The Use of the PCR-Based Dot-Blot Hybridization Assay to Detect Resistance Markers to Rifampicin and Streptomycin in Mycobacterium tuberculosis Isolates from the SW Region of Cameroon

Drug sensitivity testing to establish resistance to TB drugs takes many months to arrive at. Public health physicians have difficulties with such an approach due to long wait periods and cannot use it to establish community wide prevalence as a way to understand where resistance may be emerging faster and to limit its spread. The objective of this study was to use the dot-blot hybridization technique in the detection of resistance to rifamycin (RIF) and streptomycin (SM) in South- Western Cameroon and to compare the technique with the routine culture and drug susceptibility testing for detecting resistance in a resource poor country, Cameroon. A hospital-based study was conducted at the Regional hospitals of Buea and Limbe and Tiko Central Clinic. Tuberculosis (TB) patients aged 15 to 50 (mean age: 30.50 ± 8.33 standard deviation) were recruited for the study between December 2006 and April 2007. Cultures from 59 patients were tested for rifampicin and streptomycin sensitivity by the modified proportion method and mutational analysis for rpoB codon 516 and rrs codon 513 was performed by the dot-blot hybridization technique. Of the 59 sputum samples collected (36 were males and 23 were females) came from Buea 19 (32.2%), Limbe 20 (33.9%) and Tiko 20 (33.9%) towns respectively. Amplification for the gene showed that there was (59) 100% amplification with primers used for rpoB genes and 43 (72.9%) amplification with primers used for the rrs gene. Mutational analysis demonstrated that resistance to RIF was common in females (52.1%) than males (41.7%) while 6% of the samples were indeterminate. 12 (20.3%) samples showed phenotypic and genotypic resistance to RIF compared to 34 samples (58.1%) for SM. Phenotypic resistance and genotypic susceptibility were found in 5 (8.5%) RIF and 3 (4.7%) SM compared to phenotypic susceptibility and genotypic resistance that were found in 2 (3.5%) RIF and 3(4.7%) SM. Double mutation on rpoB and rrs genes occurred in 8 (13.6%) DNA samples. Resistance to RIF and SM due to mutations on the rpoB and rrs genes respectively in the SW region was found to be high and comparable to the drug susceptibility testing by 92%, (95% CI: 75.7 - 99.1). The Dot-blot technique will be useful in rapidly assessing the effectiveness of national TB control programs in limiting the spread of resistance strains in Cameroon.

A Retrospective Study of the Prevalence of Female Infertility in the Southwest Region, Cameroon

Background: Infertility is a major reproductive health care problem that affects the wellbeing of women. Although views vary between cultures, infertility is seen almost exclusively as a woman’s problem in Africa with secondary infertility being the most prevalent while sexually transmitted infections the most investigated cause of infertility. Objective: The aim of this study was to determine the prevalence of female infertility in the Limbe and Buea Regional hospitals of the Southwest region of Cameroon from 2015-2019. Materials and Methods: A retrospective descriptive design was used which involved studying clinical files of women within the reproductive age group (15 - 49) with infertility problems, at the gynaecological and maternity units of the selected hospitals in the Southwest region of Cameroon over a period of five years (2015-2019). Data were collected from all files included in the study. Results: A total of 4609 females visited the two hospitals for investigation and 1111 files were identified with infertility giving prevalence of 24 %. Three hundred and forty-three (343;31%) presented with primary infertility while seven hundred and sixty-eight (768;69%) had secondary infertility. The average age of affected female was 31.5 making age the predisposing factor of infertility because after the peak of 25 years, infertility started decreasing. Employment with salary and the association between diagnosis and age had a p-value < 0.005 which was considered significant in this study. Conclusion: This study found that the prevalence of infertility in Southwest Cameroon is high with secondary infertility being most predominant among infertile women with a prevalence of 69% caused principally by sexually transmitted infection (STIs). Age and occupation were significantly associated with infertility. Routine laboratory screening of women of reproductive age may reduce the high prevalence of infertility in the study area.

Impact of Mining Activities upon Environment in Panzhihua Region, Southwestern China

Mining activities have left huge uncovered slopes, large areas of gangue ground and extensive railings dams. In this paper, we studied some impacts of mining activities upon environment in Panzhihua region, southwestern China. The environmental impacts include ecological destruction, geological disasters, environmental pollution, land damage, solid waste and occupational health effect in study area. The author suggested that local government should take some measure to reduce environmental impact in Pan...

Early Crystallized Titanomagnetite from Evolved Magmas and Magma Recharge in the Mesoproterozoic Zhuqing Oxide-Bearing Gabbroic Intrusions,Sichuan,SW China

The ca. 1.5 Ga mafic intrusions in the Zhuqing area, predominantly composed of alkaline gabbroic rocks in the Kangdian region of SW China, occur as dykes or irregular small intrusions hosting Fe–Ti–V mineralization. All of the intrusions that intrude the dolomite or shales of the Mesoproterozoic Heishan Formation of the Huili Group are composed of three cyclic units from the base upward： a marginal cyclic unit, a lower cyclic unit and an upper cyclic unit. The Fe–Ti–V oxide ore bodies are hosted in the lower and upper cyclic units. The textural relationships between minerals in the intrusions suggest that titanomagnetite formed earlier than silicate grains because euhedral magnetite and ilmenite grains were enclosed in clinopyroxene and plagioclase. Both the magnetitess–ilmenitess intergrowths due to subsolidus oxidation–exsolutions and the relative higher V distribution coefficient between magnetite and silicate melts in the gabbros from the Zhuqing area are different from those of other typical Fe–Ti bearing mafic rocks, suggesting that the oxygen fugacity was low in the gabbric rocks from the Zhuqing area. This finding was further confirmed by calculations based on the compositions of magnetite and ilmenite pairs. The clinopyroxene, magnetite and ilmenite in the intrusions from the Zhuqing area had considerably lower Mg O than those of other typical Fe–Ti oxide-rich complexes, suggesting that the titanomagnetite from the intrusion may have crystallized at a relatively late stage of evolution from a more evolved magma. Titanomagnetite first fractionally crystallized and subsequently settled in the lower parts of the magma chamber, where it concentrated and formed Fe–Ti–V oxide ore layers at the bases of the lower and upper cycles. Moreover, the occurrence of multiple Fe-Ti oxide layers alternating with Fe-Ti oxide-bearing silicate layers suggests that multiple pulses of magma were involved in the formation of the intrusions and related Fe-Ti-V oxide deposits in the Zhuqing area.

云南德宏州种子植物区系研究(Ⅰ)——科和属的地理成分分析

德宏地区野生种子植物共记录有 2 2 7科 ,1 43 2属 ,493 7种。按种数以禾本科 (2 69种 ) ,菊科 (2 67种 ) ,兰科 (2 5 9种 ) ,蝶形花科 (2 2 9种 ) ,茜草科 (1 66种 ) ,蔷薇科 (1 5 3种 ) ,大戟科 (1 1 0种 ) ,樟科 (1 0 1种 ) ,莎草科 (97种 ) ,荨麻科 (90种 ) ,桑科 (89种 ) ,爵床科 (77种 )等为优势科。在属的分布区类型构成上 ,以热带亚洲成分为最多 ,占总属数的 2 5 .1 % ,其次是泛热带成分 ,占总属数的 1 8.4% ,旧世界热带成分占 1 0 .3 % ,北温带成分占 1 1 .6% ,东亚成分占 9.2 % ,中国特有成分占 1 .8%。所有热带成分合计共 92 5属 ,占总属数的 68.2 % ,构成该植物区系的主体 ,温带成分 (类型 8～ 1 4)共有 40 6属 ,约占总属数的 3 0 % ,故认为该植物区系仍属于热带性质的植物区系 ,受热带亚洲植物区系的渗透和强烈影响 ,在世界植物区系分区上属于古热带植物区 ,马来西亚亚区 (热带亚洲植物区系区 )中的滇—缅—泰地区。

攀西地区新街层状岩体粒间不混熔作用:来自斜长石环带结构的记录

位于攀西地区的新街层状岩体赋含大量钒钛磁铁矿,是峨眉山大火成岩省的一部分。岩体下部带和中部带以单斜辉石岩为主,并伴生浸染状钒钛磁铁矿矿化;上部带以辉长岩为主,赋存厚层的钒钛磁铁矿矿体。之前研究认为厚层的钒钛磁铁矿矿体的形成与粒间不混熔的富Fe熔体有关,但对富Fe熔体的演化过程缺乏细致研究。本文通过对新街岩体上部带的富矿辉长岩层和上覆浅色辉长岩中斜长石环带结构和成分的研究,揭示了富Fe熔体的演化过程。在浅色辉长岩中保存的岩浆不混熔的直接证据表现为矿物粒间共轭的富Si交生体和富钛铁矿交生体代表的非反应结构。本次研究发现,与粒间富Si交生体接触的斜长石边部的FeO和TiO_2含量随斜长石牌号(An)值的降低而降低,而与粒间富钛铁矿交生体接触的斜长石边部的FeO和TiO_2含量随An值的降低而升高,说明斜长石的边部成分变化记录了粒间共轭的富Si和富Fe熔体的成分特征。在富矿辉长岩中,斜长石可分为初生和新生两种,初生斜长石的An值介于57~62,FeO含量为0.34%~0.50%,TiO_2含量为0.06%~0.13%,新生斜长石具有相对较高的An值(61~81)和FeO、TiO_2含量,二者的内部和边部还发育增生斜长石,其An值(~50)相对较低;在初生斜长石边部可见不连续的新生斜长石环带和增生斜长石边,造成其内部成分显著不均一,并发育复杂的环带结构。本文认为,初生斜长石是岩浆正常分离结晶作用的产物。在粒间熔体发生不混熔后,不混熔的富Fe熔体逐渐向岩浆房下方迁移并结晶出了一些相对高An值的新生斜长石,或沿一些初生斜长石边部生长形成不连续的高An环带。当富Fe熔体演化至晚期,由于矿物生长空间受限,仅在初生和新生斜长石局部形成了相对低An值的增生边、或沿颗粒裂隙进入斜长石内部形成增生斜长石核。

基于Landsat-8热红外数据的太湖地区地表温度反演与热岛效应分析

应用Landsat-8 TIRS遥感数据结合气象资料,使用三种不同的反演方法获得苏南太湖地区的地表温度(LST)数据.分析发现,辐射传输方程法反演的结果最接近于实测值;在缺乏实时大气廓线的情况下,普适性单通道算法更适用于Landsat-8热红外波段的地表温度反演;分裂窗算法在三种算法中精度最差.在反演结果的基础上,分析了不同地物的LST特征,建筑用地温度最高,水体最低.归一化植被指数(NDVI)和LST之间存在明显的负相关关系,证明了城市绿地是缓解城市热岛效应、改善城市热环境的重要途径.最后对2000年和2014年的两时相LST进行标准化和分区处理,分析发现,苏南太湖地区的热岛现象近些年来在不断加剧,城市热岛由原来单个存在逐渐成为多个热岛并存的局面,建筑用地的增加是导致整个城市热岛加剧的主要原因.

太赫兹返波振荡器的PIC仿真

研究太赫兹(THz)频点的返波振荡器(BWO)设计问题。由于信号源被加载不同位置的漂移区对于矩形波导光栅式返波振荡器输出信号的功率不同,同时频率以及输出信号功率达到稳定需要一定的时间。为了得到最大的输出功率,以及使输出功率达到稳定所需时间最少,运用单模近似的场匹配方法推导得到色散关系,依据牛顿迭代法原理用数值计算软件MATLAB编制数值计算程序,计算了慢波结构的色散特性,用粒子仿真软件完成电子注和电磁波互作用的仿真。仿真结果表明,漂移区在慢波线的位置并不影响输出信号的频率,但是会影响输出功率,以及输出功率达到稳定所需要的时间。最后结果为太赫兹返波振荡器的设计提供了依据。

西南边疆民族地区地方高校大学生消费价值观调查研究——以楚雄师范学院为例

近几年来,在西南边疆民族地区的地方高校中出现了非理性消费的现象,大学生的消费价值观正在发生较大的变化。本文以楚雄师范学院大学生为调查对象,在数据分析的基础上对边疆民族地区地方高校大学生的消费价值观现状、非理性消费存在的原因等进行分析,并力求从理论指导、实践认知和自我提高三个角度对西南边疆民族地区地方高校大学生树立正确的消费价值观提出合理化建议。

长江三峡库区玉溪遗址的环境与人类活动的孢粉记录

对玉溪遗址剖面53个地层样品和附近山地的9个现代表土样品进行了孢粉分析,结果表明:玉溪文化时期(6 000a.BP—7 200a.BP)孢粉组合以乔灌木为主,草本次之,蕨类孢子含量较少。乔灌木中以松属、桦木属、栎属占绝对优势;草本中藜科、蒿属含量较高;蕨类孢子以凤尾蕨为主。孢粉谱反映了较为湿润的气候特征。表土孢粉以超代表性的松属占绝对优势,可能是植被群落演替过程中松属植物作为先锋种类表现在演替初级阶段具有明显生长优势的结果,表土孢粉组合基本与当地植被状况相吻合。本研究在14 C测年基础上结合其它代用指标发现在剖面上部第4—8层和下部淤泥层中Rb/Sr值较高且乔灌木花粉百分含量明显增加,可以解释为该段淤泥层为古洪水遗迹,洪水可能有利于对孢粉的富集。地层剖面中文化层与淤泥层呈现交互沉积,表明周期性的洪水事件影响到了人类活动的连续性。