Student Perceptions of Chemistry Laboratory Learning Environments, Student–Teacher Interactions and Attitudes in Secondary School Gifted Education Classes in Singapore

This study investigated the chemistry laboratory classroom environment, teacher–student interactions and student attitudes towards chemistry among 497 gifted and non-gifted secondary-school students in Singapore. The data were collected using the 35-item Chemistry Laboratory Environment Inventory (CLEI), the 48-item Questionnaire on Teacher Interaction (QTI) and the 30-item Questionnaire on Chemistry-Related Attitudes (QOCRA). Results supported the validity and reliability of the CLEI and QTI for this sample. Stream (gifted versus non-gifted) and gender differences were found in actual and preferred chemistry laboratory classroom environments and teacher–student interactions. Some statistically significant associations of modest magnitude were found between students' attitudes towards chemistry and both the laboratory classroom environment and the interpersonal behaviour of chemistry teachers. Suggestions for improving chemistry laboratory classroom environments and the teacher–student interactions for gifted students are provided.     

Clinico-Biochemical indexing of calcium urolithiasis on the basis of urinary citrate to calcium ratio and inhibition of mineralisation of urinary stone forming minerals by human urine

Urinary citric acid and calcium levels have been estimated in the urine of 20 normal healthy persons as well as 12 urinary stone patients. Inhibition efficiency of these urine samples towards the mineralisation of urinary stone forming minerals, viz., calcium phosphate, oxalate or carbonate, has been studied in an experimental model. Statistical correlation of the above data has been made by computing the coefficient of determination and unexplained variance. Clinico-biochemical indexing of calcium urolithiasis risk factor has been attempted in the light of the data.     

Alkaptonuric ochronosis: Report of a case and brief review

Alkaptonuria, a metabolic disorder characterized by a triad of homogentisic aciduria, arthritis and ochronosis is one of the first conditions in the charter of group of inborn errors of metabolism proposed to have Mendelian recessive inheritance. It is due to the deficiency of the enzyme homogentisic acid oxidase which catalyzes the conversion of homogentisic acid to maleylacetoacetic acid in the catabolism of tyrosine. Homogentisic acid thus accumulates in cells and body fluids and its oxidized polymers bind to collagen, leading to progressive deposition of grey to bluish black pigment resulting in degenerative changes in cartilage, intervertebral disc and other connective tissues, leading to arthritis which is the only disabling effect in an affected older individual. However the diagnosis can be made in neonates when blackish stain is noticed in an unwashed diaper. Alkaptonuria is treated symptomatically, surgical intervention necessitates in advanced stages, treatment with ascorbic acid (Vitamin C) and dietary restrictions of food containing phenylalanine and tyrosine have proved to be successful in alleviating the symptoms.     

A case of IgA multiple myeloma: Nutritional perspective in diagnostic testing

A 64-year-old security guard and longstanding known hypertensive presented with hypertensive heart disease (HHD), weight loss, an enlarged prostate, and a spontaneously fractured rib. Malignancy of the prostate with possible metastases to the ribs was strongly suspected. Biochemical profiling revealed a paraprotein. Other biochemical and hematological correlates that were on hand before serum protein electrophoresis were rather atypical. Paraprotein studies by immunofixation revealed IgA myelomatosis. Unlike previous reports from Caucasians there was normocalcaemia, normal protein level, microcytic hypochromia, low MCHC, cholesterol level at the lower limit of the reference range and normal urea level (in the face of markedly raised creatinine level). Nutritional modulation of the classical laboratory features of this disease may account for the fairly atypical laboratory picture. The need to appreciate the influence of nutritional status on the laboratory (especially biochemical) features of a disease and thus interpretation of diagnostic tests appears of exceptional current importance, given the widening gap in socioeconomic status and the level of poverty between the resource poor and developed countries from which the classical, clinical and laboratory features of most diseases were first described. This case report reminds of the need not only to recognize theoretically the impact of nutritional status on the laboratory characteristics of a disease but of the practical application of the nutritional perspective in the interpretation of diagnostic investigations, especially in nutritionally disadvantaged communities.     

Evaluations of matrix functions by real similarity transformation

An effective way of constructing transforming matrix which similarly transforms a real square matrix to a quasi-diagonal form, is obtained. The transforming matrix as well as the quasi-diagonal form are real, regardless whether the given matrix has real eigenvalues or not. Formulas are included; they can be applied conveniently to evaluate a matrix function f(A) from the given scalar function f(λ). Three examples are given to illustrate the ease of application. These are the solutions of system differential equations of first and second order, and the determination of Nth root of a square matrix.     

Prostate specific antigen in patients of benign prostate hypertrophy and carcinoma prostate

Prostate Specific Antigen (PSA) has emerged as the most applicable and important tumor marker for carcinoma prostate. In the present study PSA was determined in serum of healthy subjects, patients of benign prostate hypertrophy (BPH) and Carcinoma Prostate (Ca−P) to evaluate its diagnostic efficiency in day to day management of prostate cancer patients and in differentiating patients of early prostate cancer from those with BPH. Receiver operating characteristic curve (ROC) revealed 2 ng/ml and 10 ng/ml cut off serum PSA level for BPH and untreated carcinoma prostate patients (Ca−P). An extremely significant increase (P<0.0001) was observed in mean PSA concentration in BPH patients and adenocarcinoma prostate patients when compared to healthy males. Clinical relevance of PSA was highlighted by a case study of cancer patient prior to any therapy till death.     

A “twisted” microfluidic mixer suitable for a wide range of flow rate applications

This paper proposes a new “twisted” 3D microfluidic mixer fabricated by a laser writing/microfabrication technique. Effective and efficient mixing using the twisted micromixers can be obtained by combining two general chaotic mixing mechanisms: splitting/recombining and chaotic advection. The lamination of mixer units provides the splitting and recombination mechanism when the quadrant of circles is arranged in a two-layered serial arrangement of mixing units. The overall 3D path of the microchannel introduces the advection. An experimental investigation using chemical solutions revealed that these novel 3D passive microfluidic mixers were stable and could be operated at a wide range of flow rates. This micromixer finds application in the manipulation of tiny volumes of liquids that are crucial in diagnostics. The mixing performance was evaluated by dye visualization, and using a pH test that determined the chemical reaction of the solutions. A comparison of the tornado-mixer with this twisted micromixer was made to evaluate the efficiency of mixing. The efficiency of mixing was calculated within the channel by acquiring intensities using ImageJ software. Results suggested that efficient mixing can be obtained when more than 3 units were consecutively placed. The geometry of the device, which has a length of 30 mm, enables the device to be integrated with micro total analysis systems and other lab-on-chip devices.     

Providing Bottom-Up Support to Middle School Science Teachers’ Reform Efforts in Using Inquiry-Based Kits

Middle grades science teachers need professional support in practice as they implement new inquiry-based science. Professional development schools can provide this bottom-up support through connecting preservice and inservice teacher education programs in classroom practice. In this study, coteaching arrangements with secondary science education majors provided additional teachers in the classroom to support a materials-rich curriculum and the needed associated pedagogies. Science education majors provided needed assistance in troubleshooting difficulties with the new curriculum. They also provided needed content knowledge to support inquiry, along with creating moments and space for teachers to reflect on inquiry practice. Ongoing assistance by preservice teachers allowed inservice teachers to progress from logistical concerns in implementing kit curriculum to concerns regarding student learning and the supporting professional development.