512 research outputs found
Bis(2-amino-4-methylpyridinium) tetrachloridocuprate(II)
The asymmetric unit of the title compound, (C6H9N2)2[CuCl4], consists of one cation and one half-anion, bisected by a twofold rotation axis through the metal center. The anion exhibits a geometry that is intermediate between a Td and D
4h arrangement about the Cu atom. The crystal structure contains chains of cations alternating with stacks of anions. The cationic groups interact via offset face-to-face π–π stacking, forming chains running along the c axis. The anion stacks are parallel to the cation chains, with no significant inter- nor intrastack Cl⋯Cl interactions. There are several anion–cation hydrogen-bonding interactions of the (N—H)pyridine⋯Cl and (N—H)amino⋯Cl types, connecting the chains of cations to the stacks of anions. Both the N—H⋯Cl and π–π stacking interactions [centroid–centroid distances 3.61 (8) and 3.92 (2) Å] contribute to the formation of a three-dimensional supramolecular architecture
A disseminated variant of pancreatic serous cystadenoma causing obstructive jaundice, a very rare entity: a case report and review of the literature
BACKGROUND: Microcystic adenoma or serous cystadenoma (SCA) is an uncommon tumor type, accounting for only 1–2% of pancreatic exocrine neoplasms. Usually unifocal, SCAs present as single, large, well-demarcated, multiloculated, cystic tumors, 1–25 cm in size. CASE PRESENTATION: A 73-year-old man initially presented with epigastric abdominal pain and was diagnosed with SCA involving the whole pancreas. Eleven months later, he presented with obstructive jaundice, and total pancreatectomy was performed. The removed tissue allowed histological verification of pancreatic SCA. Histopathological examination showed both microcysts and macrocysts, lined by cuboidal epithelium, with optically clear cytoplasm and the absence of detectable mitosis or necrosis. CONCLUSIONS: Thus, although relatively rare, pancreatic SCA is one of the differential diagnoses of epigastric abdominal pain; we recommend early surgical intervention for symptomatic pancreatic SCA
2,5-Dibromopyridine
In the title compound, C5H3Br2N, C—H⋯N hydrogen-bonding interactions and Br⋯Br interactions [3.9418 (3) and 3.8986 (3) Å] connect the molecules into planar sheets stacked perpendicular to the b axis. In addition, pyridyl–pyridyl intersheet π–π stacking interactions [centroid–centroid distance = 4.12 (1) Å] result in a three-dimensional network
Perception and intentions to quit among waterpipe smokers in Qatar: a cross-sectional survey
Objective: To evaluate the perceptions and attitudes of waterpipe (shisha) smokers in Qatar regarding the health risks associated with addiction and to determine their intentions to quit.
Methods: A cross-sectional survey was conducted among 181 self-reported waterpipe smokers. Participants were approached in public places as well as in shisha cafes in Qatar. The questionnaire included items related to perception, attitude and intention to quit. Both descriptive and inferential statistics were performed for data analyses, with P ≤ 0.05 considered statistically significant.
Results: About 44% of the respondents believed that waterpipe smoking was safer than cigarette smoking, and more than 70% would not mind if their children became involved in waterpipe smoking. More than half of the current smokers wanted to quit smoking shisha at some point, and 17% identified health concerns as the main motivating factor for their intention to quit.
Conclusion: A large proportion of shisha smokers viewed shisha as a safer alternative to cigarettes, yet they admitted to intending to quit. These findings underscore the need to design educational interventions and awareness campaigns as well as impose stringent laws on waterpipe smoking in public places in Qatar.Undergraduate Research Experience Program (UREP) grant (UREP 13-063-3-016) from the Qatar National Research Fund (a member of the Qatar Foundation)
3-Ammoniopyridinium tetrabromidomercurate(II) monohydrate
The asymmetric unit of the title compound, (C5H8N2)[HgBr4]·H2O, consists of one cation, one anion and one water molecule. The anion exhibits a distorted tetrahedral arrangement about the Hg atom. The crystal structure contains alternating sheets of cations (in the ac plane) and stacks of anions. Several strong hydrogen-bonding interactions (pyN—H⋯Br and C—H⋯Br; py is pyridine), along with O—H⋯Br interactions, connect the sheets of cations to the stacks of anions. Cation–cation π–π stacking is also present (C⋯C distances in the range 3.424–3.865 Å). The shortest Br⋯Br distance is 3.9527 (9) Å
Bis(2,6-dimethylpyridinium) tetrabromidocobaltate(II)
In the crystal structure of the title compound, (C7H10N)2[CoBr4], the [CoBr4]2− anion is connected to two cations through N—H⋯Br and H2C—H⋯Br hydrogen bonds to form two-dimensional cation–anion–cation layers normal to the crystallographic b axis. Interactions of the π–π type are absent between cations in the stacks [centroid–centroid separation = 5.01 (5) Å]. Significant intermolecular Br–aryl interactions are present in the structure, especially an unusually short Br–ring centroid interaction of 3.78 (1) Å. The coordination geometry of the anion is approximately tetrahedral and a twofold rotation axis passes through the Co atom
Bis(2-amino-6-methylpyridinium) tetrabromidocuprate(II)
In the crystal structure of the title compound, (C6H9N2)2[CuBr4], the geometry around the Cu atom is intermediate between tetrahedral (Td) and square planar (D4h). Each [CuBr4]2− anion is connected non-symmetrically to four surrounding cations through N—H⋯X (pyridine and amine proton) hydrogen bonds, forming chains of the ladder-type running parallel to the crystallographic b axis. These layers are further connected by means of offset face-to-face interactions (parallel to the a axis), giving a three-dimensional network. Cation π–π stacking [centroid separations of 3.69 (9) and 3.71 (1) Å] and Br⋯aryl interactions [3.72 (2) and 4.04 (6) Å] are present in the crystal structure. There are no intermolecular Br⋯Br interactions
Clinical Characteristics, Prognostic Factors and Treatment Outcomes of Patients with Bone-Only Metastatic Breast Cancer
Introduction: Bone is the most frequent site of breast cancer metastasis. Differences between those who present with de novo bone-only metastasis (BOM) and those who progress to bone-only disease following a diagnosis of early-stage breast cancer are not clear. Such differences in clinical course might have an impact on the aggressiveness of treatment. This study presents the clinical and pathological features, along with treatment outcomes, of breast cancer patients with BOM in relation to the timing and type of bone metastasis.
Patients and Methods: Patients with breast cancer and BOM were retrospectively reviewed. De novo BOM was defined as bone metastasis diagnosed at presentation or within the first 4 months of follow-up. Treatment outcomes of patients with de novo, compared to those with subsequent BOM, are presented.
Results: 242 patients, median age (range) at diagnosis was 52 (27-80) years were enrolled. The majority of the patients (77.3%) had de novo BOM with multiple sites of bone involvement (82.6%). At a median follow-up of 37.7 months, the median overall survival (OS) for patients with de novo BOM disease was significantly shorter than those who developed so subsequently; 40.8 months (95% CI, 51.1-184.1) compared to 80.9 months (95% CI, 36.4-47.9), p \u3c 0.001. Tumor grade, hormone receptor status and type of bone lesions (lytic versus sclerotic) had a significant impact on survival outcomes.
Conclusion: Breast cancer with de novo BOM is a distinct clinical entity with unfavorable prognosis and is associated with shorter survival. Several risk factors for poor outcomes were identified and might inform treatment plans
Bis(2,6-diamino-3,5-dibromopyridinium) hexabromidostannate(IV)
The asymmetric unit of the title compound, (C5H6Br2N3)2[SnBr6], contains one cation and one half-anion in which the Sn atom is located on a crystallographic centre of inversion and is in a quasi-octahedral geometry. The crystal structure is assembled via hydrogen-bonding interactions of two kinds, N(pyridine/amine)—H⋯Br—Sn, along with C—Br⋯Br—Sn interactions [3.4925 (19) Å]. The cations are involved in π–π stacking, which adds an extra supramolecularity as it presents a strong case of offset-face-to-face motifs [centroid–centroid distance = 3.577 (3) Å]. The intermolecular hydrogen bonds, short Br⋯Br interactions and π–π stacking result in the formation of a three-dimensional supramolecular architecture
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