Self-Assembly of an Anion-Binding Cryptand for the Selective Encapsulation, Sequestration, and Precipitation of Phosphate from Aqueous Systems.

The self-assembled trimetallic species [L2 Cu3 ]6+ contains a cavity that acts as a host to many different anions. By using X-ray crystallography, ESI-MS, and UV/Vis spectroscopy we show that these anions are encapsulated both in the solid state and aqueous systems. Upon encapsulation, the anions Br- , I- , CO32- , SiF62- , IO63- , VO43- , WO42- , CrO42- , SO42- , AsO43- , and PO43- are all precipitated from aqueous solution and can be removed by filtration. Furthermore, the cavity can be tuned to be selective to either phosphate or sulfate anions by variation of the pH. Phosphate anions can be removed from water, even in the presence of other common anions, reducing the concentration from 1000 to <0.1 ppm and recovering approximately 99 % of the phosphate anions.

Formation of a dimer of trinuclear helicates which encapsulates an array of six hydrogen-bonded anions.

The amine-containing ligand L, composed of two bidentate pyridyl-thiazole moieties linked by a 1,3-diaminophenylene unit, reacts with copper(II) ions to form a dinuclear double helicate [Cu2 L2 ](4+) . Reaction of [Cu2 L2 ](4+) with dihydrogen phosphate (0.5 equivalents) gives the unsaturated dinuclear double helicate [Cu2 L2 (OPO3 H2 )](3+) . [Cu2 L2 (OPO3 H2 )](3+) further reacts with another 0.5 equivalents of dihydrogen phosphate to give a trinuclear circular helicate which then self-assembles into a hexameric cluster [{Cu3 L3 (OPO3 H2 )3 }](26+) .

Building Complex Autologous Breast Reconstruction Program: A Preliminary Experience.

Autologous breast reconstruction is an increasingly popular method of reconstruction for breast cancer survivors. While deep inferior epigastric perforator (DIEP) flaps are the gold standard, not all patients are ideal candidates for DIEP flaps due to low BMI, body habitus, or previous abdominal surgery. In these patients, complex autologous breast reconstruction can be performed, but there is a limited number of programs around the world due to high technical demand. Given the increased demand and need for complex autologous flaps, it is critical to build programs to increase patient access and teach future microsurgeons. In this paper, we discuss the steps, pearls, and preliminary experience of building a complex autologous breast reconstruction program in a tertiary academic center. We performed a retrospective chart review of patients who underwent starting the year prior to the creation of our program. Since the start of our program, a total of 74 breast mounds have been reconstructed in 46 patients using 87 flaps. Over 23 months, there was a decrease in median surgical time for bilateral reconstruction by 124 min (p = 0.03), an increase in the number of co-surgeon cases by 66% (p < 0.01), and an increase in the number of complex autologous breast reconstruction by 42% (p < 0.01). Our study shows that a complex autologous breast reconstruction program can be successfully established using a multi-phase approach, including the development of a robust co-surgeon model. In addition, we found that a dedicated program leads to increased patient access, decreased operative time, and enhancement of trainee education.

Collagen fibrils from both positional and energy-storing tendons exhibit increased amounts of denatured collagen when stretched beyond the yield point.

Collagen molecules are the base structural unit of tendons, which become denatured during mechanical overload. We recently demonstrated that during tendon stretch, collagen denaturation occurs at the yield point of the stress-strain curve in both positional and energy-storing tendons. We were interested in investigating how this load is transferred throughout the collagen hierarchy, and sought to determine the onset of collagen denaturation when collagen fibrils are stretched. Fibrils are one level above the collagen molecule in the collagen hierarchy, allowing more direct probing of the effect of strain on collagen molecules. We isolated collagen fibrils from both positional and energy-storing tendon types and stretched them using a microelectromechanical system device to various levels of strain. We stained the fibrils with fluorescently labeled collagen hybridizing peptides that specifically bind to denatured collagen, and examined whether samples stretched beyond the yield point of the stress-strain curve exhibited increased amounts of denatured collagen. We found that collagen denaturation in collagen fibrils from both tendon types occurs at the yield point. Greater amounts of denatured collagen were found in post-yield positional fibrils than in energy-storing fibrils. This is despite a greater yield strain and yield stress in fibrils from energy-storing tendons compared to positional tendons. Interestingly, the peak modulus of collagen fibrils from both tendon types was the same. These results are likely explained by the greater crosslink density found in energy-storing tendons compared to positional tendons. The insights gained from this study could help management of tendon and other musculoskeletal injuries by targeting collagen molecular damage at the fibril level. STATEMENT OF SIGNIFICANCE: When tendons are stretched or torn, this can lead to collagen denaturation (damage). Depending on their biomechanical function, tendons are considered positional or energy-storing with different crosslink profiles. By stretching collagen fibrils instead of fascicles from both tendon types, we can more directly examine the effect of tensile stretch on the collagen molecule in tendons. We found that regardless of tendon type, collagen denaturation in fibrils occurs when they are stretched beyond the yield point of the stress-strain curve. This provides insight into how load affects different tendon sub-structures during tendon injuries and failure, which will help clinicians and researchers understand mechanisms of injuries and potentially target collagen molecular damage as a treatment strategy, leading to improved clinical outcomes following injury.

Does preoperative weight loss in a specialist medical weight management centre influence postoperative weight loss after bariatric surgery?

Weight loss of 5%-10% is advised in medical weight management (MWM) programmes prior to bariatric surgery but it remains to be established whether it influences postoperative weight loss outcomes. We studied postoperative percent total weight loss (%TWL) in 168 patients categorized by preoperative referral weight loss <5% or ≥5% in a UK NHS bariatric centre. Eighty-six (51.2%) patients achieved sustained referral weight loss <5% (Group A) and 82 (48.8%) ≥5% (Group B). Overall postoperative %TWL in Group A compared with Group B was 30.0% versus 28.3% (p = .30) at 12 months and 32.5% versus 29.6% (p = .20) at 24 months. There were no significant differences in postoperative %TWL at 12 and 24 months when categorized by procedure (gastric bypass, n = 106; or sleeve gastrectomy, n = 62), age or sex. Preoperative weight loss during intensive specialist MWM did not influence postoperative weight loss up to 24 months with gastric bypass or sleeve gastrectomy.

Haemoglobin and Hematinic Status Before and After Bariatric Surgery over 4 years of Follow-Up.

PURPOSE: Bariatric surgery is associated with deficiencies of vitamins and minerals, and patients are routinely advised supplements postoperatively. We studied prevalence of vitamin B12, folate and iron deficiencies and anaemia before and after bariatric surgery over 4 years of follow-up. MATERIALS AND METHODS: We performed a retrospective cohort analysis of 353 people with obesity, including 257 (72.8%) women, who underwent gastric bypass (252, 71.4%) or sleeve gastrectomy (101, 28.6%) at our National Health Service bariatric centre in Northwest England. RESULTS: At baseline, mean (standard error) age was 46.0 (0.6) years, body mass index 53.1 (0.4) kg/m2, serum vitamin B12 400.2 (16.4) pg/L, folate 7.7 (0.2) µg/L, iron 12.0 (0.3) µmol/L, ferritin 118.3 (8.4) µg/L and haemoglobin 137.9 (0.8) g/L. Frequency of low vitamin B12 levels reduced from 7.5% preoperatively to 2.3% at 48 months (P < 0.038). Mean folate levels increased from baseline to 48 months by 5.3 µg/L (P < 0.001) but frequency of low folate levels increased from 4.7% preoperatively to 10.3% (P < 0.048). Ferritin levels increased from baseline to 48 months by 51.3 µg/L (P < 0.009). Frequency of low ferritin levels was greater in women (39.1%) than in men (8.9%) at baseline (P < 0.001) and throughout the study period. Haemoglobin was low in 4.6% of all patients at baseline with no significant change over the study period. CONCLUSION: There were notable rates of haematinic insufficiencies in bariatric surgical candidates preoperatively. Our study lends further support to regular supplementation with vitamin B12, folic acid, and iron in people undergoing bariatric surgery.

A ligand strand that displays anion-dependant reactivity with acetonitrile; formation of either a mononuclear complex or head-to-tail circular helicate.

The ligand L2,2 contains two bidentate domains separated by a 3,3-diamino-2,2'-biphenyl spacer unit and with Cu(ClO4)2 a mononuclear species is formed (e.g. [Cu(L2,2)]2+). Upon coordination with Cu(triflate)2 the ligand undergoes reaction with an acetonitrile solvent, producing a different ligand with unsymmetrical bidentate and tridentate domains (L2,3). This new ligand results in the formation of a tetranuclear head-to-tail circular helicate [Cu4(L2,3)4]8+ showing that in the presence of the triflate anion the ligand denticity is changed.

Dihydrogen phosphate-containing dinuclear double assemblies that demonstrate phosphate reactivity to the tetrafluoroborate anion.

The ligands L1 and L2 both form dinuclear assemblies with Cu(ii) and these react with dihydrogen phosphate so that the anion is incorporated within the assembly (e.g. [Cu2L2(H2PO4)]3+). However, in the presence of tetrafluoroborate anions the phosphate undergoes reaction with the anion forming [Cu3(L1)3(O3POBF3)]3+ and [Cu2(L2)2(O2P(OBF3)2)]+.

Nutrition in Pregnancy Following Bariatric Surgery.

The widespread use of bariatric surgery for the treatment of morbid obesity has led to a dramatic increase in the numbers of women who become pregnant post-surgery. This can present new challenges, including a higher risk of protein and calorie malnutrition and micronutrient deficiencies in pregnancy due to increased maternal and fetal demand. We undertook a focused, narrative review of the literature and present pragmatic recommendations. It is advisable to delay pregnancy for at least 12 months following bariatric surgery. Comprehensive pre-conception and antenatal care is essential to achieving the best outcomes. Nutrition in pregnancy following bariatric surgery requires specialist monitoring and management. A multidisciplinary approach to care is desirable with close monitoring for deficiencies at each trimester.

Self-assembly of a heteroleptic one-dimensional chain comprising different dinuclear meso-helicates in the solid-state.

We describe two mesocate assemblies that contain either an ethylene glycol or ammonium group which form a heteroleptic one-dimensional infinite chain in the solid state.

Steric control of the formation of dinuclear double helicate and dinuclear meso-helicate assemblies.

We describe a ligand system that forms either a dinuclear double helicate or a dinuclear double mesocate dependent upon the size of the metal ion or the steric bulk of the ligand strand.