Getting into Shape: Reflections on a New Generation of Cylindrical Nanostructures' Self-Assembly Using Polymer Building Blocks.

Cylinders are fascinating structures with uniquely high surface area, internal volume, and rigidity. On the nanoscale, a broad range of applications have demonstrated advantageous behavior of cylindrical micelles or bottlebrush polymers over traditional spherical nano-objects. In the past, obtaining pure samples of cylindrical nanostructures using polymer building blocks via conventional self-assembly strategies was challenging. However, in recent years, the development of advanced methods including polymerization-induced self-assembly, crystallization-driven self-assembly, and bottlebrush polymer synthesis has facilitated the easy synthesis of cylindrical nano-objects at industrially relevant scales. In this Perspective, we discuss these techniques in detail, highlighting the advantages and disadvantages of each strategy and considering how the cylindrical nanostructures that are obtained differ in their chemical structure, physical properties, colloidal stability, and reactivity. In addition, we propose future challenges to address in this rapidly expanding field.

Poly(Pentafluorophenyl Methacrylate)-Based Nano-Objects Developed by Photo-PISA as Scaffolds for Post-Polymerization Functionalization.

The preparation of a functional fluorine-containing block copolymer using reversible addition-fragmentation chain-transfer dispersion polymerization in DMSO as a "platform/scaffold" is explored. The nanostructures, comprised of poly(ethyleneglycol)-b-poly(pentafluorophenyl methacrylate) or PEG-b-P(PFMA), are formulated via photo-initiated polymerization-induced self-assembly (PISA) followed by post-polymerization modification using different primary amines. A combination of light scattering and microscopy techniques are used to characterize the resulting morphologies. It is found that upon varying the degree of polymerization of the core-forming block of PFMA, only uniform spheres (with textured surfaces) are obtained. These nanostructures are subsequently modified by cross-linking using a non-responsive and a redox-responsive diamine, thus imparting stability to the particles in water. In response to intracellular glutathione (GSH) concentration, destabilization of the micelles occurs as evidenced by dynamic light scattering. The well-defined size, inherent reactivity of the nanoparticles toward nucleophiles, and GSH-responsiveness of the nanospheres make them ideal scaffolds for drug delivery to intracellular compartments with reductive environments.

Predicting Monomers for Use in Polymerization-Induced Self-Assembly.

We report an in silico method to predict monomers suitable for use in polymerization-induced self-assembly (PISA). By calculating the dependence of LogPoct /surface area (SA) on the length of the growing polymer chain, the change in hydrophobicity during polymerization was determined. This allowed for evaluation of the capability of a monomer to polymerize to form self-assembled structures during chain extension. Using this method, we identified five new monomers for use in aqueous PISA via reversible addition-fragmentation chain transfer (RAFT) polymerization, and confirmed that these all successfully underwent PISA to produce nanostructures of various morphologies. The results obtained using this method correlated well with and predicted the differences in morphology obtained from the PISA of block copolymers of similar molecular weight but different chemical structures. Thus, we propose this method can be utilized for the discovery of new monomers for PISA and also the prediction of their self-assembly behavior.

Glycerol- and diglycerol-based polyesters: Evaluation of backbone alterations upon nano-formulation performance.

Despite the success of polyethylene glycol-based (PEGylated) polyesters in the drug delivery and biomedical fields, concerns have arisen regarding PEG's immunogenicity and limited biodegradability. In addition, inherent limitations, including limited chemical handles as well as highly hydrophobic nature, can restrict their effectiveness in physiological conditions of the polyester counterpart. To address these matters, an increasing amount of research has been focused towards identifying alternatives to PEG. One promising strategy involves the use of bio-derived polyols, such as glycerol. In particular, glycerol is a hydrophilic, non-toxic, untapped waste resource and as other polyols, can be incorporated into polyesters via enzymatic catalysis routes. In the present study, a systematic screening is conducted focusing on the incorporation of 1,6-hexanediol (Hex) (hydrophobic diol) into both poly(glycerol adipate) (PGA) and poly(diglycerol adipate) (PDGA) at different (di)glycerol:hex ratios (30:70; 50:50 and 70:30 mol/mol) and its effect on purification upon NPs formation. By varying the amphiphilicity of the backbone, we demonstrated that minor adjustments influence the NPs formation, NPs stability, drug encapsulation, and degradation of these polymers, despite the high chemical similarity. Moreover, the best performing materials have shown good biocompatibility in both in vitro and in vivo (whole organism) tests. As preliminary result, the sample containing diglycerol and Hex in a 70:30 ratio, named as PDGA-Hex 30%, has shown to be the most promising candidate in this small library analysed. It demonstrated comparable stability to the glycerol-based samples in various media but exhibited superior encapsulation efficiency of a model hydrophobic dye. This in-depth investigation provides new insights into the design and modification of biodegradable (di)glycerol-based polyesters, potentially paving the way for more effective and sustainable PEG-free drug delivery nano-systems in the pharmaceutical and biomedical fields.

Synthesis of Multifunctional Polymersomes Prepared by Polymerization-Induced Self-Assembly.

Polymersomes are an exciting modality for drug delivery due to their structural similarity to biological cells and their ability to encapsulate both hydrophilic and hydrophobic drugs. In this regard, the current work aimed to develop multifunctional polymersomes, integrating dye (with hydrophobic Nile red and hydrophilic sulfo-cyanine5-NHS ester as model drugs) encapsulation, stimulus responsiveness, and surface-ligand modifications. Polymersomes constituting poly(N-2-hydroxypropylmethacrylamide)-b-poly(N-(2-(methylthio)ethyl)acrylamide) (PHPMAm-b-PMTEAM) are prepared by aqueous dispersion RAFT-mediated polymerization-induced self-assembly (PISA). The hydrophilic block lengths have an effect on the obtained morphologies, with short chain P(HPMAm)16 affording spheres and long chain P(HPMAm)43 yielding vesicles. This further induces different responses to H2O2, with spheres fragmenting and vesicles aggregating. Folic acid (FA) is successfully conjugated to the P(HPMAm)43, which self-assembles into FA-functionalized P(HPMAm)43-b-P(MTEAM)300 polymersomes. The FA-functionalized P(HPMAm)43-b-P(MTEAM)300 polymersomes entrap both hydrophobic Nile red (NR) and hydrophilic Cy5 dye. The NR-loaded FA-linked polymersomes exhibit a controlled release of the encapsulated NR dye when exposed to 10 mM H2O2. All the polymersomes formed are stable in human plasma and well-tolerated in MCF-7 breast cancer cells. These preliminary results demonstrate that, with simple and scalable chemistry, PISA offers access to different shapes and opens up the possibility of the one-pot synthesis of multicompartmental and responsive polymersomes.

Comparing 200,000 Breast Implants and 85,000 Patients over Four National Breast Implant Registries.

BACKGROUND: Growing awareness about breast implant-related adverse events has stimulated the demand for large, independent data resources. For this, data from breast implant registries could be combined. However, that has never been achieved yet. METHODS: Real-world data from four currently active national breast implant registries were used. All permanent breast implants from the Australian, Dutch, Swedish, and American registries were included. A subpopulation present across all registries between 2015 and 2018 was subsequently selected, including only permanent breast implants inserted during primary surgery for breast reconstruction or augmentation in patients without previous breast device surgery. Nationwide coverage, patient and implant characteristics, infection control measures, and revision incidences were analyzed. RESULTS: A total of 207,189 breast implants were registered. Nationwide coverage varied between 3% and 98%. The subpopulation included 111,590 implants (7% reconstruction, 93% augmentation). Across the registries, mean patient age varied between 41 and 49 years ( P < 0.001) for reconstruction and 31 and 36 years ( P < 0.001) for augmentation. Variation was observed in implant preferences across the countries and over the years. Infection control measures were most frequently registered in Australia. Cumulative revision incidence at 2 years ranged from 6% to 16% after reconstruction and from 1% to 4% after augmentation. CONCLUSIONS: For the first time, independent, national, registry-based data from four breast implant registries were combined. This is a powerful step forward in optimizing international breast implant monitoring, evidence-based decision-making, and patient safety.

Polymer-metal-organic framework self-assembly (PMOFSA) as a robust one-step method to generate well-dispersed hybrid nanoparticles in water.

A new process, PMOFSA, is described here, that opens the way for the one-pot straightforward and versatile manufacture of polymer-MOF nanoparticles in water. It can be expected that this study will not only expand the scope of in situ preparation of polymer-MOF nano-objects but also inspire researchers in the field to prepare a new generation of polymer-MOF hybrid materials.

Poly (diglycerol adipate) variants as enhanced nanocarrier replacements in drug delivery applications.

Sustainably derived poly(glycerol adipate) (PGA) has been deemed to deliver all the desirable features expected in a polymeric scaffold for drug-delivery, including biodegradability, biocompatibility, self-assembly into nanoparticles (NPs) and a functionalisable pendant group. Despite showing these advantages over commercial alkyl polyesters, PGA suffers from a series of key drawbacks caused by poor amphiphilic balance. This leads to weak drug-polymer interactions and subsequent low drug-loading in NPs, as well as low NPs stability. To overcome this, in the present work, we applied a more significant variation of the polyester backbone while maintaining mild and sustainable polymerisation conditions. We have investigated the effect of the variation of both hydrophilic and hydrophobic segments upon physical properties and drug interactions as well as self-assembly and NPs stability. For the first time we have replaced glycerol with the more hydrophilic diglycerol, as well as adjusting the final amphiphilic balance of the polyester repetitive units by incorporating the more hydrophobic 1,6-n-hexanediol (Hex). The properties of the novel poly(diglycerol adipate) (PDGA) variants have been compared against known polyglycerol-based polyesters. Interestingly, while the bare PDGA showed improved water solubility and diminished self-assembling ability, the Hex variation demonstrated enhanced features as a nanocarrier. In this regard, PDGAHex NPs were tested for their stability in different environments and for their ability to encode enhanced drug loading. Moreover, the novel materials have shown good biocompatibility in both in vitro and in vivo (whole organism) experiments.

Distinct merkel cell polyomavirus molecular features in tumour and non tumour specimens from patients with merkel cell carcinoma.

Merkel Cell Polyomavirus (MCPyV) is associated with Merkel Cell carcinoma (MCC), a rare, aggressive skin cancer with neuroendocrine features. The causal role of MCPyV is highly suggested by monoclonal integration of its genome and expression of the viral large T (LT) antigen in MCC cells. We investigated and characterized MCPyV molecular features in MCC, respiratory, urine and blood samples from 33 patients by quantitative PCR, sequencing and detection of integrated viral DNA. We examined associations between either MCPyV viral load in primary MCC or MCPyV DNAemia and survival. Results were interpreted with respect to the viral molecular signature in each compartment. Patients with MCC containing more than 1 viral genome copy per cell had a longer period in complete remission than patients with less than 1 copy per cell (34 vs 10 months, P = 0.037). Peripheral blood mononuclear cells (PBMC) contained MCPyV more frequently in patients sampled with disease than in patients in complete remission (60% vs 11%, P = 0.00083). Moreover, the detection of MCPyV in at least one PBMC sample during follow-up was associated with a shorter overall survival (P = 0.003). Sequencing of viral DNA from MCC and non MCC samples characterized common single nucleotide polymorphisms defining 8 patient specific strains. However, specific molecular signatures truncating MCPyV LT were observed in 8/12 MCC cases but not in respiratory and urinary samples from 15 patients. New integration sites were identified in 4 MCC cases. Finally, mutated-integrated forms of MCPyV were detected in PBMC of two patients with disseminated MCC disease, indicating circulation of metastatic cells. We conclude that MCPyV molecular features in primary MCC tumour and PBMC may help to predict the course of the disease.

Polymerization-Induced Self-Assembly (PISA) for in situ drug encapsulation or drug conjugation in cancer application.

HYPOTHESIS: We describe the possibility of using the same block copolymer carriers prepared by PISA for in situ drug encapsulation or drug conjugation. EXPERIMENTS: Block copolymers containing poly((ethylene glycol) methacrylate)-co-poly(pentafluorophenyl methacrylate)-b-poly(hydroxypropyl methacrylate) (P((PEGMA-co-PFBMA)-b-PHPMA)) were synthesized at 10 wt% using PISA. The first approach involved in situ Doxorubicin (DOX) loading during PISA, while the second exhibited surface functionalization of PISA-made vesicles with dual drug therapies, N-acetyl cysteine (NAC) and DOX using para-fluoro-thiol reaction (PFTR) and carbodiimide chemistry, respectively. Cytotoxicity, cell uptake, and cell apoptosis were assessed on MDA-MB-231 cell lines. FINDINGS: P((PEGMA-co-PFBMA)-b-PHPMA) nanocarriers were prepared, showing size and shape transformations from spheres, cylinders to raspberry-forming vesicles. DOX was readily loaded into NPs during PISA with relatively high encapsulation efficiency of 70 %, whereas the plain PISA-made vesicles could be functionalized with NAC and DOX at high yields. DOX-free NPs showed biocompatibility, whilst DOX-conjugated NPs imparted a concentration-dependent cytotoxicity, as well as an enhanced cell uptake compared to free DOX. The results demonstrated that the same PISA-derived self-assemblies enabled either in situ drug encapsulation, or post-polymerization surface engineering with useful functionalities upon tuning the macro-CTA block, thus holding promises for future drug delivery and biomedical applications.

Total orbital exenteration with temporalis muscle transfer and secondary healing.

OBJECTIVE: To evaluate the outcomes of orbital exenteration with temporalis muscle flap repair of the socket and secondary healing of the anterior surface of the flap in ocular, conjunctival, and eyelid malignancies. DESIGN: Retrospective single-centre study. PARTICIPANTS: Consecutive patients who underwent total exenteration for malignancy with temporal muscle flap repair of the socket between December 2009 and January 2016. METHODS: We report the outcomes of this surgical technique in terms of healing without fistula formation and time to epithelialization. RESULTS: Twenty-nine patients underwent surgery using this technique. Diagnoses consisted of 18 conjunctival melanomas, 2 choroidal melanomas, 6 squamous cell carcinomas, 2 sebaceous cell carcinomas, and 1 basal cell carcinoma. Mean age at surgery was 70.7 years and mean follow-up was 27.4 months. On histological analysis, tumour excision was complete in 25 patients, of whom 3 had an orbital recurrence after exenteration (3 conjunctival melanomas). Four patients had incomplete tumour excision, of whom 3 underwent postoperative orbital radiotherapy with no subsequent orbital recurrences. Complete epithelialization of the socket occurred in mean 7.9 weeks (range 2-16 weeks). Flap necrosis occurred in 1 patient after postoperative radiotherapy (with sino-nasal fistula formation); 2 other patients developed sino-orbital fistulas. CONCLUSION: After orbital exenteration, spontaneous epithelialization of the socket may take up to several months. Use of a temporalis muscle flap can reduce the duration of socket healing postoperatively, even if left to heal by secondary intention. This may facilitate early postoperative radiotherapy when indicated. Aesthetic results are acceptable and local surgical complications are rare.

Safe-margin surgery by plastic reconstruction in extremities or parietal trunk soft tissue sarcoma: A tertiary single centre experience.

INTRODUCTION: Tertiary centers recruit a large proportion of locally advanced or recurrent soft tissue sarcomas (STSs) that may have been preoperatively irradiated. The objective of this study was to evaluate the results of oncoplastic surgery (OPS) for patients affected by extremities or parietal trunk STS. MATERIALS AND METHODS: This retrospective study includes patients who underwent a flap reconstruction after sarcoma resection between January 2018 and December 2020 at Institut Curie. The primary endpoint was the evaluation of the impact of OPS on the quality of surgical margins. The secondary endpoint was to quantify the morbidity of OPS and identify predictive factors for wound complications. RESULTS: Of 211 patients, 89 (42.2%) had a flap reconstruction. Surgery was realized on an irradiated field in 56 (62.9%) patients. Without OPS, all patients were candidates either for amputation (n = 9,10.1%) due to vessels/nerve infiltration, or R1/R2 resection (n = 80,89.9%). Seventy-two (80.0%) pedicle flaps and 18 (20.0%) free flaps were used. No R2 resections were performed. R0 and R1 margins were achieved in 82 (92.1%) and 7 (7.9%), respectively. The median closest margin was 3 mm (IQR 1-6 mm). Among R1 patients, 5 had positive margins along a preserved critical structure, 2 patients had well-differentiated liposarcomas. The surgical morbidity rate was 33.3% (30/90 flaps). The reoperation rate was 15.7% (14/89 patients). CONCLUSIONS: In a referral sarcoma center, the collaboration between the surgical oncologist and the plastic surgery team should be considered upfront in the surgical plan, allowing the most adequate wide oncological resection with acceptable postoperative morbidity.

Monitoring Breast Cancer Care Quality at National and Local Level Using the French National Cancer Cohort.

PURPOSE: The French National Cancer Institute has developed, in partnership with the French National Authority for Health, breast cancer-specific Care Quality, and Safety Indicators (BC QIs). With regard to the most common form of cancer, our aim is to support local and national quality initiatives, to improve BC pathways and outcomes, reduce heterogeneity of practice and regional inequities. In this study, we measure the BC QIs available in the French National medico-administrative cancer database, the French Cancer Cohort, for 2018. MATERIALS AND METHODS: BC QIs are developed according to the RAND method. QIs are based on good clinical practice and care pathway recommendations. QI computation should be automatable without any additional workload for data collection. They will be published annually for all stakeholders, and especially hospitals. RESULTS: Finally, ten feasible and pertinent QIs were selected. In France, BC care was found to be close to compliance with most QIs: proportion of patients undergoing biopsy prior to first treatment (94.5%), proportion of patients undergoing adjuvant radiotherapy after breast-conserving surgery for BC (94.5%), proportion of women undergoing radiotherapy within 12 weeks after surgery and without chemotherapy (86.2%), proportion of DCIS patients undergoing immediate breast reconstruction (54.3%) and proportion of women with NMIBC undergoing breast reintervention (14.4%). However, some are still far from their recommended rate. In particular, some QIs vary considerably from one region, or one patient, to another. CONCLUSION: Each result needs to be analyzed locally to find care quality leverage. This will strengthen transparency actions aimed at the public.

Proviral role of human respiratory epithelial cell-derived small extracellular vesicles in SARS-CoV-2 infection.

Small Extracellular Vesicles (sEVs) are 50-200 nm in diameter vesicles delimited by a lipid bilayer, formed within the endosomal network or derived from the plasma membrane. They are secreted in various biological fluids, including airway nasal mucus. The goal of this work was to understand the role of sEVs present in the mucus (mu-sEVs) produced by human nasal epithelial cells (HNECs) in SARS-CoV-2 infection. We show that uninfected HNECs produce mu-sEVs containing SARS-CoV-2 receptor ACE2 and activated protease TMPRSS2. mu-sEVs cleave prefusion viral Spike proteins at the S1/S2 boundary, resulting in higher proportions of prefusion S proteins exposing their receptor binding domain in an 'open' conformation, thereby facilitating receptor binding at the cell surface. We show that the role of nasal mu-sEVs is to complete prefusion Spike priming performed by intracellular furin during viral egress from infected cells. This effect is mediated by vesicular TMPRSS2 activity, rendering SARS-CoV-2 virions prone to entry into target cells using the 'early', TMPRSS2-dependent pathway instead of the 'late', cathepsin-dependent route. These results indicate that prefusion Spike priming by mu-sEVs in the nasal cavity plays a role in viral tropism. They also show that nasal mucus does not protect from SARS-CoV-2 infection, but instead facilitates it.

Management of phyllodes breast tumors.

Phyllodes tumors are a rare distinctive fibroepithelial tumors of the breast and their management continues to be questioned. The aim of our study was to examine the treatment and outcome of 165 patients with phyllodes tumors and to review the options for surgical management. This is a retrospective study of 165 patients who presented to the Institut Curie between January 1994 and November 2008 for benign, borderline or malignant phyllodes tumors. The median follow-up was 12.65 months [range 0-149.8]. The median age at diagnosis was 44 years [range 17-79]. One hundred and sixty patients (97%) had breast-conserving treatment, of whom 3 patients (1.8%) had oncoplastic breast surgery. Younger women had a significantly higher chance of having a benign phyllodes tumor (p = 0.0001) or a tumor of small size (p < 0.0001). Histologic examination showed 114 benign (69%), 37 borderline (22%) and 14 malignant tumors (9%). The median tumor size was 30 mm [range 5-150]. The tumor margins were considered incomplete (< 10 mm) in 46 out of 165 cases (28%) with 52% revision surgery. Only the tumor grade was a significant risk factor for incomplete tumor margins (p = 0.005). Fifteen patients developed local recurrence (10%) and two, metastases. In univariate analysis, the histologic grade (p = 0.008), and tumor size (p = 0.02) were significative risk factors for local recurrence with an accentuated risk for "borderline" tumors and tumors of large size.).Similar results were obtained using multivariate analysis (p = 0.07). The mainstay of treatment for phyllodes tumors remains excision with a safe surgical margin, taking advantage breast conserving surgery where amenable. For borderline or malignant phyllodes tumors or in cases of local tumor recurrence, mastectomy, and immediate breast reconstruction may become the preferred option. Genetic analysis will potentially supplement classical histologic examination in order to improve our management of these tumors. The role of adjuvant treatments is unproven and must be considered on a case-by-case basis.

Sentinel lymph node biopsy or nodal observation in melanoma: a prospective study of patient choices.

BACKGROUND: There is no consensus regarding the therapeutic utility of sentinel lymph node biopsy (SLNB) versus that of nodal observation (NO) in melanoma. OBJECTIVE: To prospectively evaluate a standardized counseling procedure and its effect on patient choices to undergo SLNB or NO. METHODS: In four centers, patients with melanoma eligible for SLNB or NO received a complete counseling procedure that included verbal information from dermatologists and surgeons, a detailed information sheet, and a written consent form. Data collected included patient and tumor characteristics, counseling conditions, and specialties of informing doctors. Factors influencing patients' choices were studied using multivariate analysis. RESULTS: Of 343 consecutive patients, 309 were offered SLNB and NO and received complete verbal and written information from a dermatologist alone (62%) or in association with a surgeon (38%). Approximately half took advice from trusted persons, and half asked for additional time before making a decision; 268 (86.7%) ultimately decided to undergo SLNB. Multivariate analysis showed that older patients, those with a head and neck melanoma, and those informed without a surgeon present were more likely to prefer NO. CONCLUSIONS: This counseling procedure was easily implemented in clinical practice. Patients favored SLNB but were able to understand uncertainties and express preferences.

[The therapeutic function of cosmetic surgery and nursing practice]. / La fonction thérapeutique de la chirurgie esthétique et de l'exercice infirmier.

Reconstructive surgery restores the original shape of a part of the human body. Aesthetic surgery aims to beautify a part of the body perceived by the person as unsightly. Nursing care aims to avoid the physiological risks inherent in any type of surgery, but also to alleviate the suffering of people with a negative self-image.

Polymerisation-induced self-assembly (PISA) as a straightforward formulation strategy for stimuli-responsive drug delivery systems and biomaterials: recent advances.

Stimuli-responsive amphiphilic block copolymers have emerged as promising nanocarriers for enhancing site-specific and on-demand drug release in response to a range of stimuli such as pH, the presence of redox agents, and temperature. The formulation of amphiphilic block copolymers into polymeric drug-loaded nanoparticles is typically achieved by various methods (e.g. oil-in-water emulsion solvent evaporation, solid dispersion, microphase separation, dialysis or microfluidic separation). Despite much progress that has been made, there remain many challenges to overcome to produce reliable polymeric systems. The main drawbacks of the above methods are that they produce very low solid contents (<1 wt%) and involve multiple-step procedures, thus limiting their scope. Recently, a new self-assembly methodology, polymerisation-induced self-assembly (PISA), has shown great promise in the production of polymer-derived particles using a straightforward one-pot approach, whilst facilitating high yield, scalability, and cost-effectiveness for pharmaceutical industry protocols. We therefore focus this review primarily on the most recent studies involved in the design and preparation of PISA-generated nano-objects which are responsive to specific stimuli, thus providing insight into how PISA may become an effective formulation strategy for the preparation of precisely tailored drug delivery systems and biomaterials, while some of the current challenges and limitations are also critically discussed.

Terpene polyacrylate TPA5 shows favorable molecular hydrodynamic properties as a potential bioinspired archaeological wood consolidant.

There is currently a pressing need for the development of novel bioinspired consolidants for waterlogged, archaeological wood. Bioinspired materials possess many advantages, such as biocompatibility and sustainability, which makes them ideal to use in this capacity. Based on this, a polyhydroxylated monomer was synthesised from α-pinene, a sustainable terpene feedstock derived from pine trees, and used to prepare a low molar mass polymer TPA5 through free radical polymerisation. This polymer was extensively characterised by NMR spectroscopy (chemical composition) and molecular hydrodynamics, primarily using analytical ultracentrifugation reinforced by gel filtration chromatography and viscometry, in order to investigate whether it would be suitable for wood consolidation purposes. Sedimentation equilibrium indicated a weight average molar mass Mw of (4.3 ± 0.2) kDa, with minimal concentration dependence. Further analysis with MULTISIG revealed a broad distribution of molar masses and this heterogeneity was further confirmed by sedimentation velocity. Conformation analyses with the Perrin P and viscosity increment ν universal hydrodynamic parameters indicated that the polymer had an elongated shape, with both factors giving consistent results and a consensus axial ratio of ~ 4.5. These collective properties-hydrogen bonding potential enhanced by an elongated shape, together with a small injectable molar mass-suggest this polymer is worthy of further consideration as a potential consolidant.

Breast Magnetic Resonance Image Analysis for Surgeons Using Virtual Reality: A Comparative Study.

PURPOSE: The treatment of breast cancer, the leading cause of cancer and cancer mortality among women worldwide, is mainly on the basis of surgery. In this study, we describe the use of a medical image visualization tool on the basis of virtual reality (VR), entitled DIVA, in the context of breast cancer tumor localization among surgeons. The aim of this study was to evaluate the speed and accuracy of surgeons using DIVA for medical image analysis of breast magnetic resonance image (MRI) scans relative to standard image slice-based visualization tools. MATERIALS AND METHODS: In our study, residents and practicing surgeons used two breast MRI reading modalities: the common slice-based radiology interface and the DIVA system in its VR mode. Metrics measured were compared in relation to postoperative anatomical-pathologic reports. RESULTS: Eighteen breast surgeons from the Institut Curie performed all the analysis presented. The MRI analysis time was significantly lower with the DIVA system than with the slice-based visualization for residents, practitioners, and subsequently the entire group (P < .001). The accuracy of determination of which breast contained the lesion significantly increased with DIVA for residents (P = .003) and practitioners (P = .04). There was little difference between the DIVA and slice-based visualization for the determination of the number of lesions. The accuracy of quadrant determination was significantly improved by DIVA for practicing surgeons (P = .01) but not significantly for residents (P = .49). CONCLUSION: This study indicates that the VR visualization of medical images systematically improves surgeons' analysis of preoperative breast MRI scans across several different metrics irrespective of surgeon seniority.