Functional materials discovery using energy-structure-function maps

Molecular crystals cannot be designed in the same manner as macroscopic objects, because they do not assemble according to simple, intuitive rules. Their structures result from the balance of many weak interactions, rather than from the strong and predictable bonding patterns found in metal-organic frameworks and covalent organic frameworks. Hence, design strategies that assume a topology or other structural blueprint will often fail. Here we combine computational crystal structure prediction and property prediction to build energy-structure-function maps that describe the possible structures and properties that are available to a candidate molecule. Using these maps, we identify a highly porous solid, which has the lowest density reported for a molecular crystal so far. Both the structure of the crystal and its physical properties, such as methane storage capacity and guest-molecule selectivity, are predicted using the molecular structure as the only input. More generally, energy-structure-function maps could be used to guide the experimental discovery of materials with any target function that can be calculated from predicted crystal structures, such as electronic structure or mechanical properties.

Prostate cancer screening practices in a large, integrated health system: 2007-2014

OBJECTIVES

To assess prostate cancer screening practices in primary care since the initial United States Preventive Services Task Force (USPSTF) recommendation against prostate-specific antigen (PSA) testing for older men, and to assess primary provider variation associated with prostate cancer screening.

PATIENTS AND METHODS

Our study population included 160 211 men aged ≥40 years with at least one visit to a primary care clinic in any of the study years in a large, integrated health system. We conducted a retrospective cohort study using electronic medical record data from January 2007 to December 2014. Yearly rates of screening PSA testing by primary care providers (PCPs), rates of re-screening, and rates of prostate biopsies were assessed.

RESULTS

Annual PSA-screening testing declined from 2007 to 2014 in all age groups, as did biennial and quadrennial screening. Yearly rates declined for men aged ≥70 years, from 22.8% to 8.9%; ages 50-69 years, from 39.2% to 20%; and ages 40-49 years, from 11% to 4.6%. Overall rates were lower for African-American (A-A) men vs non-A-A men; for men with a family history of prostate cancer, rates were similar or slightly higher than for those without a family history. PCP variation associated with ordering of PSA testing did not substantially change after the USPSTF recommendations. While the number of men screened and rates of follow-up prostate cancer screening declined in 2011-2014 compared to 2007-2010, similar re-screening rates were noted for men aged 45-75 years with initial PSA levels of <1 ng/mL or 1-3 ng/mL in both the earlier and later cohorts. For men aged >75 years with initial PSA levels of <3 ng/mL screened in both cohorts, follow-up screening rates were similar. Rates of prostate biopsy declined for men aged ≥70 years in 2014 compared to 2007. For men who had PSA screening, rates of first prostate biopsy increased in later years for A-A men and men with a family history of prostate cancer.

CONCLUSIONS

Prostate cancer screening declined from 2007 to 2014 even in higher-risk groups and follow-up screening rates were not related to previous PSA level. However, rates of first prostate biopsy in men who were screened with a PSA test were higher for men with an increased risk of prostate cancer in later years. Variation in PSA testing was noted among PCPs. Future work should further explore sources of variation in screening practices and implementation of risk-based strategies for prostate cancer screening in primary care.

Styrene Purification by Guest-Induced Restructuring of Pillar[6]arene

The separation of styrene (St) and ethylbenzene (EB) mixtures is important in the chemical industry. Here, we explore the St and EB adsorption selectivity of two pillar-shaped macrocyclic pillar[n]arenes (EtP5 and EtP6; n = 5 and 6). Both crystalline and amorphous EtP6 can capture St from a St-EB mixture with remarkably high selectivity. We show that EtP6 can be used to separate St from a 50:50 v/v St:EB mixture, yielding in a single adsorption cycle St with a purity of >99%. Single-crystal structures, powder X-ray diffraction patterns, and molecular simulations all suggest that this selectivity is due to a guest-induced structural change in EtP6 rather than a simple cavity/pore size effect. This restructuring means that the material “self-heals” upon each recrystallization, and St separation can be carried out over multiple cycles with no loss of performance.

Understanding gas capacity, guest selectivity, and diffusion in porous liquids

An in-depth study of porous liquids using measurement techniques, molecular simulations, and control experiments to advance their quantitative understanding.

Porous liquids are a new class of material that could have applications in areas such as gas separation and homogeneous catalysis. Here we use a combination of measurement techniques, molecular simulations, and control experiments to advance the quantitative understanding of these liquids. In particular, we show that the cage cavities remain unoccupied in the absence of a suitable guest, and that the liquids can adsorb large quantities of gas, with gas occupancy in the cages as high as 72% and 74% for Xe and SF₆, respectively. Gases can be reversibly loaded and released by using non-chemical triggers such as sonication, suggesting potential for gas separation schemes. Diffusion NMR experiments show that gases are in dynamic equilibrium between a bound and unbound state in the cage cavities, in agreement with recent simulations for related porous liquids. Comparison with gas adsorption in porous organic cage solids suggests that porous liquids have similar gas binding affinities, and that the physical properties of the cage molecule are translated into the liquid state. By contrast, some physical properties are different: for example, solid homochiral porous cages show enantioselectivity for chiral aromatic alcohols, whereas the equivalent homochiral porous liquids do not. This can be attributed to a loss of supramolecular organisation in the isotropic porous liquid.

Change in Psoas Muscle Volume as a Predictor of Outcomes in Patients Treated with Chemotherapy and Radical Cystectomy for Muscle-Invasive Bladder Cancer

Objective: Sarcopenia, or the age-related loss of skeletal muscle mass and function, has been investigated as a potential marker of adverse outcomes among surgical patients. Our aim was to assess for changes in psoas muscle volume (PMV) following administration of neoadjuvant chemotherapy (NAC) in patients with bladder cancer and to examine whether changes in PMV following NAC are predictive of perioperative complications, pathologic response or survival.

Methods: During the period of 2009–2013, patients undergoing NAC and radical cystectomy (RC) at our institution with pre and post NAC cross sectional images available were included. Bilateral total psoas muscle volume (PMV) was obtained from pre- and post- NAC images and the proportion of PMV change was calculated by dividing the change PMV by pre-NAC PMV. Analyses for the assessment of factors predicting PMV loss, partial/complete pathologic response (pPR/pCR), complications, readmission, cancer specific (CSS), recurrence-free (RFS) and overall survival (OS) were performed.

Results: Total of 60 patients had complete radiological data available. Post-NAC PMV and BMI declines were statistically significant, 4.9% and 0.05%, respectively. NAC dose reduction/delay was a significant predictor of PMV loss (coefficient B 4.6; 95% CI 0.05–9.2; p = 0.047). The proportion of PMV decline during NAC was not a predictor of pPR, pCR, complications, readmission, CSS, RFS, or OS.

Conclusions: We observed an interval decline in PMV during the period of NAC administration and this decline was more than it could be appreciated with changes in BMI during the same period. PMV decline was associated with the need for dose reduction/dose delay during NAC. In our series, PMV changes occurring during NAC administration were not predictive of pathologic response to chemotherapy, postoperative complications or survival.

A systems approach to strategic infrastructure delivery

This paper discusses a systems approach to the strategic delivery of infrastructure in the regulated UK water sector as part of a participatory-focused research project. Part of an ongoing PhD programme, this paper highlights the value of a strategic approach to the procurement of infrastructure-related services in accordance with the quinquennial water sector reprocurement exercise being undertaken by infrastructure client organisations (ICOs). As a strategic approach is concerned with understanding the delivery environment into which an organisation places, engages and delivers projects, this paper surfaces how a UK-based water and wastewater ICO has engaged with its delivery market, through procurement, to position itself strategically within the wider delivery environment to serve its customers better. Using a systems approach, what is brought to light here is the importance of organisational transitioning through change management and how a delivery strategy can encompass the facilitation of organisational change.

Tissue Effects in a Randomized Controlled Trial of Short-term Finasteride in Early Prostate Cancer

BACKGROUND

In the Prostate Cancer Prevention Trial, finasteride selectively suppressed low-grade prostate cancer and significantly reduced the incidence of prostate cancer in men treated with finasteride compared with placebo. However, an apparent increase in high-grade disease was also observed among men randomized to finasteride. We aimed to determine why and hypothesized that there is a grade-dependent response to finasteride.

METHODS

From 2007 to 2012, we randomized dynamically by intranet-accessible software 183 men with localized prostate cancer to receive 5mg finasteride or placebo daily in a double-blind study during the 4-6weeks preceding prostatectomy. As the primary end point, the expression of a predefined molecular signature (ERβ, UBE2C, SRD5A2, and VEGF) differentiating high- and low-grade tumors in Gleason grade (GG) 3 areas of finasteride-exposed tumors from those in GG3 areas of placebo-exposed tumors, adjusted for Gleason score (GS) at prostatectomy, was compared. We also determined androgen receptor (AR) levels, Ki-67, and cleaved caspase 3 to evaluate the effects of finasteride on the expression of its downstream target, cell proliferation, and apoptosis, respectively. The expression of these markers was also compared across grades between and within treatment groups. Logistic regression was used to assess the expression of markers.

FINDINGS

We found that the predetermined molecular signature did not distinguish GG3 from GG4 areas in the placebo group. However, AR expression was significantly lower in the GG4 areas of the finasteride group than in those of the placebo group. Within the finasteride group, AR expression was also lower in GG4 than in GG3 areas, but not significantly. Expression of cleaved caspase 3 was significantly increased in both GG3 and GG4 areas in the finasteride group compared to the placebo group, although it was lower in GG4 than in GG3 areas in both groups.

INTERPRETATION

We showed that finasteride's effect on apoptosis and AR expression is tumor grade dependent after short-term intervention. This may explain finasteride's selective suppression of low-grade tumors observed in the PCPT.

Porous Organic Cages for Sulfur Hexafluoride Separation

A series of porous organic cages is examined for the selective adsorption of sulfur hexafluoride (SF6) over nitrogen. Despite lacking any metal sites, a porous cage, CC3, shows the highest SF6/N2 selectivity reported for any material at ambient temperature and pressure, which translates to real separations in a gas breakthrough column. The SF6 uptake of these materials is considerably higher than would be expected from the static pore structures. The location of SF6 within these materials is elucidated by X-ray crystallography, and it is shown that cooperative diffusion and structural rearrangements in these molecular crystals can rationalize their superior SF6/N2 selectivity.

Does cumulative prostate cancer length (CCL) in prostate biopsies improve prediction of clinically insignificant cancer at radical prostatectomy in patients eligible for active surveillance?

OBJECTIVES

To evaluate if cumulative prostate cancer length (CCL) on prostate needle biopsy divided by the number of biopsy cores (CCL/core) could improve prediction of insignificant cancer on radical prostatectomy (RP) in patients with prostate cancer eligible for active surveillance (AS).

PATIENTS AND METHODS

Patients diagnosed with prostate cancer on extended (≥10 cores) biopsy with an initial prostate-specific antigen (iPSA) level of <15 ng/mL, clinical stage (cT) ≤ 2a, and highest biopsy Gleason score 3 + 3 = 6 or 3 + 4 = 7 with <3 positive cores who underwent RP were included in the study. The CCL/core and presence of insignificant cancer (organ-confined, volume <0.5 mL, Gleason score at RP ≤6) were recorded. pT2 prostate cancer with RP Gleason score ≤3 + 4 = 7 and volume <0.5 mL were categorised as low-tumour-volume organ-confined disease (LV-OCD).

RESULTS

In all, 221 patients met the inclusion criteria: the mean age was 59 years and the median iPSA level was 4.5 ng/mL. The clinical stage was cT1 in 86% of patients; biopsy Gleason score was 3 + 3 = 6 in 67% (group 1) and 3 + 4 = 7 in 33% of patients (group 2). The maximum percentage of biopsy core involvement was <50 in 85%; the median CCL/core was 0.15 mm. Insignificant cancer was found in 27% and LV-OCD in 44% of patients. Group 2 was associated with higher number of positive cores, maximum percentage core involvement, total prostate cancer length, and CCL/core. Group 1 was more likely to have insignificant cancer (39%) or LV-OCD (54%) than group 2 (3% and 23%, respectively). Group 2 had significantly higher RP Gleason score and pathological stage. Univariate analysis of group 1 showed that the iPSA level, maximum percentage core involvement, prostate cancer length, and CCL/core were all significantly associated with insignificant cancer and LV-OCD. For group 2, the number of positive cores (1 vs 2) was also significantly associated with LV-OCD. On multivariate logistic regression analysis, maximum percentage core involvement of <50, and number of positive cores (1 vs 2) were independent predictors of insignificant cancer in group 1; biopsy Gleason score, maximum percentage core involvement of <50 and prostate cancer length of <3 mm or CCL/core of <0.2 mm were all independent predictors of LV-OCD in the whole population. The maximum percentage of core involvement of <50 and prostate cancer length of <3 mm or CCL/core of <0.2 mm were also independent predictors of LV-OCD in group 1 patients.

CONCLUSION

In patients eligible for AS, a CCL/core of <0.20 mm was significantly associated with insignificant cancer and LV-OCD. However, when parameters of cancer burden were considered, CCL/core did not independently add any additional value for predicting insignificant cancer in patients with biopsy Gleason score 6. The CCL/core was an independent predictor of LV-OCD in the whole population and in group 1 patients, although the model including prostate cancer length showed slightly higher area under the receiver operating characteristic curve.

Sensitisation of Eu(III)- and Tb(III)-based luminescence by Ir(III) units in Ir/lanthanide dyads: evidence for parallel energy-transfer and electron-transfer based mechanisms

A series of blue-luminescent Ir(III) complexes with a pendant binding site for lanthanide(III) ions has been synthesized and used to prepare Ir(III)/Ln(III) dyads (Ln = Eu, Tb, Gd). Photophysical studies were used to establish mechanisms of Ir→Ln (Ln = Tb, Eu) energy-transfer. In the Ir/Gd dyads, where direct Ir→Gd energy-transfer is not possible, significant quenching of Ir-based luminescence nonetheless occurred; this can be ascribed to photoinduced electron-transfer from the photo-excited Ir unit (*Ir, (3)MLCT/(3)LC excited state) to the pendant pyrazolyl-pyridine site which becomes a good electron-acceptor when coordinated to an electropositive Gd(III) centre. This electron transfer quenches the Ir-based luminescence, leading to formation of a charge-separated {Ir(4+)}˙-(pyrazolyl-pyridine)˙(-) state, which is short-lived possibly due to fast back electron-transfer (<20 ns). In the Ir/Tb and Ir/Eu dyads this electron-transfer pathway is again operative and leads to sensitisation of Eu-based and Tb-based emission using the energy liberated from the back electron-transfer process. In addition direct Dexter-type Ir→Ln (Ln = Tb, Eu) energy-transfer occurs on a similar timescale, meaning that there are two parallel mechanisms by which excitation energy can be transferred from *Ir to the Eu/Tb centre. Time-resolved luminescence measurements on the sensitised Eu-based emission showed both fast and slow rise-time components, associated with the PET-based and Dexter-based energy-transfer mechanisms respectively. In the Ir/Tb dyads, the Ir→Tb energy-transfer is only just thermodynamically favourable, leading to rapid Tb→Ir thermally-activated back energy-transfer and non-radiative deactivation to an extent that depends on the precise energy gap between the *Ir and Tb-based (5)D4 states. Thus, the sensitised Tb(iii)-based emission is weak and unusually short-lived due to back energy transfer, but nonetheless represents rare examples of Tb(III) sensitisation by a energy donor that could be excited using visible light as opposed to the usually required UV excitation.

Separation of rare gases and chiral molecules by selective binding in porous organic cages

The separation of molecules with similar size and shape is an important technological challenge. For example, rare gases can pose either an economic opportunity or an environmental hazard and there is a need to separate these spherical molecules selectively at low concentrations in air. Likewise, chiral molecules are important building blocks for pharmaceuticals, but chiral enantiomers, by definition, have identical size and shape, and their separation can be challenging. Here we show that a porous organic cage molecule has unprecedented performance in the solid state for the separation of rare gases, such as krypton and xenon. The selectivity arises from a precise size match between the rare gas and the organic cage cavity, as predicted by molecular simulations. Breakthrough experiments demonstrate real practical potential for the separation of krypton, xenon and radon from air at concentrations of only a few parts per million. We also demonstrate selective binding of chiral organic molecules such as 1-phenylethanol, suggesting applications in enantioselective separation.

d→f energy transfer in Ir(III)/Eu(III) dyads: use of a naphthyl spacer as a spatial and energetic "stepping stone"

A series of luminescent complexes based on {Ir(phpy)2} (phpy = cyclometallating anion of 2-phenylpyridine) or {Ir(F2phpy)2} [F2phpy = cyclometallating anion of 2-(2',4'-difluorophenyl)pyridine] units, with an additional 3-(2-pyridyl)-pyrazole (pypz) ligand, have been prepared; fluorination of the phenylpyridine ligands results in a blue-shift of the usual (3)MLCT/(3)LC luminescence of the Ir unit from 477 to 455 nm. These complexes have pendant from the coordinated pyrazolyl ring an additional chelating 3-(2-pyridyl)-pyrazole unit, separated via a flexible chain containing a naphthalene-1,4-diyl or naphthalene-1,5-diyl spacer. Crystal structures show that the flexibility of the pendant chain allows the naphthyl group to lie close to the Ir core and participate in a π-stacking interaction with a coordinated phpy or F2phpy ligand. Luminescence spectra show that, whereas the {Ir(phpy)2(pypz)} complexes show typical Ir-based emission--albeit with lengthened lifetimes because of interaction with the stacked naphthyl group--the {Ir(F2phpy)2(pypz)} complexes are nearly quenched. This is because the higher energy of the Ir-based (3)MLCT/(3)LC excited state can now be quenched by the adjacent naphthyl group to form a long-lived naphthyl-centered triplet ((3)nap) state which is detectable by transient absorption. Coordination of an {Eu(hfac)3} unit (hfac = 1,1,1,5,5,5-hexafluoro-pentane-2,4-dionate) to the pendant pypz binding site affords Ir-naphthyl-Eu triads. For the triads containing a {Ir(phpy)2} core, the unavailability of the (3)nap state (not populated by the Ir-based excited state which is too low in energy) means that direct Ir→Eu energy-transfer occurs in the same way as in other flexible Ir/Eu complexes. However for the triads based on the{Ir(F2phpy)2} core, the initial Ir→(3)nap energy-transfer step is followed by a second, slower, (3)nap→Eu energy-transfer step: transient absorption measurements clearly show the (3)nap state being sensitized by the Ir center (synchronous Ir-based decay and (3)nap rise-time) and then transferring its energy to the Eu center (synchronous (3)nap decay and Eu-based emission rise time). Thus the (3)nap state, which is energetically intermediate in the {Ir(F2phpy)2}-naphthyl-Eu systems, can act as a "stepping stone" for two-step d→f energy-transfer.

Early salvage radiotherapy following radical prostatectomy

CONTEXT

Depending on the pathologic tumour stage, up to 60% of prostate cancer patients who undergo radical prostatectomy will develop biochemical relapse and require further local treatment.

OBJECTIVES

We reviewed the results of early salvage radiation therapy (RT), defined as prostate-specific antigen (PSA) values prior to RT ≤ 0.5 ng/ml in the setting of lymph node-negative disease.

EVIDENCE ACQUISITION

Ten retrospective studies, including one multicentre analysis, were used for this analysis. Among them, we received previously unpublished patient characteristics and updated outcome data from five retrospective single-centre trials to perform a subgroup analysis for early salvage RT.

EVIDENCE SYNTHESIS

Patients treated with early salvage RT have a significantly improved biochemical recurrence-free survival (BRFS) rate compared with those receiving salvage RT initiated after PSA values are >0.5 ng/ml. Similarly, within the cohort of patients with pre-RT PSA values <0.5 ng/ml, improved BRFS rates were noted among those with lower rather higher pre-RT PSA levels. It is possible that higher RT dose levels and the use of adjunctive androgen-deprivation therapy improve biochemical control outcomes in the salvage setting.

CONCLUSIONS

Based on a literature review, improved 5-yr BRFS rates are observed for patients who receive early salvage RT compared with patients treated with salvage RT with a pre-RT PSA value >0.5 ng/ml. Whether the routine application of early salvage RT in patients with initially undetectable PSA levels will be associated with demonstrable clinical benefit awaits the results of ongoing prospective trials.