of unfairness and lack of objectivity during the evaluation of the clinical performance of nursing students. It also revealed that interpersonal relationships significantly influenced the evaluation process. Consequently, nursing students become preoccupied with building relationships with qualified nurses knowing the impact of such relationships on the clinical grade. The findings reveal that students employ various strategies in order to obtain good grades and this illustrates students’ overall preoccupation with “making the grade”. It is argued that the evaluation of the clinical performance of nursing students is a vital component of nursing education and it must be conducted in a manner that enables nurse educators to effectively determine the clinical proficiency of nursing students.
基金the support from the Thousand Young Talents Program of Chinathe National Natural Science Foundation of China(Nos.51602200,61874074,21603192)+3 种基金Science and Technology Project of Shenzhen(JCYJ20170817101100705,JCYJ20170817100111548,ZDSYS201707271014468)the(Key)Project of Department of Education of Guangdong Province(No.2016KZDXM008)supported by Shenzhen Peacock Plan(No.KQTD2016053112042971)Singapore Ministry of Education Academic Research Fund Tier 2(MOE2018-T2-2-178).
文摘Improving the cycling stability of metal sulfide-based anode materials at high rate is of great significance for advanced sodium ion batteries.However,the sluggish reaction kinetics is a big obstacle for the development of high-performance sodium storage electrodes.Herein,we have rationally engineered the heterointerface by designing the Fe1?xS/MoS2 heterostructure with abundant“ion reservoir”to endow the electrode with excellent cycling stability and rate capability,which is proved by a series of in and ex situ electrochemical investigations.Density functional theory calculations further reveal that the heterointerface greatly decreases sodium ion diffusion barrier and facilitates charge-transfer kinetics.Our present findings not only provide a deep analysis on the correlation between the structure and performance,but also draw inspiration for rational heterointerface engineering toward the next-generation high-performance energy storage devices.
文摘It is common knowledge that the end user of stream flow data may necessarily not have any prior knowledge of the quality control measures applied in their generation, therefore, conclusions drawn most often times may not be effective as desired. Thus, this study is an attempt at providing an independent quality construct to boost the confidence in the use of stream flow data by developing regional flow duration curves for selected ungauged stations of the upper Niger River Basin, Nigeria. Toward this end, stream flow data for seven gauging stations cover some sub basins in the Basin were obtained;precisely, monthly stream flow data covering a range of eleven to fifty-three years period. The flow duration curves from the gauging stations were fitted with three probability distribution models;i.e., logarithmic, power and exponential regression models. For the regionalisation, parameterisation was carried out in terms of the drainage area alone to allow for simplicity of models. Results obtained showed that the exponential regression model, in terms of Coefficient of Determination (R<sup>2</sup>) had the best fit. Though the regionalised model was simple, measurable agreement was obtained during the calibration and validation phases. However, considering the length of data used and probable variability in the stream flow regime, it is not possible to objectively generalise on the quality of the results. Against this backdrop, it suffices to take into cognisance the need to use an ensemble of catchment characteristics in the development of the flow duration curves and the overall regional models;this is important considering the implications of anthropogenic activities and hydro-climatic variations.
文摘The choice of a particular Artificial Neural Network (ANN) structure is a seemingly difficult task;worthy of relevance is that there is no systematic way for establishing a suitable architecture. In view of this, the study looked at the effects of ANN structural complexity and data pre-processing regime on its forecast performance. To address this aim, two ANN structural configurations: </span><b><span style="font-family:Verdana;font-size:12px;">1) Single-hidden layer, </span></b><span style="font-family:Verdana;font-size:12px;">and</span><b><span style="font-family:Verdana;font-size:12px;"> 2) Double-hidden layer</span></b><span style="font-family:Verdana;font-size:12px;"> feed</span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">forward back</span><span style="font-size:10pt;font-family:""> </span><span style="font-size:10pt;font-family:""><span style="font-family:Verdana;font-size:12px;">propagation network were employed. Results obtained revealed generally that: a) ANN comprised of double hidden layers tends to be less robust and converges with less accuracy than its single-hidden layer counterpart under identical situations;b) for a univariate time series, phase-space reconstruction using embedding dimension which is based on dynamical systems theory is an effective way for determining the appropriate number of ANN input neurons, and c) data pre-processing via the scaling approach excessively limits the output range of the transfer function. In specific terms considering extreme flow prediction capability on the basis of effective correlation: Percent maximum and minimum correlation coefficient (</span><b><span style="font-family:Verdana;font-size:12px;">R</span><sub><span style="font-family:Verdana;font-size:12px;">max</span></sub><span style="font-family:Verdana;font-size:12px;">%</span></b><span style="font-family:Verdana;font-size:12px;"> and </span><b><span style="font-family:Verdana;font-size:12px;">R</span><sub><span style="font-family:Verdana;font-size:12px;">min
文摘Anopheles gambiae is a vector that is responsible for the transmission of malaria parasites which causes high morbidity and mortality in Nigeria and the world at large.Human-vector contact can be reduced by the use of conventional repellents being sold in the market,though some of these repellent are not environmentally friendly and An.gambiae have developed resistance to some of these repellents.To this end,the phytochemical constituents and insecticidal activity of crude extracts of Hyptis suaveolens(bush mint)was determined on adult An.gambiae mosquitoes collected from Lafia,Nasarawa State,Nigeria to evaluate its effect in controlling them.Here,70%ethanolic and diethyl ether fat crude extracts were made from H.suaveolens dried leaves and used to carry out the experiment.The phytochemical screening of the ethanol extract revealed the presence of alkaloids,flavonoid,saponins,tannins,steroids and reducing sugar.Glycoside was not detected in the ethanol extract.Only steroids was detected in diethyl ether extract the rest of the phytochemical tested were absent.An.gambiae larvae were collected from the field and were raised to F1 progeny adults that were used for the study.WHO protocol for carrying out human bait repellency cage test was used.Human hand treated with the extracts was exposed to a cage containing 30 female mosquitoes for each of the extracts respectively.The ethanolic crude extract treatment proved to be more effective in repelling mosquitoes with 0%(0/30)mosquito landing than diethyl ether extract which had 40%(12/30)mosquitoes landing and the control hand(untreated left hand)had the highest landing rate 63.3%(19/30)which showed very high significant difference(χ^(2)=27.2619,df=2,P<0.00001)in relation to the treatments.After 24 hours holding period,the mortality rate of exposed mosquitoes was observed to be highest in the ethanolic treatment 73.3%(22/30).In conclusion,H.suaveolens extracts have repellency potential in controlling adult An.gambiae.
文摘Vector surveillance is very key in solving mosquito-borne health problems in Nigeria.To this end,the composition and distribution of mosquito vectors in a peri-urban community surrounding an institution of learning in Lafia metropolis,Nasarawa State,Central Nigeria was carried out between December 2016 and June 2017.The Prokopack Aspirator was used to collect indoor resting mosquitoes between 6:00 a.m.and 9:00 a.m.from 30 randomly selected houses.Mosquitoes collected were knocked down and transferred into a well labelled petri-dish and taken to the laboratory for processing.A total of 664 mosquitoes were collected which spread across Culex quinquefasciatus 572(86.14%),Anopheles gambiae 88(13.25%)and Aedes aegypti 4(0.60%).The abundance of mosquitoes in relation to seasons,species,sex,abdominal conditions as well as transmission indices across seasons significantly varied(P<0.05).But,the distribution of mosquito in relation to house types showed no significant difference(P>0.05).The inhabitants of the area should ensure that all drainages flow through so as to reduce mosquito breeding grounds.Also,members of the community should always protect themselves by sleeping under insecticide treated bed nets.
文摘Trypanosomiasis afflicts about 6~7 million people globally and to a large extent impedes livestock production in Africa.Naturally,trypanosomal parasites undergo genetic mutation and have developed resistance over a wide range of therapies.The utilization of animals and plants products has presented therapeutic potential for identifying novel anti-trypanosomal drugs.This study evaluated toad venom for anti-trypanosomal potency in-vivo in Swiss mice.Toads were collected from July to August 2019.The acute oral toxicity and biochemical characterization of the toad venom were determined.The experimental mice were administered various doses(130 mg/kg,173 mg/kg and 217 mg/kg)of the toad venom crude extract and 0.75 mg/mL of Diamizan Plus standard drug for the treatment of trypanosomiasis,once daily for 3 days.The in-vivo anti-trypanosomal activity was evaluated by a curative test,after infecting the mice with Trypanosoma brucei brucei.The pre-patent period was 72 hours before treatment commenced.The overall results showed that trypanosomal load was highest in the control group while the group treated with Diamizan drug had the least trypanosomal load.As such,the mean trypanosomal load in relation to treatments showed a very high significant difference(P<0.05).Also,the mean trypanosomal load in Swiss mice in relation to the highest dosage of toad venom versus Diamizan drug showed a very high significant difference(P<0.05).The mean change in relation to the haematological parameters across treatments groups varied significantly(P<0.05)with the exception of Hb which showed no significant difference(P>0.05)across treatment groups.The over 50%reduction in the trypanosomal load in the 130 mg/kg group in comparison with the control group brings to bare the anti-trypanosomal potency of the toad venom.The anti-trypanosomal activity demonstrated by the toad venom has provided basis for development of new therapeutic agents from different toad species.The study recommends further studies(both in-vivo and in-vitro)followed by the c
文摘Multiple endocrine neoplasia 2B(MEN2B) is a rare syndrome caused by an activating mutation of the RET gene, leading to enteric gangliomatosis. This child presented with constipation at 1-mo old, was diagnosed with MEN2 B by rectal biopsy at 4 mo, had thyroidectomy at 9 mo and a colectomy at 4 years. We studied the extent of neuronal and nerve fibre proliferation and which classes of enteric nerves are affected by examining the colon with multiple neuronal antibodies. Resected transverse colon was fixed, frozen, sectioned and processed for fluorescence immunohistochemistry labelling with antibodies against TUJ1, Hu, ChAT, NOS, VIP, SP and CGRP and cKit. Control transverse colon was from the normal margin of Hirschsprung(HSCR) colon(4-year-old) and a child with familial adenomatous polyposis(FAP, 12 year). Myenteric ganglia were increased in size to as wide as the circular muscle. There was a large increase in nerve cells and nerve fibres. ChAT-, NOS-, VIP-and SP-immunoreactive nerve fibres all increased in the myenteric ganglia. NOS-IR nerves preferentially increased in the muscle, while VIP and SP increased in submucosal ganglia and mucosal nerve fibres. The density of ICC was normal. RET overactivation in MEN2B lead to a large increase in intrinsic nerve fibres in the myenteric and submucosal ganglia, with a relative increase in NOS-IR nerve fibres in the circular muscle and VIP and SP in the submucosal ganglia and mucosa. The changes were associated with severe constipation resulting in colectomy at 4 years.
