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In this study, a morphological revision was conducted of Agroecotettix Bruner, a group of grasshoppers inhabiting open xeric desert scrub, shrublands, and plains, spanning central Texas to central Mexico. The genus was originally described by Bruner in 1908, with two taxa added by Hebard in 1922. Agroecotettix has remained unrevised despite numerous collections. This exploration, spurred by a novel discovery of significant male genitalia variation in Agroecotettixaristusaristus , suggests undescribed species. Through morphological specimen comparisons, sixteen new species are described from biologically rich regions of the South Texas Plains, Chihuahuan Desert, and Sierra Madre Oriental. The new taxa described here are A.silverheelsi sp. nov. , A.xiphophorus sp. nov. , A.glochinos sp. nov. , A.texmex sp. nov. , A.cumbres sp. nov. , A.burtoni sp. nov. , A.moorei sp. nov. , A.chiantiensis sp. nov. , A.dorni sp. nov. , A.chisosensis sp. nov. , A.turneri sp. nov. , A.quitmanensis sp. nov. , A.vaquero sp. nov. , A.forcipatus sp. nov. , A.idic sp. nov. , and A.kahloae sp. nov. This discovery sheds light on desert biodiversity and hints at a Pleistocene radiation akin to other melanoplines, urging further exploration to enrich our understanding of this fascinating lineage and unravel the biogeographic history within these arid landscapes., Competing Interests: The author has declared that no competing interests exist., (JoVonn G. Hill.)

Inventories of the flora and insect fauna of the Black Belt Prairie of Mississippi and Alabama have documented disjunct populations of species broadly distributed in the Great Plains, including two grasshopper species. During a recent survey of a large privately-owned prairie remnant in Sumter Co., Alabama, we documented a disjunct population of a third grasshopper species - Hesperotettixspeciosus , extending the known distribution of this species significantly eastwards. The discovery of this population is surprising due to the number of previous survey efforts of the Black Belt, Alabama and Mississippi overall and exemplifies the importance of conservation on private lands., Competing Interests: No conflict of interest to declare Disclaimer: This article is (co-)authored by any of the Editors-in-Chief, Managing Editors or their deputies in this journal., (Shelby Grice, JoVonn G. Hill.)

Objective: The purpose of this project was to develop a formal visual arts training curriculum and evaluate if there was improvement in the observational and descriptive skills of first- and second-year medical students for radiologic images.  Materials and methods: A demographic survey and an initial pre-test of 12 radiologic images were administered asking an open-ended question to describe the image and to identify the abnormality in their own words. Three virtual one-hour sessions of visual thinking strategy (VTS) training occurred, and an immediate post-test and a six-month post-test were administered, each with images different from the pre-test, as well as a final questionnaire. All tests were independently graded by two graders with a previously established grading rubric. Differences in scores were analyzed using paired T-tests., Results: Thirty-nine medical students participated. The mean pre-test score was 62.2 +/- 18.6, and the mean post-test score improved by 41.7 +/- 17.9 points (p<0.01) to an average score of 103.9 +/- 20.4. Nine participants were lost to follow-up at six months, and the average six-month post-test score was 110.2 +/- 29.1 for a mean improvement of 9.3 +/- 13.1 points (p=0.320) from the initial post-test.  Conclusion: There was a significant improvement in observational and descriptive skills in first- and second-year medical students when describing radiologic images, which was retained after six months. A formal VTS curriculum could play a beneficial role in medical student and radiology training programs not only to improve observational skills but also to address perceptual errors in diagnostic imaging., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Medical University of South Carolina (MUSC) Institutional Review Board (IRB) issued approval Pro00086970. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: This study was funded by an internal MUSC Scholars of Humanities and Arts Research and Education (SHARE) Grant. . Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Wulfeck et al.)

New aug-cc-pVnZ-PP-F12 basis sets (n = D, T, Q) for the heavy p-block elements, Ga-Kr, In-Xe, and Tl-Rn, have been developed by augmenting the cc-pVnZ-PP-F12 sets with additional higher angular momentum diffuse functions. These basis sets have been optimized for use in explicitly correlated F12 calculations, and matching auxiliary basis sets for density fitting of conventional and F12 integrals have also been developed. The new sets have been validated with benchmark CCSD(T)-F12b calculations of electron affinities, where an accelerated convergence to the complete basis set limit is evident. The effect of the additional diffuse functions on electron affinities is shown to be comparable to the effect of correlating the outer-core d electrons., (© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).)

The accuracy and efficiency of molecular quantum chemical calculations depend critically on the basis set used. However, the development of novel basis sets is hindered because much of the literature relies on the use of opaque processes and tools that are not publicly available. We present here BasisOpt, a tool for the automated optimization of basis sets with an easy-to-use framework. It features an open and accessible workflow for basis set optimization that can be easily adapted to almost any quantum chemistry program, a standardized approach to testing basis sets, and visualization of both the optimized basis sets and the optimization process. We provide examples of usage in realistic basis set optimization scenarios where: (i) a density fitting basis set is optimized for He, Ne, and Ar; (ii) the exponents of the def2-SVP basis are re-optimized for a set of molecules rather than atoms; and (iii) a large, almost saturated basis of sp primitives is automatically reduced to (10s5p) while achieving the lowest energy for such a basis set composition., (© 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).)

A new species, Hypothycerayi MacGown & Hill, sp. nov. (Coleoptera: Scarabaeidae: Melolonthinae: Melolonthini), is described from east central Alabama, USA. Three other species of Hypothyce , H.burnei Skelley, H.mixta Howden and H.osburni (Cartwright) are known to occur in the United States. We discuss differences between these species and provide an updated identification key to the genus., Competing Interests: No conflict of interest was declared., (Joe A. MacGown, JoVonn G. Hill.)

Melanoplusdiscolor and Melanopluskendalli were previously placed in the texanus species group. Here seven new species are described from central Texas and the combined nine species placed into the discolor group based on emergence time and shape of the male terminalia and genital structures. Six of these new species are from the Edwards Plateau, a known area of high endemism. Species of the discolor group are inhabitants of shortgrass or mixed-grass prairies, Ashe juniper or oak savannas., Competing Interests: No conflict of interest was declared., (JoVonn G. Hill.)

We present a series of auxiliary basis sets, for the elements Na to Ar, for use in density-fitted Hartree-Fock calculations with the correlation consistent cc-pV(n + d)Z orbital basis sets. Benchmarking on total molecular energies, reaction energies and the spectroscopic constants of the SO molecule demonstrate that the new sets address the deficiencies of using existing auxiliary sets in combination with these orbital basis sets. We also report auxiliary basis sets for Na and Mg matched to cc-pVnZ, along with recommendations for pairing auxiliary basis sets to the cc-pVnZ-F12 basis sets for Hartree-Fock calculations., (© 2023 The Authors. Journal of Computational Chemistry published by Wiley Periodicals LLC.)

Since their introduction into the United States in the early 1900's, imported fire ants, namely Solenopsis invicta Buren (Red Imported Fire Ant), S. richteri Forel (Black Imported Fire Ant), and their hybrid form Solenopsis invicta X richteri have spread throughout portions of the USA, especially in the southeastern region. Imported fire ants are a serious invasive and economically significant species in the USA and elsewhere, and their spread into new parts of the country is of great concern. Although early models predicted that the fire ants would not be able to survive very far north into the USA, these ants have nonetheless successfully continued their spread into higher latitudes. Based on Cooperative Agricultural Pest Survey (CAPS) samples, the Mississippi Entomological Museum Invasive Insect Screening Center, at Mississippi State University, has verified the presence of imported fire ants collected in Kentucky at multiple locations from 2014 to 2022., Competing Interests: The authors declare no conflict of interest. The sponsors had no role in the design, execution, interpretation, or writing of the study.

Background: Orthopedic literature has demonstrated a significant decrease in postoperative transfusion requirements when tranexamic acid (TXA) was given during elective joint arthroplasty. The purpose of this study was to evaluate the empiric use of TXA in semi-urgent orthopedic procedures following injury. We hypothesized that TXA would be associated with increased rates of venous thromboembolic events (VTE) and have no effect on transfusion requirements., Methods: Patients who empirically received TXA during a semi-urgent orthopedic surgery following injury (TXA+) were matched using propensity scoring to historical controls (CONTROL) who did not receive TXA. Outcomes included VTE within 6 months of injury and packed red blood cell utilization. Multivariable logistic regression and generalized linear modeling were used to determine odds of VTE and transfusion., Results: 200 patients were included in each group. There was no difference in mortality between groups. TXA+ patients did not have an increase in VTE events (OR 0.680, 95% CI 0.206 to 2.248). TXA+ patients had a significantly higher odds of being transfused during their hospital stay (OR 2.175, 95% CI 1.246 to 3.797) and during the index surgery (increased 0.95 units (SD 0.16), p<0.0001). Overall transfusion was also significantly higher in the TXA+ group (p=0.0021)., Conclusion: Empiric use of TXA in semi-urgent orthopedic surgeries did not increase the odds of VTE. Despite the elective literature, TXA administration did not associate with less transfusion requirements. A properly powered, prospective, randomized trial should be designed to elucidate the risks and benefits associated with TXA use in this setting., Level of Evidence: Level IV., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

This study investigated whether delayed receipt of antibiotics in infants with necrotizing enterocolitis (NEC) is associated with disease severity. In this retrospective, single-center cohort study of infants diagnosed with NEC over 4 years, we compared the timing of antibiotic administration in infants (time order placed to time of receipt) in medical and surgical NEC. Cases were independently reviewed, then various clinical factors were compared. Of 46 suspected cases, 25 were confirmed by a panel of radiologists with good interrater reliability (ICC 0.657; p < 0.001). Delays in antibiotic receipt were 1.7× greater in surgical than medical NEC cases (p = 0.049). Every hour after order entry increased the adjusted odds of surgical NEC by 2.4 (1.08−5.23; p = 0.032). Delayed antibiotic receipt was more common in infants with surgical than medical NEC. Larger studies will be needed to investigate if optimizing antibiotic expediency could improve intestinal outcomes.

The tawny crazy ant, Nylanderia fulva (Mayr) (Hymenoptera: Formicidae) has a native range that extends from northern Argentina to southern Brazil. In the U.S.A. this species has often been misidentified as Nylanderia ( Paratrechina ) pubens or N. cf. pubens and has likely been present in Florida and Texas for several decades [1]. In the early 2000's explosive population growth in Texas and neighboring states drew renewed taxonomic focus. Genetic analyses [2,3] aided in identifying the pest species as N. fulva . This species poses an invasive threat to native flora and fauna and human structures. In its invasive range it has been reported to displace another invasive species, the red imported fire ant. The specimens used for genome sequencing were obtained from the coastal region of Mississippi. DNA was extracted from pupae. The genome data set was deposited to the National Center for Biotechnology Information as submission ID: SUB10775679, Project ID: PRJNA796544, Accession IDs: SAMN24895442 and JAKFQQ000000000. The organism taxid is 613905, locus tag prefixes are L1K79. The assembly, USDA&#95;Nfulva&#95;1.0, was generated in collaboration with Dovetail Genomics (now Cantata Bio) to yield a chromosome-level assembly of 375 Mb with a 15.67 Mb N50 and 78X coverage and revealing 16 putative chromosomes. This high-quality chromosome-level genome assembly was released prior to publication as a public service to the research community., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Gymnoscirtetes is endemic to the southeastern portion of the North American Coastal Plain and previously comprised two species: G.pusillus Scudder, 1897 and G.morsei Hebard, 1918. Here, this genus is revised based on male genital morphology and geographic data, and four new species are described: G.georgiaensis sp. nov. , G.pageae sp. nov. , G.rex sp. nov. , and G.wadeorum sp. nov. Gymnoscirtetes is primarily associated with mesic grasslands such as pitcher plant bogs, flatwoods, and the edges of seasonal ponds, but can be found less commonly in a variety of other grasslands., (JoVonn G. Hill.)

Rationale and Objectives: Radiology and pathology are often underrepresented in undergraduate medical education. The Alliance of Medical Student Educators in Radiology (AMSER) hosts the AMSER Rad Path Case of the Month, an online archive of radiological case reports with pathology correlations submitted by medical students. The purpose of this study is to assess the value of preparing and submitting a case on medical students' educational experience., Materials and Methods: Students who had cases accepted for publication in AMSER Rad Path Case of the Month from July 2018 to December 2019 were contacted by email to request their participation in a voluntary, anonymous 22-question survey. Surveys were sent to 35 students from seven institutions., Results: Twenty three of the 35 students (65.7%) responded. Only five (21.7%) of respondents reported having previously followed a patient case through radiology and pathology during medical school, defined as interaction with a clinician in each specialty to discuss the case. When asked about their experience with AMSER Rad Path Case of the Month, most agreed or strongly agreed it was a valuable case-based learning experience (100%). Respondents also reported high satisfaction with improved understanding of disease process, increased understanding and ability to collaborate, and increased likelihood of participating in future academic work., Conclusion: AMSER Rad Path Case of the Month is a valuable case-based educational experience that deepens students' understanding of disease processes while affording them an opportunity for interdisciplinary and scholarly collaboration., (Copyright © 2022 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

New correlation consistent basis sets for the second-row atoms (Al-Ar) to be used with the neon-core correlation consistent effective core potentials (ccECPs) have been developed. The basis sets, denoted cc-pV( n +d)Z-ccECP ( n = D, T, Q), include the "tight"-d functions that are known to be important for second-row elements. Sets augmented with additional diffuse functions are also reported. Effective core polarization potentials (CPPs) to account for the effect of core-valence correlation have been adjusted for the same elements, and two different forms of the CPP cutoff function have been analyzed. The accuracy of both the basis sets and the CPPs is assessed through benchmark calculations at the coupled-cluster level of theory for atomic and molecular properties. Agreement with all-electron results is much improved relative to the basis sets that originally accompanied the ccECPs; moreover, the combination of cc-pV( n +d)Z-ccECP and CPPs is found to be a computationally efficient and accurate alternative to including core electrons in the correlation treatment.

Background: In soybean fields containing insecticide- and herbicide-resistant genetically engineered varieties, some weed species have increasingly become difficult to manage and may favor the population growth of secondary pests like Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae). To test this hypothesis, we measured life-history traits, population growth parameters and adult nutrient content of S. cosmioides reared on foliage from four Amaranthus species, from Cry1Ac Bt and non-Bt soybean varieties, and on meridic artificial diet., Results: Larvae reared on A. palmeri and A. spinosus had a shorter development time (5-7 days) than larvae raised on the soybean varieties and A. hybridus. Armyworm survival probability was zero on A. viridis and highest (80% and 71%) on soybeans and A. palmeri. The latter and the artificial diet produced the heaviest larvae and pupae, in contrast to the non-Bt soybean variety. Body nutrient content diverged mostly for adults reared on artificial diet compared with those raised on the soybean varieties. The intrinsic rate of population increase (overall fitness) was 27.88% higher for the armyworms on A. palmeri, Cry1Ac Bt soybean and artificial diet compared with those on non-Bt soybean, A. spinosus and A. hybridus., Conclusions: Cry1Ac soybean fields infested by some Amaranthus weeds, especially A. palmeri, are conducive to the population growth of S. cosmioides. Integrated pest management programs may be needed to properly manage S. cosmioides in soybean fields, with surveillance for population peaks and judicious control measures when needed. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)

Objectives: Ovarian torsion (OT) is an emergency that mandates early detection and surgical detorsion to avoid catastrophic consequences of further adnexal injury. Prompt ultrasound is critical for accurate diagnosis. Traditionally, evaluation of arterial and venous flow was used as a diagnostic tool for OT, but recent radiologic research has indicated that ovarian size and size discrepancy between sides is a better diagnostic criterion. This study seeks to determine whether ovarian size discrepancy or vascular flow to the ovary is more accurate in the diagnosis of OT in the pediatric emergency population and to better describe symptoms that distinguish OT from other abdominal and pelvic pathology., Methods: This was a retrospective, cross-sectional study evaluating all female pediatric patients, aged 1 to 18 years, who underwent a pelvic ultrasound to evaluate for OT over a 2-year period in our pediatric emergency department. Patients suitable for inclusion were identified via Nuance mPowerTM, a search engine that provides clinical analytics based on radiology reports generated within our institution., Results: We reviewed the medical records of 193 female patients aged 1 to 18 years, all of whom had a pelvic ultrasound (with or without Doppler) to evaluate for OT during the study period. In comparing ovarian size on ultrasound, patients with OT had a significantly larger magnitude of difference in ovarian volume than patients without torsion (5.57× [interquartile range, 3-12.5] vs 1.56× [interquartile range, 1.24-2.25; P < 0.001]). Ovarian torsion was associated with a 33-fold increased risk of lack of arterial flow (relative risk, 33.33) and with a 9-fold increased risk of lack of venous flow (relative risk, 9.27), when compared with those patients without OT. Patients with OT were significantly more likely to have emesis and peritoneal signs on examination, as well as previous history of OT (P = 0.01, 0.02, and 0.002, respectively) than those without OT. All patients with OT reported abdominal pain., Conclusions: We found that a large size discrepancy between ovaries is indicative of OT. Our data also suggest that presence of Doppler flow on ultrasound cannot be used to exclude OT but that lack of Doppler flow on ultrasound is a significant diagnostic marker. As previous studies have also found, clinical symptoms of OT are nonspecific and do not offer any certainty in differentiating OT from other pathologies., Competing Interests: Disclosure: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Animal movement can impact human-wildlife conflict by influencing encounter and detection rates. We assess the movement and space use of the highly venomous and medically important Malayan krait (Bungarus candidus) on a suburban university campus. We radio-tracked 14 kraits for an average of 114 days (min: 19, max: 218), during which we located individuals an average of 106 times (min: 21, max: 229) each. Most individuals displayed some level of attraction to buildings (n = 10) and natural areas (n = 12); we identified a similar unambiguous pattern of attraction to buildings and natural areas at the population level (of our sample). Snakes remained in shelter sites for long durations (max: 94 days) and revisited sites on average every 15.45 days. Over 50% of locations were within human settlements and 37.1% were associated with buildings. We found generally seasonal patterns of activity, with higher activity in wet seasons, and lower activity in the hot season. These results show frequent proximity between Malayan kraits and humans at the university; thereby, suggesting a near constant potential for human-wildlife conflict. Despite the fact that no snakebites from this species occurred at the university during our study period, substantial education and awareness training should be considered to ensure continued coexistence on campus., (© 2022. The Author(s).)

Energies of linear, halogen-bonded complexes in the isoelectronic series YX···ClF (YX = FB, OC, or N 2 ) are calculated at several levels of theory as a function of the intermolecular distance r (X···Cl) to yield radial potential energy functions. When YX = OC, a secondary minimum is observed corresponding to lengthened and shortened distances r (ClF) and r (CCl), respectively, relative to the primary minimum, suggesting a significant contribution from the Mulliken inner complex structure [O═C-Cl] + ···F - . A conventional weak, halogen-bond complex OC···ClF occurs at the primary minimum. For YX = FB, the primary minimum corresponds to the inner complex [F═B-Cl] + ···F - , while the outer complex FB···ClF is at the secondary minimum. The effects on the potential energy function of systematic substitution of Y and X by second-row congeners and of reversing the order of X and Y are also investigated. Symmetry-adapted perturbation theory and natural population analyses are applied to further understand the nature of the various halogen-bond interactions.

Predator/parasitoid functional response is one of the main tools used to study predation behavior, and in assessing the potential of biological control candidates. It is generally accepted that predator learning in prey searching and manipulation can produce the appearance of a type III functional response. Holling proposed that in the presence of alternative prey, at some point the predator would shift the preferred prey, leading to the appearance of a sigmoid function that characterized that functional response. This is supported by the analogy between enzyme kinetics and functional response that Holling used as the basis for developing this theory. However, after several decades, sigmoidal functional responses appear in the absence of alternative prey in most of the biological taxa studied. Here, we propose modeling the effect of learning on the functional response by using the explicit incorporation of learning curves in the parameters of the Holling functional response, the attack rate ( a ), and the manipulation time ( h ). We then study how the variation in the parameters of the learning curves causes variations in the shape of the functional response curve. We found that the functional response product of learning can be either type I, II, or III, depending on what parameters act on the organism, and how much it can learn throughout the length of the study. Therefore, the presence of other types of curves should not be automatically associated with the absence of learning. These results are important from an ecological point of view because when type III functional response is associated with learning, it is generally accepted that it can operate as a stabilizing factor in population dynamics. Our results, to the contrary, suggest that depending on how it acts, it may even be destabilizing by generating the appearance of functional responses close to type I., Competing Interests: The authors declare no competing interests., (© 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

The purpose of this study was to examine the effects of a single acute dose of yohimbine hydrochloride on repeated anaerobic sprint ability. Physically active females ( n = 18) completed two separate repeated supramaximal sprint trials each with a different single-dose treatment: placebo (PL; gluten-free corn starch) or yohimbine hydrochloride (YHM; 2.5 mg). For each trial, participants consumed their respective treatment 20 min before exercise. Following a warm-up, participants completed 3 × 15 s Wingate anaerobic tests (WAnTs) separated by 2 min of active recovery. A capillary blood sample was obtained pre- and immediately post-exercise to measure blood concentrations of lactate (LA), epinephrine (EPI), and norepinephrine (NE). Heart rate (HR) and rate of perceived exertion (RPE) were measured following each WAnT. Findings showed that mean power ( p < 0.001; η 2 = 0.024), total work ( p < 0.001; η 2 = 0.061), and HR ( p < 0.001; η 2 = 0.046), were significantly higher with YHM supplementation versus PL. Fatigue index ( p < 0.001; η 2 = 0.054) and post-exercise LA ( p < 0.001; d = 1.26) were significantly lower with YHM compared to PL. YHM resulted in significantly higher EPI concentrations versus PL ( p < 0.001; η 2 = 0.225) pre- and post-exercise while NE only increased as a function of time ( p < 0.001; η 2 = 0.227) and was unaffected by treatment. While RPE increased after each WAnT, no differences between treatments were observed ( p = 0.539; η 2 < 0.001). Together, these results suggest that acute YHM ingestion imparts ergogenic benefits which may be mediated by lower blood LA and fatigue concomitantly occurring with blood EPI increases. Thus, YHM may improve sprint performance although more mechanistic study is warranted to accentuate underlying processes mediating performance enhancement.

Objectives: There is debate regarding the timing of procedural sedation and analgesia (PSA) in relation to fasting status. Point-of-care ultrasound (POCUS) provides the ability to measure gastric content and is being used as a surrogate for aspiration risk in anesthesia. We sought to evaluate the gastric content of pediatric emergency department (PED) patients undergoing PSA using POCUS., Methods: We performed a prospective observational study using a convenience sample of pediatric patients undergoing PSA between July 1, 2018, and June 30, 2019. Following a brief history, gastric content was measured using POCUS in both supine and right lateral decubitus positions at 2-hour intervals until the time of PSA. Qualitative content and calculated volume were classified based on the Perlas Model of anesthesia "Risk" assessment., Results: Ninety-three patients were enrolled with 61.3% male and mean age of 6.5 years. Gastric content was determined in 92 patients. There were 79.3% that had "high risk" content at the time of PSA, with a median fasting time of 6.25 hours and no serious adverse events. Fasting duration had a weak to moderate ability to predict "risk" category (area under the curve = 0.73), with no patient (n = 17) who underwent multiple evaluations awaiting PSA progressing from "high" to "low risk.", Conclusions: The majority of PED patients undergoing PSA at our institution had "high risk" gastric content with no clinically significant change occurring during serial evaluations. This calls into question the utility of delaying PSA based upon fasting status and lends support to a more comprehensive risk-benefit approach when planning pediatric PSA., Competing Interests: Disclosure: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

New correlation consistent basis sets for the group 11 (Cu, Ag, Au) and 12 (Zn, Cd, Hg) elements have been developed specifically for use in explicitly correlated F12 calculations. This includes orbital basis sets for valence only (cc-pVnZ-PP-F12, n = D, T, Q) and outer core-valence (cc-pCVnZ-PP-F12) correlation, along with both of these augmented with additional high angular momentum diffuse functions. Matching auxiliary basis sets required for density fitting and resolution-of-the-identity approaches to conventional and F12 integrals have also been optimized. All of the basis sets are to be used in conjunction with small-core relativistic pseudopotentials [Figgen et al., Chem. Phys. 311, 227 (2005)]. The accuracy of the basis sets is determined through benchmark calculation at the explicitly correlated coupled-cluster level of theory for various properties of atoms and diatomic molecules. The convergence of the properties with respect to the basis set is dramatically improved compared to conventional coupled-cluster calculations, with cc-pVTZ-PP-F12 results close to conventional estimates of the complete basis set limit. The patterns of convergence are also greatly improved compared to those observed from the use of conventional correlation consistent basis sets in F12 calculations.

We present CHARMM-compatible force field parameters for a series of fluorescent dyes from the Alexa, Atto, and Cy families, commonly used in Förster resonance energy transfer (FRET) experiments. These dyes are routinely used in experiments to resolve the dynamics of proteins and nucleic acids at the nanoscale. However, little is known about the accuracy of the theoretical approximations used in determining the dynamics from the spectroscopic data. Molecular dynamics simulations can provide valuable insights into these dynamics at an atomistic level, but this requires accurate parameters for the dyes. The complex structure of the dyes and the importance of this in determining their spectroscopic properties mean that parameters generated by analogy to existing parameters do not give meaningful results. Through validation relative to quantum chemical calculation and experiments, the new parameters are shown to significantly outperform those that can be generated automatically, giving better agreement in both the charge distributions and structural properties. These improvements, in particular with regard to orientation of the dipole moments on the dyes, are vital for accurate simulation of FRET processes.

Following damage by herbivores, many plants release volatiles that dissuade future conspecifics from feeding. In many crop plants however, induced volatiles mediating this kind of interactions among plants, herbivores and also their natural enemies have been altered through the process of domestication. The selection of crops for increased yield may have gone at a cost of defense, possibly including defense-related volatiles. Dalbulus maidis (Hemiptera: Cicadellidae), a specialist leafhopper that only feeds on Zea spp., is a vector of Corn Stunt Spiroplasma, a serious maize disease. Here, we compared the volatiles released following D. maidis attack by a maize landrace and two maize hybrids of temperate and tropical background. Also, we performed behavioral assays with the leafhopper contrasting healthy non-attacked maize seedlings versus attacked seedlings. The maize landrace produced more than 6-fold larger quantities of induced volatiles compared to the maize hybrids after herbivory. Corn leafhopper females were able to detect and significantly preferred the odors of healthy seedlings over the attacked ones only in the landrace. They did not discriminate between the attacked and non-attacked hybrids. Additionally, we found that the attraction of the parasitoid wasp Anagrus virlai (Hymenoptera: Mymaridae) to its host was diminished in the tested hybrids. The parasitoid was able to detect the odors of the attacked landrace, however it was unable to discriminate between healthy and attacked maize hybrid plants. These results suggest that those more domesticated germplasms may have lost the ability not only to release volatiles that avoid colonization of future herbivores, but also to attract their natural enemies in a tritrophic system.

The alkali-metal bonds formed by simple molecules LiR and NaR (R = F, H or CH3) with each of the six Lewis bases B = OC, HCN, H2O, H3N, H2S and H3P were investigated by ab initio calculations at the CCSD(T)/AVTZ and CCSD(T)/awCVTZ levels of theory with the aim of characterising this type of non-covalent interaction. In some complexes, two minima were discovered, especially for those involving the NaR. The higher-energy minimum (referred to as Type I) for a given B was found to have geometry that is isomorphous with that of the corresponding hydrogen-bonded analogue BHF. The lower-energy minimum (when two were present) showed evidence of a significant secondary interaction of R with the main electrophilic region of B (Type II complexes). Energies DCBSe for dissociation of the complexes into separate components were found to be directly proportional to the intermolecular stretching force constant kσ The value of DCBSe could be partitioned into a nucleophilicity of B and an electrophilicity of LiR or NaR, with the order ELiH ⪆ ELiF = ELiCH3 for the LiR and ENaF > ENaH ≈ ENaCH3 for the NaR. For a given B, the order of the electrophilicities is ELiR > ENaR, which presumably reflects the fact that Li+ is smaller than Na+ and can approach the Lewis base more closely. A SAPT analysis revealed that the complexes BLiR and BNaR have larger electrostatic contributions to De than do the hydrogen- and halogen-bonded counterparts BHCl and BClF.

Background: Infant videofluoroscopic swallow studies (VFSSs) require clinicians to make determinations about swallowing deficits based on a limited number of fluoroscopically observed swallows. Although airway protection is known to decline throughout a bottle-feed, the paucity of data regarding the timing of this degradation has limited the development of procedural protocols that maximize diagnostic validity., Objective: We tested the stability of key components of swallow physiology and airway protection at four standardized timepoints throughout the VFSS., Materials and Methods: Thirty bottle-fed infants with clinical signs of swallow dysfunction underwent VFSS. Fluoroscopy was turned on to allow visualization of five swallows at 0:00, 0:30, 1:30 and 2:30 (minutes:seconds [min:s]). We evaluated swallows for components of swallow physiology (oral bolus hold, initiation of pharyngeal swallow, timing of swallow initiation) and airway protection (penetration, aspiration). We used model-based linear contrasts to test differences in the percentage of swallows with low function component attributes., Results: All components of swallow physiology exhibited a change throughout the VFSS (P≤0.0005). Changes were characterized by an increase in the number of sucks per swallow (P<0.0001), percentage of swallows with incomplete bolus hold (P=0.0005), delayed initiation of pharyngeal swallow (P<0.0001), delayed timing of swallow initiation (P=0.0004) and bolus airway entry (P<0.0001). These findings demonstrate that infants with dysphagia exhibit a change in swallow physiology throughout the videofluoroscopic swallow exam., Conclusion: Fluoroscopic visualization that is confined to the initial swallows of the bottle feed limit the exam's diagnostic validity. Developing evidence-based procedural guidelines for infant VFSS execution is crucial for maximizing the exam's diagnostic and treatment yield.

A novel method for the accurate and efficient calculation of interaction energies in weakly bound complexes composed of a large number of molecules is presented. The new ALMO+RPAd method circumvents the prohibitive scaling of coupled cluster singles and doubles while still providing similar accuracy across a diverse range of weakly bound chemical systems. Linear-scaling procedures for the Fock build are given utilizing absolutely localized molecular orbitals (ALMOs), resulting in the a priori exclusion of basis set superposition errors. A bespoke data structure and algorithm using density fitting are described, leading to linear scaling for the storage and computation of the two-electron integrals. Electron correlation is included through a new, linear-scaling pairwise local random phase approximation approach, including exchange interactions, and decomposed into purely dispersive excitations (RPAxd). Collectively, these allow meaningful decomposition of the interaction energy into physically distinct contributions: electrostatic, polarization, charge transfer, and dispersion. Comparison with symmetry-adapted perturbation theory shows good qualitative agreement. Tests on various dimers and the S66 benchmark set demonstrate results within 0.5 kcal mol -1 of coupled cluster singles and doubles results. On a large cluster of water molecules, we achieve calculations involving over 3500 orbital and 12,000 auxiliary basis functions in under 10 min on a single CPU core.

Volatile organic compounds (VOCs) released by plants are generally involved in host recognition and host selection for many phytophagous insects. However, for leafhoppers and planthoppers, host recognition is mainly thought to involve a phototactic response, but it is not clear if a host plant could be selected based on the volatile cues it emits. In this study we evaluated olfactory responses in dual choice tests of two Hemiptera species, Dalbulus maidis (De Long) (Cicadellidae) and Peregrinus maidis (Ashmead) (Delphacidae), vectors of maize-stunting diseases, to three maize (Zea mays L.) germplasms, a temperate and a tropical hybrid and a landrace. VOCs emitted by the germplasms were collected and identified using gas chromatography-mass spectrometry. The temperate hybrid released significantly more VOCs than the tropical hybrid and the landrace, and its volatile profile was dominated by (±)-linalool. D. maidis preferred odours emitted from the temperate hybrid, whereas P. maidis preferred odours from the tropical hybrid and the landrace over the temperate one. In order to test if linalool plays a role in the behavioural responses, we assayed this compound in combination with the tropical hybrid, to provide other contextual olfactory cues. D. maidis was attracted to the tropical hybrid plus a 0.0001% linalool solution, indicating that this compound could be part of a blend of attractants. Whereas addition of linalool resulted in a slight, though not significant, reduction in host VOC attractiveness for P. maidis. Both hopper species responded to olfactory cues in the absence of supplementary visual cues.

The rare octahedral EC 6 coordination skeleton type is unknown for complexes with coordination centers consisting of group 14 elements. Here, the first examples of such EC 6 species, the hexacoordinate homoleptic cyanido complexes E(CN) 6 2- , E = Si, Ge, Sn, have been synthesized from element halides SiCl 4 , GeCl 4 and SnF 4 and isolated as salts with PPN counterions (PPN + = (Ph 3 P) 2 N + ) on a scale of 0.2-1 g. Characterization by spectroscopic techniques and by structure determination through single crystal crystallographic methods show that these pseudohalogen complexes have effective octahedral symmetry in solution and in the solid state. Infrared spectra obtained in solution reveal that the T 1 u symmetric IR-active vibrations in all three complexes have unusually small oscillator strengths. The observed reluctance of Si(CN) 6 2- , Ge(CN) 6 2- , and Sn(CN) 6 2- to form from chloro-precursors was rationalized in terms of Gibbs free energies, which were found by ab initio calculations at the CCSD(T)-F12b/aug-cc-pVTZ(-PP)-F12 level of theory to be small or even positive. The work demonstrates that E(CN) 6 2- complexes of silicon, germanium and tin are in fact stable at room temperature and exist as well-defined units in the presence of noncoordinating counterions. The results add to our understanding of the chemistry of pseudohalogens and structure and bonding.

The competition and cooperation between weak intermolecular interactions are important in determining the conformational preferences of molecules. Understanding the relative strengths of these effects in the context of potential drug candidates is therefore essential. We use a combination of gas-phase spectroscopy and quantum-chemical calculations to elucidate the nature of such interactions for the analgesic salicin [2-(hydroxymethyl)phenyl β-d-glucopyranoside], an analog of aspirin found in willow bark. Of several possible conformers, only three are observed experimentally, and these are found to correspond with the three lowest energy conformers obtained from density functional theory calculations and simulated Franck-Condon spectra. Natural bond orbital analyses show that these are characterized by a subtle interplay between weak n→π* interaction and conventional strong hydrogen bond, with additional insights into this interaction provided by analysis of quantum theory of atoms in molecules and symmetry-adapted perturbation theory calculations. In contrast, the higher energy conformers, which are not observed experimentally, are mostly stabilized by the hydrogen bond with negligible contribution of n→π* interaction. The n→π* interaction results in a preference for the benzyl alcohol group of salicin to adopt a gauche conformation, a characteristic also found when salicin is bound to the β-glucosidase enzyme. As such, understanding the interplay between these weak interactions has significance in the rationalization of protein structures.

The alkali-metal trihalides MX 3 (M = Li, Na, K, Rb, and Cs; X = Cl, Br, and I) are systematically studied using coupled-cluster methods. Benchmarks using CCSD(T) against diatomic experimental results suggest satisfactory performance for the weighted core-valence basis sets (new basis sets for K, Rb, and Cs) selected for predicting reliable structures and harmonic vibrational frequencies. An isomer search using the B3LYP functional yields a planar, yet asymmetric T-shaped C s structure as the global minimum for all MX 3 species. Much higher level CCSD(T) computations show a moderate to strong distortion of the X 3 - anion by the M + cation in the respective equilibrium geometries. Most obviously, for LiCl 3 , the two Cl-Cl distances are separated by 0.786 Å. Even for CsI 3 , the structure least distorted from the M + X 3 - model, the two I-I distances differ by 0.243 Å. It does not take much energy to distort the parent anions along an antisymmetric stretch, so this is no surprise. The normal modes of vibration of the MX 3 molecules are in better agreement with matrix isolation experiments than previous calculations. And these normal modes reveal that, instead of the well-established antisymmetric and symmetric stretches of the "free" X 3 - anions, relatively localized and mutually perturbed X-X and M-X stretches are calculated. The suggestion emerges that the MX 3 system may be alternatively described as an MX-X 2 complex rather than the M + X 3 - ion pair. This perspective is supported by bonding analyses showing low electron densities at the bond critical points and natural bond orders between the MX and X 2 moieties. The thermochemistry of fragmentations of MX 3 to MX + X 2 versus M + + X 3 - also supports the alternative viewpoint of the bonding in this class of molecules.

Geometry parameters, vibrational frequencies, heats of formation, bond dissociation energies, cohesive energies, and selected fluoride affinities (difluorides) are predicted for the late alkaline earth (Sr, Ba, and Ra) oxides, fluorides, chlorides, and hydroxides at the coupled cluster theory CCSD(T) level. Additional corrections (scalar relativistic and pseudopotential corrections, vibrational zero-point energies, and atomic spin-orbit effects) were included to accurately calculate the total atomization energies and heats of formation following the Feller-Peterson-Dixon methodology. The calculated values are compared to the experimental data where available. In some cases, especially for Ra compounds, there are no experimental results, or the experimental energetics and geometries are not reliable or have very large error bars. All of the Sr, Ba, and Ra difluorides, dichlorides, and dihydroxides are bent structures with the OMO bond angles decreasing going down the group. The cohesive energies of bulk Be dihalides are predicted to be quite low, while those of Ra are relatively large. The fluoride affinities show that the difluorides are moderately strong Lewis acids and that such trifluorides may form under the appropriate experimental conditions.

New correlation consistent basis sets based on pseudopotential (PP) Hamiltonians have been developed from double- to quintuple-zeta quality for the late alkali (K-Fr) and alkaline earth (Ca-Ra) metals. These are accompanied by new all-electron basis sets of double- to quadruple-zeta quality that have been contracted for use with both Douglas-Kroll-Hess (DKH) and eXact 2-Component (X2C) scalar relativistic Hamiltonians. Sets for valence correlation (ms), cc-pVnZ-PP and cc-pVnZ-(DK,DK3/X2C), in addition to outer-core correlation [valence + (m-1)sp], cc-p(w)CVnZ-PP and cc-pwCVnZ-(DK,DK3/X2C), are reported. The -PP sets have been developed for use with small-core PPs [I. S. Lim et al., J. Chem. Phys. 122, 104103 (2005) and I. S. Lim et al., J. Chem. Phys. 124, 034107 (2006)], while the all-electron sets utilized second-order DKH Hamiltonians for 4s and 5s elements and third-order DKH for 6s and 7s. The accuracy of the basis sets is assessed through benchmark calculations at the coupled-cluster level of theory for both atomic and molecular properties. Not surprisingly, it is found that outer-core correlation is vital for accurate calculation of the thermodynamic and spectroscopic properties of diatomic molecules containing these elements.

Renal myxoma is a very rare benign neoplasm seen almost exclusively in adults with only 16 reported cases in the literature. All of these cases have been reported in native kidneys with none being reported in a transplant kidney. We report the case of a renal myxoma in a 17-year-old boy's transplant kidney that was found as an incidental mass on ultrasonography and further evaluated with CT and PET scans. PET findings of a renal myxoma are reported here for the first time, and imaging findings from previous cases are briefly reviewed. This case report highlights the fact that adult-predominant tumors and pathology should always be a consideration in pediatric patients who receive organ transplants from adult donors.

Photolysis of geminal diiodoalkanes in the presence of molecular oxygen has become an established route to the laboratory production of several Criegee intermediates, and such compounds also have marine sources. Here, we explore the role that the trihaloalkane, chlorodiiodomethane (CHI 2 Cl), may play as a photolytic precursor for the chlorinated Criegee intermediate ClCHOO. CHI 2 Cl has been synthesized and its UV absorption spectrum measured; relative to that of CH 2 I 2 the spectrum is shifted to longer wavelength and the photolysis lifetime is calculated to be less than two minutes. The photodissociation dynamics have been investigated using DC slice imaging, probing ground state I and spin-orbit excited I* atoms with 2 + 1 REMPI and single-photon VUV ionization. Total translational energy distributions are bimodal for I atoms and unimodal for I*, with around 72% of the available energy partitioned in to the internal degrees of freedom of the CHICl radical product, independent of photolysis wavelength. A bond dissociation energy of D 0 = 1.73 ± 0.11 eV is inferred from the wavelength dependence of the translational energy release, which is slightly weaker than typical C-I bonds. Analysis of the photofragment angular distributions indicate dissociation is prompt and occurs primarily via transitions to states of A'' symmetry. Complementary high-level MRCI calculations, including spin-orbit coupling, have been performed to characterize the excited states and confirm that states of A'' symmetry with highly mixed singlet and triplet character are predominantly responsible for the absorption spectrum. Transient absorption spectroscopy has been used to measure the absorption spectrum of ClCHOO produced from the reaction of CHICl with O 2 over the range 345-440 nm. The absorption spectrum, tentatively assigned to the syn conformer, is at shorter wavelengths relative to that of CH 2 OO and shows far weaker vibrational structure.

New, efficient schemes for the prescreening and evaluation of integrals over effective core potentials (ECPs) are presented. The screening is shown to give a rigorous, and close bound, to within on average 10% of the true value. A systematic rescaling procedure is given to reduce this error to approximately 0.1%. This is then used to devise a numerically stable recursive integration routine that avoids expensive quadratures. Tests with coupled clusters with single and double excitations and perturbative triple calculations on small silver clusters demonstrate that the new schemes show no loss in accuracy, while reducing both the power and prefactor of the scaling with system size. In particular, speedups of roughly 40 times can be achieved compared to quadrature-based methods.

Auxiliary basis sets for use in the resolution of the identity (RI) approximation in explicitly correlated methods are presented for the elements H-Ar. These extend the cc-pVnZ-F12/OptRI (n = D-Q) auxiliary basis sets of Peterson and co-workers by the addition of a small number of s- and p-functions, optimized so as to yield the greatest complementary auxiliary basis set (CABS) singles correction to the Hartree-Fock energy. The new sets, denoted OptRI+, also lead to a reduction in errors due to the RI approximation and hence an improvement in correlation energies. The atomization energies and heats of formation for a test set of small molecules, and spectroscopic constants for 27 diatomics, calculated at the CCSD(T)-F12b level, are shown to have improved error distributions for the new auxiliary basis sets with negligible additional effort. The OptRI+ sets retain all of the desirable properties of the original OptRI, including the production of smooth potential energy surfaces, while maintaining a compact nature.

π-Hydrogen bonding interactions are ubiquitous in both materials and biology. Despite their relatively weak nature, great progress has been made in their investigation by experimental and theoretical methods, but this becomes significantly more complicated when secondary intermolecular interactions are present. In this study, the effect of successive methyl substitution on the supramolecular structure and interaction energy of indole⋅⋅⋅methylated benzene (ind⋅⋅⋅n-mb, n=1-6) complexes is probed through a combination of supersonic jet experiments and benchmark-quality quantum chemical calculations. It is demonstrated that additional secondary interactions introduce a subtle interplay among electrostatic and dispersion forces, as well as steric repulsion, which fine-tunes the overall structural motif. Resonant two-photon ionization and IR-UV double-resonance spectroscopy techniques are used to probe jet-cooled ind⋅⋅⋅n-mb (n=2, 3, 6) complexes, with redshifting of the N-H IR stretching frequency showing that increasing the degree of methyl substitution increases the strength of the primary N-H⋅⋅⋅π interaction. Ab initio harmonic frequency and binding energy calculations confirm this trend for all six complexes. Electronic spectra of the three dimers are broad and structureless, with quantum chemical calculations revealing that this is likely to be due to multiple tilted conformations of each dimer possessing similar stabilization energies., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Background: Although practice patterns vary, scout radiographs are often routinely performed with pediatric fluoroscopic studies. However few studies have evaluated their utility in routine pediatric fluoroscopy., Objective: To evaluate the value of scout abdomen radiographs in routine barium or water-soluble enema, upper gastrointestinal (GI) series, and voiding cystourethrogram pediatric fluoroscopic procedures., Materials and Methods: We retrospectively evaluated 723 barium or water-soluble enema, upper GI series, and voiding cystourethrogram fluoroscopic procedures performed at our institution. We assessed patient history and demographics, clinical indication for the examination, prior imaging findings and impressions, scout radiograph findings, additional findings provided by the scout radiograph that were previously unknown, and whether the scout radiograph contributed any findings that significantly changed management., Results: We retrospectively evaluated 723 fluoroscopic studies (368 males and 355 females) in pediatric patients. Of these, 700 (96.8%) had a preliminary scout radiograph. Twenty-three (3.2%) had a same-day radiograph substituted as a scout radiograph. Preliminary scout abdomen radiographs/same-day radiographs showed no new significant findings in 719 (99.4%) studies. New but clinically insignificant findings were seen in 4 (0.6%) studies and included umbilical hernia, inguinal hernia and hip dysplasia. No findings were found on the scout radiographs that would either alter the examination performed or change management with regard to the exam., Conclusion: Pre-procedural scout abdomen radiographs are unnecessary in routine barium and water-soluble enema, upper GI series, and voiding cystourethrogram pediatric fluoroscopic procedures and can be substituted with a spot fluoroscopic last-image hold.

Intermolecular halogen bonding in complexes of phosphine and dihalogens has been theoretically investigated using explicitly correlated coupled cluster methods and symmetry-adapted perturbation theory. The complexes H 3 P···ClF, H 3 P···BrF, and H 3 P···IF are demonstrated to possess unusually strong interactions that are accompanied by an increase in the induction component of the interaction energy and significant elongation of the X-Y halogen distance on complex formation. The combination of these factors is indicative of Mulliken inner complexes, and criteria for identifying this classification are further developed. The importance of choosing an electronic structure method that describes both dispersion and longer range interactions is demonstrated, along with the need to account for the change in geometry on complexation formation via relaxation energy and overall stabilization energies.

Background: The evaluation of children with suspected ventriculoperitoneal shunt (VPS) malfunction has evolved into a diagnostic dilemma. This patient population is vulnerable not only to the medical risks of hydrocephalus and surgical complications but also to silent but harmful effects of ionizing radiation secondary to imaging used to evaluate shunt efficacy and patency. The combination of increased medical awareness regarding ionizing radiation and public concern has generated desire to reduce the reliance on head computed tomography (CT) for the evaluation of VPS malfunction. Many centers have started to investigate the utility of low-dose CT scans and alternatives, such as fast magnetic resonance imaging for the investigation of VP shunt malfunction in order to keep radiation exposure as low as reasonably achievable. This pilot study hopes to add to the armamentarium available to the clinician charged with evaluating this challenging patient population by testing the feasibility of a limited CT protocol as an alternative to a full head CT examination., Objective: To evaluate the efficacy of a limited head CT protocol compared with a complete head CT for the evaluation of children presenting to the pediatric emergency department with suspected shunt malfunction., Methods: We retrospectively reviewed all pediatric patients who received a head CT for suspected VPS malfunction evaluation at a tertiary care children's hospital from January 2001 through January 2013. Children were included in the pilot study if they had at least 2 CT scans in this study period interpreted by a specific senior attending neuroradiologist. For each patient enrolled, a limited series was generated from the most recent CT scan by selecting four representative axial slices based on the sagittal scout image. These 4 slices where selected at the level of the fourth ventricle, third ventricle, basal ganglia level, and lateral ventricles, respectively. A blinded, senior attending neuroradiologist first reviewed the limited 4-slice CT data set and was asked to determine if the ventricular system had increased, decreased, or remained stable. Subsequently, the neuroradiologist compared their interpretation of the limited examination with the official report from the full CT data set as the standard of reference as well as the interpretation of the most recent prior scan., Results: Forty-six patients (age range, 2 months to 18 years; average age, 6.4 years (SD, 4.2), 54% male) were included in the study. Forty-four of 46 (95.7%) limited CT scans matched the official report of the full CT scan. No cases of increased ventricular size were missed (100% positive predictive value for increased ventricular size). The use of a limited head CT (4 axial images) instead of a complete head CT (average of 31 axial images in our studied patients) confers a radiation dose reduction of approximately 87%., Conclusions: Our pilot study demonstrates that utilization of limited head CT scan in the evaluation of children with suspected VP shunt malfunction is a feasible strategy for the evaluation of the ventricular size. Further prospective and multidisciplinary studies are needed to evaluate the reliability of limited head CT for the clinical evaluation of VP shunt malfunction.