Automated Multi-Wavelength Quality Assessment of Photoplethysmography Signals Using Modulation Spectrum Shape Features.

Photoplethysmography (PPG) is used to measure blood volume changes in the microvascular bed of tissue. Information about these changes along time can be used for estimation of various physiological parameters, such as heart rate variability, arterial stiffness, and blood pressure, to name a few. As a result, PPG has become a popular biological modality and is widely used in wearable health devices. However, accurate measurement of various physiological parameters requires good-quality PPG signals. Therefore, various signal quality indexes (SQIs) for PPG signals have been proposed. These metrics have usually been based on statistical, frequency, and/or template analyses. The modulation spectrogram representation, however, captures the second-order periodicities of a signal and has been shown to provide useful quality cues for electrocardiograms and speech signals. In this work, we propose a new PPG quality metric based on properties of the modulation spectrum. The proposed metric is tested using data collected from subjects while they performed various activity tasks contaminating the PPG signals. Experiments on this multi-wavelength PPG dataset show the combination of proposed and benchmark measures significantly outperforming several benchmark SQIs with improvements of 21.3% BACC (balanced accuracy) for green, 21.6% BACC for red, and 19.0% BACC for infrared wavelengths, respectively, for PPG quality detection tasks. The proposed metrics also generalize for cross-wavelength PPG quality detection tasks.

Effects of toothbrushing on surface characteristics of microhybrid and nanofilled resin composites following different finishing and polishing procedures.

OBJECTIVES: To evaluate the effects of simulated tooth brushing (STB) on the surface roughness of microhybrid and nanofilled resin composites following different finishing and polishing procedures. MATERIALS AND METHODS: Ninety cylindrical-shaped specimens of Filtek Supreme XT (a universal nano resin composite) and Filtek Z250 (a universal microhybrid resin composite) were prepared. The specimens were allocated at random into 9 paired groups each of 10 specimens. The finishing and polishing systems included were Tungsten Carbide bur (TC); Diamond bur (Db); Sof-Lex discs (S); PoGo discs (PG); TC + S; Db + S; TC + PG; Db + PG. Polymerisation against a Mylar strip without finishing and polishing acted as the control. Surface roughness was measured using a 3D non-contact optical profilometer and surface morphology was examined by scanning electron microscopy. Specimens were subjected to the equivalent of four years STB and surface roughness was measured again. RESULTS: Mylar formed surfaces were the smoothest for both composites before and after STB. Finishing with the diamond finishing bur caused significantly greater surface irregularity (p < 0.0001) before and after STB compared to the tungsten carbide bur. The surface treatment with Db + PG resulted in significantly greater surface roughness following STB than all other regimes of finishing and polishing (p < 0.01). CONCLUSION: Where indicated clinically, finishing is better conducted using a tungsten carbide bur rather than a diamond finishing bur. The combination of tungsten carbide bur/Enhance PoGo and tungsten carbide bur/Sof-Lex surface protocols produced a similarly smooth finish for both composites. The composite surfaces in all groups increased in surface irregularity following STB. CLINICAL SIGNIfiCANCE: Whilst finishing using a tungsten carbide finishing bur followed by either the Sof-Lex or PoGo polishing system may be found to result in a smooth surface finish, all the surfaces investigated increased in surface roughness following toothbrushing.

Using the Healthy Community Assessment Tool: Applicability and Adaptation in the Midwest of Western Australia.

Population-based studies have associated poor living conditions with the persistent disparity in the health of Aboriginal and non-Aboriginal Australians. This project assesses the applicability of the Health Community Assessment Tool and its role in improving the environment of a small community in the Midwest of Western Australia (WA). The action research cycles started with the initial reflection on the suitability of the HCAT version 2 for the local community context and whether it was fit-for-purpose. The researcher provided 'critical companionship', while the participants of the study were invited to be co-researchers (the Assessors) who critically examined the HCAT and assess the community. The relevant domains to the serviced town (an outer regional community) were pest control and animal management; healthy housing; food supply; community vibrancy, pride and safety; reducing environmental tobacco smoke; and promoting physical activity. The Assessors found the HCAT descriptors mostly aligned with their community context but found some of the items difficult to apply. Based on participant's suggestions, some of the original scoring scales were reformatted. School attendance and illicit drug use were identified as a key outcome indicator for youth but were missing from the HCAT. The HCAT domains applied helped streamlining core business of agencies in the local community. The face validity of HCAT items were confirmed in this research with minor adjustments to reflect local context. Youth engagement to education is of high community concern and the development of an item would create similar interagency collaborative dialogues.

A randomised controlled study on the use of finishing and polishing systems on different resin composites using 3D contact optical profilometry and scanning electron microscopy.

OBJECTIVES: The aim of this study was to evaluate theeffects of different finishing and polishing techniques on the surface roughness of microhybrid and nanofilled resin composites. METHODS: The resin composites included were Filtek Z250 (a universal microhybrid resin composite) and Filtek Supreme XTE (a universal nanofill resin composite). Ninety cylindrical-shaped specimens were prepared for each composite resin material. The polishing methods used included tungsten carbide bur (TC); diamond bur (Db); Sof-Lex discs (S); Enhance PoGo discs (PG); TC + S; Db + S; TC + PG; Db + PG. Polymerisation against a Mylar strip without finishing and polishing acted as the control group. Surface roughness was measured using a 3D contact optical profilometer and surface morphology was examined by scanning electron microscope examination. RESULTS: The results showed that the Mylar-formed surfaces were smoothest for both composites. Finishing with the 20 µm diamond finishing bur caused significantly greater surface irregularity (P < 0.0001) and damage than finishing with the tungsten carbide finishing bur. The Enhance PoGo polishing system produced smoother surfaces than the Sof-Lex disc polishing system; this difference was statistically highly significant (P < 0.0001). CONCLUSION: For both composites, the Mylar-formed surfaces were smoothest. Where indicated clinically, finishing is better conducted using a tungsten carbide bur- rather than a diamond finishing bur. The Enhance PoGo system was found to produce a smoother surface finish than the Sof-Lex system. CLINICAL SIGNIFICANCE: If finishing and polishing is required the use a tungsten carbide finishing bur followed by Enhance PoGo polishing may be found to result in the smoothest surface finish.

Differential Mechanisms of Photosynthetic Acclimation to Light and Low Temperature in Arabidopsis and the Extremophile Eutrema salsugineum.

Photosynthetic organisms are able to sense energy imbalances brought about by the overexcitation of photosystem II (PSII) through the redox state of the photosynthetic electron transport chain, estimated as the chlorophyll fluorescence parameter 1-qL, also known as PSII excitation pressure. Plants employ a wide array of photoprotective processes that modulate photosynthesis to correct these energy imbalances. Low temperature and light are well established in their ability to modulate PSII excitation pressure. The acquisition of freezing tolerance requires growth and development a low temperature (cold acclimation) which predisposes the plant to photoinhibition. Thus, photosynthetic acclimation is essential for proper energy balancing during the cold acclimation process. Eutrema salsugineum (Thellungiella salsuginea) is an extremophile, a close relative of Arabidopsis thaliana, but possessing much higher constitutive levels of tolerance to abiotic stress. This comparative study aimed to characterize the photosynthetic properties of Arabidopsis (Columbia accession) and two accessions of Eutrema (Yukon and Shandong) isolated from contrasting geographical locations at cold acclimating and non-acclimating conditions. In addition, three different growth regimes were utilized that varied in temperature, photoperiod and irradiance which resulted in different levels of PSII excitation pressure. This study has shown that these accessions interact differentially to instantaneous (measuring) and long-term (acclimation) changes in PSII excitation pressure with regard to their photosynthetic behaviour. Eutrema accessions contained a higher amount of photosynthetic pigments, showed higher oxidation of P700 and possessed more resilient photoprotective mechanisms than that of Arabidopsis, perhaps through the prevention of PSI acceptor-limitation. Upon comparison of the two Eutrema accessions, Shandong demonstrated the greatest PSII operating efficiency (ΦPSII) and P700 oxidizing capacity, while Yukon showed greater growth plasticity to irradiance. Both of these Eutrema accessions are able to photosynthetically acclimate but do so by different mechanisms. The Shandong accessions demonstrate a stable response, favouring energy partitioning to photochemistry while the Yukon accession shows a more rapid response with partitioning to other (non-photochemical) strategies.

Acquisition of freezing tolerance in Arabidopsis and two contrasting ecotypes of the extremophile Eutrema salsugineum (Thellungiella salsuginea).

Eutrema salsugineum (Thellungiella salsuginea) is an extremophile, a close relative of Arabidopsis, but possessing much higher constitutive levels of tolerance to abiotic stress. This study aimed to characterize the freezing tolerance of Arabidopsis (Columbia ecotype) and two ecotypes of Eutrema (Yukon and Shandong) isolated from contrasting geographical locations. Under our growth conditions, maximal freezing tolerance was observed after two- and three-weeks of cold acclimation for Arabidopsis and Eutrema, respectively. The ecotypes of Eutrema and Arabidopsis do not differ in their constitutive level of freezing tolerance or short-term cold acclimation capacity. However Eutrema remarkably outperforms Arabidopsis in long-term acclimation capacity suggesting a wider phenotypic plasticity for the trait of freezing tolerance. The combination of drought treatment and one-week of cold acclimation was more effective than long-term cold acclimation in achieving maximum levels of freezing tolerance in Eutrema, but not Arabidopsis. Furthermore, it was demonstrated growth conditions, particularly irradiance, are determinates of the level of freezing tolerance attained during cold acclimation suggesting a role for photosynthetic processes in adaptive stress responses.

An exploration of inter-organisational partnership assessment tools in the context of Australian Aboriginal-mainstream partnerships: a scoping review of the literature.

BACKGROUND: The need for better partnerships between Aboriginal organisations and mainstream agencies demands attention on process and relational elements of these partnerships, and improving partnership functioning through transformative or iterative evaluation procedures. This paper presents the findings of a literature review which examines the usefulness of existing partnership tools to the Australian Aboriginal-mainstream partnership (AMP) context. METHODS: Three sets of best practice principles for successful AMP were selected based on authors' knowledge and experience. Items in each set of principles were separated into process and relational elements and used to guide the analysis of partnership assessment tools. The review and analysis of partnership assessment tools were conducted in three distinct but related parts. Part 1- identify and select reviews of partnership tools; part 2 - identify and select partnership self-assessment tool; part 3 - analysis of selected tools using AMP principles. RESULTS: The focus on relational and process elements in the partnership tools reviewed is consistent with the focus of Australian AMP principles by reconciliation advocates; however, historical context, lived experience, cultural context and approaches of Australian Aboriginal people represent key deficiencies in the tools reviewed. The overall assessment indicated that the New York Partnership Self-Assessment Tool and the VicHealth Partnership Analysis Tools reflect the greatest number of AMP principles followed by the Nuffield Partnership Assessment Tool. The New York PSAT has the strongest alignment with the relational elements while VicHealth and Nuffield tools showed greatest alignment with the process elements in the chosen AMP principles. CONCLUSIONS: Partnership tools offer opportunities for providing evidence based support to partnership development. The multiplicity of tools in existence and the reported uniqueness of each partnership, mean the development of a generic partnership analysis for AMP may not be a viable option for future effort.

Accumulation of Phosphorus-Containing Compounds in Developing Seeds of Low-Phytate Pea (Pisum sativum L.) Mutants.

Low phytic acid (lpa) crops are low in phytic acid and high in inorganic phosphorus (Pi). In this study, two lpa pea genotypes, 1-150-81, 1-2347-144, and their progenitor CDC Bronco were grown in field trials for two years. The lpa genotypes were lower in IP6 and higher in Pi when compared to CDC Bronco. The total P concentration was similar in lpa genotypes and CDC Bronco throughout the seed development. The action of myo-inositol phosphate synthase (MIPS) (EC 5.5.1.4) is the first and rate-limiting step in the phytic acid biosynthesis pathway. Aiming at understanding the genetic basis of the lpa mutation in the pea, a 1530 bp open reading frame of MIPS was amplified from CDC Bronco and the lpa genotypes. Sequencing results showed no difference in coding sequence in MIPS between CDC Bronco and lpa genotypes. Transcription levels of MIPS were relatively lower at 49 days after flowering (DAF) than at 14 DAF for CDC Bronco and lpa lines. This study elucidated the rate and accumulation of phosphorus compounds in lpa genotypes. The data also demonstrated that mutation in MIPS was not responsible for the lpa trait in these pea lines.

Gelation in protein extracts from cold acclimated and non-acclimated winter rye (Secale cereale L. cv Musketeer).

A protein gel is a three-dimensional network consisting of molecular interactions between biopolymers that entrap a significant volume of a continuous liquid phase (water). Molecular interactions in gels occur at junction zones within and between protein molecules through electrostatic forces, hydrogen bonding, hydrophobic associations (van der Waals attractions) and covalent bonding. Gels have the physicochemical properties of both solids and liquids, and are extremely important in the production and stability of a variety of foods, bioproducts and pharmaceuticals. In this study, gelation was induced in phenol extracted protein fractions from non-acclimated (NA) and cold-acclimated (CA) winter rye (Secale cereale L. cv Musketeer) leaf tissue after repeated freeze-thaw treatments. Gel formation only occurred at high pH (pH 12.0) and a minimum of 3-4 freeze-thaw cycles were required. The gel was thermally stable and only a specific combination of chemical treatments could disrupt the gel network. SDS-PAGE analysis identified ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) as the major protein component in the gel, although Rubisco itself did not appear to be a factor in gelation. Raman spectroscopy suggested changes in protein secondary structure during freeze-thaw cycles. Overall, the NA and CA gels were similar in composition and structure, with the exception that the CA gel appeared to be amyloidic in nature based on thioflavin T (ThT) fluorescence. Protein gelation, particularly in the apoplast, may confer protection against freeze-induced dehydration and potentially have a commercial application to improve frozen food quality.

A novel porcine model of traumatic thoracic spinal cord injury.

Spinal cord injury (SCI) researchers have predominately utilized rodents and mice for in vivo SCI modeling and experimentation. From these small animal models have come many insights into the biology of SCI, and a growing number of novel treatments that promote behavioral recovery. It has, however, been difficult to demonstrate the efficacy of such treatments in human clinical trials. A large animal SCI model that is an intermediary between rodent and human SCI may be a valuable translational research resource for pre-clinically evaluating novel therapies, prior to embarking upon lengthy and expensive clinical trials. Here, we describe the development of such a large animal model. A thoracic spinal cord injury at T10/11 was induced in Yucatan miniature pigs (20-25 kg) using a weight drop device. Varying degrees of injury severity were induced by altering the height of the weight drop (5, 10, 20, 30, 40, and 50 cm). Behavioral recovery over 12 weeks was measured using a newly developed Porcine Thoracic Injury Behavior Scale (PTIBS). This scale distinguished locomotor recovery among animals of different injury severities, with strong intra-observer and inter-observer reliability. Histological analysis of the spinal cords 12 weeks post-injury revealed that animals with the more biomechanically severe injuries had less spared white matter and gray matter and less neurofilament immunoreactivity. Additionally, the PTIBS scores correlated strongly with the extent of tissue sparing through the epicenter of injury. This large animal model of SCI may represent a useful intermediary in the testing of novel pharmacological treatments and cell transplantation strategies.

The PSBP2 protein of Chlamydomonas reinhardtii is required for singlet oxygen-dependent signaling.

In the green alga Chlamydomonas reinhardtii, the cytosolic Glutathione Peroxidase 5 gene (GPX5) is known to be transcriptionally up-regulated in response to singlet oxygen ((1)O(2)). As demonstrated by previous studies, fusion of the promoter region of GPX5 to the Arylsulfatase 2 gene (ARS2) creates an effective reporter system that can be used to monitor (1)O(2)-driven GPX5 expression. This system was also used in this study to generate a stably transformed C. reinhardtii strain which expresses ARS2 in a (1)O(2)-dependent manner, resulting in the synthesis of a functional protein with detectable activity. Using the strain of C. reinhardtii harboring a (1)O(2)-sensitive reporter construct, a secondary mutagenic screen was performed. This allowed identification of mutant cell lines that were unable to up-regulate expression of the GPX5-ARS2 fusion in response to (1)O(2). In one of these lines, the mutation was subsequently localized to the first exon of the PSBP-like gene (PSBP2). The PSBP2 gene is part of a small protein family in C. reinhardtii, also present in all angiosperms studied thus far. While each member of the PSBP protein family contains a similar domain to the PSBP1 protein, which is a member of the oxygen evolving complex of photosystem II (PSII), the PSBP2 protein does not appear to be involved in PSII function, but may function as a sensor and/or signal mediating molecule of the (1)O(2) generated in the chloroplast.

Cage-change interval preference in mice.

Before animal research facilities began using individually ventilated cage (IVC) systems for mice, cages were often changed one or more times per week. When using IVC systems, however, it is standard practice to change cages only once every 2-3 weeks. When deciding how often to change cages, personnel may consider the cost of labor needed to change the cage, as well as the cage type and bedding type, rather than animal preference or concern for animal well-being. The authors carried out a simple preference test in groups of mice. Mice were allowed to choose between an unsoiled cage and cages that had not been changed for 1 d, 7 d or 14 d. When evaluating where mice positioned their nests and the amount of time mice spent in the various cages, the authors found that the mice preferred the unsoiled cage. Younger mice (<150 d old) showed a stronger preference for the unsoiled cage than did older mice (>150 d old). Further studies are warranted to evaluate mice's preferences for cages changed at different intervals and to determine whether prolonging the interval between cage changes has any negative effects on mice.

A role for the anaphase promoting complex in hormone regulation.

To increase our knowledge of anaphase promoting complex (APC/C) function during plant development, we characterized an Arabidopsis thaliana T-DNA-insertion line where the T-DNA fell within the 5' regulatory region of the APC10 gene. The insert disrupted endogenous expression, resulting in overexpression of APC10 mRNA from the T-DNA- internal CaMV 35S promoter, and increased APC10 protein. Overexpression of APC10 produced phenotypes resembling those of known auxin and ethylene mutants, and increased expression of two tested auxin-regulated genes, small auxin up RNA (SAUR) 15 and SAUR24. Taken together, our data suggests that elevated APC10 likely mimics auxin and ethylene sensitive phenotypes, expanding our understanding of proteolytic processes in hormone regulation of plant development.

SUPPRESSOR OF VARIEGATION4, a new var2 suppressor locus, encodes a pioneer protein that is required for chloroplast biogenesis.

VAR2 is an integral thylakoid membrane protein and a member of the versatile FtsH class of metalloproteases in prokaryotes and eukaryotes. Recessive mutations in the VAR2 locus give rise to variegated plants (var2) that contain white sectors with abnormal plastids and green sectors with normal-appearing chloroplasts. In a continuing effort to isolate second-site suppressors of var2 variegation, we characterize in this report ems2505, a suppressor strain that has a virescent phenotype due to a missense mutation in At4g28590, the gene for a pioneer protein. We designated this gene SVR4 (for SUPPRESSOR OF VARIEGATION4) and the mutant allele in ems2505 as svr4-1. We demonstrate that SVR4 is located in chloroplasts and that svr4-1 single mutants are normal with respect to chloroplast anatomy and thylakoid membrane protein accumulation. However, they are modestly impaired in several aspects of photochemistry and have enhanced non-photochemical quenching (NPQ) capacity. A T-DNA insertion allele of SVR4, svr4-2, is seedling-lethal due to an early blockage of chloroplast development. We conclude that SVR4 is essential for chloroplast biogenesis, and hypothesize that SVR4 mediates some aspect of thylakoid structure or function that controls NPQ. We propose that in the suppressor strain, photoinhibitory pressure caused by a lack of VAR2 is ameliorated early in chloroplast development by enhanced NPQ capacity caused by reduced SVR4 activity. This would result in an increase in the number of chloroplasts that are able to surmount a threshold necessary to avoid photo-damage and thereby develop into functional chloroplasts.

Temperature-driven plasticity in growth cessation and dormancy development in deciduous woody plants: a working hypothesis suggesting how molecular and cellular function is affected by temperature during dormancy induction.

The role of temperature during dormancy development is being reconsidered as more research emerges demonstrating that temperature can significantly influence growth cessation and dormancy development in woody plants. However, there are seemingly contradictory responses to warm and low temperature in the literature. This research/review paper aims to address this contradiction. The impact of temperature was examined in four poplar clones and two dogwood ecotypes with contrasting dormancy induction patterns. Under short day (SD) conditions, warm night temperature (WT) strongly accelerated timing of growth cessation leading to greater dormancy development and cold hardiness in poplar hybrids. In contrast, under long day (LD) conditions, low night temperature (LT) can completely bypass the short photoperiod requirement in northern but not southern dogwood ecotypes. These findings are in fact consistent with the literature in which both coniferous and deciduous woody plant species' growth cessation, bud set or dormancy induction are accelerated by temperature. The contradictions are addressed when photoperiod and ecotypes are taken into account in which the combination of either SD/WT (northern and southern ecotypes) or LD/LT (northern ecotypes only) are separated. Photoperiod insensitive types are driven to growth cessation by LT. Also consistent is the importance of night temperature in regulating these warm and cool temperature responses. However, the physiological basis for these temperature effects remain unclear. Changes in water content, binding and mobility are factors known to be associated with dormancy induction in woody plants. These were measured using non-destructive magnetic resonance micro-imaging (MRMI) in specific regions within lateral buds of poplar under SD/WT dormancing inducing conditions. Under SD/WT, dormancy was associated with restrictions in inter- or intracellular water movement between plant cells that reduces water mobility during dormancy development. Northern ecotypes of dogwood may be more tolerant to photoinhibition under the dormancy inducing LD/LT conditions compared to southern ecotypes. In this paper, we propose the existence of two separate, but temporally connected processes that contribute to dormancy development in some deciduous woody plant: one driven by photoperiod and influenced by moderate temperatures; the other driven by abiotic stresses, such as low temperature in combination with long photoperiods. The molecular changes corresponding to these two related but distinct responses to temperature during dormancy development in woody plants remains an investigative challenge.

Structural control of chemoselectivity, stereoselectivity, and substrate specificity in membrane-bound fatty acid acetylenases and desaturases.

The FAD2-like desaturases comprise a group of membrane-bound oxygenases involved in the modification of fatty acyl groups in plants and fungi. This group includes typical oleate desaturases which introduce a Delta12 cis double bond and more unusual enzymes such as Crep1, an acetylenase from the plant Crepis alpina, which introduces a triple bond in linoleate at the Delta12 position. In this study, the structure-function relationship between FAD2-like acetylenases and desaturases was examined through site-directed mutagenesis and heterologous expression. Eleven amino acid positions were identified that show complete evolutionary conservation within acetylenases or desaturases but have different amino acids in the other class of enzyme. Point mutants in Crep1 were constructed and expressed in yeast to test the role in fatty acid modification of the amino acids at the 11 positions. Results indicate the importance of five amino acid positions within Crep1 with regard to desaturase and acetylenase chemoselectivity, stereoselectivity, and substrate recognition. For example, relative to wild-type Crep1, the Y150F, F259L, and H266Q mutations all favored desaturation over acetylenation. The data indicate that small changes in primary sequence, particularly in the vicinity of the active site, can have profound changes on chemoselectivity and other aspects of the function of membrane-bound desaturase-like enzymes.

Mitochondrial and chloroplastic targeting signals of NADP+-dependent isocitrate dehydrogenase.

Many mitochondrial and chloroplast proteins are encoded in the nucleus and subsequently imported into the organelles via active protein transport systems. While usually highly specific, some proteins are dual-targeted to both organelles. In tobacco (Nicotiana tabacum L.), the cDNA encoding the mitochondrial isoform of NADP+-dependent isocitrate dehydrogenase (NADP+-ICDH) contains two translational ATG start sites, suggesting the possibility of tandem targeting signals. In this work, the putative mitochondrial and chloroplastic targeting signals from NADP+-ICDH were fused to a yellow fluorescent protein (YFP) reporter to generate a series of constructs and introduced into tobacco leaves by Agrobacterium-mediated transient transformation. The subsequent sub-cellular locations of the ICDH:YFP fusion proteins were then examined using confocal microscopy. Constructs predicted to be targeted to the chloroplast all localized to the chloroplast. However, this was not the case for all of the constructs that were predicted to be mitochondrial targeted. Although some constructs localized to mitochondria as expected, others appeared to be chloroplast localized. This was attributed to an additional 50 amino acid residues of the mature NADP+-ICDH protein that were present in those constructs, generated from either 'Xanthi' or 'Petit Havana' cultivars of tobacco. The results of this study raise interesting questions regarding the targeting and processing of organellar isoforms of NADP+-ICDH.

Teaching dental pain with and without underlying oral physiology: learning implications.

This study investigated whether teaching undergraduate dental students the diagnosis and management of acute dental pain alongside the underpinning oral physiology helped them to understand the topic better than teaching them acute dental pain as a separate entity. Each of three clinical years of dental students at the same dental school was taught in two groups. Each group was taught the signs/symptoms of five acute dental pain conditions by the same member of the staff. However, the teaching for one group of students in each year reminded the students about the physiology that underpinned the clinical symptoms. One week later, the students completed an open-ended questionnaire that required them to list signs/symptoms of the five dental pain conditions. For each year of dental students that was examined, the mean student marks were significantly higher (p<0.05) for those who were taught dental pain and the underlying physiology compared with students who were only taught dental pain as a stand-alone subject. This suggests that integrating biomedical science and clinical teaching is beneficial.

Phenolic compounds contribute to dark bran pigmentation in hard white wheat.

Unacceptably dark bran color has prevented the white-kernelled variety Argent from meeting grain color marketing standards for hard white wheats (Triticum aestivum L.). The objective of this research was to identify phenolic compounds that negatively affect bran color in white wheat using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and vanillin-HCl and NaOH staining methods. In mature bran, FT-ICR-MS detected derivatives of the flavonol quercetin in varieties Argent and RL4137 (red-kernelled wheat) but not in W98616, a white wheat variety with acceptable grain color. Derivatives of the isoflavone formononetin were more abundant in W98616 relative to RL4137 and Argent. Vanillin-HCl staining indicated that RL4137 sequestered high levels of proanthocyanidin (PA) throughout its entire seed coat, whereas white wheats sequestered PAs as discrete speckles. Argent possessed abundant speckles over its entire seed coat, whereas speckles were almost undetectable in W98616. In mature kernels, flavonoids throughout the seed coat of RL4137 reacted with NaOH, but only the speckles appeared to react in white wheats. W98616 consistently had lighter grain than Argent before and after NaOH treatment. Free and bound phenolic differences in bran samples confirmed that the darker seed coat color of Argent, relative to W98616, was likely due to higher total phenolic acid content. Although isoflavones accumulated in Argent and RL4137, it appears that the majority of the flux through the flavonoid pathway ultimately accumulates quercetin derivatives and PAs. In W98616, PAs accumulate, but it appears that flavonoid biosynthesis ultimately accumulates isoflavones. Argent, compared to W98616, generally accumulated higher levels of total phenolics (flavonols, stilbenes, and PAs) within its darker pigmented bran.

Thellungiella: an Arabidopsis-related model plant adapted to cold temperatures.

Thellungiella salsuginea, a wild crucifer that grows in subarctic Canada and is closely related to Arabidopsis thaliana, was examined for its suitability as a model plant for studies of tolerance to cold and freezing temperatures. Thellungiella completed its life cycle at 5 degrees C, demonstrating that temperature-sensitive processes such as seed germination and the production of pollen and seeds were resistant to cold temperatures. Moreover, the plant exhibited dramatically different vegetative and flowering phenotypes in response to growth at cold temperature and shifts to cold temperature. Northern analyses showed that genes induced by cold in Arabidopsis, including CBF1, the transcriptional activator for the cold-regulated (COR) genes COR15a and COR47, were also expressed in Thellungiella. Freezing tolerance, assayed by the regrowth of intact plants, increased from -13.0 to -18.5 degrees C after cold treatment. The plants lacked endogenous ice nucleation or anti-freeze activity, indicating a potential for supercooling. As a close relative to Arabidopsis, Thellungiella exhibits extreme cold tolerance and should be an important model system in the elucidation of stress tolerance mechanisms.