Differential changes of neuroactive amino acids in samples obtained from discrete rat brain regions after systemic administration of saxitoxin

Aspartic acid, glutamic acid, γ-amino-n-butyric acid (GABA) and 2-aminoethanesulfonic acid are neuroactive amino acids. They are found in the central rat nervous system. Here, we have studied if a relationship exists between the presence of saxitoxin (STX) a paralytic poisoning shellfish (PSP) and the neuroactive amino acids. Samples of striatum (S), hypothalamus (H), mid brain (MB), frontal cortex (FC), brain stem (BS), right hemisphere (RH) and left hemisphere (LH) of rat brain were collected and analyzed for neuroactive amino acids (AAn_t) by Aswad method (1984). Experiments, consisting of intraperitoneal injection of SXT (5 and 10 μg kg^?1 body weight) to young male rats, evoked significant changes in AAn_t above basal values. Aspartic and glutamic acid significantly increased for RH and LH (after 30 min the increased was 116% and 210%, P ≤ 0.001 over basal values, respectively). On the other hand, aspartic, glutamic, taurine and GABA significantly decreased for S (after 30 min the decreased was 77.4%; 84%; 93.8% and 95.3%, P ≤ 0.001 over basal values, respectively). These results suggest that STX alters AAn_t. It is produced at least in part, because STX blocks voltage-gated sodium channels and this blockade could decrease AAn_t release by exocytotic dependent mechanism of depolarization.     

The sexual preference of female rats is influenced by males' adolescent social stress history and social status

Ongoing development of brain systems for social behaviour renders these systems susceptible to the influence of stressors in adolescence. We previously found that adult male rats that underwent social instability stress (SS) in mid-adolescence had decreased sexual performance compared with control males (CTL). Here, we test the hypotheses that SS in adolescence decreases the “attractiveness” of male rats as sexual partners compared with CTL rats and that dominance status is a protective factor against the effects of SS. The main prediction was that females would spend more time with CTL males than SS males, and that this bias would be greater for submissive than for dominant rats. Among dominant pairs (n = 16), females preferred SS males, spending more time with and visiting more often SS than CTL males (each pair tested 5 ×), and SS males had shorter latencies to ejaculation, shorter inter-ejaculation intervals, and made more ejaculations compared with CTL males. Among submissive pairs (n = 16), females spent more time with, visited more often, and displayed more paracopulatory behaviour with CTL than with SS males, and differences in sexual performance between SS and CTL males were modest and in the opposite direction from that in dominant pairs. The heightened motivation of SS males relative to CTL males for natural rewards may have attenuated differences in sexual performance in a paced mating context. In sum, the experience of stress in adolescence leads to long-lasting changes in males that are perceptible to females, are moderated by social status, and influence sexual behaviour.     

Are there magnet plants in Australian ecosystems: Pollinator visits to neighbouring plants are not affected by proximity to mass flowering plants

Aggregations of resource-rich plants can act as “magnets” drawing pollinators from other plants. Magnets can have positive and negative impacts on co-flowering neighbours: enhanced pollination via a ‘spillover-effect’ or a reduction in pollination via competition. Support for the importance of magnets largely comes from studies conducted in the northern hemisphere. We used a comparative approach to test two hypotheses for three pairs of Australian native plants: (1) putative magnets attract a greater number and more diverse suites of pollinators than co-flowering species; and (2) the quantity, diversity and specificity of pollinators varies with distance from putative magnets. We surveyed pollinator activity on co-flowering plants before and after bagging to experimentally exclude pollinators from putative magnets, dominant flowering species with populations ranging in size from 700 to 4000 m². Selected focal species were found to be pollinator magnets, but did not appear to influence the pollination of neighbours. Prior to bagging, putative magnets received more visits but visitors were predominantly (90–100%) exotic honeybees (Apis mellifera). The number and diversity of pollinators on co-flowering species did not consistently increase when magnets were bagged. Moreover, pollinator visitation, diversity and constancy did not vary with distance from putative magnets before or after bagging. All sampled (n = 388) honeybees had pollen of only one plant species on their bodies and no honeybee sampled on a co-flowering species carried pollen of magnet species (n = 212). We found that interactions between pollinators and co-flowering Australian plants differ substantially from those reported for the northern hemisphere; this is most likely due to the impact of abundant, introduced honeybees.     

Rapid torque development in older female fallers and nonfallers: A comparison across lower-extremity muscles

The objective of this study was to compare reaction time, joint torque, rate of torque development, and magnitude of neuromuscular activation of lower-extremity muscles in elderly female fallers and nonfallers. Participants included 11, elderly, female fallers (71.3 ± 5.4 years) and twelve nonfallers (71.3 ± 6.2 years) who completed a fall risk questionnaire. Then, maximal, voluntary, isometric contractions of the knee and ankle muscles were performed in reaction to a visual cue to determine joint torque, rate of torque development, reaction time, and nervous activation of agonists and antagonists. Results indicated that significantly more fallers reported “dizziness upon rising”, “use of balance altering medications”, “stress or depression”, “not enough sleep”, “arthritis in lower body”, “chronic pain in lower body”, and “tiring easily while walking” (all P < 0.05). Normalized dorsiflexion and plantarflexion strength scores (summation of peak torque, rate of torque development and impulse) were lower in fallers than in nonfallers (P < 0.05). When summed across lower-extremity muscle groups, fallers demonstrated 19% lower peak torque and 29% longer motor time (P < 0.05). In conclusion, comprehensive fall risk screening and prevention programs should address both neuromuscular and non-muscular factors, and, weakness of the ankle dorsiflexors and plantarflexors should be further studied as potential contributors to falls in older adults.     

A new data of worker polymorphism in the ant genus Dorylus (Hymenoptera: Formicidae: Dorylinae)

Recently, in southern and central Vietnam, foraging columns of D. orientalis which contained not only “typical” workers but also a few “atypical” workers were collected. The atypical worker mentioned above is characterized by a set of the following features: (1) head narrowed anteriorly, (2) median portion of clypeus strongly projecting anteriad, and (3) antenna 8-segmented. Sequences of the 658-base standard mitochondrial DNA barcoding region were completely identical between typical and atypical workers. Therefore, the condition observed was a case of worker polymorphism within a colony. The mode of polymorphism observed has the following interesting aspects: (1) workers are clearly subdivided into two series by a set of qualitative characters; (2) the “typical series” is numerically much more dominant than the “atypical series” (the latter occupied less than 1% of the whole of the workers collected); (3) a wider size variation was observed in the former (HW, 0.48–1.41 mm; ML, 0.42–1.12 mm) than in the latter (HW, 0.44–1.13 mm; ML, 0.35–0.79 mm); and (4) within the atypical series, smaller workers are numerically much dominant. Rareness of the workers belonging to the atypical series in foraging column as well as morphological differences between the two series suggests a certain possibility that the atypical series does not adapt to foraging but to other tasks in the colony's life history.     

Corrective sitting strategies: An examination of muscle activity and spine loading

The purpose of this study was to quantify the load on the lumbar spine of subjects when they are asked to adjust from a slouched sitting posture into an upright posture with one of three different strategies: “free” (no instruction) and two coached patterns: “lumbopelvic” dominant and “thoracic” dominant. The activity of selected muscles and kinematic data was recorded from 20 volunteers while performing the three movement patterns to adjust sitting posture. Moments and forces at the lumbar spine were computed from an anatomically detailed model that uses kinematics and muscle activation as input variables.The lumbopelvic pattern produces less joint moment on the lumbar spine (on average 31.2 ± 3.9 N m) when compared to the thoracic pattern (43.8 ± 5.8 N m). However, the joint compression force was similar for these two patterns, but it was smaller in the free pattern, when no coaching was given (lumbopelvic: 1279 ± 112 N, thoracic: 1367 ± (125 N, free: 1181 ± 118 N). Lower thoracic erector muscle activity and higher lumbar erector activity were measured in the lumbopelvic pattern in comparison with the other two. In summary the lumbopelvic pattern strategy using predominantly the movement of anterior pelvic tilt results in smaller joint moments on the lumbar spine and also positions the lumbar spine closest to the neutral posture minimizing passive tissue stress. This may be the strategy of choice for people with low back flexion intolerance.     

The influence of rapid urbanization and land use changes on terrestrial carbon sources/sinks in Guangzhou,China

Complex changes in carbon sources and sinks caused by rapid urbanization have been observed with extensive changes in the quantity, structure, and spatial pattern of land use types. Based on the modified Carnegie-Ames-Stanford Approach model and on gray relational analysis, we analyzed the influence of land use changes on carbon sinks and emissions in Guangzhou from 2000 to 2012. The aim was to identify suitable options for built-up land expansion that would allow for minimal carbon losses. The key results were as follows: (1) Built-up land increased by 118.91% in Guangzhou city over the study period, with this expansion taking the form of concentric circles extending around the old Yuexiu district. (2) Carbon emissions over the period of analysis significantly exceeded carbon sink capabilities. The total carbon sink decreased by 30.02%, from 535.40 × 10³ t to 374.6 × 10³ t. Total carbon emissions increased by 1.89 times, from 13.73 × 10⁶ t to 39.67 × 10⁶ t; 80% of carbon emissions were derived from energy consumption. (3) There were large differences in the extent of carbon sink losses at different scales of built-up land expansion and land use change. In Guangzhou, the loss of carbon sink is small when cultivated land (though not prime farmland) and water bodies are converted to built-up land on a small scale. The loss of carbon sink is much smaller when grasslands are converted to built-up land on a large scale. However, forested land, which has excellent carbon sink functions, should not be converted. (4) Changes in carbon sinks were mainly affected by natural factors and land urbanization. Changes in carbon emissions were mainly affected by population urbanization, economic urbanization, and land urbanization. (5) To achieve “economical and intensive use of land”, “urban growth boundary” and “ecological red lines” should be determined for government policies on land use management. These factors have great significance for “increasing carbon sinks and reducing carbon emissions” in urban ecological systems.     

Results of the implementation of the System for the Integrated Assessment of Protected Areas (SIAPA) to the protected areas of the Autonomous Region of Madrid (Spain)

The long-term conservation of biodiversity and related ecosystems goods and services of the Autonomous Region of Madrid is jeopardized by the intensive resource-consuming development model followed by the region in the past few decades. This paper presents the aggregated results of the first integrated assessment of the protected areas of the Autonomous Region of Madrid (Spain) with the System for the Integrated Assessment of Protected Areas (SIAPA). Detailed results are also provided for individual protected areas as supplementary data. The assessment was done during 2009–2010, on ten protected areas differing in their sizes (from 2.5 to 52,796 ha), protection categories (seven categories) and types of ecosystems present. Comparison of results from both assessment models of the SIAPA (the Complete Model and the Simplified Model) is also presented. The results from the Complete Model show that eight out of the ten protected areas of the Autonomous Region of Madrid are currently ineffective. The poorest partial indexes overall were: “State of Conservation” and “Social and Economic Context”. The only indexes significantly correlated with the effectiveness of a protected area were: the “State of Conservation” (r = 0.851**) and the “Social Perception and Valuation” (r = 0.786**). Although not as relevant as was thought, “Management” and the other non-significant factors are likely to influence the effectiveness of protected areas as well. The results for the Simplified Model are slightly better than those for the Complete Model, although this is probably a specific result of this assessment. The two models of the SIAPA were very significantly correlated, although their aggregated results should not be compared directly.     

Mrp-8 and -14 mediate CNS injury in focal cerebral ischemia

Several reports have recently demonstrated a detrimental role of Toll-like receptors (TLR) in cerebral ischemia, while there is little information about the endogenous ligands which activate TLR-signaling. The myeloid related proteins-8 and-14 (Mrp8/S100A8; Mrp14/S100A9) have recently been characterized as endogenous TLR4-agonists, and thus may mediate TLR-activation in cerebral ischemia. Interestingly, not only TLR-mRNAs, but also Mrp8 and Mrp14 mRNA were found to be induced in mouse brain between 3 and 48 h after transient 1 h focal cerebral ischemia/reperfusion. Mrp-protein was expressed in the ischemic hemisphere, and co-labeled with CD11b-positive cells. To test the hypothesis that Mrp-signaling contributes to the postischemic brain damage, we subjected Mrp14-deficient mice, which also lack Mrp8 protein expression, to focal cerebral ischemia. Mrp14-deficient mice had significantly smaller lesion volumes when compared to wild-type littermates (130 ± 16 mm³ vs. 105 ± 28 mm³) at 2 days after transient focal cerebral ischemia (1 h), less brain swelling, and a reduced macrophage/microglia cell count in the ischemic hemisphere. We conclude that upregulation and signaling of Mrp-8 and-14 contribute to neuroinflammation and the progression of ischemic damage.     

Biological treatment of n-hexane and methanol in trickle bed air biofilters under acidic conditions

This study focuses on evaluating the degradation of n-hexane/methanol mixture in trickle-bed-air-biofilters (TBABs). Two different concentration ratios of methanol:n-hexane were evaluated (3:1) for TBAB “A” and (5:1) for TBAB “B”. Both TBABs were run and fed with nutrients buffered at pH 4 for encouraging the growth of fungi. The TBABs were loaded with pelletized diatomaceous earth support media and were run at an empty bed residence time of 120 s. n-Hexane loading rates (LRs) ranged from 0.9 to 13.2 g/m³ h for both TBABs. The corresponding methanol LRs varied from 2.3 to 37.7 g/m³ h and from 4.6 to 64.5 g/m³ h for TBABs “A” and “B”, respectively. Experimental results have shown that the degradation of n-hexane in presence of methanol is enhanced for n-hexane LRs less than 10.6 g/m³ h as compared to previous study for sole-fed n-hexane, but for n-hexane LRs of 13.2 g/m³ h, the performance of TBABs in eliminating n-hexane depended on the methanol to n-hexane ratios. The impact was less severe for TBAB “A” (RE 85%) as compared to TBAB “B” (RE 72%). This is attributed to the high LRs of methanol in TBAB “B”. n-Hexane performance stability was another advantage attained.     

In vivo skin dose measurement using MOSkin detectors in tangential breast radiotherapy

The purpose of this study is to measure patient skin dose in tangential breast radiotherapy. Treatment planning dose calculation algorithm such as Pencil Beam Convolution (PBC) and in vivo dosimetry techniques such as radiochromic film can be used to accurately monitor radiation doses at tissue depths, but they are inaccurate for skin dose measurement. A MOSFET-based (MOSkin) detector was used to measure skin dose in this study. Tangential breast radiotherapies (“bolus” and “no bolus”) were simulated on an anthropomorphic phantom and the skin doses were measured. Skin doses were also measured in 13 patients undergoing each of the techniques. In the patient study, the EBT2 measurements and PBC calculation tended to over-estimate the skin dose compared with the MOSkin detector (p < 0.05) in the “no bolus radiotherapy”. No significant differences were observed in the “bolus radiotherapy” (p > 0.05). The results from patients were similar to that of the phantom study. This shows that the EBT2 measurement and PBC calculation, while able to predict accurate doses at tissue depths, are inaccurate in predicting doses at build-up regions. The clinical application of the MOSkin detectors showed that the average total skin doses received by patients were 1662 ± 129 cGy (medial) and 1893 ± 199 cGy (lateral) during “no bolus radiotherapy”. The average total skin doses were 4030 ± 72 cGy (medial) and 4004 ± 91 cGy (lateral) for “bolus radiotherapy”. In some cases, patient skin doses were shown to exceed the dose toxicity level for skin erythema. Hence, a suitable device for in vivo dosimetry is necessary to accurately determine skin dose.     

The effect of inspiratory and expiratory loads on abdominal muscle activity during breathing in subjects “at risk” for the development of chronic obstructive pulmonary disease and healthy

The abdominal muscle activity has been shown to be variable in subjects with chronic obstructive pulmonary disease (COPD) when respiratory demand increases and their recruitment pattern may change the mechanics, as well as the work and cost of breathing. The scientific evidence in subjects “at risk” for the development of COPD may be important to understand the natural history of this disease. This study aims to evaluate the effect of inspiratory and expiratory loads on the abdominal muscle activity during breathing in subjects “at risk” for the development of COPD and healthy. Thirty-one volunteers, divided in “At Risk” for COPD (n = 17; 47.71 ± 5.11 years) and Healthy (n = 14; 48.21 ± 6.87 years) groups, breathed at the same rhythm without load and with 10% of the maximal inspiratory or expiratory pressures, in standing. Surface electromyography was performed to assess the activation intensity of rectus abdominis (RA), external oblique and transversus abdominis/internal oblique (TrA/IO) muscles, during inspiration and expiration. During inspiration, in “At Risk” for COPD group, RA muscle activation was higher with loaded expiration (p = 0.016); however, in Healthy group it was observed a higher activation of external oblique and TrA/IO muscles (p < 0.050). During expiration, while in “At Risk” for COPD group, RA muscle activation was higher with loaded inspiration (p = 0.009), in Healthy group TrA/IO muscle showed a higher activation (p = 0.025). Subjects “at risk” for the development of COPD seemed to have a specific recruitment of the superficial layer of ventrolateral abdominal wall for the mechanics of breathing.     

Estimating the contribution of N-sulfocarbamoyl paralytic shellfish toxin analogs GTX6 and C3 + 4 to the toxicity of mussels (Mytilus galloprovincialis) over a bloom of Gymnodinium catenatum

Gymnodinium catenatum, a dinoflagellate species with a global distribution, is known to produce paralytic shellfish poisoning (PSP) toxins. The profile of toxins of G. catenatum is commonly dominated by sulfocarbamoyl analogs including the C3 + 4 and GTX6, which to date has no commercial certified reference materials necessary for their quantification via chemical methods, such as liquid chromatography. The aim of this study was to assess the presence of C3 + 4 and GTX6 and their contribution to shellfish toxicity. C3 + 4 and GTX6 were indirectly quantified via pre-column oxidation liquid chromatography with fluorescence detection after hydrolysis conversion into their carbamate analogs. Analyses were carried out in mussel samples collected over a bloom of G. catenatum (>63 × 10³ cells l⁻¹) in Aveiro lagoon, NW Portuguese coast. Concentration levels of sulfocarbamoyl toxin analogs were two orders of magnitude higher than decarbamoyl toxins, which were in turn one order of magnitude higher than carbamoyl toxins. Among the sulfocarbamoyl toxins, C1 + 2 were clearly the dominant compounds, followed by C3 + 4 and GTX6. The least abundant sulfocarbamoyl toxin was GTX5. The most important compounds in terms of contribution for sample toxicity were C1 + 2, which justified 26% of the PSP toxicity. The lesser abundant dcSTX constitutes the second most important compound with similar % of toxicity to C1 + 2, C3 + 4 and GTX6 were responsible for approximately 11% and 13%, respectively. The median of the sum of C3 + 4 and GTX6 was 27%. These levels reached a maximum of 60% as was determined for the sample collected closest to the G. catenatum bloom. This study highlights the importance of these low potency PSP toxin analogs to shellfish toxicity. Hydrolysis conversion of C3 + 4 and GTX6 is recommended for determination of PSP toxicity when LC detection methods are used for PSP testing in samples exposed to G. catenatum.     

Differential diagnosis between progression and radionecrosis in brain metastases after stereotactic radiosurgery using hybrid FDG-PET and MRI coregistered images

IntroductionDual phase 18 FDG brain PET is helpful to assess brain metastases (BM) as tracer will build up in metastases or tumor recurrences while its retention remains stable within normal tissue or inflammatory processes. This is useful when MRI can’t discriminate brain tumor recurrence (TR) rom radionecrosis (RN) after stereotaxic radiosurgery (SRS) for BM. Many studies have sought to improve diagnostic performance by associating FDG-PET and MRI with interesting results but many biases, mostly within image post-processing. Coregistered MRI and dual phase FDG-PET images could alleviate these biases and be used to extract prognostic biomarkers.Materials and methodsWe retrospectively evaluated patients treated with SRS for BM which developed a contrast-enhanced MRI lesion with non-conclusive diagnosis for TR or RN. All patients underwent MRI and FDG-PET at least 3 months after their last SRS session. Dual FDG-PET consisted in an “early” and “delayed” acquisition, respectively 30 minutes and 4 h after injection. MRI included permeability and perfusion sequences. PET and MRI data were all coregistered on the contrast enhanced T1 MRI images. Semi-automated Volumes of Interest (VOI) of the tumor were drawn on the BM and a reference contralateral white-matter ROI (WM) was drawn for standardization; every metric was calculated inside these ROIs, in particular the tumor SUVmax and its variation in time. A 20% increase in the tumor SUVmax was in favor of TR while a modification of less than 100% was in favor of RN. Imaging metrics were then evaluated for their association with TR or RN based on histological, radiological and clinical criteria after at least 6 months follow-up.ResultsNine patients were ruled out as TR and 6 as RN. After standardization, there was a significant difference between groups for VP (P = 0.042), Washin (P = 0.035), Peak Enhancement (P = 0.037), standardized delayed SUVmax (P = 0.008) and RI (P = 0.016). Semi-quantitative analysis found respectively for PET and MRI a Sensitivity of 100% and 87.5% and a Specificity of 100% and 85.71%.ConclusionCoregistered PET-MRI images accurately discriminate between TR and RN. With FDG being the most commonly used PET radiotracer, this protocol remains easily transposable and should be encouraged to obtain non-invasive prognostic and clinically relevant biomarkers.     

Ostéomalacie secondaire au cisplatine : un diagnostic difficile

IntroductionCisplatin is an antineoplastic agent which can cause renal magnesium loss.Case reportA 42-year-old female followed for a primary duodenal large B-cell lymphoma treated with 12 cycles of chemotherapy including “CHOP” (cyclophosphamide, adriamycin, vincristine, prednisone) and bleomycin then 3 cures “DHAP” (cisplatin, cytosine-arabinoside, dexamethasone) consulted for bone pain with muscle cramps. Serum calcium and magnesium were low. The radiograph of the pelvis showed an osteolytic lesion in the right sacroiliac joint. The bone scan showed increased uptakes in the left fronto-parietal bone, the right sacroiliac and the mandible. Iliac, sacral and skull biopsies were negative. The parathormone value was 564 ng, l, 25-(OH) vitamin D lower than 7 μg/L and 1, 25-(OH) 2 vitamine D 15 ng/L. Bone densitometry showed osteopenia. The diagnosis was osteomalacia caused by hypomagnesemia secondary to cisplatin.ConclusionCisplatin can cause osteomalacia through hypomagnesemia.     

Constraints in the identification and interpretation of ozone as a significant predictor of effects on the supersensitive indicator Nicotiana tabacum Bel-W3 in biomonitoring studies

Biomonitoring by means of the supersensitive cultivar Nicotiana tabacum Bel-W3 is frequently used to obtain information on ozone effects on plants and estimates of ozone exposure. However, most of biomonitoring surveys do not account for other environmental variables (predictors in a statistical model) and their inherent multicollinearity with ozone. We tested the relative role of different predictors (fixed: time and site; random: ozone, temperature and humidity) on height growth and on the development of visible foliar symptoms of N. tabacum Bel-W3 plants. To do this, we investigated a relatively small area (256 km²), used a random design at every stage of the survey, controlled watering and protected plants from direct solar radiation and wind. QA/QC procedures were adopted at every stage of the investigation. Linear correlation shows that Leaf Injury Index (LII) and height increment (H.I.) positively related to ozone concentration, elevation and temperature, and negatively to relative humidity. All the predictors correlate to each other. However, relationships between response and ozone vary with the site and the monitoring week. The effect of the random factor “ozone” in combination with fixed factors “site” and “time” on the response variables was therefore formally investigated using the ANCOVA model. Besides ozone, the interactions “ozone × site” and “ozone × time” resulted always significant (0.001 < P < 0.05). While the factor “time” emphasize the inherent development of injury and growth through time, the interaction “ozone × site” pointed out the importance of local conditions. When watering, solar radiation, wind and plant characteristics were controlled, the remaining site-specific covariates of interest were temperature (T) and humidity (RH). When T and RH were accounted for by means of partial correlation analysis, no significant relationship was found between ozone and LII. On the other side, O₃ and RH resulted significant for both absolute and relative height increment. In short, LII seemed to be not solely dependent on ozone, T and RH, but showed to integrate their combined effect. On the other side, H.I. seemed to be favoured by high RH and T, and depressed by high ozone. Based on the above results, we recommend caution when handling bioindicator data: if the purpose is to infer ozone concentrations by leaf injury data, results may be affected by a serious bias, as the frequently reported correlations may be partly an artefact due to co-variation between predictors.     

“Edge-on” MOSkin detector for stereotactic beam measurement and verification

Dosimetry in small radiation field is challenging and complicated because of dose volume averaging and beam perturbations in a detector. We evaluated the suitability of the “Edge-on” MOSkin (MOSFET) detector in small radiation field measurement. We also tested the feasibility for dosimetric verification in stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT). “Edge-on” MOSkin detector was calibrated and the reproducibility and linearity were determined. Lateral dose profiles and output factors were measured using the “Edge-on” MOSkin detector, ionization chamber, SRS diode and EBT2 film. Dosimetric verification was carried out on two SRS and five SRT plans. In dose profile measurements, the “Edge-on” MOSkin measurements concurred with EBT2 film measurements. It showed full width at half maximum of the dose profile with average difference of 0.11 mm and penumbral width with difference of ±0.2 mm for all SRS cones as compared to EBT2 film measurement. For output factor measurements, a 1.1% difference was observed between the “Edge-on” MOSkin detector and EBT2 film for 4 mm SRS cone. The “Edge-on” MOSkin detector provided reproducible measurements for dose verification in real-time. The measured doses concurred with the calculated dose for SRS (within 1%) and SRT (within 3%). A set of output correction factors for the “Edge-on” MOSkin detector for small radiation fields were derived from EBT2 film measurement and presented. This study showed that the “Edge-on” MOSkin detector is a suitable tool for dose verification in small radiation field.     

Stress as adaptation? A test of the adaptive boost hypothesis among Batswana men

Many studies have found elevated cortisol linked to negative events (“stress”) and subsequent negative outcomes, such as reduced immunity and stunted growth, leading to the conclusion that high cortisol is “bad.” However, a growing number of studies have found more advantaged groups showing relatively elevated cortisol. For example, higher morning cortisol followed by a steeper diurnal decline among Caucasians compared to ethnic minorities has been interpreted as a context-specific “adaptive boost” to meet daily demands. We tested the adaptive boost hypothesis using data on socioeconomic status, depressive affect and salivary cortisol among adult men (n = 32) in Botswana. Three findings emerged: (i) depressive affect was associated with lower morning cortisol (r = ? 0.43, p = 0.014); (ii) depressive affect was associated with a diurnal increase in cortisol when comparing morning and evening samples (r = 0.49, p = 0.004); and (iii) depressive affect was associated with lower income (r = ? 0.55, p = 0.001). Findings are consistent with the adaptive boost hypothesis and add to a growing body of evidence that elevated cortisol is not universally bad. Hypothalamic–pituitary adrenal axis (HPAA) activity, such as cortisol, may be adaptive depending on a person's contextual circumstances. Based on our findings and those of previous studies, we develop a “person-in-context” model of the threat appraisal process. Integrated with life history theory, our model facilitates testable hypotheses about intra- and inter-individual variability in HPAA and adaptive consequences.     

In vitro penetration of swine oocytes by homologous spermatozoa: Distinct systems for gamete's co-incubation and oocyte's cryopreservation

In vitro penetration (IVP) of swine oocytes by homologous spermatozoa was evaluated in two experiments using four boars as semen donors. In experiment 1, the IVP rate and the number of penetrating spermatozoa (PSP) were compared using three co-incubation systems for vitrified oocytes and fresh sperm: (1) 35 mL petri dishes in a CO₂ incubator, (2) 35 mL petri dishes in bags (submarine system) and (3) glass flasks partially submerged in water bath with the same gas mixture used for the bag system. Mean PSP was 8.2 ± 10.1 and the IVP rate was 90.5%. The PSP differed across all systems (P = 0.0006): 15.5 ± 0.5 for flasks, 6.3 ± 0.4 for CO₂, and 3.9 ± 0.4 for bags. The IVP rate for flasks (95.0%) was greater (P = 0.01) than for CO₂ and bags (90.8% and 85.0%, respectively), but it did not differ between flasks and CO₂ for three boars (P > 0.05). In experiment 2, co-incubation was done as described for glass flasks in experiment 1. The IVP rate and PSP were compared for cryopreserved oocytes: either vitrified in open pulled straws (OPS), or frozen in cryotubes. Mean PSP was 5.4 ± 6.5 and IVP rate was 89.6%. Both PSP and IVP rate were greater (P < 0.0001) for oocytes frozen in cryotubes (7.0 ± 0.3% and 95.8%, respectively) than those frozen in OPS (3.7 ± 0.3% and 83.4%, respectively), with no differences found for three boars (P > 0.05). In summary, successful IVP of swine oocytes by homologous spermatozoa can be achieved using gametes incubated in glass flasks and oocytes frozen in cryotubes.     

Capacities of soil water reservoirs and their better regression models by combining “merged groups PCA” in Chongqing,China

Soil water resource, together with the surface and sub-surface water resource, is essential to the regional water balance and world water cycle. A total of 90 soil samples were collected from 30 different soil profiles of dry fields throughout Chongqing, China randomly to show how soil could be a crucial part of water resources by discussing their five types of calculated soil water reservoir capacities, namely the total soil water reservoir capacity (mm) (TC), soil water storage capacity (mm) (SC), unavailable soil water reservoir capacity (mm) (UC), available soil water reservoir capacity (mm) (AC), and soil dead water storage capacity (mm) (DC) in certain layer, respectively. Overall, the total soil water reservoir capacity in 0–40 cm was about 209 mm, of which 70 mm belonged to available soil water reservoir capacity. Not all the five types of soil water reservoir capacities had significant correlations between each other. Soil structure, especially the size and quantity of soil pore was mainly determined by soil particle composition (clay, silt, and sand content). The more sand and less clay led to the more soil macropores, which provided room for soil water. Thus, clay, silt, and sand content jointly produced profound influence on soil water reservoir capacities. Nevertheless, specific water capacity and topographic factors displayed weak correlations to soil water reservoir capacities, which required further research works. Ultimately, the better regression models were achieved by multiple regression analysis coupled with “merged groups PCA” than by multiple regression analysis with “all variables PCA”. UC, SC, TC and DC could be well simulated (mostly R² > 0.70; P < 0.05) through normal multiple regression analysis using original variables as well as multiple regression analysis with “merged groups PCA”. Only regression models of TC and DC were highly significant (mostly R² > 0.70; P < 0.05) through “all variables PCA” method. And there were poor coefficients of determination (R²) for AC (mostly R² < 0.40; P < 0.05) by all the three regression methods.