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The aromaticity of cyclic 4nπ-electron molecules in their first ππ* triplet state (T1), labeled Baird aromaticity, has gained growing attention in the past decade. Here we explore computationally the limitations of T1state Baird aromaticity in macrocyclic compounds, [n]CM’s, which are cyclic oligomers of four different monocycles (M = p-phenylene (PP), 2,5-linked furan (FU), 1,4-linked cyclohexa-1,3-diene (CHD), and 1,4-linked cyclopentadiene (CPD)). We strive for conclusions that are general for various DFT functionals, although for macrocycles with up to 20 π-electrons in their main conjugation paths we find that for their T1states single-point energies at both canonical UCCSD(T) and approximative DLPNO-UCCSD(T) levels are lowest when based on UB3LYP over UM06-2X and UCAM-B3LYP geometries. This finding is in contrast to what has earlier been observed for the electronic ground state of expanded porphyrins. Yet, irrespective of functional, macrocycles with 2,5-linked furans ([n]CFU’s) retain Baird aromaticity until larger nthan those composed of the other three monocycles. Also, when based on geometric, electronic and energetic aspects of aromaticity, a 3[n]CFUwith a specific nis more strongly Baird-aromatic than the analogous 3[n]CPPwhile the magnetic indices tell the opposite. To construct large T1state Baird-aromatic [n]CM’s, the design should be such that the T1state Baird aromaticity of the macrocyclic perimeter dominates over a situation with local closed-shell Hückel aromaticity of one or a few monocycles and semilocalized triplet diradical character. Monomers with lower Hückel aromaticity in S0than benzene (e.g., furan) that do not impose steric congestion are preferred. Structural confinement imposed by, e.g., methylene bridges is also an approach to larger Baird-aromatic macrocycles. Finally, by using the Zilberg–Haas description of T1state aromaticity, we reveal the analogy to the Hückel aromaticity of the corresponding closed-shell dications yet observe stronger Hückel aromaticity in the macrocyclic dications than Baird aromaticity in the T1states of the neutral macrocycles.

According to the currently accepted structure–property relationships, aceno-pentalenes with an angular shape (fused to the 1,2-bond of the acene) exhibit higher antiaromaticity than those with a linear shape (fused to the 2,3-bond of the acene). To explore and expand the current view, we designed and synthesized molecules where two isomeric, yet, different, 8π antiaromatic subunits, a benzocyclobutadiene (BCB) and a pentalene, are combined into, respectively, an angular and a linear topology via an unsaturated six-membered ring. The antiaromatic character of the molecules is supported experimentally by 1H NMR, UV–vis, and cyclic voltammetry measurements and X-ray crystallography. The experimental results are further confirmed by theoretical studies including the calculation of several aromaticity indices (NICS, ACID, HOMA, FLU, MCI). In the case of the angular molecule, double bond-localization within the connecting six-membered ring resulted in reduced antiaromaticity of both the BCB and pentalene subunits, while the linear structure provided a competitive situation for the two unequal [4n]π subunits. We found that in the latter case the BCB unit alleviated its unfavorable antiaromaticity more efficiently, leaving the pentalene with strong antiaromaticity. Thus, a reversed structure–antiaromaticity relationship when compared to aceno-pentalenes was achieved.

Singlet exciton fission photovoltaic technology requires chromophores with their lowest excited states arranged so that 2E(T1) < E(S1) and E(S1) < E(T2). Herein, qualitative theory and quantum chemical calculations are used to develop explicit strategies on how to use Baird’s 4nrule on excited-state aromaticity, combined with Hückel’s 4n+ 2 rule for ground-state aromaticity, to tailor new potential chromophores for singlet fission. We first analyze the E(T1), E(S1), and E(T2) of benzene and cyclobutadiene (CBD) as excited-state antiaromatic and aromatic archetypes, respectively, and reveal that CBD fulfills the criteria on the state ordering for a singlet fission chromophore. We then look at fulvenes, a class of compounds that can be tuned by choice of substituents from Baird-antiaromatic to Baird-aromatic in T1and S1and from Hückel-aromatic to Hückel-antiaromatic in S0. The T1and S1states of most substituted fulvenes (159 of 225) are described by singly excited HOMO → LUMO configurations, providing a rational for the simultaneous tuning of E(T1) and E(S1) along an approximate (anti)aromaticity coordinate. Key to the tunability is the exchange integral (KH,L), which ideally is constant throughout the compound class, providing a constant ΔE(S1– T1). This leads us to a geometric model for the identification of singlet fission chromophores, and we explore what factors limit the model. Candidates with calculated E(T1) values of ∼1 eV or higher are identified among benzannelated 4nπ-electron compound classes and siloles. In brief, it is clarified how the joint utilization of Baird’s 4nand Hückel’s 4n+ 2 rules, together with substituent effects (electronic and steric) and benzannelation, can be used to tailor new chromophores with potential use in singlet fission photovoltaics.

Freezing and freeze-drying processes are commonly used to extend the shelf life of drug products and to ensure their safety and efficacy upon use. When designing a freezing process, it is beneficial to characterize multiple physicochemical properties of the formulation, such as nucleation rate, crystal growth rate, temperature and concentration of the maximally freeze-concentrated solution, and melting point. Differential scanning calorimetry has predominantly been used in this context but does have practical limitations and is unable to quantify the kinetics of crystal growth and nucleation. In this work, we introduce a microfluidic technique capable of quantifying the properties of interest and use it to investigate aqueous sucrose solutions of varying concentration. Three freeze–thaw cycles were performed on droplets with 75-μm diameters at cooling and warming rates of 1 °C/min. During each cycle, the visual appearance of the droplets was optically monitored as they experienced nucleation, crystal growth, formation of the maximally freeze-concentrated solution, and melting. Nucleation and crystal growth manifested as increases in droplet brightness during the cooling phase. Heating was associated with a further increase as the temperature associated with the maximally freeze-concentrated solution was approached. Heating beyond the melting point corresponded to a decrease in brightness. Comparison with the literature confirmed the accuracy of the new technique while offering new visual data on the maximally freeze-concentrated solution. Thus, the microfluidic technique presented here may serve as a complement to differential scanning calorimetry in the context of freezing and freeze-drying. In the future, it could be applied to a plethora of mixtures that undergo such processing, whether in pharmaceutics, food production, or beyond.

Phytobezoars are concretions of indigested fruit and vegetables fibers in the gastrointestinal tract. The past of gastric surgery is most common risk factor of phytobezoar. We present the case of a 39-year-old female was admitted to the emergency department and who presented with small bowel obstruction due to phytobezoar, her past medical history was marqued by truncal vagotomy and simple suture recurrent perforated gastric ulcer 15 years earlier. Her postoperative recovery was uneventful.

Primary lymphomas of appendix are extremely rare tumors. The incidence is 0.015% out of all gastrointestinal lymphomas; furthermore, limited data is available in literature. The appendiceal neoplasms are most commonly presented as acute appendicitis followed intestinal obstruction, intussusception or perforation. We present a case of a 22 year-old male patient who presented with acute appenditis and underwent emergency laparotomy. On abdominal exploration, swollen and enlarged appendix measured 3cm was present for which appendectomy were performed. The histopathological examination of appendectomy specimen revealed a Burkitt's Lymphoma. The patient received R-COPADEM protocol of chemotherapy. Primary gastrointestinal lymphoma is a extremely rare neoplasm without guidelines for therapy.

Hydatidosis is a cosmopolitan parasitic disease which presents a real public health problem especially in endemic countries of which Morocco is part. The objective of the present work is to analyze the clinical, paraclinical, therapeutic, evolutionary and prognostic aspects of disseminated peritoneal hydatidosis with multiple localization.

Malignant tumours of the small bowel are uncommon in clinical practice. Adenocarcinoma is the most common of these tumours, accounting for approximately 35–45% of all tumours. It may occur sporadically, in association with familial adenomatous polyposis coli or Peutz-Jeghers syndrome or hereditary non-polyposis colorectal cancer, or in association with chronic inflammatory bowel changes (such as Crohn's disease or celiac disease).

Neuroendocrine tumors of the small bowel are rare but represent the most frequent histological type at this level; their incidence is increasing thanks to the evolution of diagnostic means.Intestinal NETs, developed at the expense of enterochromaffin cells of the embryological midgut, are frequently associated with mesenteric lymph node dissemination and distant metastasis (liver, peritoneum);

Serous cystadenomas account for approximately 25% of benign ovarian tumors in patients of childbearing age. Their growth is insidious, and the diagnosis can be difficult as they are often asymptomatic, Patients with serous cystadenoma often experience symptoms only if the lesion is twisted or has a mass effect because of its size.This was the case in our patient, whose cough and low back pain prompted her To consult a doctor, which led to the definitive diagnosis and treatment.

and importance: Acute appendicitis is one of the most common causes of acute abdomen in surgical patients. The objectives of the study were to evaluate efficacy of Alvarado scoring system in preoperative diagnosis of acute appendicitis and correlating it with postoperative findings.

Several fully π-conjugated macrocycles with puckered or cage-type structures were recently found to exhibit aromatic character according to both experiments and computations. We examine their electronic structures and put them in relation to 3D-aromatic molecules (e.g., closo-boranes) and to 2D-aromatic polycyclic aromatic hydrocarbons. Using qualitative theory combined with quantum chemical calculations, we find that the macrocycles explored hitherto should be described as 2D-aromatic with three-dimensional molecular structures (abbr. 2D-aromatic-in-3D) and not as truly 3D-aromatic. 3D-aromatic molecules have highly symmetric structures (or nearly so), leading to (at least) triply degenerate molecular orbitals, and for tetrahedral or octahedral molecules, an aromatic closed-shell electronic structure with 6n+ 2 electrons. Conversely, 2D-aromatic-in-3D structures exhibit aromaticity that results from the fulfillment of Hückel’s 4n+ 2 rule for each macrocyclic path, yet their π-electron counts are coincidentally 6n+ 2 numbers for macrocycles with three tethers of equal lengths. It is notable that 2D-aromatic-in-3D macrocyclic cages can be aromatic with tethers of different lengths, i.e., with π-electron counts different from 6n+ 2, and they are related to naphthalene. Finally, we identify tetrahedral and cubic π-conjugated molecules that fulfill the 6n+ 2 rule and exhibit significant electron delocalization. Yet, their properties resemble those of analogous compounds with electron counts that differ from 6n+ 2. Thus, despite the fact that these molecules show substantial π-electron delocalization, they cannot be classified as true 3D-aromatics.

and importance: Duplications, which rare anomalies of the gastroin-testinal tract, may be located in any part of the gastro-intestinal system from the oral cavity to the anus. The aim of this paper is to present and discuss a case of an asymptomatic jejunal duplication cyst associated with adhesive small bowel obstruction in an elderly lady.

AbstractThis paper evaluates the bioavailability of As, Cd, Cu, Mn, Hg, Ni and Zn in the coastal waters of the two most important bays in southern Spain (Cádiz and Algeciras). Concentrations of these metals were measured in the bodies of Balanus amphitritebarnacles in 2005 and 2006. Seawater samples were collected from the same sites as the barnacles to assess metal concentrations and to gain additional information on the environmental conditions. Analysis of variance (ANOVA) showed significant geographic differences in the local bioavailability of metals to the barnacles, as reflected in the concentrations of accumulated metals. Balanus amphitriteaccumulates large amounts of metals, with high concentration factors for Zn, Cd, Cu and Mn, in relation to the concentrations in marine waters.

This work aims to describe and discuss the epidemiological, clinical, therapeutic and evolution of Fournier's gangrene.

Retroperitoneal Retrocecal hernias are a rare variety of internal hernias and represent an unusual cause of bowel obstruction. Early diagnosis is based on CT scan and requires knowledge of the pathology in order to avoid small bowel resection. We report a case of retrocecal hernia treated surgically and review the characteristics and treatment of retrocecal hernias in the literature.

Internal hernias are a rare cause of acute intestinal obstruction. Supravesical hernia is an exceptional form of hernia that is often diagnosed intraoperatively. The abdominal CT scan performed in the emergency guides the preoperative diagnosis. Our work concerns a patient admitted to the visceral surgical department of the university hospital ibn Rochd of Casablanca for an occlusion dating back to 05 days, the abdmonial x-ray objectified hydro-aerial levels in the small intestine, and the CT scan found an invagination at the left fossa iliaca associated with a double hernia: internal supravesical and left inguinal. The patient was then operated after conditioning and the diagnosis of an internal supravesical hernia was retained per operatively. Internal supravesical hernia is a very rare cause of acute intestinal occlusion and is often diagnosed at the time of surgical exploration.

Cushing's syndrome (CS) is a rare and severe disease. Acute pancreatitis is the leading cause of hospitalization. The association of the two disease is rare and uncommon. We report the case of a 37-year-old woman admitted in our service for acute pancreatitis and whose Cushing syndrome was diagnosed during hospiatilisation. The aim of this work is to try to understand the influence of de Cushing in acute pancreatitis and to establish a causative relationship between the two diseases.