CHALLENGES TEACHERS OF ENGLISH FACE WHEN TEACHING THE ENGLISH ARTICLE SYSTEM TO LEARNERS IN SECONDARY SCHOOLS IN VIHIGA COUNTY, KENYA

This paper is a product of a study carried that was out examining the challenges teachers face when teaching the English article system in secondary schools, conducted in Vihiga County, Western Kenya. The need to carry out the study arose from the fact that performance in English as a subject in national examinations has been dismal as reflected in the Vihiga County results. The study was guided by Krashen’s learning- acquisition theory. The study adopted a pragmatic paradigm and a case study design. A mixed method approach was employed to allow for the use of both quantitative and qualitative methodologies leading to a better understanding of the article teaching and use phenomenon. The study sample included 6 schools and 24 teachers of English from the schools. A semi- structured in-depth interview was used to generate data. The data was analyzed using content and thematic analysis procedures. The study revealed the challenges teachers face including: complexity of the English article system, learners' L1 influence and scanty English article content coverage in the English language curriculum. Based on the study findings, it was concluded that the pedagogy utilized in the instruction of the English article is flawed, there is minimum content coverage for the English article and that both learners’ L1 and L2 negatively influence the acquisition and learning of English article making teaching difficult for teachers. Thus, it is recommended that teachers adopt an eclectic approach in teaching the English article system and that the curriculum developers review the English language syllabus with regard to the article system and accord it the prominence it deserves in terms of content coverage, spread and instructional guidance

Direct immobilization of DNA probes on non-modified plastics by UV irradiation and integration in microfluidic devices for rapid bioassay

DNA microarrays have become one of the most powerful tools in the field of genomics and medical diagnosis. Recently, there has been increased interest in combining microfluidics with microarrays since this approach offers advantages in terms of portability, reduced analysis time, low consumption of reagents, and increased system integration. Polymers are widely used for microfluidic systems, but fabrication of microarrays on such materials often requires complicated chemical surface modifications, which hinders the integration of microarrays into microfluidic systems. In this paper, we demonstrate that simple UV irradiation can be used to directly immobilize poly(T)poly(C)-tagged DNA oligonucleotide probes on many different types of plastics without any surface modification. On average, five- and fourfold improvement in immobilization and hybridization efficiency have been achieved compared to surface-modified slides with aminated DNA probes. Moreover, the TC tag only costs 30% of the commonly used amino group modifications. Using this microarray fabrication technique, a portable cyclic olefin copolymer biochip containing eight individually addressable microfluidic channels was developed and used for rapid and parallel identification of Avian Influenza Virus by DNA hybridization. The one-step, cost-effective DNA-linking method on non-modified polymers significantly simplifies microarray fabrication procedures and permits great flexibility to plastic material selection, thus making it convenient to integrate microarrays into plastic microfluidic systems

Esophageal foreign body retrieved by cervical esophagotomy four years after ingestion

Background: Foreign body ingestion is common pediatric population with more than 55% from ingestion of coins. Over 80% pass spontaneously through the digestive tract, but substantial amount lodge in the UES causing esophageal perforation. Failure to recognize and treat as an emergency can cause significant complications and mortality aggravated by longer duration of impaction. Impacted FB can be retrieved by endoscopy with over 95% success rate. In the event of failed endoscopic retrieval, surgery offers safe alternative. The latter usually indicated in perforation, stricture, esophago-aortic and trachea-esophageal fistulas. Clinical case: A 12-year old female patient with a coin impaction in the cervical esophagus for over four years managed for recurrent respiratory infection. Conclusion: Foreign body – coins ingestion is common in pediatric population. Timely recognition and treatment is required to prevent severe complications and mortality. Diagnosis involves a triad of clinical history, X-ray appearances and esophagoscopy

Flexible fabrication and applications of polymer nanochannels and nanoslits

Fluidic devices that employ nanoscale structures (< 100 nm in one or two dimensions, slits or channels, respectively) are generating great interest due to the unique properties afforded by this size domain compared to their micro-scale counterparts. Examples of interesting nanoscale phenomena include the ability to preconcentrate ionic species at extremely high levels due to ion selective migration, unique molecular separation modalities, confined environments to allow biopolymer stretching and elongation and solid-phase bioreactions that are not constrained by mass transport artifacts. Indeed, many examples in the literature have demonstrated these unique opportunities, although predominately using glass, fused silica or silicon as the substrate material. Polymer microfluidics has established itself as an alternative to glass, fused silica, or silicon-based fluidic devices. The primary advantages arising from the use of polymers are the diverse fabrication protocols that can be used to produce the desired structures, the extensive array of physiochemical properties associated with different polymeric materials, and the simple and robust modification strategies that can be employed to alter the substrate's surface chemistry. However, while the strengths of polymer microfluidics is currently being realized, the evolution of polymer-based nanofluidics has only recently been reported. In this critical review, the opportunities afforded by polymer-based nanofluidics will be discussed using both elastomeric and thermoplastic materials. In particular, various fabrication modalities will be discussed along with the nanometre size domains that they can achieve for both elastomer and thermoplastic materials. Different polymer substrates that can be used for nanofluidics will be presented along with comparisons to inorganic nanodevices and the consequences of material differences on the fabrication and operation of nanofluidic devices (257 references)close312