Flexible Block Copolymer Metamaterials Featuring Hollow Ordered Nanonetworks with Ultra-High Porosity and Surface-To-Volume Ratio.

By utilizing bicontinuous and nanoporous ordered nanonetworks, such as double gyroid (DG) and double diamond (DD), metamaterials with exceptional optical and mechanical properties can be fabricated through the templating synthesis of functional materials. However, the volume fraction range of DG in block copolymers is significantly narrow, making it unable to vary its porosity and surface-to-volume ratio. Here, the theoretically limited structural volume of the DG phase in coil-coil copolymers is overcome by enlarging the conformational asymmetry through the association of mesogens, providing fast access to achieving flexible structured materials of ultra-high porosities. The new materials design, dual-extractable nanocomposite, is created by incorporating a photodegradable block with a solvent-extractable mesogen (m) into an accepting block, resulting in a new hollow gyroid (HG) with the largely increased surface-to-volume ratio and porosity of 77 vol%. The lightweight HG exhibits a low refractive index of 1.11 and a very high specific reduced modulus, almost two times that of the typical negative gyroid (porosity≈53%) and three times that of the positive gyroid (porosity≈24%). This novel concept can significantly extend the DG phase window of block copolymers and the corresponding surface-to-volume ratio, being applicable for nanotemplate-synthesized nanomaterials with a great gain of mechanical, catalytic, and optoelectronic properties.

Mesoscale networks and corresponding transitions from self-assembly of block copolymers.

A series of cubic network phases was obtained from the self-assembly of a single-composition lamellae (L)-forming block copolymer (BCP) polystyrene-block-polydimethylsiloxane (PS-b-PDMS) through solution casting using a PS-selective solvent. An unusual network phase in diblock copolymers, double-primitive phase (DP) with space group of [Formula: see text], can be observed. With the reduction of solvent evaporation rate for solution casting, a double-diamond phase (DD) with space group of [Formula: see text] can be formed. By taking advantage of thermal annealing, order-order transitions from the DP and DD phases to a double-gyroid phase (DG) with space group of [Formula: see text] can be identified. The order-order transitions from DP (hexapod network) to DD (tetrapod network), and finally to DG (trigonal planar network) are attributed to the reduction of the degree of packing frustration within the junction (node), different from the predicted Bonnet transformation from DD to DG, and finally to DP based on enthalpic consideration only. This discovery suggests a new methodology to acquire various network phases from a simple diblock system by kinetically controlling self-assembling process.

Networks with controlled chirality via self-assembly of chiral triblock terpolymers.

Nanonetwork-structured materials can be found in nature and synthetic materials. A double gyroid (DG) with a pair of chiral networks but opposite chirality can be formed from the self-assembly of diblock copolymers. For triblock terpolymers, an alternating gyroid (GA) with two chiral networks from distinct end blocks can be formed; however, the network chirality could be positive or negative arbitrarily, giving an achiral phase. Here, by taking advantage of chirality transfer at different length scales, GA with controlled chirality can be achieved through the self-assembly of a chiral triblock terpolymer. With the homochiral evolution from monomer to multichain domain morphology through self-assembly, the triblock terpolymer composed of a chiral end block with a single-handed helical polymer chain gives the chiral network from the chiral end block having a particular handed network. Our real-space analyses reveal the preferred chiral sense of the network in the GA, leading to a chiral phase.

Left-sided acute appendicitis: a pitfall in the emergency department.

BACKGROUND: Acute appendicitis continues to be a condition at high risk for missed and delayed diagnosis. It characteristically presents with right lower quadrant pain after vague epigastric or periumbilical discomfort. Left-sided appendicitis is an atypical presentation and has been reported rarely. The majority of these cases have been described to be associated with congenital midgut malrotation, situs inversus, or an extremely long appendix. We report a case of left-sided acute appendicitis occurring in a patient with a redundant and hypermobile ascending colon. OBJECTIVES: To alert emergency physicians to an anatomical anomaly that could delay the diagnosis of appendicitis. CASE REPORT: A 50-year-old man presented with fever and left lower abdominal pain. Physical examination revealed local tenderness over the left lower quadrant. Abdominal computed tomography scan revealed a redundant, floating, ascending colon and inflammatory appendix adhering to the descending colon over the left lower abdomen. Exploratory laparotomy was performed and perforated appendicitis with turbid ascites was found during the surgery. Appendectomy was performed and the patient recovered uneventfully. CONCLUSION: This case is presented to increase awareness among emergency physicians of this anatomical variant and atypical presentation of appendicitis.

Increased expression of visfatin in monocytes and macrophages in male acute myocardial infarction patients.

We demonstrated that visfatin expressed in monocytes and neutrophils and increased their reactivity in male acute ST-segment elevation myocardial infarction patients. Furthermore, visfatin was strongly appeared in lipid rich coronary rupture plaques and macrophages. These results suggest another explanation about leukocytes mediated visfatin that may play a pathogenesis role in coronary vulnerable plaques rupture.

Interpretation of elevated plasma visfatin concentrations in patients with ST-elevation myocardial infarction.

Visfatin is a cytokine that is expressed in many tissues, including the heart, and has been proposed to play a role in plaque destabilization leading to acute myocardial injury. The present study evaluates plasma levels of visfatin in acute ST-elevation myocardial infarction (STEMI) patients and examines the temporal changes in visfatin levels from the acute period to the subacute period to determine a correlation with the degree of myocardial ischemia. We evaluated 54 patients with STEMI. Circulating levels of visfatin and brain natriuretic peptide (BNP) were measured by ELISA. In addition, local expression of visfatin and BNP were detected by quantitative real-time polymerase chain reaction and immunohistochemical (IHC) analysis of left ventricular myocytes in a mouse model of myocardial infarction (MI). Plasma levels of visfatin were significantly increased in patients with STEMI on admission, relative to controls (effort angina patients and individuals without coronary artery disease). The visfatin levels reached a peak 24h after percutaneous coronary intervention (PCI) and then decreased toward the control range during the first week after PCI. The basal plasma visfatin levels were found to correlate with peak troponin-I, peak creatine kinase-MB, total white blood cell count, and BNP levels. Trend analyses confirmed that visfatin levels correlated with the number of diseased coronary arteries. Further, in MI mice, mRNA levels of visfatin and BNP were found to be higher than in sham-treated mice. IHC analysis showed that visfatin and BNP immunoreactivity was diffusely observable in left ventricular myocytes of the MI mice. This study indicates that plasma visfatin levels are significantly higher in STEMI patients and that these higher visfatin levels correlate with elevated levels of cardiac enzymes, suggesting that increased plasma visfatin may be closely related to the degree of myocardial damage.

Increased levels of total P-Cresylsulphate and indoxyl sulphate are associated with coronary artery disease in patients with diabetic nephropathy.

BACKGROUND: Indoxyl sulphate (IS) and p-cresylsulphate (PCS) are uremic toxins with similar protein-binding, dialytic clearance, and proinflammatory features. Few studies have evaluated the possible associations between these solutes and coronary artery disease (CAD) in type 2 diabetes (T2D) patients. METHODS: A hospital-based case control study was performed. A total of 209 T2D patients were divided into two groups based on the presence/absence of significant CAD (≥50% luminal reduction). Serum total PCS and IS levels were measured using the Ultra Performance LC System. The relationship between total PCS and IS levels were investigated. Coronary calcium scores and the modified Gensini score were analyzed. RESULTS: Serum total PCS and IS levels were significantly higher in patients with both T2D and significant CAD, than in non-diabetic control subjects and T2D patients without CAD (all p < 0.05). Logistic regression analysis revealed independent and significant associations between the two solutes and CAD status. Serum total PCS, IS, and numbers of diseased vessels were elevated in groups with estimated glomerular filtration rate (eGFR) of 60-89 ml/min/1.73 m2 and below. Also, serum total PCS and IS levels were significantly associated with eGFR, coronary calcium scores, Gensini score, adipocytokines (adiponectin, visfatin, and leptin), and total white blood cell count. CONCLUSIONS: Serum total PCS and IS levels were elevated in patients with T2D and CAD. These increases were associated with renal function deterioration, inflammation, and coronary atherosclerosis.