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In this work we demonstrate that the phase shift detection technique can be applied to reveal, with very high sensitivity and resolution, concentrations of chemical/biological substances optically detectable by measuring power variations of a light source. The system is based on the synchronous demodulation technique and employs a Si photodiode (PD) operating in photovoltaic regime biased through a small modulating sinusoidal waveform. The phase shift variations are measured between this biasing voltage and that one generated by the Si PD illuminated by the light, that interacts with the chemical/biological sample under analysis, providing the phase shift change. Experimental results demonstrate that is possible to achieve phase detection sensitivity, with respect to light power variations, up to 3100°/μW as a function of the Si PD settable operating conditions. By using a commercial lock-in amplifier with a 0.01° phase resolution, a light power variation resolution of about 3pW has been achieved. As a case-example, variations of the molar concentration of a methylene blue solution are detected by performing optical absorption standard measurements. Despite the phase resolution limitation of the used lock-in amplifier, the comparison between the data obtained through the proposed technique and those ones achieved by conventional amplitude measurements demonstrates a high improvement of the detection sensitivity. As a consequence, the measurement of molar concentration variations with a resolution of 80pM is achieved resulting 33 times higher than that one obtained with the amplitude detection. [ABSTRACT FROM AUTHOR]

The main objective of this work is to improve the learning in the chemistry laboratory to first year engineering students. We have first established the conditions in which this subject is taught and how students work in it. The initial situation of practical Chemistry subjects has been analyzed using opinion questionnaires, which were answered by teachers and by students. The results from the questionnaires have been used to introduce some changes in laboratory activities, and their effects on students have been analyzed. Changes have been introduced in learning materials, in classroom strategies and in evaluation. Contextualized practices closed to students' environment and to their future job have been proposed. Diverse classroom strategies have been used: It has been favoured work and reflexion done by each single student, work in small groups and in plenary discussions. Our results indicate changes in the habits of working of the students. [ABSTRACT FROM AUTHOR]

The article focuses on laboratory manuals. It notes that the earliest laboratory manual "Kitāb al-Asrār" or "Book of Secrets," by Abu Bakr Muhammad ibn Zakariya al-Razi and "Alchemia", by Andreas Libavius are presented. It provides information on how the "Kitab al-Asrar" was organized into parts including the introduction, required materials, equipment, and procedures. Translations of his books are also described along with his popularity. Also discussed is the comparison of the structure of his book with "Alchemia."

The article presents information on practical laboratory manuals on alchemy from "Kitab al-Asrar," by Persian physician and alchemist Abu Bakr Muhammad ibn Zakariya al-Razi in 920 C.E. to Andreas Libavius' "Alchemia" published in 1597 C.E. It is stated that the Kitab al-Asrar, was not a defense of alchemy, but a systematic procedure manual with a modern resonance that contrasts with theoretical medieval texts. The Kitab al-Asrar is organized into four parts, consisting of an introduction, required materials, equipment, and procedures. It also contains the procedure for the sublimation of mercury.

The article outlines steps that laboratory managers must take to maintain their valuable and sensitive equipment, as well as the rationale for these steps. It mentions the importance of preventive maintenance (PM) and provision of PM manuals which can be made for each automated machine that does not have its own maintenance manual. It also discusses the significance of a variety of forms to document that these maintenance activities are performed. Meanwhile, it lists certain steps to be followed to ensure the proper functioning of autoclaves.

A review of the web site "The Virtual Lab Book," at http://delliss.people.cofc.edu/virtuallabbook, is presented.

Ocular Collection Protocol for the Laboratory Rabbit, Dog, and Monkey is a CD-ROM, which will serve as an educational tool and resource for pathologists, technicians, pathologists-in-training, and any other individuals involved in the collection, processing, and evaluation of ocular specimens of large laboratory animals (monkey, dog, and rabbit). The three species are dealt with separately in order to address the species-specific differences in anatomy and ocular pathology. This CD-ROM covers various ocular methods, including ocular tissue collection, histotechnology (fixation, trimming, processing, embedding, sectioning and other aspects of slide preparation), normal macroscopic and microscopic anatomy, immunohistochemistry, and histopathology. The viewer will be fully engaged in the learning experience by the use of computer graphics and numerous images of normal ocular structures and spontaneous and treatment-induced lesions. Although the emphasis is on toxicologic pathology of the eye and associated extraocular structures, this CD-ROM also provides a valuable resource for those working in the area of diagnostic pathology. Ocular Collection Protocol for the Laboratory Rabbit, Dog, and Monkey will be available free of charge near the end of 2008 by requesting a copy at the 2008 ESTP poster session or by contacting Dr. Jerry Hardisty at Experimental Pathology Laboratories, Inc. (jhardisty@epl-inc.com). [Copyright &y& Elsevier]

Abstract: The impact of using a multimedia laboratory manual on preparation, learning, satisfaction and performance in a mass and energy balance laboratory within a mixed discipline student cohort (Engineering, Science And Technology) at the University of Auckland was examined with respect to matching teaching styles with student learning styles over one semester. Learning styles were measured by both the Felder–Silverman–Soloman Index of Learning styles and VARK learning styles instruments. The multimedia manual was beneficial to the learning styles of the students’ surveyed, as they were mainly sensing, sequential, reflective, visual and read/write learners. The surveyed Auckland Engineering students were more reflective learners than overseas cohorts, possibly due to differences in culture and/or pre-university teaching styles. Feedback survey and focus group results suggest teaching and learning benefits that indicate that multimedia manuals should be used in all laboratory courses. This is because student preparation, satisfaction and learning was enhanced, with students more easily performing laboratory tasks and producing laboratory reports demonstrating increased global understanding. This was directly attributable to the multimedia manual matching teaching styles to a wider range of learning styles than the paper manual. [ABSTRACT FROM AUTHOR]