Ectopic spleen: An easily identifiable but commonly undiagnosed entity until manifestation of complications

AbstractINTRODUCTIONEctopic spleen is an uncommon clinical entity as splenectomy for treatment of ectopic spleens accounts for less than 0.25% of splenectomies. The most common age of presentation is childhood especially under 1 year of age followed by the third decade of life.PRESENTATION OF CASEThe present report refers to a patient with torsion of a pelvic spleen treated with splenectomy. The patient exhibited a period of vague intermittent lower abdominal pain lasted 65 days followed by a period of constant left lower quadrant pain of increasing severity lasted 6 days. On the first 65 days, vague pain was attributed to progressive torsion of the spleen which resulted in venous congestion. On the last 6 days, exacerbation of pain was attributed to irreducible torsion, infraction of the arterial supply, acute ischemia, strangulation and rupture of the gangrenous spleen. Diagnosis was made by CT which revealed absence of the spleen in its normal position, a homogeneous pelvic mass with no contrast enhancement, free blood in the peritoneal cavity, and confirmed by laparotomy.DISCUSSIONClinical manifestations of ectopic spleen vary from asymptomatic to abdominal emergency. Symptoms are most commonly attributed to complications related to torsion. Operative management, including splenopexy or splenectomy, is the treatment of choice in uncomplicated and complicated cases because conservative treatment of an asymptomatic ectopic spleen is associated with a complication rate of 65%.CONCLUSIONAlthough an ectopic spleen can be easily identified on clinical examination, it is commonly misdiagnosed until the manifestation of complications in adulthood

Current rectification by simple molecular quantum dots: an ab-initio study

We calculate a current rectification by molecules containing a conjugated molecular group sandwiched between two saturated (insulating) molecular groups of different length (molecular quantum dot) using an ab-initio non-equilibrium Green's function method. In particular, we study S-(CH2)m-C10H6-(CH2)n-S dithiol with Naphthalene as a conjugated central group. The rectification current ratio ~35 has been observed at m = 2 and n = 10, due to resonant tunneling through the molecular orbital (MO) closest to the electrode Fermi level (lowest unoccupied MO in the present case). The rectification is limited by interference of other conducting orbitals, but can be improved by e.g. adding an electron withdrawing group to the naphthalene.Comment: 8 pages, 9 figure

First-Principles Analysis of Molecular Conduction Using Quantum Chemistry Software

We present a rigorous and computationally efficient method to do a parameter-free analysis of molecular wires connected to contacts. The self-consistent field approach is coupled with Non-equilibrium Green's Function (NEGF) formalism to describe electronic transport under an applied bias. Standard quantum chemistry software is used to calculate the self-consistent field using density functional theory (DFT). Such close coupling to standard quantum chemistry software not only makes the procedure simple to implement but also makes the relation between the I-V characteristics and the chemistry of the molecule more obvious. We use our method to interpolate between two extreme examples of transport through a molecular wire connected to gold (111) contacts: band conduction in a metallic (gold) nanowire, and resonant conduction through broadened, quasidiscrete levels of a phenyl dithiol molecule. We obtain several quantities of interest like I-V characteristic, electron density and voltage drop along the molecule.Comment: Accepted for publication in J. Chem. Phys. (Special issue on molecular electronics, Ed. Mark Ratner

Congenital bronchial atresia presenting as a cavitary lesion on chest radiography: a case report

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Meckel's Diverticulum in Adults: Surgical Concerns

Since Meckel's diverticulum (MD) is rarely diagnosed in adults, there is no consensus on what type of procedure to be performed for symptomatic MD and whether to resect or not an accidentally discovered MD. Treatment of symptomatic MD is definitive surgery, including diverticulectomy, wedge, and segmental resection. The type of procedure depends on: (a) the integrity of diverticulum base and adjacent ileum; (b) the presence and location of ectopic tissue within MD. The presence of ectopic tissue cannot be accurately predicted intraoperatively by palpation and macroscopic appearance. When present, its location can be predicted based on height-to-diameter ratio. Long diverticula (height-to-diameter ratio >2) have ectopic tissue located at the body and tip, whereas short diverticula have wide distribution of ectopic tissue including the base. When indication of surgery is simple diverticulitis, diverticulectomy should be performed for long and wedge resection for short MD. When indication of surgery is complicated diverticulitis with perforated base, complicated intestinal obstruction and tumor, wedge, or segmental resection should be performed. When the indication of surgery is bleeding, wedge and segmental resection are the preferred methods for resection. Regarding management of incidentally discovered MD, routine resection is not indicated. The decision making should be based on risk factors for developing future complications, such as: (1) patient age younger than 50 years; (2) male sex; (3) diverticulum length >2 cm; and (4) ectopic or abnormal features within a diverticulum. In this case, diverticulectomy should be performed for long and wedge resection for short MD

Modulating the charge injection in organic field-effect transistors: fluorinated oligophenyl self-assembled monolayers for high work function electrodes

Financial support from the ERC project SUPRAFUNCTION (GA-257305), the EC Marie-Curie projects IEF-MULTITUDES (PIEF-GA-2012-326666) and ITN iSwitch (GA no. 642196), the Agence Nationale de la Recherche through the LabEx project Chemistry of Complex Systems (ANR-10-LABX-0026_CSC), and the International Center for Frontier Research in Chemistry (icFRC). The computational work was supported by the Interuniversity Attraction Pole Programme (P7/05) initiated by the Belgian Science Policy Office, and by the Belgian National Fund for Scientific Research (FNRS). J.C. is an FNRS research director. Colin Van Dyck is a recipient of a Gustave Boël – Sofina Fellowship of the Belgian American Educational Foundation (BAEF). K.M., F.R. and M.M. acknowledge financial support by the Swiss National Science Foundation (SNF) and the Swiss Nanoscience Institute (SNI)

The challenges of teaching and learning during a pandemic become an opportunity: reflections on a student and academic partnership

The current pandemic has forced us to implement major changes in the way we communicate, interact and work, all of which have had a massive impact upon all aspects of our lives. Academics and students alike have had to adapt very quickly to the new situation and the challenges encountered, although viewed from different perspectives, are largely similar. Changes are often unsettling and taxing, especially when they are not the result of a personal choice, but they can also offer great opportunities, the most significant of which is for lecturers and learners to develop best practice together, in partnership (Kurczek and Johnson, 2014). This article reflects upon how sharing our experience of a students-and- staff partnership at the University of Greenwich 2021 SHIFT conference has affected our experience of teaching and learning during a pandemic

A single-electron transistor made from a cadmium selenide nanocrystal

The techniques of colloidal chemistry permit the routine creation of semiconductor nanocrystals, whose dimensions are much smaller than those that can be realized using lithographic techniques. The sizes of such nanocrystals can be varied systematically to study quantum size effects or to make novel electronic or optical materials with tailored properties. Preliminary studies of both the electrical and optical properties of individual nanocrystals have been performed recently. These studies show clearly that a single excess charge on a nanocrystal can markedly influence its properties. Here we present measurements of electrical transport in a single-electron transistor made from a colloidal nanocrystal of cadmium selenide. This device structure enables the number of charge carriers on the nanocrystal to be tuned directly, and so permits the measurement of the energy required for adding successive charge carriers. Such measurements are invaluable in understanding the energy-level spectra of small electronic systems, as has been shown by similar studies of lithographically patterned quantum dots and small metallic grains.Comment: 3 pages, PDF forma

Voltammetric Characterization of Redox-Inactive Guest Binding to Ln III [15-Metallacrown-5] Hosts Based on Competition with a Redox Probe

A novel competitive binding assay was implemented to monitor the binding of a redox inactive substrate to a redox inactive metallacrown host based on its competition with ferrocene carboxylate (FcC − ) using cyclic voltammetry (CV). First, the binding of FcC − to Ln III [15-MC Cu II ,N,L-pheHA -5] (LnMC) hosts was characterized by cyclic voltammetry. It was shown that the voltammetric half wave potentials, E 1/2 , shifted to more positive potentials upon the addition of LnMC. The explicit dependence of E 1/2 with the concentration of LnMC was used to determine the association constants for the complex. The FcC − binding strength decreased with larger central lanthanide metals in the LnMC hosts, and substantially weaker binding was observed with La III . X-ray crystallography revealed that the hydrophobic host cavity incompletely encapsulated FcC − when the guest was bound to the nine-coordinate La III , suggesting the LnMC’s ligand side chains play a substantial role in guest recognition. With knowledge of the MC-FcC − solution thermodynamics, the binding affinity of a redox inactive guest was then assessed. Addition of sodium benzoate to a LnMC and FcC − mixture resulted in E 1/2 shifting back to the value observed for FcC − in the absence of LnMC. The association constants between benzoate and LnMC’s were calculated via the competitive binding approach. Comparison with literature values suggests this novel assay is a viable method for determining association constants for host–guest systems that exhibit the proper electrochemical behavior. Notably, this CV competitive binding approach does not require the preparation of a modified electrode or a tethered guest, and thus can be generalized to a number of host–guest systems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77442/1/chem_200903015_sm_miscellaneous_information.pd