The umbrella value of caribou management strategies for biodiversity conservation in boreal forests under global change

Single-species conservation management is often proposed to preserve biodiversity in human-disturbed landscapes. How global change will impact the umbrella value of single-species management strategies remains an open question of critical conservation importance. We assessed the effectiveness of threatened boreal caribou as an umbrella for bird and beetle conservation under global change. We combined mechanistic, spatially explicit models of forest dynamics and predator-prey interactions to forecast the impact of management strategies on the survival of boreal caribou in boreal forest. We then used predictive models of species occupancy to characterize concurrent impacts on bird and beetle diversity. Landscapes were simulated based on three scenarios of climate change and four of forest management. We found that strategies that best mitigate human impact on boreal caribou were an effective umbrella for maintaining bird and beetle assemblages. While we detected a stronger effect of land-use change compared to climate change, the umbrella value of management strategies for caribou habitat conservation were still impacted by the severity of climate change. Our results showed an interplay among changes in forest attributes, boreal caribou mortality, as well as bird and beetle species assemblages. The conservation status of some species mandates the development of recovery strategies, highlighting the importance of our study which shows that single-species conservation can have important umbrella benefits despite global change.

Truxene-to-Fluorenone Energy Transfer in a Robust Mesoporous Zn-MOF

A new metal-organic framework (MOF; [Zn4O(hett)4/3(fluo)1/2(bdc)1/2]n; TFT-MOF) constructed on chromophoric ligands 5,5',10,10',15,15'-hexaethyltruxene-2,7,12-triacetate (hett), 9-fluorenone-2,7-dicarboxylate (fluo), terephthalate (bdc), and the Zn4O node has been prepared and identified by powder X-ray diffraction. This luminescent MOF exhibits large mesoporous pores of 2.7 nm based on computer modeling using density functional theory (DFT) calculations. The steady-state and time-resolved fluorescence spectra and photophysical parameters of TFT-MOF have been investigated and compared with those of the free ligands and their basic chromophores. All in all, TFT-MOF exhibits particularly efficient singlet-singlet energy-transfer processes described as 1(hett)* → (fluo) and 1(bdc)* → (fluo), leading to fluorescence arising for the fluo lumophore operating only through Förster resonance energy transfer (FRET) with an efficiency of transfer of up to >95%. This experimental conclusion was corroborated by DFT and time-dependent DFT (TDDFT). For the 1(hett)* → (fluo) process, the approximated overall rate constant of energy transfer was evaluated to be at most 2.04 × 1010 s-1 (using a Stern-Volmer approach of solution data and the relationship between distance and concentration). This process was analyzed using the Förster theory, where two intrapore energy transfer paths of center-to-center distances of 13 and 25 Å have been identified. TFT-MOF photosensitizes the formation of singlet oxygen (1O2 (1Σg)) as detected by its phosphorescence signal at 1275 nm.

Public opinion on the conflict between the conservation of at-risk species and the extraction of natural resources: The case of caribou in boreal forest

Conflicts between economic development and conservation are increasingly hampering efforts to restore imperiled wildlife populations. Public opinion can influence how these conflicts translate into conservation actions, encouraging stakeholders to express their views through various public channels. The outcome of these campaigns typically remains unknown. Via an online survey, we collected to the opinion of 1000 citizens of Québec, Canada, regarding the ongoing conflict between logging and the conservation of at-risk caribou populations (Rangifer tarandus). We found that people expect conservation actions that are sufficient to recover caribou populations, even if millions of government investment are required and jobs are lost in the process. When respondents learned that academic caribou researchers indicated that the two management strategies being studied by government would be insufficient for population recovery, one-third withdrew their support for either strategy. Age, gender and education all explain variation in public opinion, but it was the region of residence that most consistently explained variation in opinion. Residents of caribou-inhabited regions were less concerned about caribou conservation and more supportive of forestry than residents of other regions, reflecting regional differences in expected economic impacts of conservation, not negative interactions with caribou. In fact, most people supported strong conservation actions for the recovery of caribou populations, regardless of their socio-demographics. Our analysis provides general insights into how public opinion on the trade-off between conservation and economy is influenced by socio-demographics and scientific conclusions. We found that current government conservation actions (or lack thereof) are not in line with mainstream public opinion. Moreover, we show that making species at-risk lists does not ensure that the species will benefit from strong conservation actions without lengthy delays, even for a high-profile, flagship species like caribou. This observation echoes concerns about the fate of less charismatic, at-risk species, and thus about future biodiversity conservation efforts.

Strong Host-Guest Dependence on the Emissive Properties of MOF-5 and [Zn2(BTTB)(DMF)2•(H2O)3]n

3D-[Zn4O(1,4-BDC)3•x(solvent)]n (MOF-5; BDC = 1,4-benzodicarboxylate) and 3D-[Zn2(BTTB)(DMF)2•(H2O)3]n (MOF-D; BTTB = 4,4',4″,4‴-benzene-1,2,4,5-tetrayltetrabenzoate) have been investigated by means of steady-state UV-visible and fluorescence and time-resolved emission spectroscopy, as a function of solvent and power of the excitation irradiation. The low-temperature X-ray structures (173 K) were permitted to locate solvent molecules (here H2O) in the lattice. They were found distributed in the middle in the voids with no evidence of specific interactions (H-bond, coulombic, and dipole-dipole) with the framework. The fluorescence decays of the ligands (ππ* excited state), τF, for the host-guest composites MOF-5@solvent and MOF-D@solvent (solvent = air, MeCN, EtCN, MeOH, EtOH, and DMF) were found bi-exponential (short τF1 (ps), and long τF2 (ns)) with one important feature: upon cooling from 298 to 77 K, MOF-5's τF1 decreases and τF2 increases, while the opposite trend is generally observed in MOF-D. The low values for τF1 (ps) in MOF-5 are associated with the augmented probability of solvent-ligand collisions leading to nonradiative deactivation, which upon cooling to 77 K increases further as the scaffolding contracts. The augmentation in τF2 is readily associated with the increased rigidity of the ligands that are not submitted to this effect (at the surface of the MOF and as pendent groups). For the low emitter MOF-D, the reversed situation is noted but not as clearly due to the uncertainties in the data. Upon increasing the excitation flux, the fluorescence intensity increases linearly with the laser power indicating the absence of singlet-singlet annihilation, inferring the absence of efficient exciton migration. This observation is explained by the small absorptivity coefficients, which leads to a small J spectral overlap between absorption and fluorescence according to the Forster and Dexter theories, and consequently, a small rate for energy migration. This conclusion drastically changes the perception of the photocatalytic mechanism of MOF-5 and other MOFs exhibiting similar absorption features (i.e., no antenna effect).

Triple Thorpe-Ingold Effect in the Synthesis of 18-Membered C3 Symmetric Lactams Stacking as Endless Supramolecular Tubes

Three C₃ symmetric macrolactams were very efficiently cyclized from their linear precursors. Adequately located substituents are responsible for the enhancement of reactivity that is not observed in the unsubstituted parent. DFT calculations show that the properly folded cyclization precursor, the reactive conformer, is more populated than other conformers, leading to a decrease of free energy of activation. The crystal structure of the ring substituted with three very bulky esters indicates that tubular stacking is preserved.

Multi-mode movement decisions across widely ranging behavioral processes

Movement of organisms plays a fundamental role in the evolution and diversity of life. Animals typically move at an irregular pace over time and space, alternating among movement states. Understanding movement decisions and developing mechanistic models of animal distribution dynamics can thus be contingent to adequate discrimination of behavioral phases. Existing methods to disentangle movement states typically require a follow-up analysis to identify state-dependent drivers of animal movement, which overlooks statistical uncertainty that comes with the state delineation process. Here, we developed population-level, multi-state step selection functions (HMM-SSF) that can identify simultaneously the different behavioral bouts and the specific underlying behavior-habitat relationship. Using simulated data and relocation data from mule deer (Odocoileus hemionus), plains bison (Bison bison bison) and plains zebra (Equus quagga), we illustrated the HMM-SSF robustness, versatility, and predictive ability for animals involved in distinct behavioral processes: foraging, migrating and avoiding a nearby predator. Individuals displayed different habitat selection pattern during the encamped and the travelling phase. Some landscape attributes switched from being selected to avoided, depending on the movement phase. We further showed that HMM-SSF can detect multi-modes of movement triggered by predators, with prey switching to the travelling phase when predators are in close vicinity. HMM-SSFs thus can be used to gain a mechanistic understanding of how animals use their environment in relation to the complex interplay between their needs to move, their knowledge of the environment and navigation capacity, their motion capacity and the external factors related to landscape heterogeneity.

Chain Length Effect on the Structural and Emission Properties of the CuI/Bis((4-methoxyphenyl)thio)alkane Coordination Polymers

A systematic chain length variation of the ligand para-MeOC₆H₄S(CH₂)_mSC₆H₄OMe (1 ≤ m ≤ 8) was performed to study its effect on the structures and photophysical properties of the coordination polymers (CP) when reacted with CuI. Indeed, direct correlations are noted between these features and m. When m is an odd number, the secondary building unit is systematically the common closed-cubane Cu₄I₄ cluster, rendering the material strongly luminescent (i.e., emission quantum yield, Φ_e > 20%), and the CP is one-dimensional (1D). However, when m is 2, 4, and 6, the SBUs exhibit rare polymeric motifs of (Cu₂I₂)_n: staircase ribbon, fused poly(rhombic pseudo-dodecahedron), and accordion ribbon, respectively, and the emission intensities are either very weak (Φ_e < 0.001%) or of medium intensity (Φ_e ∼ 10% when m = 6). When m = 8 (i.e. the most flexible chain), the SBU is a closed-cubane Cu₄I₄ and the emission intensity is medium (Φ_e ∼ 10%). A special case was observed for m = 3, where a co-crystallization of the molecular cluster Cu₄I₄(NCCH₃)₄ is observed in the lattice, which turns out to be quite important for the stability of the network.

Comparison of Measurement Techniques and Response Criteria for MR Imaging Follow-up in Adult Primary Central Nervous System Lymphoma

BACKGROUND AND PURPOSE

Current guidelines proposed for the measurement of primary central nervous system lymphoma in 2005 have indicated that unidimensional and bidimensional measurements may be used, using the same threshold for response categorization, because no clinical study has evaluated the agreement among the measurement techniques. Hence, our study assessed the agreement among different measurements.

MATERIALS AND METHODS

In this retrospective study, primary central nervous system lymphoma lesions were measured with different techniques (longest 1D, axial 1D, 2D, 3D, and the Response Evaluation Criteria in Solid Tumor) on consecutive MR images. Intra- and interobserver correlations were calculated with intraclass correlation coefficients. Correlations between raw measurements and variations in size compared with baseline were evaluated with the Spearman rank correlation, and agreement among response categories was evaluated.

RESULTS

A total of 304 examinations obtained in 40 patients was assessed. The intraobserver intraclass correlation coefficient for 3D, 2D, and longest 1D were ≥0.993. The interobserver intraclass correlation coefficient was ≥0.967. The correlations in raw measurements and size variation in comparison with 3D were respectively; 0.99 and 0.98 for 2D; 0.94 and 0.92 for longest 1D; 0.94 and 0.83 for axial 1D; and 0.90 and 0.79 for Response Evaluation Criteria in Solid Tumor. With 20%-30% and 25%-50% thresholds for unidimensional techniques, response categorizations were 95% and 95% for 2D, 92.5% and 90% for the longest 1D, 87.5% and 82.5% for axial 1D, and 90% and 85% for the Response Evaluation Criteria in Solid Tumor.

CONCLUSIONS

Both longest 1D and 2D demonstrated excellent correlations with 3D measurements. The longest 1D could be used for the follow-up of primary central nervous system lymphoma. If unidimensional measurements were used, 20% and 30% cutoffs should be used for defining response categorization instead of the current guidelines.

Differences in Uptake of Low-Dose CT Scan for Lung Cancer among White and Black Adult Smokers in the United States-2017

To study racial/ethnic differences in the utilization of low-dose computerized tomography (LDCT) scan for lung cancer among adult smokers. Cross-sectional data (n=2,640) of adults aged 55-74, were from the 2017 Behavioral Risk Factor Surveillance System, Lung Cancer Screening module. Weighted, multivariable logistic regression was conducted. Most, 70.9%, were White and 52.2% male. About 16.0 % reported receiving LDCT scan in the past 12 months, 12.0% of Blacks and 17.4% of Whites. More Whites (55.0%) had ≥30 pack-years smoking history than Blacks (20%). Blacks had lower odds, .52 (CI: 0.28-0.96) of receiving LDCT scan than Whites. The odds of receiving LDCT scan were higher for those who were male, who tried to quit smoking in the past year, and for those with more education, health insurance, high blood pressure, lung disease, or cancer history (other than skin or lung cancer). This study suggests racial differences in the use of LDCT scan.

Crop raiders in an ecological trap: optimal foraging individual-based modeling quantifies the effect of alternate crops

Crop raiding is an increasing source of human-wildlife conflict that antagonizes humans and can lead to heightened killing of wildlife. Attraction to crops can trigger ecological traps, where animals prefer areas of their range that confer relatively low fitness. Food can be used to draw animals away from problematic areas, but an alternative considered less often is to replace high-quality food with poorer alternatives. In any case, managers often have no means of anticipating by how much such interventions should impact animal use of space. Optimal foraging theory predicts that foragers optimizing their diet should choose food items according to their relative profitability (i.e., digestible energy/ handling time), a theoretical prediction that can orient management actions. Accordingly, we developed an individual-based model (IBM) simulating movement through empirical rules under an optimal foraging framework. Our objective was to quantify the effect size of cultivating alternate crops to reduce crop raiding and the associated human-induced mortality driving an ecological trap for an energy maximizer, plains bison (Bison bison bison). Results showed that almost tripling the area of cultivation of crops of lower profitability (from 24.3% of the bison range outside the protected area in one management scenario to 70.3% in another) only led to a 25% additional decrease in the intensity of crop raiding (from a decrease of 40% in the first scenario to a decrease of 65% in the second). This suggests that localized interventions in the landscape are likely to have a stronger impact in mitigating crop raiding than broad actions ignoring spatial patterns in food distribution. However, we obtained no significant reduction in the number of simulated bison being harvested in the first scenario, and only a small reduction in the second, when the intervention was spatially broad. Our individual-based approach to animal movement informed by optimal foraging demonstrates that linking landscape configuration to mortality rates can help managers anticipate the effectiveness of manipulating food to keep animals away from problematic zones. Yet disarming ecological traps driven by human hunting appears to be a much more challenging undertaking.

From Short-Bite Ligand Assembled Ribbons to Nanosized Networks in Cu(I) Coordination Polymers Built Upon Bis(benzylthio)alkanes (BzS(CH2)nSBz; n = 1-9)

With the objective to establish a correlation between the spacer distance and halide dependence on the structural features of coordination polymers (CPs) assembled by the reaction between CuX salts (X = Cl, Br, I) and dithioether ligands BzS(CH₂)_nSBz (n = 1-9; Bz = benzyl), a series of 26 compounds have been prepared and structurally investigated. A particular attention has been devoted to the design of networks with extremely long and flexible methylene spacer units between the SBz donor sites. Under identical conditions, CuI and CuBr react with BzSCH₂Bz (L1) affording respectively the one-dimensional (1D) CPs {Cu(μ₂-I)₂Cu}(μ-L1)₂]_n (CP1) and {Cu(μ₂-Br)₂Cu}(μ-L1)₂] (CP2), which incorporate Cu(μ₂-X)₂Cu rhomboids as secondary building units (SBUs). The hitherto unknown architecture of two-dimensional (2D) layers obtained with CuCl (CP3) differs from that of CP1 and CP2, which bear inorganic -Cl-Cu-Cl-Cu-Cl- chains interconnected through bridging L1 ligands, thus forming a 2D architecture. The crystallographic characterization of a 1D CP obtained by reacting CuI with 1,3-bis(benzylthio)propane (L2) reveals that [{Cu(μ₂-I)₂Cu}(μ-L2)₂]_n (CP4) contains conventional Cu₂I₂ rhomboids as SBUs. In contrast, unusual isostructural CPs [{Cu(μ₂-X)}(μ₂-L2)]_n (CP5) and (CP6) are obtained with CuX when X = Br and Cl, respectively, in which the isolated Cu atoms are bridged by a single μ₂-Br or μ₂-Cl ion giving rise to infinite [Cu(μ₂-X)Cu]_n ribbons. The crystal structure of the strongly luminescent three-dimensional (3D) polymer [{Cu₄(μ₃-I)₃(μ₄-I)(μ-L3)_1.5]_n (CP7) issued from reacting 2 equiv of CuI with BzS(CH₂)₄SBz (L3) has been redetermined. CP7 features unusual [(Cu₄I₃)(μ₄-I)]_n arrays securing the 3D connectivity. In contrast, mixing CuI with an excess of L3 provides the nonemissive material [{Cu(μ₂-I)₂Cu}(μ-L3)₂]_n (CP8). Treatment of CuBr and CuCl with L3 leads to [{Cu(μ₂-Br)₂Cu}(μ-L3)₂]_n (CP9) and the 0D complex [{Cu(μ₂-Cl)₂Cu}(μ-L3)₂] (D1), respectively. The crystallographic particularity for CP9 is the coexistence of two topological isomers within the unit cell. The first one, CP9-1D, consists of simple 1D ribbons running along the a axis of the unit cell. The second topological isomer, CP9-2D, also consists of [Cu(μ₂-Br)₂Cu] SBUs, but these are interconnected in a 2D manner forming 2D sheets placed perpendicular to the 1D ribbons. Four 2D CPs, namely, [{Cu₄(μ₃-I)₄}(μ-L4)₂]_n (CP10), [{Cu(μ₂-I)₂Cu}(μ-L4)₂]_n (CP11), [{Cu(μ₂-Br)₂Cu}(μ-L4)₂]_n (CP12), and [{Cu(μ₂-Cl)₂Cu}(μ-L4)₂]_n (CP13), stem from the self-assembly process of CuX with BzS(CH₂)₆SBz (L4). A similar series of 2D materials comprising [{Cu₄(μ₃-I)₄}(μ-L5)₂]_n (CP14), [{Cu(μ₂-I)₂Cu}(μ-L5)₂]_n (CP15), [{Cu(μ₂-Br)₂Cu}(μ-L5)₂]_n (CP16), and [{Cu(μ₂-Cl)₂Cu}(μ-L5)₂]_n (CP17) result from the coordination of BzS(CH₂)₇SBz (L5) on CuX. Ligation of CuX with the long-chain ligand BzS(CH₂)₈SBz (L6) allows for the X-ray characterization of the luminescent 2D [{Cu₄(μ₃-I)₄}(μ-L6)₂]_n (CP18) and the isostructural 1D series [{Cu(μ₂-X)₂Cu}(μ-L6)₂]_n CP19 (X = I), CP20 (X = Br) and CP21(X = Cl). Noteworthy, BzS(CH₂)₉SBz (L7) bearing a very flexible nine-atom chain generated the crystalline materials 2D [{Cu₄(μ₃-I)₄}(μ-L7)₂]_n (CP22) and the isostructural 1D series [{Cu(μ₂-X)₂Cu}(μ-L6)₂]_n CP23 (X = I), CP24 (X = Br), and CP25 (X = Cl), featuring nanometric separations between the cubane- or rhomboid-SBUs. This comparative study reveals that the outcome of the reaction of CuX with the shorter ligands BzS(CH₂)_nSBz (n = 1-4) is not predictable. However, with more flexible spacer chains BzS(CH₂)_nSBz (n = 6-9), a clear structural pattern can be established. Using a 1:1 CuX-to-ligand ratio, [{Cu(μ₂-X)₂Cu}(μ-L4-7)₂] CPs are always formed, irrespectively of L4-L7. Employing a 2:1 CuX-to-ligand ratio, only CuI is able to form networks incorporating Cu₄(μ₃-I)₄ clusters as SBUs. All attempts to construct polynuclear cluster using CuBr and CuCl failed. The materials have been furthermore analyzed by powder X-ray diffraction, Raman spectroscopy, and thermogravimetric analysis, and the photophysical properties of the emissive materials have been studied.

When the protection of a threatened species depends on the economy of a foreign nation

A significant challenge of conservation biology is to preserve species in places where their critical habitat also attracts significant economic interest. The problem is compounded when species distributions occur across large spatial extents. Threatened boreal caribou (Rangifer tarandus caribou) epitomize this problem: their critical habitat encompasses a vast expanse of forest that also supplies much of Canada’s merchantable timber. Boreal caribou were protected under the Canada Species at Risk Act in 2003. We investigated putative drivers of reduced disturbance for caribou habitat since then. Where the cumulative logging footprint slowed within caribou habitat, this has resulted neither from decreases in annual allowable cut of timber nor the creation or expansion of protected areas. Rather, it has fluctuated with the American economy relative to that of Canada. For each $0.05 US lost over the $CAD, 129 km² of caribou habitat was not disturbed by logging in a given year. Recent population declines have been occurring even though logging typically remained at <70% of allowed levels. Our study raises concerns about how caribou are functionally being conserved under the current application of existing legislation. In this globalized world, the economy of foreign nations is increasingly likely to govern national conservation objectives.

Further studies on the signal enhancement effect in laser diode thermal desorption-triple quadrupole mass spectrometry using microwell surface coatings

The laser diode thermal desorption (LDTD) ionization source allows ultrafast and sensitive analysis of small molecules by mass spectrometry. Signal enhancement in LDTD has been observed when coating the surface of sample microwells with a solution of ethylenediaminetetraacetic acid (EDTA) or nitrilotriacetic acid. Here we present a quantitative analysis of signal enhancement using solutions of diverse commercial proteins (lysozyme, immunoglobulin G, albumin, and fibrinogen) as coatings. Results showed that compounds with polar chemical functions such as carboxylic acid, sulfonyl, and nitro had signal enhancement factors, in most cases higher than 10, when using any of the tested proteins as coating agent. Analysis of variance revealed that immunoglobulin G and fibrinogen gave the best results. However, the signal enhancement factors obtained with these proteins were not superior to those observed with EDTA. To explain the signal enhancement effect of proteins, analysis by scanning electron microscopy of dried samples on the microwell sample plates was carried out. Images showed that salicylic acid, one of the compounds with the highest observed signal enhancement, formed a thick layer when applied directly on the uncoated surface, but it formed small crystals (<1 μm) in the presence of protein or EDTA coatings. Further crystallographic studies using powder X-ray diffraction showed that the crystalline form of salicylic acid is modified in the presence of EDTA. Salicylic acid when mixed with EDTA had a higher percentage of amorphous phase (38.1%) than without EDTA (23.1%). These results appear to confirm that the diminution of crystal size of analytes and the increase of amorphous phase are implicated in signal enhancement effect observed in LDTD using microwell surface coatings. To design better coatings and completely elucidate the signal enhancement effect in LDTD, more studies are necessary to understand the effects of coatings on the ionization of analytes.

Managing Genetic Diversity and Extinction Risk for a Rare Plains Bison (Bison bison bison) Population

Unfenced plains bison are rare and only occur in a small number of locations throughout Canada and the United States. We examined management guidelines for maintenance of genetic health and population persistence for a small and isolated population of plains bison that occupy the interface between a protected national park and private agricultural lands. To address genetic health concerns, we measured genetic diversity relative to other populations and assessed the potential effects of genetic augmentation. We then used individual-based population viability analyses (PVA) to determine the minimum abundance likely to prevent genetic diversity declines. We assessed this minimum relative to a proposed maximum social carrying capacity related to bison use of human agricultural lands. We also used the PVA to assess the probability of population persistence given the limiting factors of predation, hunting, and disease. Our results indicate that genetic augmentation will likely be required to achieve genetic diversity similar to that of other plains bison populations. We also found that a minimum population of 420 bison yields low probability of additional genetic loss while staying within society-based maxima. Population estimates based on aerial surveys indicated that the population has been below this minimum since 2007. Our PVA simulations indicate that current hunting practices will result in undesirable levels of population extinction risk and further declines in genetic variability. Our study demonstrates that PVA can be used to evaluate potential management scenarios as they relate to long-term genetic conservation and population persistence for rare species.

P14.84 Intraarterial chemotherapy and osmotic blood-brain barrier modification in the treatment of primary CNS lymphoma

BACKGROUND

Primary central nervous system lymphomas (PCNSL) are considered a rare and aggressive form of central nervous system (CNS) tumors. High-dose methotrexate has become the backbone of PCNSL treatment, and is recommended by the EANO guidelines. In most recent protocols, investigators tend to postpone or even avoid the use of radiotherapy; indeed, its use has become controversial with findings of associated severe neuro-toxicity, especially in elderly patients. To maximize delivery across the BBB, we use cerebral intra-arterial chemotherapy (CIAC) coupled with osmotic blood-brain barrier disruption (OBBBD). We hereby report our single-center experience over 18 years with the CIAC + BBBD technique using 2 different HD-MTX protocols.

MATERIAL AND METHODS

This phase II study was conducted at the Centre hospitalier Universitaire de Sherbrooke (CHUS) from November 1999 to May 2018. The protocol was approved by the institutional review board, and informed consent was obtained in accordance to institutional regulation in every patient After enrollment and initial evaluation, patients were treated every four weeks (1 cycle) for 12 cycles, unless progression. After general anesthesia, a transfemoral approach was used to catheterize either the right or left internal carotid artery or the dominant vertebral artery, depending on tumor(s) location. OBBBD was performed by infusing 20% mannitol in the selected vascular distribution for 30 seconds at a rate that fills the vascular distribution so as to maximize the contact of the mannitol with the endothelial cells.Two different chemotherapy regimens were sequentially used in this study. High-dose MTX (5 g IV) was the cornerstone of both regimens: the first regimen (1999 to 2007) also included etoposide phosphate IV (400 mg/m²) and cyclophosphamide IV (660 mg/m²), whereas the 2nd regimen (1998 to 2018) also included carboplatin IA (400 mg/m²).

RESULTS

The present analysis therefore concerns a cohort of 44 naive patients recruited over 18 years in a single center. Median follow-up was 38 months. Overall, a CR was induced in 34 patients (79%). Themedian time to CR was 7.3 months (IQR: 7.8). Of these 34 patients, 11 (25.6%) are still alive, and 9 of these are disease-free after treatment discontinuation. The actuarial median survival (MS) was 46.5 months (95% CI: 30.9–62.2) for the cohort. Survival was 88%, 64%, 54%, 39% and 18% at 1, 2, 3,5 and 10 years (Figure 1 and Table 2).The progression-free survival was 43.4 months (95% CI: 17.9–68.9). Five occurrences of vascular complications related to the treatment were observed (11.6%).

Conclusion: CIAC HD-MTX-based protocols with OBBBD is a safe and well-tolerated procedure for the management of primary CNS lymphoma. Our single center data suggests better PFS and survival outcomes compared to IV protocols with less hematologic toxicity and good tolerability, especially in the elderly.

P11.39 Chloroquine as an anti-glioblastoma therapeutic: repurposing of an old drug

BACKGROUND

Glioblastoma (GBM) is the most common and aggressive type of primary brain tumour in adults. These tumours depict anarchic proliferation and brain infiltration as well as radio- and chemoresistant profiles. The complete surgical resection is unachievable and responses to standard therapy are transitory. Recurrence is thus inevitable and patient prognosis is generally less than 15 months. Transforming growth factor-beta (TGF-β) holds a substantial role in supporting the GBM phenotype. We showed that TGF-β 1 expression levels correlate with overall and progression-free survival in newly diagnosed GBM patient. We also observed that chloroquine (CQ) can reduce the production of TGF-β together with proliferation, invasion, radioresistance and radio-induced invasion in vitro. Unfortunately, little is known regarding the ability of CQ to penetrate the blood-brain barrier (BBB). Therefore, our objective is to determine whether intravenous (IV) or intra-arterial (IA) infusions of CQ and hydroxychloroquine (HCQ), a pharmacological analog of CQ, can yield therapeutic brain concentrations.

MATERIAL AND METHODS

To assess BBB penetration, the brain, plasma and cerebrospinal fluid (CSF) concentrations of CQ/HCQ were measured by LCMS/MS at different timepoints post-IV or post-IA infusions with 20 mg/kg of CQ/HCQ in tumour-free Wistar rat. For the survival studies, We implanted 10’000 F98 murin glioblastoma cells in the right putamen of Fischer rats. Ten days post-implantation, IA and IV infusion were accomplished through cannulations of the external right carotid and tail vein respectively.

RESULTS

With IV injections, CQ/HCQ brain concentrations 15 minutes post-injection reached 15.76 mg/g (0.18 µM) and 1.67 mg/g (0.078 µM) respectively. However, following IA infusions, we observed a 1.74 and 20.9 fold increase (20 mg/kg HCQ) as well as 7.1 and 84.7-fold-increase (20 mg/kg CQ) in contra- and ipsilateral brain concentrations respectively. Although brain concentrations gradually decreased over time post-IA infusions, the ipsilateral hemisphere CQ concentration was still 82.81 mg/g (34.52 µM) after 6 hours. Whereas plasma concentrations were very similar following IV and IA infusions, both molecules barely accumulated in the CSF and only when using IA infusions. The median survival of the control group (IA phosphate-buffered saline) and the group treated with 20 mg/kg CQ IV were 23.5 days and 24.5 days respectively. However, rats injected with 20 mg/kg CQ IA had a median survival of 28.5 days.

CONCLUSION

These results suggest that IA CQ could be used to abrogate the GBM phenotype. As TGF-β is associated with resistance to both radio- and chemotherapy, we plan to characterize the combination of IA infusions of CQ in combination with radiation or chemotherapy (carboplatin).

P11.40 Development of an implantable multifunctional biodevice (GlioGel) in the treatment of recurrent glioblastoma

BACKGROUND

Glioblastoma (GBM) is a devastating disease with a median survival of 14–16 months. This poor prognosis can be explained by 3 factors. First, the infiltrative nature of the disease prohibits a complete removal of the tumor. Second, some of the tumor cells are brain tumor stem cells, which are highly migratory and highly resistant to treatments. Finally, the presence of the blood-brain barrier prohibits entry of therapeutics. This situation implies that new treatment approaches must be directed toward the infiltrated brain surrounding the resection cavity. To bypass this problem and improve the potency of adjuvant treatment, we have designed a new “GlioGel-device” that will have the ability to: 1- attract the migrating tumor cells into or nearby the device, and 2- subsequently deliver chemotherapy to the locally pooled tumor cells and 3- irradiate these cells with radioisotopes embedded in the GlioGel.

MATERIAL AND METHODS

In vitro proof of principle of chemoattraction was investigated by agarose drops method releasing chemokines molecules (CCL2, CCL11, CXCL10) with F98 and U87MG GBM cells. In vivo experiments evaluated the efficiency of chemokines and doxorubicin released by the implanted GlioGel on the tumor behaviour in our Fischer-F98 rat glioma model. An histology of tumour behaviour exposed to chemokines and survival of GBM rats treated with doxorubicin were analysed.

RESULTS

In vitro preliminary results for chemoattraction assays show that up to 2 times more cells invade the gel when it releases chemoattractant compared to PBS. The In vivo chemotherapy experiments with a fast, medium and slow release of doxorubicin from the GlioGel show that a local dose that represent a 1300-fold smaller dose than a normal intravenous systemic dose gave a significant reduction in tumour growth (median survival) compared to a control group. We investigated the effect provided by the GlioGel impregnated with chemokines on tumor cells migration, after implantation in the Fischer-F98 rat glioma model.

CONCLUSION

This preliminary study shows the ability of GlioGel releasing chemokines and doxorubicin to respectively attract and kill orthotopic glioblastoma cells. These encouraging results will be completed with a combination of short-range (high LET) radiation by embedded radioisotope into the GlioGel aiming for synergistic combination to eradicate as much tumour cells as possible, while limiting systemic side effects.

Functional response of wolves to human development across boreal North America

AIM

The influence of humans on large carnivores, including wolves, is a worldwide conservation concern. In addition, human-caused changes in carnivore density and distribution might have impacts on prey and, indirectly, on vegetation. We therefore tested wolf responses to infrastructure related to natural resource development (i.e., human footprint).

LOCATION

Our study provides one of the most extensive assessments of how predators like wolves select habitat in response to various degrees of footprint across boreal ecosystems encompassing over a million square kilometers of Canada.

METHODS

We deployed GPS-collars on 172 wolves, monitored movements and used a generalized functional response (GFR) model of resource selection. A functional response in habitat selection occurs when selection varies as a function of the availability of that habitat. GFRs can clarify how human-induced habitat changes are influencing wildlife across large, diverse landscapes.

RESULTS

Wolves displayed a functional response to footprint. Wolves were more likely to select forest harvest cutblocks in regions with higher cutblock density (i.e., a positive functional response to high-quality habitats for ungulate prey) and to select for higher road density in regions where road density was high (i.e., a positive functional response to human-created travel routes). Wolves were more likely to use cutblocks in habitats with low road densities, and more likely to use roads in habitats with low cutblock densities, except in winter when wolves were more likely to use roads regardless of cutblock density.

MAIN CONCLUSIONS

These interactions suggest that wolves trade-off among human-impacted habitats, and adaptively switch from using roads to facilitate movement (while also risking encounters with humans), to using cutblocks that may have higher ungulate densities. We recommend that conservation managers consider the contextual and interacting effects of footprints when assessing impacts on carnivores. These effects likely have indirect impacts on ecosystems too, including on prey species.

Unusual triplet-triplet annihilation in a 3D copper(i) chloride coordination polymer

A new coordination polymer (CP) defined as [Cu₂Cl₂(EtS(CH₂)₄SEt)₄]_n (CP2) was prepared by reacting EtS(CH₂)₄SEt with CuCl in acetonitrile in a 1 : 2 stoichiometric ratio. The X-ray structure reveals formation of non-porous 3D material composed of parallel 2D-[Cu₂Cl₂S₂]_n layers of Cl-bridged Cu₂(μ-Cl)₂ rhomboids assembled by EtS(CH₂)₄SEt ligands. A weak triplet emission (Φ_e < 0.0001) is observed in the 400-500 nm range with τ_e of 0.93 (298 K) and 3.5 ns (77 K) as major components. CP2 is the only 2nd example of emissive thioether/CuCl-containing material and combined DFT/TDDFT computations suggest the presence of lowest energy M/XLCT excited states. Upon increasing the photon flux (i.e. laser power), a triplet-triplet annihilation (TTA) is induced with quenching time constants of 72 ps (k_Q = 1.3 × 10¹⁰ s^-1) and 1.0 ns (k_Q = 7.1 × 10⁸ s^-1) at 298 and 77 K, respectively, proceeding through an excitation energy migration operating via a Dexter process. Two distinct (I_o)^1/2 (I_o = laser power) dependences of the emission intensity are depicted, indicating saturation as the observed emission increases with the excitation flux. These findings differ from that previously reported isomorphous CP [Cu₂Br₂(μ-EtS(CH₂)₄SEt)₄]_n (CP1), which exhibits no TTA behaviour at 77 K, and only one (laser power)² dependence at 298 K. The ∼18-fold increase in k_Q upon warming CP2 from 77 to 298 K indicates a temperature-aided TTA process. The significant difference between the presence (slower, CP2) and absence (CP1) of TTA at 77 K is explained by the larger unit cell contraction of the former upon cooling. This is noticeable by the larger change in inter-rhomboid CuCu separation for CP2.

Space Use and Leadership Modify Dilution Effects on Optimal Vigilance under Food-Safety Trade-Offs

Dilution of predation risk within groups allows individuals to be less vigilant and forage more while still facing lower risk than if they were alone. How group size influences vigilance when individuals can also adjust their space use and whether this relationship differs among individuals contributing differently to space use decisions remain unknown. We present a model-based study of how dilution affects the optimal antipredator behavior of group members in groups where all individuals determine their vigilance level while group leaders also determine space use. We showed that optimal vigilance did not always decrease with group size, as it was sometimes favorable for individuals in larger groups to use riskier patches while remaining vigilant. Followers were also generally less vigilant than leaders. Indeed, followers needed to acquire more resources than leaders, as only the latter could decide when to go to richer patches. Followers still benefit from dilution of predation risk compared with solitary individuals. For leaders, keeping their leadership status can be more important than incorporating new group members to increase dilution. We demonstrate that risk dilution impacts both optimal vigilance and space use, with fitness reward being tied to a member's ability to influence group space use.

Polar crystal of vanillylformamide through replacement of the alkene by an isosteric formamide group

Vanillylformamide [systematic name: N-(4-hydroxy-3-methoxybenzyl)formamide], C9H11NO3, (II), has been synthesized from vanillylamine hydrochloride and studied by single-crystal X-ray diffraction. Compound (II) and the well known biologically active eugenol compound (I) can be considered to be `isosteres' of each other, since they share comparable molecular shape and volume. The product (II) crystallizes in the space group P1. In the crystal, the vanillylformamide molecules are linked mainly by N—H...O, O—H...O and Csp 2—H...O hydrogen bonds, forming infinite two-dimensional polar sheets. These two-dimensional layers pack in a parallel fashion, constructing a polar three-dimensional network. Except for van der Waals forces and weak Csp 3—H...O hydrogen bonds, there are no significant intermolecular interactions between the layers. A Cambridge Structural Database search revealed that vanillylamide-related crystals are scarce.

Ecological processes determining the distribution dynamics of vole populations during forest succession

The size and distribution of animal populations may vary drastically over time following a disturbance event. While both competition and predation can control the size of animal populations, changes in the relative importance of these two density-dependent processes remain poorly documented during ecological succession. Here, we combined habitat selection and optimal foraging theory to identify the processes that can explain the increase in red-backed voles (Myodes gapperi) during post-logging forest succession in boreal ecosystems. Specifically, we assessed the extent to which changes in intra- and interspecific competition and in predation risk can explain variation in abundance and distribution of voles during post-harvest forest succession. We estimated the abundances of the red-backed vole and of its main competitor, the deer mouse (Peromyscus maniculatus), in adjacent pairs of logged (5-66 years old) forest stands and uncut stands (> 120 years old). We found that voles increased their preference for uncut stands with increasing conspecific density. Foraging experiments revealed that in early-seral forest stands, voles increased their feeding effort in the presence of deer mice, particularly in safer food patches. This behaviour is expected from foraging theory when interspecific competitors increase predation risk. Apparent competition would thus limit the density of red-backed voles, and changes in the relative strength of this process during forest succession would control patterns of distribution and abundance of the species.

Temporal dynamics in animal community assembly during post-logging succession in boreal forest

Species assemblages can result from deterministic processes, such as niche differentiation and interspecific interactions, and from stochastic processes, such as random colonisation and extinction events. Although changes in animal communities following disturbances have been widely examined, few studies have investigated the mechanisms structuring communities during ecological succession. We assessed the impact of logging on small mammal and beetle assemblages in landscapes dominated by old-growth boreal forests. Our objectives were to 1) characterize variations in communities during the first 66 years of post-harvest forest succession, 2) determine if there are non-random patterns of species co-occurrence (i.e., deterministic processes), and if there are, 3) establish whether non-random co-occurrences are best explained by habitat attributes or by interspecific interactions. We captured small mammals and beetles along a gradient of forest succession (5-66 years) and in old-growth forest, and characterized key vegetation attributes. First, we tested whether community compositions in clear-cut stands became similar to those in natural stands after 66 years. We then used null models, which were either unconstrained or constrained by habitat attributes, to address the last two objectives and distinguish effects of vegetation attributes from interspecific interactions on community assembly. We showed that beetle assemblages differed in stands 21-30 years post-harvest compared to old-growth forests. In contrast, harvesting did not influence the composition of small mammal communities. Overall, our results suggest that community assembly during forest succession is driven by both stochastic and deterministic processes, the latter being linked to interspecific interactions more strongly than to vegetation attributes.

Rendering cross-conjugated azophenine derivatives emissive to probe the silent photophysical properties of emeraldine

An azophenine derivative was synthesized by coupling truxene and azophenine via the copper-free Sonagashira reaction using Pd₂(dba)₃ and As(PPh)₃ as catalysts. The crystal structure of this heavy azophenine model (∼4000) was made and the identity of the structure was confirmed. By introducing truxene groups into this cross-conjugated structure, the deactivating rotations around the NH-C₆H₄ bonds were slowed down, which rendered this derivative near-IR emissive at 298 K. This species provided then the appropriate spectral and kinetic signatures for knowing where and what to look for in emeraldine, which was called non-emissive. Besides, two other compounds were also synthesized as models for this azophenine derivative for comparison and interpretation purposes.

Nanogel-like UCST triblock copolymer micelles showing large volume expansion before abrupt dissolution

A comprehensive study of the thermally induced large expansion in volume prior to the abrupt dissociation of the micelles of a novel UCST triblock copolymer.

Multiply “trapped” 3[trans-Pt(PR3)2(CCC6H4X)2]* conformers in rigid media

The triplet emission exhibits multiple well-defined decays depending on the θ₁ and θ₂ values and environment in the crystal sites.

The trans-Bis(p-thioetherphenylacetynyl)bis(phosphine)platinum(II) Ligands: A Step towards Predictability and Crystal Design

Two organometallic ligands L1 (trans-[p-MeSC₆H₄C≡C-Pt(PR₃)₂-C≡CC₆H₄SMe; R = Me]) and L2 (R = Et) react with CuX salts (X = Cl, Br, I) in MeCN to form one-dimensional (1D) or two-dimensional (2D) coordination polymers (CPs). The clusters formed with copper halide can either be step cubane Cu₄I₄, rhomboids Cu₂X₂, or simply CuI. The formed CPs with L1, which is less sterically demanding than L2, exhibit a crystallization solvent molecule (MeCN), whereas those formed with L2 do not incorporate MeCN molecules in the lattice. These CPs were characterized by X-ray crystallography, thermogravimetric analysis, IR, Raman, absorption, and emission spectra as well as photophysical measurements in the presence and absence of crystallization MeCN molecules for those CPs with the solvent in the lattice (i.e., [(Cu₄I₄)L1·MeCN] _n (CP1), [(Cu₂Br₂)L1·2MeCN] _n (CP3), and [(Cu₂Cl₂)L1·MeCN] _n (CP5)). The crystallization molecules were removed under vacuum to evaluate the porosity of the materials by Brunauer-Emmett-Teller (N₂ at 77 K). The 2D CP shows a reversible type 1 adsorption isotherm for both CO₂ and N₂, indicative of microporosity, whereas the 1D CPs do not capture more solvent molecules or CO₂.