Construction of Two-Component Chemically Reactive Supramolecular Assemblies-Acyl Migration Reactions in Cocrystals of Napthalene-2,3-Diol and Its Diesters.

Reactions in solids are of contemporary interest due to applications in pharmaceutical industries to environmental sustainability. Although several reactive crystals that support chemical reactions have been identified and characterized, the same cannot be said about reactive cocrystals. Earlier we correlated the facile acyl group transfer reactions in crystals with supramolecular parameters obtained from the crystal structures. The structure-reactivity correlation revealed the requirement of proper juxtaposition of electrophile (C=O) and the nucleophile (OH) with distance (∼3.2 Å) and angle (∼90°) along the chain structure. The current article describes the preparation of cocrystals that are capable of supporting intermolecular acyl group transfer reactions in a group of structurally similar molecules. The cocrystals of naphthalene 2,3-diol and its corresponding diesters showed a facile solid state acyl transfer reaction, which has been well correlated with their crystal structures.

Diadochokinetic rate in Saudi and Bahraini Arabic speakers: Dialect and the influence of syllable type.

Arabic is spoken by more than 420 million people worldwide and still there are a limited number of studies on dialects of the Gulf Arabic regions where most selected respondents are male speakers. This study aimed to explore and establish normative data for the Diadochokinetic Rate (DDK) for two dialects (Saudi Arabia's Najdi and Bahrain's Bahraini) speakers. Furthermore, it aimed to investigate whether there are differences between the two dialects and whether sex differences are evident. In addition, it investigated syllable type differences. The study used the monosyllables /ba, da, ga/ and the multisyllabic sequence /badaga/ to analyse the DDK rates. Acoustic analysis was carried out to obtain DDK rates for the syllables. A mixed model ANOVA was performed to investigate dialect and sex differences, in addition, to syllable type. The study included 40 males and 40 female speakers from each of the two dialects. Results showed that for DDK, Saudi speakers had faster DDK rates for the monosyllables /ba/, /da/, /ga/, than Bahrainis, while, no significant differences were observed for the multisyllabic sequences. However, there were no differences between male and female speakers with regard to the DDK rates. The syllable /ga/ showed the slowest DDK rate among the monosyllables while the multisyllabic sequences displayed the slowest DDK rates. In brief, normative data for DDK rates for clinic were determined for the Arabic Nadji and Bahrain's Bahraini dialects. DDK rate was shown to be more sensitive to dialect differences for the monosyllable tasks. However, no sex differences were observed for the Arabic dialects in this study across all DDK tasks.

Lithium hydride as an efficient reagent for the preparation of 1,2-anhydro inositols: Does the reaction proceed through 'axial rich' conformation?

scyllo-Inositol derived 1,2-trans-diequatorial halohydrins can be efficiently converted to the corresponding epoxides in the presence of lithium hydride. The structure of one of the epoxides was determined by single crystal X-ray diffraction analysis. This provides a potential route for the preparation of ring modified inositol derivatives. DFT calculations suggest that this epoxide formation could be proceeding through the intermediacy of the cyclohexane ring-inverted axial-rich conformer (1,2-trans-diaxial halohydrin). This is supported by the results of DFT calculations on the formation of inositol orthoformate, where the product is locked in the axial-rich conformation, while the starting inositol has the equatorial-rich conformation.

Effect of Crystal Packing on the Thermosalient Effect of the Pincer-Type Diester Naphthalene-2,3-diyl-bis(4-fluorobenzoate): A New Class†II Thermosalient Solid.

The pincer-like double ester naphthalene-2,3-diyl-bis(4-fluorobenzoate) (2) is pentamorphic. Upon heating crystals of form I to below their melting point (441-443 K), they undergo a phase transition accompanied by a thermosalient effect, that is, rare and visually striking motility whereby the crystals jump or disintegrate. The phase transition and the thermosalient effect are reversible. Analysis of the crystal structure revealed that form I is a class II thermosalient solid. Crystals of form III also underwent a reversible phase transition in the temperature range of 160 to 170 K; however, they were not thermosalient. Comparison of the structures and the mechanical responses of the two polymorphs revealed that the thermosalient effect of form I was due to reversible closing and opening of the arms of the diester molecules in a tweezer-like action.

Fractures of the femoral shaft in children: national epidemiology and treatment trends in England following activation of major trauma networks.

AIMS: The aim of this study was to describe the epidemiology of closed isolated fractures of the femoral shaft in children, and to compare the treatment and length of stay (LOS) between major trauma centres (MTCs) and trauma units (TUs) in England. PATIENTS AND METHODS: National data were obtained from the Trauma and Audit Research Network for all isolated, closed fractures of the femoral shaft in children from birth to 15 years of age, between 2012 and 2015. Age, gender, the season in which the fracture occurred, non-accidental injury, the mechanism of injury, hospital trauma status, LOS and type of treatment were recorded. RESULTS: A total of 1852 fractures were identified. The mean annual incidence was 5.82 per 100 000 children (95% confidence interval (CI) 5.20 to 6.44). The age of peak incidence was two years for both boys and girls; this decreased with increasing age. Children aged four to six years treated in MTCs were more likely to be managed with open reduction and internal fixation compared with those treated in TUs (odds ratio 3.20; 95% CI 1.12 to 9.14; p = 0.03). The median LOS was significantly less in MTCs than in TUs for children aged between 18 months and three years treated in both a spica (p = 0.005) and traction (p = 0.0004). CONCLUSION: This study highlights the current national trends in the management of closed isolated fractures of the femoral shaft in children following activation of major trauma networks in 2012. Future studies focusing on the reasons for the differences which have been identified may help to achieve more consistency in the management of these injuries across the trauma networks. Cite this article: Bone Joint J 2018;100-B:109-18.

Engineering crystals that facilitate the acyl-transfer reaction: insight from a comparison of the crystal structures of myo-inositol-1,3,5-orthoformate-derived benzoates and carbonates.

Minor variations in the molecular structure of constituent molecules of reactive crystals often yield crystals with significantly different properties due to altered modes of molecular association in the solid state. Hence, these studies could provide a better understanding of the complex chemical processes occurring in the crystalline state. However, reactions that proceed efficiently in molecular crystals are only a small fraction of the reactions that are known to proceed (with comparable efficiency) in the solution state. Hence, for consistent progress in this area of research, investigation of newer reactive molecular crystals which support different kinds of reactions and their related systems is essential. The crystal structures and acyl-transfer reactivity of a myo-inositol-1,3,5-orthoformate-derived dibenzoate and its carbonate (4-O-benzoyl-2-O-phenoxycarbonyl-myo-inositol 1,3,5-orthoformate, C21H18O9) and thiocarbonate (4-O-benzoyl-2-O-phenoxythiocarbonyl-myo-inositol 1,3,5-orthoformate, C21H18O8S) analogs are compared with the aim of understanding the relationship between crystal structure and acyl-transfer reactivity. Insertion of an O atom in the acyl (or thioacyl) group of an ester gives the corresponding carbonate (or thiocarbonate). This seemingly minor change in molecular structure results in a considerable change in the packing of the molecules in the crystals of myo-inositol-1,3,5-orthoformate-derived benzoates and the corresponding carbonates. These differences result in a lack of intermolecular acyl-transfer reactivity in crystals of myo-inositol-1,3,5-orthoformate-derived carbonates. Hence, this study illustrates the sensitivity of the relative orientation of molecules, their packing and ensuing changes in the reactivity of resulting crystals to minor changes in molecular structure.

The Value of Tranexamic Acid in Reducing Blood Loss following Hip Reconstruction in Children with Cerebral Palsy.

This is a retrospective study of 51 consecutive hip reconstructions in children with cerebral palsy performed between 2011 and 2013. Tranexamic acid (TXA) was used in 14 hip reconstructions only. Transfusion rate was higher, postoperative Hb was lower, and patients stayed longer in the TXA group. This did not reach a statistical significance (P = 0.75, 0.5, and 0.71, resp.). More than half of the patients who had TXA underwent bilateral hip reconstructions in comparison with 27% only in the non-TXA group. Bilateral hip reconstructions mean more surgery, more blood loss, and more blood transfusion. The patients who had TXA were significantly more disabled as evident by the higher proportions of patient with worse GMFCS levels. Although we have not been able to demonstrate the value of TXA in reducing blood loss and transfusion rate in children with CP who underwent hip reconstruction, it is hoped that an interest in exploring the value of TXA in paediatric orthopaedic surgery is generated. Ideally this should be explored further in an adequately powered, randomised controlled trial where risk of bias is minimized.

Intramolecular Cyclization of Carbonate and Thiocarbonate Derivatives of myo-Inositol in the Solid State: Implications for Acyl Group Transfer Reactions in Molecular Crystals.

Racemic 4-O-phenoxycarbonyl and 4-O-phenoxythiocarbonyl derivatives of myo-inositol orthoformate undergo thermal intramolecular cyclization in the solid state to yield the corresponding 4,6-bridged carbonates and thiocarbonates, respectively. The thermal cyclization also occurs in the solution and molten states, but less efficiently, suggesting that these cyclization reactions are aided by molecular pre-organization, although not strictly topochemically controlled. Crystal structures of two carbonates and a thiocarbonate clearly revealed that the relative orientation of the electrophile and the nucleophile in the crystal lattice facilitates the intramolecular cyclization reaction and forbids the intermolecular reaction. The correlation observed between the chemical reactivity and the non-covalent interactions in the crystal of the reactants provides a way to estimate the chemical stability of analogous molecules in the solid state.

Accuracy of interchangeable implant impression systems: an in vitro pilot study.

PURPOSE: To evaluate the accuracy of impressions on changing the implant component (coping and abutment replica) between Brånemark and BIOMET 3i and between Straumann and Allfit. MATERIALS AND METHODS: Two master casts were constructed, one containing pair of Brånemark self-tap Mk II fixtures (Nobel Biocare) labeled Master cast I and the other containing pair of Straumann Standard plus implant, SLA fixtures (Straumann) labeled Master cast II. Ten impressions of each master cast were made by open tray technique using polyether impression material. Five out of 10 impressions made from master cast I contained Brånemark pair of coping and replica and the other 5 contained 3i (Implant Innovations). Five out of 10 impressions made from master cast II contained Straumann pair of copings and replica and the remaining 5 contained Allfit implants (Ihde Dental). Duplicated casts were prepared, and distances between copings were measured using traveling microscope and compared the distance in master casts. RESULT: No significant difference was observed in mean value between 2 master casts and their duplicates. CONCLUSION: The interchangeability of coping and abutment replica between Brånemark and BIOMET 3i and between Straumann and Allfit was found to be possible without compromising the quality of impressions.

Correlation of the solid-state reactivities of racemic 2,4(6)-di-O-benzoyl-myo-inositol 1,3,5-orthoformate and its 4,4'-bipyridine cocrystal with their crystal structures.

Racemic 2,4(6)-di-O-benzoyl-myo-inositol 1,3,5-orthoformate, C21H18O8, (1), shows a very efficient intermolecular benzoyl-group migration reaction in its crystals. However, the presence of 4,4'-bipyridine molecules in its cocrystal, C21H18O8·C10H8N2, (1)·BP, inhibits the intermolecular benzoyl-group transfer reaction. In (1), molecules are assembled around the crystallographic twofold screw axis (b axis) to form a helical self-assembly through conventional O-H···O hydrogen-bonding interactions. This helical association places the reactive C6-O-benzoyl group (electrophile, El) and the C4-hydroxy group (nucleophile, Nu) in proximity, with a preorganized El···Nu geometry favourable for the acyl transfer reaction. In the cocrystal (1)·BP, the dibenzoate and bipyridine molecules are arranged alternately through O-H···N interactions. The presence of the bipyridine molecules perturbs the regular helical assembly of the dibenzoate molecules and thus restricts the solid-state reactivity. Hence, unlike the parent dibenzoate crystals, the cocrystals do not exhibit benzoyl-transfer reactions. This approach is useful for increasing the stability of small molecules in the crystalline state and could find application in the design of functional solids.

Identification of molecular crystals capable of undergoing an acyl-transfer reaction based on intermolecular interactions in the crystal lattice.

Investigation of the intermolecular acyl-transfer reactivity in molecular crystals of myo-inositol orthoester derivatives and its correlation with crystal structures enabled us to identify the essential parameters to support efficient acyl-transfer reactions in crystals: 1) the favorable geometry of the nucleophile (-OH) and the electrophile (C-O) and 2) the molecular assembly, reinforced by C-H⋅⋅⋅π interactions, which supports a domino-type reaction in crystals. These parameters were used to identify another reactive crystal through a data-mining study of the Cambridge Structural Database. A 2:1 co-crystal of 2,3-naphthalene diol and its di-p-methylbenzoate was selected as a potentially reactive crystal and its reactivity was tested by heating the co-crystals in the presence of solid sodium carbonate. A facile intermolecular p-toluoyl group transfer was observed as predicted. The successful identification of reactive crystals opens up a new method for the detection of molecular crystals capable of exhibiting acyl-transfer reactivity.

Static vs. mobile sink: The influence of basic parameters on energy efficiency in wireless sensor networks.

Over the last decade a large number of routing protocols has been designed for achieving energy efficiency in data collecting wireless sensor networks. The drawbacks of using a static sink are well known. It has been argued in the literature that a mobile sink may improve the energy dissipation compared to a static one. Some authors focus on minimizing Emax, the maximum energy dissipation of any single node in the network, while others aim at minimizing Ebar, the average energy dissipation over all nodes. In our paper we take a more holistic view, considering both Emax and Ebar. The main contribution of this paper is to provide a simulation-based analysis of the energy efficiency of WSNs with static and mobile sinks. The focus is on two important configuration parameters: mobility path of the sink and duty cycling value of the nodes. On the one hand, it is well known that in the case of a mobile sink with fixed trajectory the choice of the mobility path influences energy efficiency. On the other hand, in some types of applications sensor nodes spend a rather large fraction of their total lifetime in idle mode, and therefore higher energy efficiency can be achieved by using the concept of reduced duty cycles. In particular, we quantitatively analyze the influence of duty cycling and the mobility radius of the sink as well as their interrelationship in terms of energy consumption for a well-defined model scenario. The analysis starts from general load considerations and is refined into a geometrical model. This model is validated by simulations which are more realistic in terms of duty cycling than previous work. It is illustrated that over all possible configuration scenarios in terms of duty cycle and mobility radius of the sink the energy dissipation in the WSN can vary up to a factor of nine in terms of Emax and up to a factor of 17 in terms of Ebar. It turns out that in general the choice of the duty cycle value is more important for achieving energy efficiency than the choice of the mobility radius of the sink. Moreover, for small values of the duty cycle, a static sink turns out to be optimal in terms of both Emax and Ebar. For larger values of the duty cycle, a mobile sink has advantages over a static sink, especially in terms of Emax. These insights into the basic interrelationship between duty cycle value and mobility radius of a mobile sink are relevant for energy efficient operation of homogeneous WSNs beyond our model scenario.

Potential new indication for ivabradine: treatment of a patient with congenital junctional ectopic tachycardia.

Ivabradine is a new antiarrhythmic agent with direct inhibition of the pacemaker (If) current. It has been used extensively to decrease sinus rate in the treatment of cardiac failure, and also in a single case of atrial ectopic tachycardia in a child. Here we report the case of a 3-year-old girl with congenital junctional ectopic tachycardia (JET), resistant to conventional antiarrhythmic medications, who was successfully treated with ivabradine. We suggest that ivabradine can be an effective treatment for junctional automatic tachycardias and can be considered as a new line of therapy for this incessant form of tachycardia.

Outcome of carpal tunnel decompression: the influence of age, gender, and occupation.

The aim of this study was to investigate the effect of age, gender, and occupation on the outcome of carpal tunnel decompression. A total of 479 patients (342 females, 137 males) with a mean age of 56 years undergoing 608 carpal tunnel decompressions were prospectively studied. Outcome was assessed using the Brigham Hospital carpal tunnel questionnaire at two weeks pre-operatively and six months post-operatively. Cases were divided into four age categories (less than 40 years of age, 40-59, 60-79, and over 80 years of age) and two occupation (repetitive and non-repetitive) groups. The mean differences for both the symptom-severity and functional-status scores amongst the four age categories were similar and no significant difference was found. The mean differences for both the symptom-severity and functional-status scores between females and males and the two occupation groups were similar and no significant differences were found. The majority of the patient's symptoms improved following carpal tunnel decompression. However, we found no influence of age, gender, or occupation on the outcome of carpal tunnel decompression in our series of patients.

Diagnosis and management of colovesical fistulae; six-year experience of 90 consecutive cases.

INTRODUCTION: Colovesical fistulae are well-recognized but relatively uncommon presentation to colorectal surgery. As a result, few centres have sufficient experience in the investigation and surgical treatment of colovesical fistulae to develop clear protocols in its management. METHODS: This study examines the diagnostic and treatment pathways of 90 consecutive patients with colovesical fistulae presenting to a single surgeon, over a six-year period. Using the findings from this study and previously published data, the authors suggest tentative guidelines for the diagnosis and management of such patients. RESULTS: Pneumaturia and faecaluria were present in 90.1% of all cases. The diagnosis of colovesical fistula is predominately a clinical one, however, cystoscopy was the most accurate test to detect fistulae (46.2%) followed by barium enema (20.1%). Barium enema was the most sensitive test to detect stricture formation (70.6%). Colonic endoscopy was the most reliable means of excluding a colonic malignancy. The most common pathology was diverticular disease (72.2%), colonic carcinoma (15.3%) and Crohn's disease (9.7%). Left sided colonic resections were undertaken in 73.6% of patients, right hemicolectomy in 4.2% and defunctioning loop colostomies in 18.5%. Of the left sided resections, primary anastomosis was achieved in 92% of cases (n = 48) with one postoperative leak and no mortality. DISCUSSION: Resection and primary anastomosis should be the treatment of choice for colovesical fistulae, with an acceptable risk of anastomotic leak and mortality. Barium enema, colonic endoscopy and CT should be routine in the investigation of colovesical fistulae.

Exteriorisation of the heart in two siblings.

We report two siblings with isolated ectopic hearts. Neither child had associated congenital diseases. To the best of our knowledge, this is the first reported familial occurrence of ectopic hearts.

Evaluation of dexamethasone pulse therapy in systemic sclerosis.

The treatment of systemic sclerosis, a multisystem disorder, is for from satisfactory. Dexamethasone pulse therapy was started in 25 patients of systemic sclerosis and of the 10 patients who successfully completed the treatment, the results have been quite encouraging. Adverse effects to the pulse were minimal.

Dexamethasone cyclophosphamide pulse therapy in pemphigus: experience in Kashmir valley.

Thirty patients of pemphigus have been treated with Dexamethasone Cyclophosphamide Pulse (DCP) in our hospital in the past three years. Of these twelve patients are off all treatment and are in complete remission while the rest are in different phases of the treatment and responding quite well to the pulse therapy. Only one case of relapse has been experienced till date.

Acute pulmonary oedema following smoke inhalation.

A case of acute pulmonary oedema after smoke inhalation from a chip pan fire is presented. The role of bronchial and pulmonary circulation in the development of pulmonary oedema after smoke inhalation is discussed. We stress the importance not only of observation after smoke inhalation, as the manifestation of pulmonary oedema may be delayed, but also of a baseline chest X-ray before admission for comparison.

Psychomotor retardation - an unusual association of keratosis follicularis spinulosa decalvans.

Keratosis follicularis spinulosa decalvans is one of a group of related disorders that shows keratosis pilaris with inflammation followed by atrophy. Here we report a case of this relatively rare disorder in a 6-year old boy who had associated psychomotor retardation.