Eco-friendly biodegradable polyurethane based coating for antibacterial and antifouling performance

Biofouling, which comprises the absorption of proteins and the adhesion of bacteria to the surface of living entities, is a severe concern for the maritime sector since it ultimately leads to hydrodynamic drag,resulting in a higher increase in fuel consumption. As a result, polymer resins are crucial in the marine sector for anti-biofouling coatings. In this work, the poly(caprolactone-ethylene glycol-caprolactone)-p olyurethane(PECL-PU) are prepared through ε-caprolactone(CL), poly(ethylene glycol)(PEG), 4,4'-methylene bis(cyclohexyl isocyanate) and 1,4 butanediol. Our study demonstrate that the PECL-PU copolymer degraded in artificial seawater(5.21%), enzymatic solution(12.63%), and seawater(13.75%)due to the presence of PEG segments in the laboratory-based test under static condition. Because the addition of PEG segments are increased the polymer's amorphous area and decreased the crystallization of the polycaprolactone(PCL) in the copolymer, as demonstrated by differential scanning calorimetry, X-ray diffraction, and water contact angle studies. Therefore, the hydrolysis rates of PECL-PU were higher than the caprolactone-co-polyurethane(CL-PU). The antifouling test showed that PECL-PU3 copolymer had about 90.29% protein resistance, 85.2% Escherichia coli(E. coli) reduction and 94.61% marine diatom Navicula incerta reduction comparison to the control. We have developed an eco-friendly and inexpensive promising degradable polyurethane for reduction of bacterial biofilm, which can preserve the formation of biofouling on marine coating under practical sea conditions.

Towards Intelligent Detection and Classification of Rice Plant Diseases Based on Leaf Image Dataset

The detection of rice leaf disease is significant because,as an agricultural and rice exporter country,Pakistan needs to advance in production and lower the risk of diseases.In this rapid globalization era,information technology has increased.A sensing system is mandatory to detect rice diseases using Artificial Intelligence(AI).It is being adopted in all medical and plant sciences fields to access and measure the accuracy of results and detection while lowering the risk of diseases.Deep Neural Network(DNN)is a novel technique that will help detect disease present on a rice leave because DNN is also considered a state-of-the-art solution in image detection using sensing nodes.Further in this paper,the adoption of the mixed-method approach Deep Convolutional Neural Network(Deep CNN)has assisted the research in increasing the effectiveness of the proposed method.Deep CNN is used for image recognition and is a class of deep-learning neural networks.CNN is popular and mostly used in the field of image recognition.A dataset of images with three main leaf diseases is selected for training and testing the proposed model.After the image acquisition and preprocessing process,the Deep CNN model was trained to detect and classify three rice diseases(Brown spot,bacterial blight,and blast disease).The proposed model achieved 98.3%accuracy in comparison with similar state-of-the-art techniques.

香蕉假茎象甲成虫的田间活动规律

本文利用引诱剂诱捕器,对香蕉假茎象甲Odoiporus longicollis(Oliver)成虫在蕉园中的活动高度、活动方向和活动节律进行研究,旨在明确该虫的田间活动规律,为其防控技术的研究与应用提供科学依据。结果表明,诱捕器的挂置高度对香蕉假茎象甲成虫的诱捕效果有一定影响,距地面160 cm的诱捕器所诱捕的成虫数量最大,而该高度是香蕉叶鞘及叶柄所处位置,说明成虫多在此处活动。而诱捕器的挂置方位对诱捕效果影响不大,挂设在东南西北四个方位的诱捕器的诱虫量差异不显著,说明香蕉假茎象甲成虫在蕉园活动时,对方向没有明显偏好。此外,在活动节律上,香蕉假茎象甲成虫多在傍晚至凌晨时分活动,16∶00至翌日4∶00的雌、雄虫诱虫量分别占全天雌、雄虫诱虫量的92%和96%。

不同类型药剂对水稻褐飞虱的活性及复配增效作用

采用稻茎浸渍法测定了18种杀虫剂对褐飞虱的毒力,选活性较好的药剂进行复配,筛选出具有较高活性的混剂,测定不同类型增效剂的增效作用与复合增效作用,并研究混剂与复合增效剂的最佳增效配伍。结果表明,18种药剂对褐飞虱的毒力大小次序为：氟虫腈〉噻嗪酮〉烯啶虫胺〉氟铃脲〉噻虫嗪〉甲维盐〉吡蚜酮〉阿维菌素〉丁醚脲〉毒死蜱〉速灭威〉啶虫脒〉异丙威〉联苯菊酯〉吡虫啉〉高效氯氟氰菊酯〉三唑磷〉马拉硫磷,其中氟虫腈的活性最高,是吡虫啉的128.38倍。不同药剂复配中,烯啶虫胺与噻嗪酮（30∶70）复配的共毒系数最高,为246.02。6种增效剂与药剂混配增效作用,以氮酮、有机硅最好,增效比在2.69~2.85之间,并且将两者按40∶60配比后,其联合增效作用有显著提高。

Synthesis and characterization of caprolactone based polyurethane with degradable and antifouling performance

In this work,a degradable polyurethane composed of caprolactone(CL)and L-Lactide(LLA)as soft segments,and 4,40-methylenebis(cyclohexyl isocyanate)(H12 MDI)and polytetramethylene ether glycol(PTMEG)as hard segments,was prepared.Hydrolytic degradation experiment revealed that the degradable polyurethane(PU)could be degraded in artificial seawater.It also showed that caprolactone-copolyurethane(CL-PU)copolymer with higher crystallinity degraded much slower in artificial seawater.However,the introduction of LLA resulted in an increase in the hydrophilicity and reduction in the crystallinity of degradable PU,as demonstrated by the contact angle analysis.The result of the scanning electron microscope showed that the surface of degradable PU renewed under static condition.Moreover,degradable PU was able to be used as a carrier,and it controlled the release rate of 4,5-dichloro-2-octyl-isothiazolone(DCOIT).The anti-diatom(Navicula incerta)test demonstrated that the(caprolactone-co-L-lactide)-co-polyurethane 4(CL/LAx-PU4)with DCOIT contents prevented the adhesion of diatom Navicula incerta(88.37%reduction)due to their self-polishing and the release of antifoulants.Therefore,the degradable PU consisted of CL,LLA,and DCOIT could be a durable resin with good antifouling activity for the application in the marine anti-biofouling field.

Effectively Handling Network Congestion and Load Balancing in Software-Defined Networking

The concept of Software-Defined Networking(SDN)evolves to overcome the drawbacks of the traditional networks with Internet Protocol(I.P.)packets sending and packets handling.The SDN structure is one of the critical advantages of efficiently separating the data plane from the control plane tomanage the network configurations and network management.Whenever there aremultiple sending devices inside the SDNnetwork,theOpenFlow switches are programmed to handle the limited number of requests for their interface.When the recommendations are exceeded from the specific threshold,the load on the switches also increases.This research article introduces a new approach named LBoBS to handle load balancing by adding the load balancing server to the SDN network.Besides,it is used to maximize SDN’s reliability and efficiency.It also works in coordination with the controller to effectively handle the load balancing policies.The load balancing server is implemented to manage the switches load effectively.Results are evaluated on the NS-3 simulator for packet delivery,bandwidth utilization,latency control,and packet decision ratios on the OpenFlow switches.It has been found that the proposed method improved SDN’s load balancing by 70%compared to the previous state-of-the-art methods.

Intelligent Transmission Control for Efficient Operations in SDN

Although the Software-Defined Network(SDN)is a well-controlled and efficient network but the complexity of open flow switches in SDN causes multiple issues.Many solutions have been proposed so far for the prevention of errors and mistakes in it but yet,there is still no smooth transmission of pockets from source to destination specifically when irregular movements follow the destination host in SDN,the errors include packet loss,data compromise etc.The accuracy of packets received at their desired destination is possible if networks for pockets and hosts are monitored instead of analysis of network snapshot statistically for the state,as these approaches with open flow switches,discover bugs after their occurrence.This article proposes a design to achieve the said objective by defining the Intelligent Transmission Control Layer(ITCL)layer.It monitors all the connections of end hosts at their specific locations and performs necessary settlements when the connection state changes for one or multiple hosts.The layer informs the controller regarding any state change at one period and controller collects information of end nodes reported via ITCL.Then,updates flow tables accordingly to accommodate a location-change scenario with a routechange policy.ICTL is organized on prototype-based implementation using the popular POX platform.In this paper,it has been discovered that ITCL produces efficient performance in the trafficking of packets and controlling different states of SDN for errors and packet loss.

Call Census,Habitat Suitability Modeling,and Local Communities’Perceptions for the Conservation of a Globally Threatened Avian Flagship Species

The Western tragopan(Tragopan melanocephalus)is recorded in the IUCN Red List of 2017 as a vulnerable bird species in Pakistan.This study provides valuable information for the conservation of Western tragopan,which is a globally threatened avian flagship species in Pakistan.This study was conducted to investigate and resolve the conservation challenges surrounding the species in two major habitat zones-Salkhala Game Reserve and Machiara National Park.The study was implemented in May-June 2020 for population density using call count data.Also,questionnaire was used for local residents’perceptions and habitat suitability modeling map was generated using the MaxEnt model based on previously recorded occurrence points as well as recorded in the survey.A total of 26 western Tragopans were identified by call count during the sampling period.Moreover,about 77.3%cited Western Tragopan they more likely to hunt while the remaining 22.6%locals recorded other pheasant.About 45.3%of this hunting for fun but only 22%for economic values and only 3%of people consider hunting as a part of their culture.Results of modeling habitat suitability of the Western tragopan showed that the species suitable habitats are small and patchy in Pakistan.We found that the Normalized Difference Vegetation Index(NDVI)with 40.6 percent contribution was the most important variable in shaping the species distribution.Our model identified some new suitable patches which can be the target of future field monitoring for finding new populations of the species and future conservation planning.

蜘蛛飞航研究进展

种群扩散能够避免生物类群在同一栖息地中的资源竞争和同类相残,促进基因流动,具有重要的进化和生态意义。相比于昆虫的迁飞行为,某些不具翅的节肢动物也能够借助细丝的作用而实现远距离扩散,即飞航。蜘蛛为肉食性动物,是陆地生态系统的重要组成部分,在生态系统中防控害虫方面作用显著。飞航是蜘蛛的一种重要扩散方式,在其物种形成、生态位分化及害虫防控等方面具有重要意义,但有关其飞航扩散的报道较少。本文回顾了蜘蛛飞航的研究历程,大致可分为三个阶段;总结了其研究现状,包括飞航蜘蛛的优势类群及特征、飞航过程中的三个环节(即起飞、空中航行和降落)及影响因子、两种飞航机制及四种相关模型、飞航蜘蛛采集和研究方法。同时基于过往研究,指出了未来蜘蛛飞航研究的重点领域:加强飞航蜘蛛类群鉴定工作,继续深度挖掘飞航数据与环境因子间的关系,探索蜘蛛飞航的全过程(包括起飞、空中航行和降落),更加明确蜘蛛飞航作为一种扩散方式的意义。本综述将为蜘蛛飞航的知识普及、资源保护和利用等方面提供重要参考。

影响杀螺胺乙醇胺盐药效的因素及使用技术

[目的]通过室内毒力测定评价5种因素对50%杀螺胺乙醇胺盐WP杀螺活性的影响。[方法]采用室内浸螺法进行毒力测定。[结果]浸螺时间越长,死亡率越高,但48 h后,福寿螺死亡率上升不明显;螺龄越大,敏感性越低;药液pH值小于6或大于8,活性显著下降;用雨水、严重浑浊的田水和沟渠水稀释时,药效均显著下降;环境温度越高,活性越强。[结论]应在田水相对清澈、福寿螺低龄时用药,避免在早春低温季节和偏酸、偏碱稻田中使用。