Graphene-Based Aqueous Lubricants: Dispersion Stability to the Enhancement of Tribological Properties.

The present investigation demonstrates a green and scalable chemical approach to prepare aminoborate-functionalized reduced graphene oxide (rGO-AmB) for aqueous lubricants. The chemical, structural, crystalline, and morphological features of rGO-AmB are probed by XPS, FTIR, Raman, XRD, and HRTEM measurements. The spectroscopic analyses revealed the multiple interaction pathways between rGO and AmB. rGO-AmB exhibited long-term dispersion stability and improved the thermal conductivity of water by 68%. The thermal conductivity increased with increasing concentration of rGO-AmB and temperature. rGO-AmB as an additive to water (0.2%) enhanced the tribological properties of a steel tribopair under the boundary lubrication regime by the significant reduction in friction (70%) and wear (68%). The tribo-induced gradual deposition of an rGO-AmB-based thin film facilitated the interfacial sliding between the steel tribopair and protected it from the wear. The ultralow thickness, excellent dispersibility in water, high thermal conductivity, intrinsic low frictional properties, and good affinity toward the tribo-interfaces make rGO-AmB a potential candidate for aqueous lubricants.

Synergistic lubrication performance by incommensurately stacked ZnO-decorated reduced graphene oxide/MoS2 heterostructure.

Incommensurate stacking between two different types of two-dimensional layered materials furnished the weak interfacial interaction due to the mismatch of their lattice structure, which can be harnessed for development of new generation lubricant additives. Herein, a facile approach is presented to synthesize the ZnO-decorated reduced graphene oxide/MoS2 (Gr-MS-Zn) nanosheets. The Fourier transform infrared, X-ray photoelectron spectroscopic, Raman, and transmission electron microscopic analyses confirmed the preparation of Gr-MS-Zn heterostructure. The MoS2 nanosheets having 3-7 molecular lamellae are thoroughly distributed over the graphene skeleton via weak interfacial interaction. The curved and bent structure of MoS2 nanosheets grown over the graphene lamellae subsidized the cohesive interaction and furnished the stable dispersion of Gr-MS-Zn in the fully formulated engine oil. The minute dose of Gr-MS-Zn as a nano-additive to engine oil significantly enhanced the tribological performance between the steel-steel tribopair by decreasing the friction (37%) and the wear volume (87%). The microscopic and spectroscopic analyses revealed the formation of a Gr-MS-Zn-based surface protective tribo thin film of low shear strength. The enhanced tribo performance is collectively attributed to (a) uninterrupted supply of ultrathin Gr-MS-Zn nanosheets to tribo-interfaces, (b) stable dispersion of Gr-MS-Zn, and (c) the significantly low shear strength, arising from weak interfacial interaction between the incommensurately stacked graphene and MoS2 nanosheets.

Gold catalysis: regio- and stereoselective total synthesis of xyloketals D and G and the related natural product alboatrin.

A new and efficient one-pot desilylation-gold-catalyzed cycloisomerization of alkynes containing a silyl-protected phenolic -OH and a free alcoholic -OH unit leads selectively to the formation of tetrahydrofuranobenzopyran ring system. This approach has been used for the regio- and stereoselective synthesis of xyloketal D, xyloketal G, and the related natural product alboatrin.

Heteroatom-directed Wacker oxidations. A protection-free synthesis of (-)-heliophenanthrone.

The first enantioselective six-step synthesis of (-)-heliophenanthrone has been achieved without any protection-deprotection protocol at an overall yield of 28%. Key features of this synthesis comprise a heteroatom-directed Wacker oxidation of an internal cyclic olefin in addition to asymmetric Brown allylation and ring closing metathesis (RCM).

On the [3 + 2] annulation of cyclic allylsilanes with N-phenyltriazolinedione: an enantio- and diastereoselective synthesis of cis-1,3-diaminocyclitols.

Improved conditions were found to trigger [3 + 2] annulation of cyclic allylsilanes with N-phenyltriazolinedione (PTAD); the products from this reaction were readily tailored into cis-1,3-diaminocyclitols in highly enantioenriched form with full stereochemical control of up to four contiguous stereogenic centers.

A diversity-oriented synthesis of bicyclic cis-dihydroarenediols, cis-4-hydroxyscytalones, and bicyclic conduritol analogues.

A common-intermediate-based enantioselective strategy has been developed aiming at bicyclic arene cis-dihydrodiols, cis-4-hydroxyscytalones, and bicyclic mimics of conduritol. Key features of this protocol include Barrett's asymmetric hydroxyallylation, ring-closing metathesis (RCM), and completely regioselective Wacker oxidation of internal cyclic olefins.

Gold and palladium combined for the Sonogashira-type cross-coupling of arenediazonium salts.

The Sonogashira-type cross-coupling of arenediazonium salts is reported for the first time using a Pd-Au dual catalytic system.

Immuno-modulatory effects of relaxation training and guided imagery in women with locally advanced breast cancer undergoing multimodality therapy: a randomised controlled trial.

Eighty women undergoing multimodality treatment for large (>4cm) or locally advanced (T3, T4, Tx, N2), breast cancers participated in a randomised controlled trial (RCT) to evaluate the immuno-modulatory effects of relaxation training and guided imagery. Patients underwent chemotherapy followed by surgery, radiotherapy, and hormone therapy. Those in the intervention group were taught relaxation and guided imagery. Patients kept diaries of the frequency of relaxation practice and imagery vividness. On 10 occasions during the 37 weeks following the diagnosis, blood was taken for immunological assays CD phenotyping: T cell subsets (helper, cytotoxic), natural killer (NK) and lymphokine activated killer (LAK) cells, B lymphocytes and monocytes; cytotoxicity: NK and LAK cell activities; cytokines interleukin 1 beta (1beta), 2, 4 and 6 and tumour necrosis factor alpha. Significant between-group differences were found in the number of CD25+ (activated T cells) and CD56+ (LAK cell) subsets. The number of CD3+ (mature) T cells was significantly higher following chemotherapy and radiotherapy, in patients randomised to relaxation and guided imagery. Using a median split, women who rated their imagery ratings highly had elevated levels of NK cell activity at the end of chemotherapy and at follow-up. Significant correlations were obtained between imagery ratings and baseline corrected values for NK and LAK cell activity, and IL1beta. Relaxation frequency correlated with the number of CD4+ (T helper) cells, the CD4+:8+ (helper:cytotoxic) ratio, and IL1beta levels. Relaxation training and guided imagery beneficially altered putative anti-cancer host defences during and after multimodality therapy. Such changes, to the best of our knowledge, have not been previously documented in a RCT.

Patterns of local and distant disease relapse in patients with breast cancer treated with primary chemotherapy: do patients with a complete pathological response differ from those with residual tumour in the breast?

This study aimed to evaluate patterns of local and distant disease recurrence in patients having primary chemotherapy and compared patterns of relapse in patients with a complete pathological response with those who had residual breast disease. This is an observational study using a sequential series of patients treated with primary chemotherapy. They were followed up for a minimum of 5 years. All data was collected prospectively. Three hundred forty-one consecutive patients with breast cancer were treated with up to eight cycles of doxorubicin-based chemotherapy. Clinical and pathological response rates were evaluated and patients were followed up for disease recurrence (local and distant) and overall survival. Fifty-two patients (16.5%) had a complete pathological response to chemotherapy. Distant disease recurrence occurred in nine patients (17.3%) but no local recurrence was observed. In patients not having a complete pathological response, 86 patients (32.6%) subsequently developed metastases. Local recurrence of disease occurred in 12 (4.5%). There was a statistically significant difference in overall survival between patients whose tumours had a complete pathological response compared with patients who had residual disease in the breast following chemotherapy (88% versus 70% at 5 years, p = 0.036). Following primary chemotherapy, about 84% of patients had residual disease in the breast. Surgery is necessary to ensure complete removal of residual tumour and excellent rates of local control are achievable. A complete pathological response is associated with fewer local and distant recurrences as well as improved survival although there are no differences in time to development of metastatic relapse.

Guidelines, guidelines and more guidelines: and we still do not know how to follow-up patients with breast cancer.

BACKGROUND: A major challenge facing us is the provision of health care and appropriate allocation of available resources for the treatment of patients with breast cancer. This is of particular concern in the provision of follow-up care. With the increasing incidence of breast cancer and the improvements in survival which have resulted in up to 75% of patients surviving for more than five years, an increasing resource is required. However, there is controversy as to the most appropriate schedule for follow-up of these patients. This brief review has focused on the evidence-base and guidelines that currently exist in the United Kingdom for the follow-up of patients who have been treated for breast cancer. METHODS: A review of the current guidelines published in the United Kingdom for the follow-up of patients with breast cancer (National Institute for Clinical Excellence, Scottish Intercollegiate Guidelines Network, British Association of Surgical Oncology) and the randomised controlled trials evaluating the follow-up of patients with breast cancer was undertaken. RESULTS: The results have demonstrated the different follow-up protocols currently indicated in these guidelines within the same country. Furthermore, the lack of well designed, randomised controlled trials on which to base a follow-up protocol for patients with breast cancer is apparent. CONCLUSION: The evidence-base on which these guidelines have been developed is lacking. It is apparent that well designed randomised controlled trials are needed urgently if we are to understand the most appropriate and effective ways of following up patients with breast cancer.

Coaxing a pyridine nucleus to give up its aromaticity: synthesis and pharmacological characterization of novel conformationally restricted analogues of nicotine and anabasine.

A series of novel nicotine and anabasine related conformationally restricted compounds including those with pi-bonds in the connecting tether were synthesized following the hitherto unprecedented phenylsulfanyl group assisted generation of pyridine o-quinodimethane intermediates and their trapping by an intramolecular Diels-Alder reaction. Pharmacological characterization of some of these analogues at activating alpha3beta4 nAChRs was investigated, and constrained anabasine analogues 35 and 43 as well as constrained nicotine analogue 42 were found to exhibit moderately potent nicotinic agonist activity. Of special note is the fact that the pyrrolidinic nitrogen in these compounds is bound to a carbomethoxy group and, therefore, is not free to be protonated unlike all the known analogues of nicotine and anabasine, specifically designed as nAChRs agonists/antagonists. The structure-activity relationship studies indicate that when pi-cation interaction is absent, the position of chlorine atom in the pyridine ring and steric bulk at the connecting tether between the pyridine and pyrrolidine ring of the constrained nicotinic ligands are important descriptors for their binding affinity at alpha4beta2 and alpha3beta4 nAChRs as well as the subtype selectivity issue. These findings are likely to improve our understanding of the structural requirements for selectivity, which, at present, is probably the most important goal in the field of nicotinic ligands.

On-line screening of conformationally constrained nicotines and anabasines for agonist activity at the alpha3beta4- and alpha4beta2-nicotinic acetylcholine receptors using immobilized receptor-based liquid chromatographic stationary phases.

Liquid chromatography columns containing stationary phases based upon immobilized nicotinic acetylcholine receptors (nAChRs) were used to screen a series of conformationally constrained nicotine and anabasine derivatives for agonist activity. The alpha3beta4 nAChR and alpha4beta2 nAChR subtypes were used to prepare the chromatographic columns and [(3)H] epibatidine dihydrochloride ([(3)H] EB) was used as the marker ligand. Single displacement experiments were conducted with the test ligands and with nicotine and carbachol. Nicotine was used as an internal control for compounds with agonist activity and carbachol was used as an internal control for compounds with very weak agonistic activity (K(d) > 4700 nM for alpha3beta4). The displacement of [(3)H] EB by each of the test compounds and internal controls was calculated and expressed as Deltaml. Functional studies were then conducted using a stably transfected cell line that expresses the alpha3beta4 nAChR and EC(50) values were determined for the test compounds and the internal controls. A comparison of the Deltaml and EC(50) values indicated that 9/11 compounds had been correctly identified as agonists or non-agonists of the alpha3beta4 nAChR. A similar comparison could not be made for the alpha4beta2 nAChR, since the intact cell line was not available for testing. The results of the study suggest that the immobilized nAChR columns can be used for the rapid on-line screening of compounds for their relative affinities for the immobilized receptor and as an initial determination of qualitative functional activities.

Approach to geminally alkylated azaphthalans via a consecutive double desilylation-alkylation reaction: application to a synthesis of cerpegin.

A new approach to geminally alkylated azaphthalans and an application of this chemistry to the synthesis of the pyridone alkaloid, cerpegin, is reported.

Can patients' likelihood of benefiting from primary chemotherapy for breast cancer be predicted before commencement of treatment?

PURPOSE: Primary chemotherapy is commonly used in patients with breast cancer to downstage the primary tumour prior to surgery. There is a need to establish, prior to commencement of chemotherapy, predictors of clinical and pathological response, which may then be surrogate markers for patient survival and thus allow identification of patients who are most likely to benefit from such treatment. PATIENTS AND METHODS: A total of 104 patients with large and locally advanced breast cancers received an anthracycline/docetaxel-based regimen prior to surgery. Immunohistochemistry was carried out on pre-treatment core biopsies of the tumour to detect hormone receptors (oestrogen-ER; progesterone-PR), a proliferation marker (MIB-1), the oncoprotein Bcl-2, an extracellular matrix degradation enzyme (cathepsin D), p53, and an oestrogen associated protein (pS2). Both clinical and pathological response were assessed following completion of chemotherapy. RESULTS: Patients whose tumours did not express oestrogen receptor (p = 0.02) or did not express Bcl-2 (p < 0.01) had a better pathological response in a univariate analysis. However, in a multivariate model, it was only the absence of detectable Bcl-2 protein that predicted a better pathological response (p = 0.001). CONCLUSIONS: This study has identified that patients whose breast cancers are most likely to experience the greatest degree of tumour destruction by primary chemotherapy do not express either oestrogen receptors or Bcl-2. This may have important implications in the selection of patients with breast cancer for primary chemotherapy who are most likely to gain a survival benefit.

A new histological grading system to assess response of breast cancers to primary chemotherapy: prognostic significance and survival.

The clinical and complete pathological response of a primary breast cancer to chemotherapy has been shown to be an important prognostic for survival. However, the majority of patients do not experience a complete pathological response to primary chemotherapy and the significance of lesser degrees of histological response is uncertain and the prognostic significance is unknown. The purpose of this study was to evaluate a new histological grading system to assess response of breast cancers to primary chemotherapy and to determine if such a system has prognostic value.A consecutive series of 176 patients with large (> or =4cm) and locally advanced breast cancers were treated with multimodality therapy comprising primary chemotherapy, surgery, radiotherapy and tamoxifen. All underwent assessment of the primary breast tumour before and after completion of chemotherapy. Residual tumour was excised after completion of chemotherapy (mastectomy or wide local excision with axillary surgery). The removed tissue was assessed and response to chemotherapy graded using a five-point histological grading system based with the fundamental feature being a reduction in tumour cellularity; comparison being made with a pre-treatment core biopsy. All patients were followed up for 5 years or more. Pathological responses were compared to 5 year overall survival and disease-free survival using log rank tests. The overall 5-year survival for all patients was 71%, and 5 year disease free interval was 60%. There was a significant correlation between pathological response using this new grading system and both overall survival (P=0.02) and disease-free interval (P=0.04). In a multivariate analysis of known prognostic factors, the Miller/Payne grading system was an independent predictor of overall patient survival. This grading system, which assesses the histological response to primary chemotherapy, can predict overall survival and disease-free interval in patients with large and locally advanced breast cancers treated with such therapy. The relationship of degree of histological response to overall and disease-free survival has been shown in univariate and multivariate analyses and could potentially have an important role in the clinical management of patients with locally advanced breast cancer undergoing primary chemotherapy.

A sequential Pummerer-Diels-Alder route for the generation and trapping of furo[3,4-c]pyridines: synthesis of heterocyclic analogues of 1-arylnaphthalene lignans.

The Pummerer reaction of an o-benzoyl-substituted pyridylmethyl sulfoxide generates an alpha-thiocarbocation, the interception of which by a neighboring keto functionality produces an alpha-thio-substituted furo[3,4-c]pyridine as transient intermediate; the latter undergoes a Diels-Alder cycloaddition with an added dienophile. Base-induced ring opening of the cycloadduct followed by aromatization gives an isoquinoline derivative that may be looked upon as a heterocyclic analogue of 1-arylnaphthalene lignans. This procedure occurs readily with electron-poor dienophiles and the entire sequence can be run in one pot. The facility of the sequential Pummerer-Diels-Alder reaction hinges on the experimental conditions, the best results being obtained with heptafluorobutyric anhydride as the triggering agent in toluene containing a catalytic amount of p-toluenesulfonic acid. In the absence of a dienophile it is possible to isolate and characterize a rather unstable furo[3,4-c]pyridine derivative. An intramolecular variant of this protocol is also feasible with use of unactivated alkenyl tethers of variable length; however, the bridged cycloadducts are unisolable in these cases as they undergo spontaneous ring opening and aromatization to yield cycloalka[h]isoquinolines. The usefulness of the sequential Pummerer-Diels-Alder reaction is further demonstrated through the synthesis of a heterolignan with a built-in lactone ring via oxidation of the initial [4+2]-cycloadduct followed by extrusion of phenyl sulfinate and elaboration of the resulting hydoxylated isoquinoline derivative.

Neoadjuvant docetaxel in locally advanced breast cancer.

Neoadjuvant chemotherapy produces substantial increases in clinical response rates and rates of breast conserving therapy. Pathologic response rate, though generally low, is an important outcome as it is presumably associated with eradication of micrometastatic disease and may likely result in improved outcomes. Anthracyclines have long been considered the most efficacious chemotherapy agents for neoadjuvant therapy of early breast cancer. Unfortunately, not all patients respond to neoadjuvant anthracycline-based chemotherapy. In an effort to improve primary tumor response, docetaxel, an active agent in breast cancer, has been evaluated in the neoadjuvant setting. Several randomized trials, including the NSABP B-27, GEPAR-duo, and the Aberdeen trial, evaluating docetaxel in sequence with a doxorubicin-based neoadjuvant regimen have been reported, with encouraging findings. We designed the Aberdeen trial with two primary aims: (1) to evaluate primary docetaxel in patients that initially fail a neoadjuvant anthracycline-based polychemotherapy regimen, and (2) to compare a docetaxel-based neoadjuvant regimen with a standard anthracycline-based regimen in patients who do respond to the first four cycles of the anthracycline-based regimen. Eligible patients (n = 162) had previously untreated large (> or = 3 cm) or locally advanced (T3, T4, T x N2) breast cancer. All received four cycles of CVAP, after which clinical response was assessed. Responding patients were then randomized to four additional cycles of CVAP or to docetaxel 100 mg/m2 every 3 weeks for four cycles. Patients failing to respond to CVAP received the docetaxel regimen. After the first four cycles of CVAP, the overall response rate (ORR) was 67%. Ultimately, responses were higher in the group randomized to docetaxel compared with those continuing CVAP (cCR: 94% vs. 66%; p = 0.001; pCR 34% vs. 16%; p = 0.04). The addition of docetaxel improved overall survival and disease-free survival for patients responding to four cycles of CVAP as compared with those receiving eight cycles of CVAP. Relative dose intensity was higher and the incidence of severe leukopenia was lower in the group randomized to docetaxel. These data and data from the NSABP B-27 and GEPAR-duo trials strongly support a combined anthracycline/docetaxel regimen in the neoadjuvant setting.

Local recurrence in patients with large and locally advanced breast cancer treated with primary chemotherapy.

BACKGROUND: Primary chemotherapy is being given in the treatment of large and locally advanced breast cancers, but a major concern is local relapse after therapy. This paper has examined patients treated with primary chemotherapy and surgery (either breast-conserving surgery or mastectomy) and has examined the role of factors which may indicate those patients who are subsequently more likely to experience local recurrence of disease. METHODS: A consecutive series of 173 women, with data available for 166 of these, presenting with large and locally advanced breast cancer (T2>/=4 cm, T3, T4, or N2) were treated with primary chemotherapy comprising cyclophosphamide, vincristine, doxorubicin, and prednisolone and then surgery (either conservation or mastectomy with axillary surgery) followed by radiotherapy were examined. RESULTS: The clinical response rate of these patients was 75% (21% complete and 54% partial), with a complete pathological response rate of 15%. A total of 10 patients (6%) experienced local disease relapse, and the median time to relapse was 14 months (ranging from 3 to 40). The median survival in this group was 27 months (ranging from 13 to 78). In patients having breast conservation surgery, local recurrence occurred in 2%, and in those undergoing mastectomy 7% experience local relapse of disease. Factors predicting patients most likely to experience local recurrence were poor clinical response and residual axillary nodal disease after chemotherapy. CONCLUSIONS: Excellent local control of disease can be achieved in patients with large and locally advanced breast cancers using a combination of primary chemotherapy, surgery and radiotherapy. However, the presence of residual tumor in the axillary lymph nodes after chemotherapy is a predictor of local recurrence and patients with a better clinical response were also less likely to experience local disease recurrence. The size and degree of pathological response did not predict patients most likely to experience recurrence of disease.

Studies on intramolecular Diels-Alder reactions of furo[3,4-c]pyridines in the synthesis of conformationally restricted analogues of nicotine and anabasine.

En route to conformationally restricted analogues of nicotine and anabasine, a novel synthetic route to bridged anabasines is described that hinges on a domino intramolecular [4 + 2]-cycloaddition/ring opening-elimination sequence of 3-amino-substituted furo[3,4-c]pyridines. Extension of this route to bridged nicotines, however, proved abortive, even when the dienophile tether is activated by a p-tolylsulfonyl group or when the diene moiety is activated by an electron-releasing methoxy substituent. A detailed density functional theoretical study (B3LYP/6-31+G) was undertaken to provide insight into the factors that facilitate an intramolecular Diels-Alder reaction in the former case.