Improving the spatial orientation of human teeth using a virtual 3D approach

Since teeth are resistant to decomposition processes, they provide important and at times unique sources of information about fossil humans. Fortunately, dental remains reflect significant evolutionary changes. These changes make a very important and often exclusive contribution to the definition of new taxa or the attribution of fossil specimens to existing taxa.The traditional approach to dental morphometric analyses usually focuses on the recording of several measures of the tooth with calipers, especially the two basic crown diameters (buccolingual and mesiodistal). However, since these measures do not adequately represent the complex morphology of the tooth, 2D images and 3D digital models of dental morphology have been used. For both types of analysis, the possibility of correctly comparing homologous teeth depends on the adoption of a common orientation system. The lack of such a system makes it difficult to compare the results of different studies.Here we describe a new method for orienting teeth specifically devised for the upper and lower first molar (M1). Samples of unworn maxillary (n = 15) and mandibular (n = 15) first molars of modern humans were scanned with a Roland Picza 3D digitizer. The 3D virtual models were used to compare our new orientation method with those proposed in the literature. The new orientation system, which meets a geometric criterion, is based on three points identified on the cervical line and ensures acceptable repeatability of the spatial positioning and orientation independent of the shape and wear of the first molar under investigation. This orientation system is a first step toward the creation of a virtual set of hominid and fossil human first molars, which will allow us to make comparisons via a sophisticated and noninvasive approach. This pilot study also provides guidelines to extend the new methodology to the other types of teeth.     

Chitosan antitranspirant activity is due to abscisic acid-dependent stomatal closure

Chitosan (CHT) is a natural compound able to activate the plant own defence machinery against pathogen attacks and to reduce both transpiration and stomatal opening when applied as foliar spray. The data here reported show that CHT-induced antitranspirant activity in bean plants is mediated by ABA, whose level raised over threefold in treated leaves, 24 h after foliar spraying. This is thought to induce partial stomatal closure via a H₂O₂-mediated process, as confirmed by scanning electron microscopy (SEM) and histo-cytochemistry, and, in turn, a decrease of stomatal conductance to water vapor (G_w) and transpiration rate (E), assessed by gas exchange measurements. The relatively high internal CO₂ concentration (C_i) values, suggest the occurrence of a slight decrease in carboxylation efficiency after CHT treatment, which however did not prevail over stomatal limitations. The intrinsic water use efficiency (WUE_i) of CHT treated plants was not statistically different from controls and the maximal photochemical efficiency (F_v/F_m) of PSII was not affected. Moreover, CHT determined a stimulation of the xanthophyll cycle towards de-epoxidation state. On the whole, these results, besides confirming the effectiveness of CHT in reducing plant transpiration, prove that the mechanism underlying this activity differs from that showed by the commercial antitranspirant Vapor Gard^® (VP). In fact, the efficacy of the latter is based on the formation of a thin antitranspirant film over the leaf and not on the reduction of stomatal opening. Finally, suggestions for possible use of the two antitranspirants in different environmental conditions are discussed.     

The surface-exposed chaperone, Hsp60, is an agonist of the microglial TREM2 receptor

Triggering receptor expressed in myeloid (TREM) cells 2, a receptor expressed by myeloid cells, osteoclasts and microglia, is known to play a protective role in bones and brain. Mutations of the receptor (or of its coupling protein, DAP12) sustain in fact a genetic disease affecting the two organs, the polycystic lipomembraneous osteodysplasia with sclerosing leukoencephalopathy (PLOSL or Nasu-Hakola disease). So far, specific agonist(s) of TREM2 have not been identified and its (their) transduction mechanisms are largely unknown. Heat shock protein 60 (Hsp60) is a mitochondrial chaperone that can also be harboured at the cell surface. By using constructs including the extracellular domain of TREM2 and the Fc domain of IgGs we have identified Hsp60 as the only TREM2-binding protein exposed at the surface of neuroblastoma N2A cells and astrocytes, and lacking in U373 astrocytoma. Treatment with Hsp60 was found to stimulate the best known TREM2-dependent process, phagocytosis, however, only in the microglial N9 cells rich in the receptor. Upon TREM2 down-regulation, the Hsp60-induced stimulation of N9 phagocytosis was greatly attenuated. Hsp60 is also released by many cell types, segregated within exosomes or shedding vesicles which might then undergo dissolution. However, the affinity of its binding ( K _d = 3.8 μM) might be too low for the soluble chaperone released from the vesicles to the extracellular space to induce a significant activation of TREM2. It might in contrast be appropriate for the binding of TREM2 to Hsp60 exposed at the surface of cells closely interacting with microglia. The ensuing stimulation of phagocytosis could play protective effects on the brain.     

Spontaneous behavioural changes in response to epidemics

We study how spontaneous reduction in the number of contacts could develop, as a defensive response, during an epidemic and affect the course of infection events. A model is proposed which couples an SIR model with selection of behaviours driven by imitation dynamics. Therefore, infection transmission and population behaviour become dynamical variables that influence each other. In particular, time scales of behavioural changes and epidemic transmission can be different. We provide a full qualitative characterization of the solutions when the dynamics of behavioural changes is either much faster or much slower than that of epidemic transmission. The model accounts for multiple outbreaks occurring within the same epidemic episode. Moreover, the model can explain “asymmetric waves”, i.e., infection waves whose rising and decaying phases differ in slope. Finally, we prove that introduction of behavioural dynamics results in the reduction of the final attack rate.     

An individual-based model of hepatitis A transmission

Viral hepatitis A, as other endemic diseases, represents a public health priority worldwide. To study long-time scale human pathogens through individual-based simulations, the development of a dynamic network of contacts is required. In this work, we introduce an individual-based model accounting for the birth and death of the individuals, the generation of new households, and the educational career of the individuals, in order to investigate viral hepatitis A dynamics in the most affected Italian areas. Intervention options such as targeted vaccination, social distancing measures (e.g., closure of day care centers and kindergartens) and improvements in standards of living and hygiene are evaluated. Results show that a very low vaccination coverage is sufficient to control hepatitis A in Italy, while its elimination is not possible since new cases are continuously imported from high endemicity areas outside the country. Finally, the considered social distancing measures can be counterproductive since the fraction of recovered individuals does not decline while the age at infection increases, thus augmenting the probability of developing acute symptoms.     

<Emphasis Type="Italic">Apis mellifera</Emphasis> and <Emphasis Type="Italic">Osmia cornuta</Emphasis> as carriers for the secondary spread of <Emphasis Type="Italic">Bacillus subtilis</Emphasis> on apple flowers

The efficiency of two pollinators, Apis mellifera L. (Hymenoptera: Apidae) and the mason bee Osmia cornuta (Latreille) (Hymenoptera: Megachilidae), as carriers of biocontrol agents (BCA) from flower to flower (secondary colonisation) was investigated on apple cv ‘Golden Delicious’. The BCA tested was Bacillus subtilis, strain BD170 (Biopro®) developed for the control of the ‘fire blight’ caused by Erwinia amylovora (Burril) Winslow et al. The two insect species were studied as secondary BCA carriers on apple plants in pots under net screened tunnels. Their behaviour and capacity to deposit the BCA in the most receptive flower parts were compared both by washing, diluting and plating the flower organs on a recovery medium and by means of PCR analyses based on a molecular marker. O. cornuta showed better performances with respect to A. mellifera. For the field trials, pollinators were introduced in four apple orchards. During apple’s flowering, the BD170 (100 g hl^?l) was sprayed once in two fields, and twice in the others. The pollinators’ efficacy in carrying the BCA from sprayed flowers to the stigmas of newly opened ones at different times after the spray treatment was evaluated. The detection of the BCA was performed by PCR analysis. The percentages of positive PCR flower samples were higher in the internal treated areas of the fields with respect to the external untreated ones, but the high colonisation level found in the latter and in the flowers opened in both areas several days after the treatment(s) demonstrated that pollinators can play an important role as secondary carriers.