Brain connectivity dynamics during social interaction reflect social network structure.

Social ties are crucial for humans. Disruption of ties through social exclusion has a marked effect on our thoughts and feelings; however, such effects can be tempered by broader social network resources. Here, we use fMRI data acquired from 80 male adolescents to investigate how social exclusion modulates functional connectivity within and across brain networks involved in social pain and understanding the mental states of others (i.e., mentalizing). Furthermore, using objectively logged friendship network data, we examine how individual variability in brain reactivity to social exclusion relates to the density of participants' friendship networks, an important aspect of social network structure. We find increased connectivity within a set of regions previously identified as a mentalizing system during exclusion relative to inclusion. These results are consistent across the regions of interest as well as a whole-brain analysis. Next, examining how social network characteristics are associated with task-based connectivity dynamics, we find that participants who showed greater changes in connectivity within the mentalizing system when socially excluded by peers had less dense friendship networks. This work provides insight to understand how distributed brain systems respond to social and emotional challenges and how such brain dynamics might vary based on broader social network characteristics.

Influence of footwear designed to boost energy return on running economy in comparison to a conventional running shoe.

Running economy is a reflection of the amount of inspired oxygen required to maintain a given velocity and is considered a determining factor for running performance. Athletic footwear has been advocated as a mechanism by which running economy can be enhanced. New commercially available footwear has been developed in order to increase energy return, although their efficacy has not been investigated. This study aimed to examine the effects of energy return footwear on running economy in relation to conventional running shoes. Twelve male runners completed 6-min steady-state runs in conventional and energy return footwear. Overall, oxygen consumption (VO2), heart rate, respiratory exchange ratio, shoe comfort and rating of perceived exertion were assessed. Moreover, participants subjectively indicated which shoe condition they preferred for running. Differences in shoe comfort and physiological parameters were examined using Wilcoxon signed-rank tests, whilst shoe preferences were tested using a chi-square analysis. The results showed that VO2 and respiratory exchange ratio were significantly lower, and shoe comfort was significantly greater, in the energy return footwear. Given the relationship between running economy and running performance, these observations indicate that the energy return footwear may be associated with enhanced running performance in comparison to conventional shoes.

Rhinoceros beetle (Trypoxylus dichotomus) cuticular hydrocarbons contain information about body size and sex.

Japanese rhinoceros beetle (Trypoxylus dichotomus) males have exaggerated horns that are used to compete for territories. Larger males with larger horns tend to win these competitions, giving them access to females. Agonistic interactions include what appears to be assessment and often end without escalating to physical combat. However, it is unknown what information competitors use to assess each other. In many insect species chemical signals can carry a range of information, including social position, nutritional state, morphology, and sex. Specifically, cuticular hydrocarbons (CHCs), which are waxes excreted on the surface of insect exoskeletons, can communicate a variety of information. Here, we asked whether CHCs in rhinoceros beetles carry information about sex, body size, and condition that could be used by males during assessment behavior. Multivariate analysis of hydrocarbon composition revealed patterns associated with both sex and body size. We suggest that Rhinoceros beetles could be communicating information through CHCs that would explain behavioral decisions.

Evolutionary variation in the mechanics of fiddler crab claws.

BACKGROUND: Fiddler crabs, genus Uca, are classic examples of how intense sexual selection can produce exaggerated male traits. Throughout the genus the enlarged "major" cheliped (claw) of the male fiddler crab is used both as a signal for attracting females and as a weapon for combat with other males. However, the morphology of the major claw is highly variable across the approximately 100 species within the genus. Here we address variation, scaling, and correlated evolution in the mechanics of the major claw by analyzing the morphology and mechanical properties of the claws of 21 species of fiddler crabs from the Pacific, Gulf and Atlantic coasts of the Americas. RESULTS: We find that the mechanics that produce claw closing forces, the sizes of claws and the mechanical strength of the cuticle of claws are all highly variable across the genus. Most variables scale isometrically with body size across species but claw force production scales allometrically with body size. Using phylogenetically independent contrasts, we find that the force that a claw can potentially produce is positively correlated with the strength of the cuticle on the claw where forces are delivered in a fight. There is also a negative correlation between the force that a claw can potentially produce and the size of the claw corrected for the mass of the claw. CONCLUSIONS: These relationships suggest that there has been correlated evolution between force production and armoring, and that there is a tradeoff between claw mechanics for signaling and claw mechanics for fighting.

Evolution of horn length and lifting strength in the Japanese rhinoceros beetle Trypoxylus dichotomus.

What limits the size of nature's most extreme structures? For weapons like beetle horns, one possibility is a tradeoff associated with mechanical levers: as the output arm of the lever system-the beetle horn-gets longer, it also gets weaker. This "paradox of the weakening combatant" could offset reproductive advantages of additional increases in weapon size. However, in contemporary populations of most heavily weaponed species, males with the longest weapons also tend to be the strongest, presumably because selection drove the evolution of compensatory changes to these lever systems that ameliorated the force reductions of increased weapon size. Therefore, we test for biomechanical limits by reconstructing the stages of weapon evolution, exploring whether initial increases in weapon length first led to reductions in weapon force generation that were later ameliorated through the evolution of mechanisms of mechanical compensation. We describe phylogeographic relationships among populations of a rhinoceros beetle and show that the "pitchfork" shaped head horn likely increased in length independently in the northern and southern radiations of beetles. Both increases in horn length were associated with dramatic reductions to horn lifting strength-compelling evidence for the paradox of the weakening combatant-and these initial reductions to horn strength were later ameliorated in some populations through reductions to horn length or through increases in head height (the input arm for the horn lever system). Our results reveal an exciting geographic mosaic of weapon size, weapon force, and mechanical compensation, shedding light on larger questions pertaining to the evolution of extreme structures.

Pneumatosis cystoides intestinalis in scleroderma-related conditions.

AIMS: Pneumatosis cystoides intestinalis (PCI) is a rare life-threatening gastrointestinal complication in the course of connective tissue disease (CTD). PCI is characterised by the appearance of intramural clusters of gas in the small and large bowel wall on X-ray or computed tomography and often is accompanied by free air in the peritoneal cavity. METHODS: We present three cases of PCI in patients with scleroderma-related conditions. A review of the English language literature published on MEDLINE from 1973 to 2008 was conducted using the terms: 'systemic sclerosis', 'connective tissue disease' and 'pneumatosis cystoides intestinalis'. This review focused on clinical features, diagnostic and treatment strategies of PCI in the context of CTD. RESULTS: Symptoms of PCI are non-specific: abdominal pain, vomiting, constipation, bloating and weight loss. Coexistence of PCI with other manifestations of CTD, such as intestinal pseudo-obstruction and/or bacterial overgrowth, complicates the clinical diagnosis. Treatment approach to PCI is mostly conservative: intestinal 'rest', parenteral nutrition, antibiotics, fluids and electrolyte supplementation, and inhaled oxygen. Surgical intervention should be performed only in cases of bowel perforation, ischaemia or necrosis. Patients with PCI have high mortality rates due to PCI itself but also to the severity and variety of basic CTD complications. CONCLUSION: Recognition of PCI, particularly in the context of underlying CTD, is necessary for proper therapeutic application. In patients with underlying CTD and symptoms of abdominal emergency, recruitment of multidisciplinary teams, including rheumatologist, gastroenterologist, imaging specialist and surgeons familiar with intestinal complications of CTD-related conditions, is warranted.

Brain system integration and message consistent health behavior change.

OBJECTIVE: Modifiable behaviors, including physical activity and sedentary behavior, are important determinants of health, and messages are important tools for influencing these behaviors. Functional neuroimaging research suggests that activity in regions of the brain's default mode and salience systems are independently associated with attending to health promoting messages. However, it remains unclear how these brain systems interact during exposure to persuasive messages and how this interaction relates to subsequent behavior change. Here, we examine how between-person differences in the relative integration between default mode and salience systems while viewing health messages relates to changes in health behavior. METHOD: Using wrist-worn accelerometers, we logged physical activity in 150 participants (mean age = 33.17 years, 64% women; 43% Black, 37% white, 7% Asian, 5% Hispanic, and 8% other) continuously for an average of 10 days. Participants then viewed health messages encouraging physical activity while undergoing functional MRI (fMRI) and completed an additional month where physical activity was logged and the health messages were reinforced with daily text reminders. RESULTS: Individuals with higher default mode and salience system integration during health message exposure were more likely to decrease their sedentary behavior and increase light physical activity in the month following fMRI than participants with lower brain integration. CONCLUSIONS: Interactions between the salience and default mode systems are associated with message receptivity and subsequent behavior change, highlighting the value of expanding the focus from the role of single brain regions in studying health behavior change to larger-scale connectivity. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The effect of a Radiology Conference consultation on cancer patients management.

BACKGROUND: The quantitative effect of consultation on cancer patient's management at a Radiology Conference was studied. PATIENTS AND METHODS: This prospective study included consecutive patients presented at the Radiology Conference of the Division of Oncology. Following the case presentation and discussion, the patient's oncologist completed a questionnaire which asked whether the consultation at the conference added new information regarding the patient's disease status, whether it influenced patient management and, if so, to what extent. RESULTS: Three hundred and eighty-three patients were included in the study. Significant new information was added for 189 (49%) patients and less consequential information was added for 134 (35%) patients. Major changes in management occurred in 143 (37%) patients after the Radiology Conference and minor changes were made in 56 (15%) patients. The influence of the cancer type on the rate of significant change in treatment and on the rate of major information addition was not statistically significant. CONCLUSION: Consultation at a Radiological Conference in a tertiary center led to major changes in the management of 37% of the cancer patients presented and provided important information regarding the patient's disease in up to 50% of patients.

Comparison of technical success and safety of transbronchial versus percutaneous CT-guided fiducial placement for SBRT of lung tumors.

OBJECTIVE: To evaluate the technical success and safety of transbronchial (bronchoscopic) fiducial placement compared to percutaneous CT-guided fiducial placement for stereotactic body radiotherapy (SBRT) of lung tumors. MATERIALS AND METHODS: This IRB-approved, HIPAA-compliant retrospective study was performed at a single tertiary institution. Consecutive patients undergoing lung fiducial placement for purposes of guiding SBRT (CyberKnife®, Accuray, Inc.) between September 2005 to January 2013 were included in the study. Fiducial seeds were placed percutaneously with CT guidance or transbronchially with bronchoscopic guidance. We compared procedure-related complications (pneumothorax, chest tube placement), technical success (defined as implantation enabling adequate treatment planning with CT simulation) and migration rate. The need for repeat procedures and their mode was noted. Statistical analysis was performed using Fisher exact and Chi square probability tests. RESULTS: Two hundred and forty-four patients with lung tumors and 272 fiducial seed placements were included in the study. Two hundred and twenty-one of the 272 (81.2%) fiducial markers were placed percutaneously and 51/272 (18.8%) were placed transbronchially. Pneumothorax was seen in 73/221 (33%) of percutaneously-placed fiducials and in 4/51 (7.8%) of transbronchial placements (p<0.001). No significant difference was seen in the rate of chest tube placement between the two groups: 20/221 (9%) of percutaneously placed fiducials and 2/51 (3.9%) of transbronchially placed fiducials (p=0.39). Fifteen of the 51 (29%) of fiducial placements with transbronchial approach were unsuccessful, as discovered at radiotherapy planning session, and required a repeat procedure. Nine of the 15 (60%) of repeat procedures were performed percutaneously, 5/15 (33%) were placed during repeat bronchoscopy, and 1/15 (7%) was placed at transesophageal endoscopic ultrasound. No repeat fiducial placements were required for patients who had the fiducials placed percutaneously (p<0.001), with a technical success rate of 100%. CONCLUSION: Transbronchial fiducial marker placement has a significantly higher rate of failed seed placements requiring repeat procedures in comparison to percutaneous placement. Complication rate of pneumothorax requiring chest drain placement is similar between the two approaches.

Comparison of embiopteran silks reveals tensile and structural similarities across Taxa.

Embioptera is a little studied order of widely distributed, but rarely seen, insects. Members of this group, also called embiids or webspinners, all heavily rely on silken tunnels in which they live and reproduce. However, embiids vary in their substrate preferences and these differences may result in divergent silk mechanical properties. Here, we present diameter measurements, tensile tests, and protein secondary structural analyses of silks spun by several embiid species. Despite their diverse habitats and phylogenetic relationships, these species have remarkably similar silk diameters and ultimate stress values. Yet, ultimate strain, Young's modulus, and toughness vary considerably. To better understand these tensile properties, Fourier transformed infrared spectroscopy was used to quantify secondary structural components. Compared to other arthropod silks, embiid silks are shown to have consistent secondary structures, suggesting that commonality of amino acid sequence motifs and small differences in structural composition can lead to significant changes in tensile properties.

Intestinal intussusception in elderly patients.

Intussusception is the most common cause of bowel obstruction in children, but it is a very rare cause of bowel obstruction in the elderly. Diagnosis is based on a high index of suspicion, complete anamnestic recall, physical examination, and imaging modalities. We find abdominal CT scans to be highly sensitive and accurate for making the diagnosis. Treatment of intussusception in adults is always surgical. Segmental bowel resection must be performed. The extent of resection should include any nonviable bowel as well as the leading point of the intussusception. We present a case of an 82-year-old patient with ileo-cecal intussusception, followed by a discussion of the diagnostic and therapeutic options.

Prospective study of digital radiographs versus conventional screen films in Small Bowel Follow-Through examination.

PURPOSE: To prospectively compare subjective radiological quality, radiation dose and effect on workflow using digital radiography (DR) vs. conventional screen film (SF) radiography in the Small Bowel Follow-Through (SBFT) examination. METHODS: Five attending and four resident radiologists compared hard-copy images from 11 SBFT examinations, for which every patient had a defined pair of SF and DR images taken 20-30 min apart. SF and DR were performed with equivalent exposure data. Overall image quality, intestinal mucosa definition and bone visualization were graded on a 5-point scale, with 5 being the highest value. Thus, 11 patients had three criteria judged by nine observers in two modalities for a total of 594 observations of image quality. The radiation doses and effect on workflow were also compared. Statistical analysis was performed with the Mann-Whitney U test. RESULTS: The mean scores on DR and SF for overall image quality, intestinal mucosa definition and bone visualization were 4.49 vs. 3.17, 4.38 vs. 3.4, and 4.5 vs. 2.4, respectively (p<0.001 in all cases). The average radiation dose with DR was 0.93+/-0.54 cGy, and -1.58+/-0.63 cGy with SF (p=0.016), reflecting a 41% dose reduction. Production of a DR image by technicians took 3.5+/-1.3 min vs. 5.5+/-1.5 min for SF (p=0.002). CONCLUSION: Subjective image quality of hard-copy digital radiographs of the small bowel through examination is superior to images obtained with conventional radiographs, with an associated reduction of 41% in radiation dose and increased efficiency.

Spider dragline silk: correlated and mosaic evolution in high-performance biological materials.

The evolution of biological materials is a critical, yet poorly understood, component in the generation of biodiversity. For example, the diversification of spiders is correlated with evolutionary changes in the way they use silk, and the material properties of these fibers, such as strength, toughness, extensibility, and stiffness, have profound effects on ecological function. Here, we examine the evolution of the material properties of dragline silk across a phylogenetically diverse sample of species in the Araneomorphae (true spiders). The silks we studied are generally stronger than other biological materials and tougher than most biological or man-made fibers, but their material properties are highly variable; for example, strength and toughness vary more than fourfold among the 21 species we investigated. Furthermore, associations between different properties are complex. Some traits, such as strength and extensibility, seem to evolve independently and show no evidence of correlation or trade-off across species, even though trade-offs between these properties are observed within species. Material properties retain different levels of phylogenetic signal, suggesting that traits such as extensibility and toughness may be subject to different types or intensities of selection in several spider lineages. The picture that emerges is complex, with a mosaic pattern of trait evolution producing a diverse set of materials across spider species. These results show that the properties of biological materials are the target of selection, and that these changes can produce evolutionarily and ecologically important diversity.

Misleading positioning of a Foley catheter balloon.

Indwelling catheters in the urinary bladder are associated with numerous and various complications, e.g. infection, haemorrhage, epididymo-orchitis and perforation. Abdominopelvic CT is frequently performed in hospitalized patients, with the bladder being included in the examination. Familiarity with the various bladder pathologies and a routine and meticulous search for them are indicated in every case. Moreover, an awareness of certain pitfalls may prevent over-diagnosis and over-treatment. We present a case in which a Foley catheter balloon inflated in a bladder diverticulum simulates sealed bladder perforation with extraluminal location of the balloon. This potentially misleading diagnosis should be considered in the presence of apparent extraluminal position of catheter tip or balloon not substantiated by the clinical presentation.

Development of the escape response in teleost fishes: do ontogenetic changes enable improved performance?

Teleost fishes typically first encounter the environment as free-swimming embryos or larvae. Larvae are morphologically distinct from adults, and major anatomical structures are unformed. Thus, larvae undergo a series of dramatic morphological changes until they reach adult morphology (but are reproductively immature) and are considered juveniles. Free-swimming embryos and larvae are able to perform a C-start, an effective escape response that is used evade predators. However, escape response performance improves during early development: as young fish grow, they swim faster (length-specific maximum velocity increases) and perform the escape more rapidly (time to complete the behavior decreases). These improvements cease when fish become juveniles, although absolute swimming velocity (m s(-1)) continues to increase. We use studies of escape behavior and ontogeny in California halibut (Paralichthys californicus), rainbow trout (Oncorhynchus mykiss), and razorback suckers (Xyrauchen texanus) to test the hypothesis that specific morphological changes improve escape performance. We suggest that formation of the caudal fin improves energy transfer to the water and therefore increases thrust production and swimming velocity. In addition, changes to the axial skeleton during the larval period produce increased axial stiffness, which in turn allows the production of a more rapid and effective escape response. Because escape performance improves as adult morphology develops, fish that enter the environment in an advanced stage of development (i.e., those with direct development) should have a greater ability to evade predators than do fish that enter the environment at an early stage of development (i.e., those with indirect development).

Filling in the gaps with non-standard body fluids.

OBJECTIVES: Body fluid specimens other than serum, plasma or urine are generally not validated by manufacturers, but analysis of these non-standard fluids can be important for clinical diagnosis and management. Laboratories, therefore, rely on the published literature to better understand the validation and implementation of such tests. This study utilized a data-driven approach to determine the clinical reportable range for 11 analytes, evaluated a total bilirubin assay, and assessed interferences from hemolysis, icterus, and lipemia in non-standard fluids. DESIGN AND METHODS: Historical measurements in non-standard body fluids run on a Beckman Coulter DxC800 were used to optimize population-specific clinical reportable ranges for albumin, amylase, creatinine, glucose, lactate dehydrogenase, lipase, total bilirubin, total cholesterol, total protein, triglyceride and urea nitrogen run on the Beckman Coulter AU680. For these 11 analytes, interference studies were performed by spiking hemolysate, bilirubin, or Intralipid® into abnormal serous fluids. Precision, accuracy, linearity, and stability of total bilirubin in non-standard fluids was evaluated on the Beckman Coulter AU680 analyzer. RESULTS: The historical non-standard fluid results indicated that in order to report a numeric result, 4 assays required no dilution, 5 assays required onboard dilutions and 2 assays required both onboard and manual dilutions. The AU680 total bilirubin assay is suitable for clinical testing of non-standard fluids. Interference studies revealed that of the 11 total AU680 analyte measurements on non-standard fluids, lipemia affected 1, icterus affected 3, and hemolysis affected 5. CONCLUSIONS: Chemistry analytes measured on the AU680 demonstrate acceptable analytical performance for non-standard fluids. Common endogenous interference from lipemia, icterus, and hemolysis (LIH) are observed and flagging rules based on LIH indices were developed to help improve the clinical interpretation of results.

Functional mechanics of beetle mandibles: Honest signaling in a sexually selected system.

Male stag beetles possess colossal mandibles, which they wield in combat to obtain access to females. As with many other sexually selected weapons, males with longer mandibles win more fights. However, variation in the functional morphology of these structures, used in male-male combat, is less well understood. In this study, mandible bite force, gape, structural strength, and potential tradeoffs are examined across a wide size range for one species of stag beetle, Cyclommatus metallifer. We found that not only does male mandible size demonstrate steep positive allometry, but the shape, relative bite force, relative gape, and safety factor of the mandibles also change with male size. Allometry in these functionally important mandibular traits suggests that larger males with larger mandibles should be better fighters, and that the mandibles can be considered an honest signal of male fighting ability. However, negative allometry in mandible structural safety factor, wing size, and flight muscle mass suggest significant costs and a possible limit on the size of the mandibles. J. Exp. Zool. 325A:3-12, 2016. © 2015 Wiley Periodicals, Inc.

Urine sensor device for fluoroscopy time reduction in pediatric voiding cystourethrography.

PURPOSE: We evaluated the feasibility of a using urine sensor for voiding cystourethrography (VCUG) and its implications for fluoroscopy time reduction. MATERIALS AND METHODS: Institutional Review Board approved the study protocol. Study population included children less than 5 years old referred to our institution for VCUG. Patients with known vesicoureteral reflux or any pacing device were excluded from the study. The urine sensor consists of an electrode that senses the fluid, an electrical circuit and an indicator to provide visual signal. The urine sensor electrode was placed on the medial thigh in the proximity of the catheter close to the urethral opening, but without direct contact to it. A standard VCUG examination was performed with retrograde filling of the urinary bladder. Once the bladder was full, fluoroscopy of the voiding stage was initiated when the indicator blinked. Peak kV and fluoroscopy time were recorded. RESULTS: Seven patients underwent VCUG with urine sensor and 22 patients without urine sensor. The urine sensor provided a reliable indication of voiding onset. The fluoroscopy time was significantly shorter with urine sensor use (1.99 min) than without urine sensor use (4.33 min) (p=0.001). In patients with normal VCUG, fluoroscopy time was also significantly shorter with urine sensor use (2.13 min) than without urine sensor use (4.39 min) (p<0.001). CONCLUSION: VCUG studies with the help of the urine sensor are feasible and its use may result in significant reduction in fluoroscopy time.