High-density Exposure Research Articles

Density-mediated foraging behavioral responses of Rhyzopertha dominica (Coleoptera: Bostrichidae) and Tribolium castaneum (Coleoptera: Tenebrionidae)

Tribolium castaneum and Rhyzopertha dominica are cosmopolitan, destructive postharvest pests. Although research has investigated how high densities of T. castaneum affect attraction to the aggregation pheromone by conspecifics, research into the behavioral response of both species to food cues after high density exposure has been lacking despite its importance to foraging ecology. Our goal was to manipulate and observe the effects of crowding on the behavioral response of both species to common food and pheromonal stimuli and to determine how the headspace emission patterns from grain differed under increasing densities. Densities of colonies for both species was altered (10–500 adults) on a fixed quantity of food (10 g of flour or whole wheat), then the behavioral response to common food and pheromonal cues was evaluated in a wind tunnel and release-recapture experiment, while volatiles were examined through gas chromatography coupled with mass spectrometry. Importantly, at least for T. castaneum, crowded conditions attenuate attraction to food-based stimuli, but not pheromonal stimuli. Crowding seemed to have no effect on R. dominica attraction to food and pheromonal stimuli in the wind tunnel, but exposure to high density cues did elicit 2.1–3.8-fold higher captures in traps. The relative composition and abundance of headspace volatiles emitted varied significantly with different densities of beetles and was also species-specific. Overall, our results have implications for expanding our understanding of the foraging ecology of two economically important pests.

Tumor-derived exosomes influence the cell cycle and cell migration of human esophageal cancer cell lines.

Our laboratory previously reported the usefulness as biomarkers of exosomes in the plasma of esophageal squamous cell carcinoma (ESCC) patients. However, the influence of tumor‐derived exosomes on the tumor itself and underlying mechanisms remain unclear. We here report changes in the phenotype and gene expression when cancer cells exist in an environment with tumor‐derived exosomes. The exosomes were isolated from the culture medium of human ESCC cells (TE2, T.Tn) by ultracentrifugation; cell proliferation assay, wound‐healing assay, and fluorescence imaging of the cell cycle were performed to clarify the phenotypic changes in the high concentration of tumor‐derived exosomes. Gene expression changes were also assessed by mRNA microarray, and the data were analyzed by gene set enrichment analysis (GSEA). The data revealed that the proliferation of both TE2 and T.Tn was inhibited, and cell migration ability was upregulated in the exosome exposure group (P < .05). Fluorescence imaging using a fluorescent ubiquitination‐based cell cycle indicator expressing ESCC cells revealed that the ratio of G1‐phase cells was significantly increased in the exosome exposure group (P < .05). Findings of the GSEA clarified that high‐density exposure of cancer‐derived exosomes to their parent cancer cells downregulated the expression of genes related to cell proliferation and cell cycle, and upregulated the expression of genes related to actin filament length and extracellular structure organization. In conclusion, an environment of high‐density tumor‐derived exosomes induces changes in the gene expression and phenotype of tumor cells and may lead to tumor progression or malignant transformation.

An investigation of Fe incorporation on the activity and stability of homogeneous (FexNi1-x)2P solid solutions as electrocatalysts for alkaline hydrogen evolution

Ni2P has been intensively investigated for hydrogen evolution reaction (HER) in recent years since the HER activity of Ni2P (001) is theoretically superior to Pt. Most of these works have focused on acid system as Ni2P is unstable in alkaline media. However, alkaline water splitting is more practical for industry due to the lack of suitable acidic oxygen evolution catalyst. Thus, providing an efficient alkaline HER catalyst by enhancing the stability and activity of Ni2P is needed. Herein, we have grown mesoporous (FexNi1-x)2P nanosheets on Ni foam (NF) as HER catalyst with activities being related to Fe/Ni ratio. FeNiP/NF with Fe/Ni ratio of 5/5 and high-density exposure of (001) surface shows much better stability and HER activity in alkaline than Ni2P. Our experimental results reveal that the homogeneous lattice substitution of Fe modified the electronic structure of Ni2P, enhanced the intrinsic activity and the number of active sites. Density functional theory calculation reveals that the Fe incorporation improves the HER activity of the highly exposed FeNiP (001) surface by reducing the energy barriers of HER reactants (H and H2O) adsorption compared with Ni2P. This work provides an effective pathway for the future development of HER catalyst in alkaline conditions by introducing hetero-atom into the host lattice.

Effects of a mixture of chloromethylisothiazolinone and methylisothiazolinone on peripheral airway dysfunction in children.

BackgroundChildren who were only exposed to a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) as humidifier disinfectant (HD) components were evaluated for humidifier disinfectant-associated lung injury (HDLI) from 2012. This study was to evaluate the pulmonary function using, impulse oscillometry (IOS) for children exposed to a mixture of CMIT/MIT from HD.MethodsTwenty-four children who were only exposed to a mixture of CMIT/MIT, with no previous underlying disease, were assessed by IOS. Diagnostic criteria for HDLI were categorized as definite, probable, possible, or unlikely. Home visits and administration of a standardized questionnaire were arranged to assess exposure characteristics.ResultsDefinite and probable cases showed higher airborne disinfectant exposure intensity during sleep (32.4 ± 8.7 μg/m3) and younger age at initial exposure (3.5 ± 3.3 months) compared with unlikely cases (17.3 ± 11.0 μg/m3, p = 0.026; 22.5 ± 26.2 months, p = 0.039, respectively). Reactance at 5 Hz was significantly more negative in those with high-density exposure during sleep (mean, -0.463 kPa/L/s vs. low density, -0.296, p = 0.001). The reactance area was also higher with high-density exposure during sleep (mean, 3.240 kPa/L vs. low density, 1.922, p = 0.039). The mean bronchodilator response with high-density exposure was within the normal range for reactance.ConclusionsSignificant peripheral airway dysfunction were found in children with high levels of inhalation exposure to a mixture of CMIT/MIT during sleep. Strict regulation of a mixture of CMIT/MIT exposure were associated with positive effects on lung function of children.

Cognitive mediation of clinical improvement after intensive exposure therapy of agoraphobia and social phobia

The present study investigated cognitive mediation of clinical improvement in patients with agoraphobia (N=427) or social phobia (N=98) receiving high-density exposure therapy in a naturalistic clinical treatment setting. Patients were assessed before therapy, 6 weeks after the end of therapy, and 1 year thereafter, using a self-report assessment battery. Lower level mediation analyses provided support for the notion that cognitive changes partially mediate clinical improvement after exposure therapy. Changes in cognitions relating to physical catastrophes mediated treatment outcome only for patients with agoraphobia, whereas changes in cognitions about loss of control mediated outcome for both agoraphobia and social phobia patients. Changes in relationship satisfaction did not mediate symptomatic improvement. The results extend previous findings by demonstrating mediation in an unselected clinical sample and by providing evidence for the specificity of mediation effects. They further support the importance of cognitive changes in cognitive-behavior therapy.

Selective Creation of Thermal Injury Zones in the Superficial Musculoaponeurotic System Using Intense Ultrasound Therapy

To transcutaneously deliver intense ultrasound (IUS) energy to target the facial superficial musculoaponeurotic system (SMAS), to produce discrete thermal injury zones (TIZs) in the SMAS, and to demonstrate the relative sparing of adjacent nontargeted layers superficial and deep to the SMAS layer. In 6 unfixed human cadaveric specimens, the SMAS layer was visualized and targeted using the ultrasound imaging component of the IUS device. Using 2 IUS handpieces, 202 exposure lines were delivered bilaterally in multiple facial regions by varying combinations of power and exposure time (0.5-8.0 J). Tissue was then excised and examined grossly and histologically for evidence of thermal injury using nitroblue tetrazolium chloride viability stain. Reproducible TIZs were produced selectively in the SMAS at depths of up to 7.8 mm, and sparing of surrounding tissue including the epidermis. Higher energy settings and high-density exposure line pattern produced a greater degree of tissue shrinkage. In human cadaveric facial tissue, IUS can noninvasively target and selectively produce TIZs of reproducible location, size, and geometry in the SMAS layer. The ability to produce focused thermal collagen denaturation in the SMAS to induce shrinkage and tissue tightening has not been previously reported and has significant implications for aesthetic facial rejuvenation.

Optimization of the purification method for dioxin analysis in human serum and temporal changes in background dioxin levels in the general population

To perform high quality and high throughput measurements, complicated purification procedure by two rounds of open column chromatography was simplified by appraising the components and adding a sufficient amount of adsorbents to the column. The procedure consists of two open column techniques using a multi-layer silica gel column and an active carbon dispersed silica gel column. This purification procedure is used in “Standard manual for dioxin analysis in human blood” published in 2000 (Ministry of Health and Welfare, Japan, 2000). Consequently, a purification procedure using only 1 g of 10% AgNO 3/silica gel can remove the matrix of blood serum as effectively as a multi-layer silica gel column. In addition, 0.1 g of carbon silica gel, equivalent to 1/10 the weight used currently in analyses, separates and recovers the dioxins in purified extract of blood serum. Furthermore, changes in the background level in the general population were clarified by monitoring the dioxin concentrations in human blood. The dioxin concentrations and ratios in blood in the general population remained at a tolerable level for three months. Therefore, the blood serum was available for the detection of a remarkable elevation in dioxins level considered to be indicative of contamination due to high-density exposure.

Short- and long-term effectiveness of an empirically supported treatment for agoraphobia.

This study examined the effectiveness of individual high-density exposure (2-3 weeks, all day) for panic disorder with agoraphobia (PDAG). Participants were 416 unselected patients with a primary diagnosis of PDAG who were treated by 52 therapists in 3 outpatient clinics of the Christoph-Dornier Foundation of Clinical Psychology in Germany. Results 6 weeks after the end of therapy and at the 1-year follow-up showed highly significant reductions in anxiety symptoms, anxious cognition, agoraphobic avoidance, general symptomatology, and depressive symptoms. Results did not differ significantly between the 3 outpatient clinics and are comparable with the average effect sizes reported by meta-analytic studies of controlled efficacy research, using selected patients and specifically trained therapists. Effectiveness was not dependent on duration of disorder, number of treatment sessions, and therapist experience. The study suggests that high-density exposure can be transported from research settings to the mental health field.

High-Density Exposure Therapy for Obsessive-Compulsive Inpatients: A 1-Year Follow-Up1

Background: This study evaluates the effects of individual high-density exposure (2–3 weeks, all day) plus response prevention therapy on 85 unselected inpatients suffering from obsessive-compulsive disorder (OCD). Methods: Twenty-eight therapist practitioners performed treatment. Results: At 1-year follow-up, self-ratings indicated that patients on average felt much improved. Impairment by both obsessions and compulsions was significantly reduced (p < 0.001 in each case), and OCD symptoms as assessed by two OCD questionnaires had also decreased significantly, as had depressiveness and overall symptomatology (all p < 0.001). Defining improvements as >30% successes, as done in other OCD treatment outcome studies, success rates were 68 and 69%, respectively, for the two OCD questionnaire scores, 75% for self-rated impairment by obsessions and 84.5% for compulsions, 85.6% for overall psychopathology (General Symptom Index), and 75% for depressiveness (Beck Depression Inventory). Effect sizes were >1 SD for all of the measures included. Conclusions: We conclude that long-term effects for high-density treatment of unselected OCD patients bring about as good results as treatments with exposure and response prevention performed with selected patient samples in a research context.

A newly designed experimental system for exposure of mammalian cells to extremely low frequency magnetic fields.

To examine the biological effects of extremely low frequency magnetic field (ELFMF), we have designed and manufactured a new equipment for long-term and high-density exposure of cells to ELFMF. The ELFMF exposure system consists of a generator of magnets with a built-in CO2 incubator, an alternating current (AC) power supply, a gas compressor and a thermocontroller for the incubator, and a cooling unit for the magnets. The CO2 incubator made of acrylic resin is inserted into the inner-space of the silicon steel strip-cores. In this system, the temperature of the incubator is maintained at 37 +/- 0.5 degrees C. The maximum magnetic flux density on the exposure area of the incubator is 500 mT (T; tesla) at a current of 556 Arms (rms; root mean square) at 50 Hz. The long-term (up to 120 hr) exposure of 400 mT ELFMF did not affect the growth of both HL60RG and CCRF-CEM cells originated from human leukemia. The post-X-irradiation exposure of 400 mT ELFMF for 2 hr also did not affect the radiation sensitivity of GM0637 and TAT2SF cells originated from a normal human and an ataxia telangiectasia patient.