Coalescence of Porous Coordination Cages into Crystalline and Amorphous Bulk Solids.

Discrete porous coordination cages are attractive as a solution processable material whose porosity is not predicated on a network structure. Here, we leverage the peripheral functionalization of these cage structures to obtain 12 novel, solution processable, porous coordination cages that afford crystalline and amorphous single-phase millimeter-scale monolithic bulk structures (six of each) upon solidification. These structures are based upon prototypal metal-organic polyhedra [Cu24(5-x-isophthalate)24] (where x = NH2, OH), wherein meta-substitution of linker ligands with acyl chloride or isocyanate moieties afforded amide and urethane functional groups, respectively. These porous cage structures were obtainable via direct synthesis between a metal salt and a ligand as well as postsynthetic modification of the cage and formed monoliths following centrifugation and drying of the product. We rationalize their self-assembly as colloidal packing of nanoscale cuboctahedral cages through weak interactions between their hydrophobic alkyl/aromatic surfaces. In general, amorphous solids were obtained via rapid precipitation from the mother liquor upon methanol addition, while crystalline solids could be obtained only following further chloroform and pyridine additions. The structure of the materials is confirmed via gas sorption and spectroscopic methods, while powder X-ray diffraction and transmission electron microscopy are used to determine the nature of these bulk solids.

Real-Time Tracking of Carbon Dioxide Concentration Using an Optical Microsphere Resonator Sensor.

Whispering gallery mode resonator sensors are nondisruptive optical sensors that can detect and monitor perturbations in a gaseous environment. Through its resonant properties of peak wavelength, amplitude, and quality factor (Q factor), changes in concentration can be quantified within seconds and monitored over days with great stability. In addition, the small footprint, low cost, and high sensitivity are ideal properties for a disposable sensor that can be utilized in extreme environments. The large Q factor of the resonant cavity enables long interaction lengths and amplifies the effect of small changes in the background refractive index, which is detectable in picometer shifts of the resonance wavelength. However, this measurement is susceptible to changes in other environmental factors such as temperature, pressure, and humidity, which manifest on the picometer wavelength scale, reinforcing the need to decouple the variables. In this work, we compare the spectral response of different diameter resonators to carbon dioxide, nitrogen, and its mixtures, observing the spectral shifting and broadening of the cavity resonance near 1550 nm. In addition, the effect of environmental temperature on spectral shifting due to the thermo-optic effect is characterized and quantified. Lastly, the gas concentrations are changed in real time to showcase the tracking and recovery capabilities of the resonator sensor.

Buffering the Suffering of Breast Lymphoscintigraphy.

Breast lymphoscintigraphy with 99mTc-sulfur colloid is frequently performed before breast-conserving surgery to delineate drainage to a sentinel node. Tracer injection for lymphoscintigraphy can be painful. Our aims were to determine whether administering a solution of buffered lidocaine immediately before lymphoscintigraphy injection could both reduce the patients' pain and increase nuclear medicine technologists' satisfaction with performing the procedure. Methods: A pain scale survey was obtained from patients undergoing breast lymphoscintigraphy with or without buffered lidocaine. Our nuclear medicine technologists were also surveyed for their satisfaction with the procedure, both with and without the addition of buffered lidocaine. Results: The patients' reported pain decreased by 86% with the addition of buffered lidocaine. Technologist satisfaction with performing the procedure increased by 36%. Conclusion: Lidocaine buffered with sodium bicarbonate injected before lymphoscintigraphy significantly reduces pain experienced by the patient and improves nuclear medicine technologist satisfaction in performing the procedure.

Nanoscale Probing of Local Electrical Characteristics on MBE-Grown Bi2Te3 Surfaces under Ambient Conditions.

The local electrical characteristics on the surface of MBE-grown Bi2Te3 are probed under ambient conditions by conductive atomic force microscopy. Nanoscale mapping reveals a 10-100× enhancement in current at step-edges compared to that on terraces. Analysis of the local current-voltage characteristics indicates that the transport mechanism is similar for step-edges and terraces. Comparison of the results with those for control samples shows that the current enhancement is not a measurement artifact but instead is due to local differences in electronic properties. The likelihood of various possible mechanisms is discussed. The absence of enhancement at the step-edges for graphite terraces is consistent with the intriguing possibility that spin-orbit coupling and topological effects play a significant role in the step-edge current enhancement in Bi2Te3.

Incidence of post-ERCP pancreatitis from direct pancreatic juice collection in hereditary pancreatitis and familial pancreatic cancer before and after the introduction of prophylactic pancreatic stents and rectal diclofenac.

OBJECTIVES: Individuals from hereditary pancreatitis (HP) and familial pancreatic cancer (FPC) kindreds are at increased risk of developing pancreatic cancer. Premalignant molecular changes may be detected in pancreatic juice collected by endoscopic retrograde cholangiopancreatography (ERCP). The objective was to determine the risk of post-ERCP pancreatitis (PEP). METHODS: A prospective study (1999-2013) was undertaken of 80 ERCPs (24 in HP and 56 in FPC) from 60 individuals and the impact of PEP prophylaxis using a self-expelling pancreatic stent and 50 mg diclofenac per rectum from 2008. RESULTS: There was no PEP in the HP cohort and 13 (23.2%) PEP from 56 procedures in the FPC cohort (P = 0.0077). Up to 2008 PEP had occurred in 7 (43.8%) of 16 procedures in FPC individuals versus none of 18 procedures in HP individuals (P = 0.0021). After the introduction of prophylaxis, the incidence of PEP fell to 6 (15.0%) of 40 procedures in FPC individuals (P = 0.0347).The odds ratio (95% confidence interval) was 0.23 (0.06-0.84) in favor of prophylaxis (0.035). CONCLUSIONS: Individuals with HP are at minimal risk for PEP. Although the risk of PEP in individuals with FPC can be reduced by using prophylactic self-expelling stents and diclofenac, it remains too high for routine screening.

Characterization of Lone Pine, California, tremolite asbestos and preparation of research material.

Well-characterized amphibole asbestos mineral samples are required for use as analytical standards and in future research projects. Currently, the National Institute for Standards and Technology Standard Reference Material samples of asbestos are listed as 'Discontinued'. The National Institute for Occupational Safety and Health (NIOSH) has a goal under the Asbestos Roadmap of locating and characterizing research materials for future use. Where an initial characterization analysis determines that a collected material is appropriate for use as a research material in terms of composition and asbestiform habit, sufficient amounts of the material will be collected to make it publicly available. An abandoned mine near Lone Pine, California, contains a vein of tremolite asbestos, which was the probable source of a reference material that has been available for the past 17 years from the Health and Safety Laboratory (HSL) in the UK. Newly collected fibrous vein material from this mine was analyzed at Research Triangle Institute (RTI International) with some additional analysis by the US Geological Survey's Denver Microbeam Laboratory. The analysis at RTI International included: (i) polarized light microscopy (PLM) with a determination of principal optical properties; (ii) X-ray diffraction; (iii) transmission electron microscopy, including energy dispersive X-ray spectroscopy and selected-area electron diffraction; and (iv) spindle stage analysis using PLM to determine whether individual fibers and bundles of the samples were polycrystalline or single-crystal cleavage fragments. The overall findings of the study indicated that the material is tremolite asbestos with characteristics substantially similar to the earlier distributed HSL reference material. A larger quantity of material was prepared by sorting, acid-washing and mixing for sub-division into vials of ~10g each. These vials have been transferred from NIOSH to RTI International, from where they can be obtained on request.

A timetable for the radiologic features of fracture healing in young children.

OBJECTIVE: Fracture dating significantly shapes decisions in child protection. With a dearth of primary evidence underpinning fracture dating in children, we examined the key radiologic features of fracture healing and their timelines. MATERIALS AND METHODS: Digital radiographs of children younger than 72 months old with accidental long bone fractures of known timing were reviewed independently by three pediatric radiologists blinded to the age of the fractures. Six radiologic features of fracture healing were evaluated: soft-tissue swelling, periosteal reaction, soft callus, hard callus, bridging, and remodeling. Interobserver agreement was assessed using kappa analysis. RESULTS: Two hundred twenty-eight films of 82 fractures in 63 children (mean age, 4.8 years) were assessed. Soft-tissue swelling was identified by two or more radiologists in 59% of the radiographs at days 1-2 after fractures, and prevalence sharply declined thereafter. Periosteal reaction was first seen at day 5 and was present in 62% of the films obtained between 15 and 35 days after the fracture. Soft callus was first seen at day 12 and was prevalent in 41% between 22 and 35 days. Hard callus and bridging began at day 19, increasing to 60% prevalence from 36 days onward. Remodeling was observed only in fractures 45 days old or more. Kappa scores were between 0.55 and 0.80 overall, with greater agreement when there was no plaster cast. CONCLUSION: The results of this study show that fractures in young children may be dated as acute (< 1 week), recent (8-35 days), or old (≥ 36 days) on the basis of the presence of six key radiologic features in combination. Furthermore, good interobserver agreement suggests these results are reproducible.

Fractures in a tertiary Neonatal Intensive Care Unit in Wales.

AIM: To explore associations with fractures reported in a tertiary neonatal intensive care unit (NICU). METHOD: Babies admitted to NICU from 1998 to 2007 in Cardiff, UK, with fractures during admission were identified. Clinical information was extracted from inpatient records. Results were reported as median (ranges). RESULTS: Seventy-one fractures were recorded in 27 (boys = 16) infants with a gestational age of 28 (23.6-40.4) weeks and birthweight of 920 g (485-4875). Fractures were recognized at 57 (1-128) days of age. Neonates with fractures without clear aetiologies (n = 17) were more preterm (p < 0.001), were born lighter (p < 0.001), required multiple medical interventions, were more commonly osteopenic (p < 0.001), had fractures detected later (p < 0.001) and had more posterior rib fractures (p = 0.009). Rib fractures were detected later than other sites (p = 0.002). Associations with rib fractures included osteopenia (p = 0.04), longer oxygen therapy (p = 0.018), length on total parental nutrition (p = 0.03), later achievement of full enteral feeds (p = 0.038), sepsis (p = 0.038) and surgical procedures (p = 0.004). Posterior rib fractures were more common in babies born more preterm (25.1 vs. 29.4 weeks, p = 0.003) and requiring diuretics (p = 0.027). CONCLUSION: Fractures in premature infants are associated with a variety of predisposing factors. Clinicians evaluating the cause of rib and multiple fractures in preterm neonates shortly after discharge need to take these factors into consideration.

Patterns of skeletal fractures in child abuse: systematic review.

OBJECTIVES: To systematically review published studies to identify the characteristics that distinguish fractures in children resulting from abuse and those not resulting from abuse, and to calculate a probability of abuse for individual fracture types. DESIGN: Systematic review. DATA SOURCES: All language literature search of Medline, Medline in Process, Embase, Assia, Caredata, Child Data, CINAHL, ISI Proceedings, Sciences Citation, Social Science Citation Index, SIGLE, Scopus, TRIP, and Social Care Online for original study articles, references, textbooks, and conference abstracts until May 2007. STUDY SELECTION: Comparative studies of fracture at different bony sites, sustained in physical abuse and from other causes in children <18 years old were included. Review articles, expert opinion, postmortem studies, and studies in adults were excluded. Data extraction and synthesis Each study had two independent reviews (three if disputed) by specialist reviewers including paediatricians, paediatric radiologists, orthopaedic surgeons, and named nurses in child protection. Each study was critically appraised by using data extraction sheets, critical appraisal forms, and evidence sheets based on NHS Centre for Reviews and Dissemination guidance. Meta-analysis was done where possible. A random effects model was fitted to account for the heterogeneity between studies. RESULTS: In total, 32 studies were included. Fractures resulting from abuse were recorded throughout the skeletal system, most commonly in infants (<1 year) and toddlers (between 1 and 3 years old). Multiple fractures were more common in cases of abuse. Once major trauma was excluded, rib fractures had the highest probability for abuse (0.71, 95% confidence interval 0.42 to 0.91). The probability of abuse given a humeral fracture lay between 0.48 (0.06 to 0.94) and 0.54 (0.20 to 0.88), depending on the definition of abuse used. Analysis of fracture type showed that supracondylar humeral fractures were less likely to be inflicted. For femoral fractures, the probability was between 0.28 (0.15 to 0.44) and 0.43 (0.32 to 0.54), depending on the definition of abuse used, and the developmental stage of the child was an important discriminator. The probability for skull fractures was 0.30 (0.19 to 0.46); the most common fractures in abuse and non-abuse were linear fractures. Insufficient comparative studies were available to allow calculation of a probability of abuse for other fracture types. CONCLUSION: When infants and toddlers present with a fracture in the absence of a confirmed cause, physical abuse should be considered as a potential cause. No fracture, on its own, can distinguish an abusive from a non-abusive cause. During the assessment of individual fractures, the site, fracture type, and developmental stage of the child can help to determine the likelihood of abuse. The number of high quality comparative research studies in this field is limited, and further prospective epidemiology is indicated.

How old is this fracture? Radiologic dating of fractures in children: a systematic review.

OBJECTIVE: We conducted a systematic review of the literature to define the evidence for radiologic dating of fractures in children in the context of child protection. CONCLUSION: Radiologic dating of fractures is an inexact science. Most radiologists date fractures on the basis of their personal clinical experience, and the literature provides little consistent data to act as a resource. There is an urgent need for research to validate the criteria used in the radiologic dating of fractures in children younger than 5 years.

Neonates do not need to be handled for radiographs.

BACKGROUND: The handling of sick neonates may have detrimental effects such as hypoxia or bradycardia. Such handling is inevitable due to the frequent need for practical procedures; however, minimising handling reduces these adverse events and may improve outcome. Radiography is one of the commonest procedures performed on neonates. Usually the infant is lifted and placed onto the radiographic cassette; however, modern incubators often incorporate a tray beneath the mattress in which the radiographic cassette can be placed without the need to disturb the infant. OBJECTIVE: To compare the quality of chest radiographs taken using the standard direct contact method, with those taken using the under-tray technique. MATERIALS AND METHODS: A series of chest radiographs taken over a 21-month period were analysed independently by two consultant paediatric radiologists unaware of the radiographic details. The position of the radiograph, i.e. direct contact or under-tray, was determined by the radiographer. Radiographic quality was scored on the following features: exposure, blurring, rotation, cut-off or coning, and side markers. A subjective score was also included. The results from each radiologist were analysed separately. RESULTS: Seventy chest radiographs were analysed-25 standard method, 45 under-tray. A statistically significant advantage for the under-tray method was seen on two analyses-radiologist 1 for exposure, and radiologist 2 for cut-off. No other significant differences were noted. There were no differences in the infants' weights or radiation exposure. CONCLUSIONS: The under-tray method for taking radiographs may produce films of at least equivalent quality to the standard method. Since the standard method involves handling with potential desaturation and bradycardia, this technique should cease.

Ballooning of the foreskin and physiological phimosis: is there any objective evidence of obstructed voiding?

OBJECTIVES To determine whether physiological phimosis with or without ballooning of the prepuce is associated with noninvasive urodynamic or radiological evidence of bladder outlet obstruction. PATIENTS AND METHODS From August 2001 to October 2002 all boys with a foreskin problem and referred to one paediatric surgeon were assessed in special clinics. Those with physiological phimosis were recruited for the study and had upper tract and bladder ultrasonography (US), followed by uroflowmetry and US-determined postvoid residual urine volumes (PVR). Data were compared between boys with and with no ballooning of the prepuce. The project was approved by the local research ethics committee and informed consent was obtained from all study participants. RESULTS In all, 54 patients were referred for circumcision; 32 boys with physiological phimosis completed the uroflow and US investigations. Ballooning of the foreskin was present in 18 boys (mean age 6.8 years, range 3-12); 14 had physiological phimosis with no ballooning (mean age 6.5 years, range 4-11). Upper tract US and bladder wall thickness were normal in all boys. The mean maximum urinary flow rate (Q(max)) was not significantly different in boys with ballooning and those without (mean 15.3 mL/s, sd 4.4, range 9-24, vs 15.4, sd 2.9, range 10.7-20, P = 0.96). In addition, all Q(max) values were within the normal range when correlated with voided volume and compared with age-related nomograms. Most boys had flow rate patterns showing a normal bell-shaped curve; a few (9%) had subtle changes in the flow-rate profile, with either a plateau-type curve or slow initial increase in flow and prolonged time to achieve Q(max). The two groups had comparable mean PVRs (3.5 mL, sd 5.1, range 0-18 with ballooning vs 6.1, sd 10.7, range 0-38 without, P = 0.37). Only one patient had a marginally abnormal PVR. CONCLUSIONS Physiological phimosis with or without ballooning of the prepuce is not associated with noninvasive objective measures of obstructed voiding. Minor abnormalities in the flow-rate pattern in this patient group deserve further study.