Halogen bonding anion recognition Brown, Asha; Beer, Paul D
Chemical communications (Cambridge, England),
01/2016, Volume:
52, Issue:
56
Journal Article
Peer reviewed
A halogen bond is an attractive non-covalent interaction between an electrophilic region in a covalently bonded halogen atom and a Lewis base. While these interactions have long been exploited as a ...tool in crystal engineering their powerful ability to direct supramolecular self-assembly and molecular recognition processes in solution has, until recently, been overlooked. During the last decade however an ever-increasing number of studies on solution-phase halogen-bond-mediated anion recognition processes has emerged. This Feature Article summarises advancements which have been made thus far in this rapidly developing research area. We survey the use of iodoperfluoroarene, haloimidazolium and halotriazole/triazolium halogen-bond-donor motifs in anion receptor design, before providing an account of our research into the application of mechanically interlocked rotaxane and catenane frameworks as halogen bonding anion host systems.
The development of solution-based anion receptor molecules which exploit halogen bonding interactions is an emerging area of research. This
Feature Article
reviews recent advances which have been made in this rapidly developing field, surveying the use of iodoperfluoroarene, haloimidazolium and halotriazole/triazolium halogen-bond-donor motifs in anion receptor design and describing the application of mechanically interlocked rotaxane and catenane frameworks as halogen bonding anion host systems.
Over the last decade, melt electrospinning has emerged as an alternative polymer processing technology to alleviate concerns associated with solvents in traditional electrospinning. This has resulted ...in the fabrication of ultrafine fibers from an increasing range of synthetic polymers and composite systems, to materials including ceramics, driving new applications in technical areas such as textiles, filtration, environment and energy as well as biomedicine. In this article, we review the significant advancements in theoretical modeling of the underlying physical principles, coupled with experimental validation using a variety of technical devices and designs that allows well-controlled fiber formation using optimized material and operating parameters. Innovative device designs are indicating avenues towards higher throughput of randomly collected melt electrospun fibers for the production of commodity nonwoven substrates, similar to solution electrospinning and many other industrial fiber-forming processes. However, we identify a recent shift in perception towards melt electrospinning in the literature, where the adaptation of additive manufacturing approaches to device designs enables precise fiber placement with filament resolutions not yet demonstrated by more established melt-extrusion based direct writing technologies. New, highly ordered arrangements of ultrafine fibers with distinctive surface topology, encapsulating and sensing properties are opening new fields of application in areas such as drug delivery, biosensors and regenerative medicine as high performance materials. The development of these materials is reviewed with an emphasis on an area of current research, where melt electrospun scaffolds are contributing to promising treatment strategies to regenerate or replace human tissue and for the new field of in vitro disease models as well as humanized mice models.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
3.
Direct Writing By Way of Melt Electrospinning Brown, Toby D.; Dalton, Paul D.; Hutmacher, Dietmar W.
Advanced materials (Weinheim),
December 15, 2011, Volume:
23, Issue:
47
Journal Article
Peer reviewed
Melt electrospun fibers of poly(ϵ‐caprolactone) are accurately deposited using an automated stage as the collector. Matching the translation speed of the collector to the speed of the melt ...electrospinning jet establishes control over the location of fiber deposition. In this sense, melt electrospinning writing can be seen to bridge the gap between solution electrospinning and direct writing additive manufacturing processes.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Although polychaetes are one of the dominant taxa in marine communities, their distributions and taxonomic diversity are poorly understood. Recent studies have shown that many species thought to have ...broad distributions are actually a complex of allied species. In Canada, 12% of polychaete species are thought to occur in Atlantic, Arctic, and Pacific Oceans, but the extent of gene flow among their populations has not been tested.
Sequence variation in a segment of the mitochondrial cytochrome c oxidase I (COI) gene was employed to compare morphological versus molecular diversity estimates, to examine gene flow among populations of widespread species, and to explore connectivity patterns among Canada's three oceans. Analysis of 1876 specimens, representing 333 provisional species, revealed 40 times more sequence divergence between than within species (16.5% versus 0.38%). Genetic data suggest that one quarter of previously recognized species actually include two or more divergent lineages, indicating that richness in this region is currently underestimated. Few species with a tri-oceanic distribution showed genetic cohesion. Instead, large genetic breaks occur between Pacific and Atlantic-Arctic lineages, suggesting their long-term separation. High connectivity among Arctic and Atlantic regions and low connectivity with the Pacific further supports the conclusion that Canadian polychaetes are partitioned into two distinct faunas.
Results of this study confirm that COI sequences are an effective tool for species identification in polychaetes, and suggest that DNA barcoding will aid the recognition of species overlooked by the current taxonomic system. The consistent geographic structuring within presumed widespread species suggests that historical range fragmentation during the Pleistocene ultimately increased Canadian polychaete diversity and that the coastal British Columbia fauna played a minor role in Arctic recolonization following deglaciation. This study highlights the value of DNA barcoding for providing rapid insights into species distributions and biogeographic patterns in understudied groups.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Lung cancer remains the most common cause of both cancer mortality and brain metastases (BM). The purpose of this study was to assess the effect of gene alterations and tyrosine kinase inhibition ...(TKI) on median survival (MS) and cause of death (CoD) in patients with BM from lung adenocarcinoma (L-adeno).
A multi-institutional retrospective database of patients with L-adeno and newly diagnosed BM between 2006 and 2014 was created. Demographics, gene alterations, treatment, MS, and CoD were analyzed. The treatment patterns and outcomes were compared with those in prior trials.
Of 1521 L-adeno patients, 816 (54%) had known alteration status. The gene alteration rates were 29%, 10%, and 26% for EGFR, ALK, and KRAS, respectively. The time from primary diagnosis to BM for EGFR-/+ was 10/15 months (P=.02) and for ALK-/+ was 10/20 months (P<.01), respectively. The MS for the group overall (n=1521) was 15 months. The MS from first treatment for BM for EGFR and ALK-, EGFR+, ALK+ were 14, 23 (P<.01), and 45 (P<.0001) months, respectively. The MS after BM for EGFR+ patients who did/did not receive TKI before BM was 17/30 months (P<.01), respectively, but the risk of death was not statistically different between TKI-naïve patients who did/did not receive TKI after the diagnosis of BM (EGFR/ALK hazard ratios: 1.06 P=.84/1.60 P=.45, respectively). The CoD was nonneurologic in 82% of patients with known CoD.
EGFR and ALK gene alterations are associated with delayed onset of BM and longer MS relative to patients without these alterations. The CoD was overwhelmingly nonneurologic in patients with known CoD.
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GEOZS, IJS, NUK, OILJ, UL, UM, UPUK
Summary CNS metastases are the most common cause of malignant brain tumours in adults. Historically, patients with brain metastases have been excluded from most clinical trials, but their inclusion ...is now becoming more common. The medical literature is difficult to interpret because of substantial variation in the response and progression criteria used across clinical trials. The Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) working group is an international, multidisciplinary effort to develop standard response and progression criteria for use in clinical trials of treatment for brain metastases. Previous efforts have focused on aspects of trial design, such as patient population, variations in existing response and progression criteria, and challenges when incorporating neurological, neuro-cognitive, and quality-of-life endpoints into trials of patients with brain metastases. Here, we present our recommendations for standard response and progression criteria for the assessment of brain metastases in clinical trials. The proposed criteria will hopefully facilitate the development of novel approaches to this difficult problem by providing more uniformity in the assessment of CNS metastases across trials.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To provide guidance to clinicians regarding therapy for patients with brain metastases from solid tumors.
ASCO convened an Expert Panel and conducted a systematic review of the literature.
Thirty-two ...randomized trials published in 2008 or later met eligibility criteria and form the primary evidentiary base.
Surgery is a reasonable option for patients with brain metastases. Patients with large tumors with mass effect are more likely to benefit than those with multiple brain metastases and/or uncontrolled systemic disease. Patients with symptomatic brain metastases should receive local therapy regardless of the systemic therapy used. For patients with asymptomatic brain metastases, local therapy should not be deferred unless deferral is specifically recommended in this guideline. The decision to defer local therapy should be based on a multidisciplinary discussion of the potential benefits and harms that the patient may experience. Several regimens were recommended for non-small-cell lung cancer, breast cancer, and melanoma. For patients with asymptomatic brain metastases and no systemic therapy options, stereotactic radiosurgery (SRS) alone should be offered to patients with one to four unresected brain metastases, excluding small-cell lung carcinoma. SRS alone to the surgical cavity should be offered to patients with one to two resected brain metastases. SRS, whole brain radiation therapy, or their combination are reasonable options for other patients. Memantine and hippocampal avoidance should be offered to patients who receive whole brain radiation therapy and have no hippocampal lesions and 4 months or more expected survival. Patients with asymptomatic brain metastases with either Karnofsky Performance Status ≤ 50 or Karnofsky Performance Status < 70 with no systemic therapy options do not derive benefit from radiation therapy.Additional information is available at www.asco.org/neurooncology-guidelines.
To investigate local control, survival outcomes, and predictors of local relapse for patients treated with spine stereotactic body radiation therapy.
We reviewed the records of 332 spinal metastases ...consecutively treated with stereotactic body radiation therapy between 2002 and 2012. The median follow-up for all living patients was 33 months (range, 0-111 months). Endpoints were overall survival and local control (LC); recurrences were classified as either in-field or marginal.
The 1-year actuarial LC and overall survival rates were 88% and 64%, respectively. Patients with local relapses had poorer dosimetric coverage of the gross tumor volume (GTV) compared with patients without recurrence (minimum dose Dmin biologically equivalent dose BED 23.9 vs 35.1 Gy, P<.001; D98 BED 41.8 vs 48.1 Gy, P=.001; D95 BED 47.2 vs 50.5 Gy, P=.004). Furthermore, patients with marginal recurrences had poorer prescription coverage of the GTV (86% vs 93%, P=.01) compared with those with in-field recurrences, potentially because of more upfront spinal canal disease (78% vs 24%, P=.001). Using a Cox regression univariate analysis, patients with a GTV BED Dmin ≥33.4 Gy (median dose) (equivalent to 14 Gy in 1 fraction) had a significantly higher 1-year LC rate (94% vs 80%, P=.001) compared with patients with a lower GTV BED Dmin; this factor was the only significant variable on multivariate Cox analysis associated with LC (P=.001, hazard ratio 0.29, 95% confidence interval 0.14-0.60) and also was the only variable significant in a separate competing risk multivariate model (P=.001, hazard ratio 0.30, 95% confidence interval 0.15-0.62).
Stereotactic body radiation therapy offers durable control for spinal metastases, but there is a subset of patients that recur locally. Patients with local relapse had significantly poorer tumor coverage, which was likely attributable to treatment planning directives that prioritized the spinal cord constraints over tumor coverage. When possible, we recommend maintaining a GTV Dmin above 14 Gy in 1 fraction and 21 Gy in 3 fractions.
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GEOZS, IJS, NUK, OILJ, UL, UM, UPUK
Summary Background Spinal stereotactic body radiation therapy (SBRT) is increasingly used to manage spinal metastases, yet the technique's effectiveness in controlling the symptom burden of spinal ...metastases has not been well described. We investigated the clinical benefit of SBRT for managing spinal metastases and reducing cancer-related symptoms. Methods 149 patients with mechanically stable, non-cord-compressing spinal metastases (166 lesions) were given SBRT in a phase 1–2 study. Patients received a total dose of 27–30 Gy, typically in three fractions. Symptoms were measured before SBRT and at several time points up to 6 months after treatment, by the Brief Pain Inventory (BPI) and the M D Anderson Symptom Inventory (MDASI). The primary endpoint was frequency and duration of complete pain relief. The study is completed and is registered with ClinicalTrials.gov , number NCT00508443. Findings Median follow-up was 15·9 months (IQR 9·5–30·3). The number of patients reporting no pain from bone metastases, as measured by the BPI, increased from 39 of 149 (26%) before SBRT to 55 of 102 (54%) 6 months after SBRT (p<0·0001). BPI-reported pain reduction from baseline to 4 weeks after SBRT was clinically meaningful (mean 3·4 SD 2·9 on the BPI pain-at-its-worst item at baseline, 2·1 2·4 at 4 weeks; effect size 0·47, p=0·00076). These improvements were accompanied by significant reduction in opioid use during the first 6 months after SBRT (43 28·9% of 149 patients with strong opioid use at baseline vs 20 20·0% of 100 at 6 months; p=0·011). Ordinal regression modelling showed that patients reported significant pain reduction according to the MDASI during the first 6 months after SBRT (p=0·00003), and significant reductions in a composite score of the six MDASI symptom interference with daily life items (p=0·0066). Only a few instances of non-neurological grade 3 toxicities occurred: nausea (one event), vomiting (one), diarrhoea (one), fatigue (one), dysphagia (one), neck pain (one), and diaphoresis (one); pain associated with severe tongue oedema and trismus occurred twice; and non-cardiac chest pain was reported three times. No grade 4 toxicities occurred. Progression-free survival after SBRT was 80·5% (95% CI 72·9–86·1) at 1 year and 72·4% (63·1–79·7) at 2 years. Interpretation SBRT is an effective primary or salvage treatment for mechanically stable spinal metastasis. Significant reductions in patient-reported pain and other symptoms were evident 6 months after SBRT, along with satisfactory progression-free survival and no late spinal cord toxicities. Funding National Cancer Institute of the US National Institutes of Health.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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