Design, clinical applications and post-surgical assessment of bioresorbable 3D-printed craniofacial composite implants.

This study details the design, fabrication, clinical trials' evaluation, and analysis after the clinical application of 3D-printed bone reconstruction implants made of nHAp@PLDLLA [nanohydroxyapatite@poly(L-lactide-co-D,L-lactide)] biomaterial. The 3D-printed formulations have been tested as bone reconstruction Cranioimplants in 3 different medical cases, including frontal lobe, mandibular bone, and cleft palate reconstructions. Replacing one of the implants after 6 months provided a unique opportunity to evaluate the post-surgical implant obtained from a human patient. This allowed us to quantify physicochemical changes and develop a spatial map of osseointegration and material degradation kinetics as a function of specific locations. To the best of our knowledge, hydrolytic degradation and variability in the physicochemical and mechanical properties of the biomimetic, 3D-printed implants have not been quantified in the literature after permanent placement in the human body. Such analysis has revealed the constantly changing properties of the implant, which should be considered to optimize the design of patient-specific bone substitutes. Moreover, it has been proven that the obtained composition can produce biomimetic, bioresorbable and bone-forming alloplastic substitutes tailored to each patient, allowing for shorter surgery times and faster patient recovery than currently available methods.

Thermal and Morphological Analysis of Linear Low-Density Polyethylene Composites Containing d-limonene/ß-cyclodextrin for Active Food Packaging.

Composites made of linear low-density polyethylene (LLDPE) and ß-cyclodextrin/d-limonene inclusion complex (CD-lim) were prepared by melt extrusion to develop a novel food packaging material. Scanning electron microscopy evidenced a fairly good dispersion of the filler within the polymeric matrix. Infrared spectroscopy coupled with thermogravimetric analysis confirmed the presence of CD-lim in the composites, proving that the applied technology of including the essential oil within ß-CD cages allows for preventing a sizable loss of d-limonene despite a high temperature and shear applied upon extrusion processing. Moreover, the influence of the filler on the thermal properties of PE was assessed. It was found that the cyclodextrin-based inclusion complex significantly fastens the crystallization path of the polyethylene matrix with an improved crystallization rate of the PE/CD-lim composites compared to the neat polymer.

Right ventricular ejection fraction with cardiac magnetic resonance using a wall motion score.

BACKGROUND: The volumetric method in cardiac magnetic resonance (CMR), the reference standard for right ventricular ejection fraction (RVEF), requires expertise because of the complex right ventricular geometry and anatomical landmarks. AIM: The aim of our retrospective study was to describe a new method to evaluate RVEF based on wall motion score index (WMSI) in CMR. METHODS: Visual assessment of wall motion was performed using an eight-segment model (normokinesia=1, hypokinesia=2, akinesia=3). Correlation between WMSI (WMS/8) and the reference volumetric RVEF was analysed. A regression equation was derived to convert the WMSI into RVEF. The accuracy of CMR WMSI-derived RVEF compared with CMR volumetric RVEF was evaluated using Bland-Altman analysis. RESULTS: In the 112 patients using the volumetric method, the mean RVEF was 48±14%. Fifty-nine patients had normal RV kinetics (WMSI=1), which corresponded to a volumetric RVEF of 56% (standard deviation 7%; range 43-76%). CMR WMSI showed a strong correlation with CMR volumetric RVEF (Spearman's Rho=-0.69). A regression equation was created: RVEF=80-22×WMSI. Overall, the WMSI-derived RVEF resulted in good agreement with the CMR volumetric RVEF (mean bias-3%, standard deviation±7.5%). In addition, using a WMSI cut-off of≥1.5 was highly accurate (92%) to predict a reference RVEF of˂45%, an important prognostic indicator in CMR. CONCLUSIONS: Our results suggest that using the WMS in CMR (eight-segment) to estimate RVEF is accurate, and correlates well with the volumetric method. A WMSI≥1.5 is optimal to categorize patients in the higher-risk subset of CMR RVEF˂45%.

Binary Green Blends of Poly(lactic acid) with Poly(butylene adipate-co-butylene terephthalate) and Poly(butylene succinate-co-butylene adipate) and Their Nanocomposites.

Poly(lactic acid) (PLA) is the most widely produced biobased, biodegradable and biocompatible polyester. Despite many of its properties are similar to those of common petroleum-based polymers, some drawbacks limit its utilization, especially high brittleness and low toughness. To overcome these problems and improve the ductility and the impact resistance, PLA is often blended with other biobased and biodegradable polymers. For this purpose, poly(butylene adipate-co-butylene terephthalate) (PBAT) and poly(butylene succinate-co-butylene adipate) (PBSA) are very advantageous copolymers, because their toughness and elongation at break are complementary to those of PLA. Similar to PLA, both these copolymers are biodegradable and can be produced from annual renewable resources. This literature review aims to collect results on the mechanical, thermal and morphological properties of PLA/PBAT and PLA/PBSA blends, as binary blends with and without addition of coupling agents. The effect of different compatibilizers on the PLA/PBAT and PLA/PBSA blends properties is here elucidated, to highlight how the PLA toughness and ductility can be improved and tuned by using appropriate additives. In addition, the incorporation of solid nanoparticles to the PLA/PBAT and PLA/PBSA blends is discussed in detail, to demonstrate how the nanofillers can act as morphology stabilizers, and so improve the properties of these PLA-based formulations, especially mechanical performance, thermal stability and gas/vapor barrier properties. Key points about the biodegradation of the blends and the nanocomposites are presented, together with current applications of these novel green materials.

Thermal and Thermo-Mechanical Properties of Poly(L-lactic Acid) Biocomposites Containing ß-Cyclodextrin/d-Limonene Inclusion Complex.

Bio-based composites made of poly(L-lactic acid) (PLLA) and ß-cyclodextrin/d-limonene inclusion complex (CD-Lim) were prepared by melt extrusion. Encapsulation of volatile d-limonene molecules within ß-cyclodextrin cages was proven to be a successful strategy to prevent evaporation during high-temperature processing. However, small amounts of limonene were released upon processing, resulting in the plasticization of the polymeric matrix. Morphological analysis revealed good dispersion of the filler, which acted as a nucleating agent, favoring the growth of PLLA crystals. The composites' lowered glass transition temperature upon the addition of CD-Lim was also proved by thermomechanical analysis (DMA). Moreover, DMA revealed constant stiffness of modified materials at room temperature, which is crucial in PLLA-based formulations.

Thermal Stability and Nucleation Efficacy of Shear-Induced Pointlike and Shishlike Crystallization Precursors.

The different thermal stabilities of shear-induced pointlike and shishlike crystallization precursors of polyamide 11, generated in a parallel-plate rheometer and coexisting in the same sample, were quantified by hot-stage microscopy, by performing self-seed crystallization experiments. Crystals formed at low supercooling of the melt from these different types of precursors melt at about the same temperature. Annealing of the melt at different temperatures for a predefined time revealed dissolution/disordering of these precursors at 10-15 K higher temperature, near the equilibrium melting point. Despite their similar thermal stabilities, pointlike and shishlike crystallization precursors exhibit distinctly different nucleation efficacies. Under identical crystallization conditions, shishlike precursors cause faster crystallization than pointlike crystal nuclei. The faster crystallization of the shishlike nuclei can be explained, for example, by (a) the larger size of the shishlike precursors, providing numerous nucleation sites; (b) the more perfect chain conformation at the shish surface, which serves as a substrate for crystallization; or perhaps (c) the higher local orientation of the surrounding melt compared with molecular segments near pointlike nuclei, reducing the activation energy for crystallization.

Temperature dependence of the rigid amorphous fraction of poly(butylene succinate).

In this contribution the temperature evolution of the constrained or rigid amorphous fraction (RAF) of biodegradable and biocompatible poly(butylene succinate) (PBS) was quantified, after detailed thermodynamic characterization by differential scanning calorimetry and X-ray diffraction analysis. At the glass transition temperature, around -40 °C, the rigid amorphous fraction in PBS is about 0.25. It decreases with increasing temperature and becomes zero in proximity of 25 °C. Thus, at room temperature and at the human body temperature, all the amorphous fraction is mobile. This information is important for the development of PBS products for various applications, including biomedical applications, since physical properties of the rigid amorphous fraction, for example mechanical and permeability properties, are different from those of the mobile amorphous fraction.

Poly(l-Lactic Acid)/Pine Wood Bio-Based Composites.

Bio-based composites made of poly(l-lactic acid) (PLLA) and pine wood were prepared by melt extrusion. The composites were compatibilized by impregnation of wood with γ-aminopropyltriethoxysilane (APE). Comparison with non-compatibilized formulation revealed that APE is an efficient compatibilizer for PLLA/wood composites. Pine wood particles dispersed within PLLA act as nucleating agents able to start the growth of PLLA crystals, resulting in a faster crystallization rate and increased crystal fraction. Moreover, the composites have a slightly lower thermal stability compared to PLLA, proportional to filler content, due to the lower thermal stability of wood. Molecular dynamics was investigated using the solid-state 1H NMR technique, which revealed restrictions in the mobility of polymer chains upon the addition of wood, as well as enhanced interfacial adhesion between the filler and matrix in the composites compatibilized with APE. The enhanced interfacial adhesion in silane-treated composites was also proved by scanning electron microscopy and resulted in slightly improved deformability and impact resistance of the composites.

Polyamide 11/Poly(butylene succinate) Bio-Based Polymer Blends.

The manuscript details the preparation and characterization of binary blends of polyamide 11 (PA 11) and poly(butylene succinate) (PBS), with PA 11 as the major component. The blends are fully bio-based, since both components are produced from renewable resources. In addition, PBS is also biodegradable and compostable, contrarily to PA 11. In the analyzed composition range (up to 40 m% PBS), the two polymers are not miscible, and the blends display two separate glass transitions. The PA 11/PBS blends exhibit a droplet-matrix morphology, with uniform dispersion within the matrix, and some interfacial adhesion between the matrix and the dispersed droplets. Infrared spectroscopy indicates the possible interaction between the hydrogens of the amide groups of PA 11 chains and the carbonyl groups of PBS, which provides the compatibilization of the components. The analyzed blends show mechanical properties that are comparable to neat PA 11, with the benefit of reduced material costs attained by addition of biodegradable PBS.

Down shifting in poly(vinyl alcohol) gels doped with terbium complex.

Novel poly(vinyl alcohol) (PVA) based soft gels with luminescent properties are detailed in this contribution. Lanthanide complex of terbium ions with anthranilic acid, Tb(ant)3·2H2O, was synthesized and incorporated into a DMSO/water solution, followed by addition of PVA, to attain soft gels at room temperature. Morphological and thermal analyses revealed homogeneous distribution of Tb(ant)3·2H2O into the PVOH/DMSO/water gel, and that incorporation of the terbium complex does not alter the thermal properties of the gels. The gels are transparent and luminescent, as they exhibit Large Stokes shift down shifting (LSS DS) up to 400nm, with very high emission quantum yield, that was found to be function of Tb complex concentration.

Phase diagrams of smart copolymers poly(N-isopropylacrylamide) and poly(sodium acrylate).

The phase behavior of linear poly(N-isopropylacrylamide) (PNIPA), linear copolymer poly(N-isopropylacrylamide) and poly(sodium acrylate) (PNIPA-SA), and chemically cross-linked PNIPA in water has been determined by temperature modulated differential scanning calorimetry (TM-DSC). Experiments related to linear polymers (PNIPA and PNIPA-SA) indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST), which do not correspond to the three classical types of limiting critical behavior. Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water. Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed.

Influence of crosslinker and ionic comonomer concentration on glass transition and demixing/mixing transition of copolymers poly(N-isopropylacrylamide) and poly(sodium acrylate) hydrogels.

Hydrogels based on N-isopropylacrylamide and sodium acrylate as ionic comonomer were synthesized by free radical polymerization in water using N,N'-methylenebisacrylamide as crosslinker and ammonium persulfate as initiator. The glass transition of dried copolymers poly(N-isopropylacrylamide) (PNIPA) and poly(sodium acrylate) (SA) gels and demixing/mixing transition of PNIPA-SA hydrogels swollen with increasing amounts of water were studied using conventional differential scanning calorimetry. In the crosslinked polymers, the glass transition linearly increases, and the transition range becomes broader, with increasing crosslinker content. Increasing content of ionic comonomer also produces an increase of glass transition temperature, which moves to higher temperatures with higher sodium acrylate fraction. The influence of chemical structure of PNIPA-SA hydrogels on the lower critical solution temperature (LCST) of PNIPA-SA/water mixtures during heating and cooling was quantified as function of the content of the crosslinker and the ionic comonomer, as well as water content of the hydrogel in the range from 95 to 70 wt%. At parity of water content, the LCST occurs at higher temperatures for gels containing higher amounts of sodium acrylate. Similarly, the introduction of N,N'-methylenebisacrylamide causes an increase of the LCST, which grows with increasing of crosslinking degree of the hydrogel.

Effect of aging the glass of isotactic polybutene-1 on form II nucleation and cold crystallization.

The effect of aging initially fully amorphous isotactic polybutene-1 (iPB-1) at temperatures between 243 and 283 K on form II nucleation and cold crystallization has been quantified by fast scanning chip calorimetry. Aging of amorphous iPB-1 at temperatures close to the glass transition temperature leads to formation of nuclei which accelerate subsequent cold crystallization. Analysis of the enthalpy of cold crystallization on heating differently aged samples revealed a maximum rate of nucleation at around 265 K. In contrast, the maximum rate of form II crystallization is observed at distinctly higher temperature of 330-340 K. It is suggested that formation of form II crystal nuclei in the glassy state requires prior densification of the glass since acceleration of cold crystallization on heating the aged glass is detected only after completion of the enthalpy relaxation. The analysis of the rates of nucleation and cold crystallization of iPB-1 at low temperatures is a necessary completion of prior work on the phase transition behavior, and contributes to further understanding of mechanisms of crystal nucleation in polymers.

The role of the crystallization temperature on the nanophase structure evolution of poly[(R)-3-hydroxybutyrate].

The nanophase structure of semicrystalline polymers, which determines the mechanical, thermal, and gas permeability behavior, can be quantified by thermal methods. A detailed investigation of the nanophase structure of poly[(R)-3-hydroxybutyrate] (PHB) was performed under conditions of isothermal, quasi-isothermal, and nonisothermal crystallizations. The experimental analyses revealed that the establishment of the nanophase rigid amorphous fraction (RAF) in PHB depends on the temperature at which crystallization occurs. The RAF grows in parallel with the crystal phase during quasi-isothermal crystallization at 30 °C, whereas during nonisothermal crystallization at higher temperatures, RAF starts to develop at 70 °C, in correspondence with the final stages of the crystallization process. The influence of crystallization temperature on the nanophase structure was rationalized taking into account the effect of the mobility of the entangled chain segments during the phase transition. The melting behavior was found to change after isothermal crystallization at 70 °C, revealing that complete RAF mobilization is achieved approximately at this temperature. The temperature of 70 °C could be the limit for the formation and the disappearance of rigid amorphous fraction in the PHB analyzed in the present study.

A Simple Noninvasive Score Based on Routine Parameters can Predict Liver Cirrhosis in Patients With Chronic Hepatitis C.

BACKGROUND: Liver biopsy has remained the gold standard for the diagnosis of chronic hepatitis C; even though, it has a low but non-negligible rate of both false negative and complications. Several authors have proposed noninvasive tools to diagnose cirrhosis. But none of them showed complete concordance with liver biopsy. OBJECTIVES: To devise a score based on noninvasive routine parameters that discriminate between patients with a high risk, and those with a low risk of cirrhosis among patients with chronic hepatitis C without performing liver biopsy, and to compare this score with other ones using routine parameters devoted to this aim. PATIENTS AND METHODS: We reviewed the charts of patients with chronic hepatitis C who performed a liver biopsy between 2000 and 2004. Multivariate analysis was used to identify independent predictors of cirrhosis. An independent group of patients with chronic hepatitis C admitted for a liver biopsy between 2007 and 2012 constituted the validation set. RESULTS: We enrolled 249 patients who had complete laboratoristic data, and sufficient liver tissue for fibrosis staging. Age, AST, prothrombin activity, and platelets were identified as independent predictors of histological cirrhosis. We categorized these variables, and devised a novel score called CISCUN (Cirrhosis Score University of Naples), giving one point to each of the following predictors: age > 40 years; AST > 2 upper normal values; platelet count < 160.000/mmc; prothrombin activity < 100%. Cirrhosis rate was 2.9% for the 103 patients with a CISCUN = 0 or 1, 23.4% for the 124 patients with a CISCUN of 2 or 3, and 86.4% for the 22 patients with a CISCUN = 4. These results were confirmed in the independent validation group of 285 patients with similar characteristics. CONCLUSIONS: Patients with chronic hepatitis C and with a CISCUN ≤ 1 had a very low rate of cirrhosis while those with a CISCUN = 4 had a high risk of cirrhosis. Patients with CISCUN = 2 or 3 had an intermediate rate of cirrhosis, and therefore needed to perform a liver biopsy to receive a reliable diagnosis.

Thermoreversible luminescent organogels doped with Eu(TTA)3phen complex.

This manuscript details the preparation and characterization of luminescent organogels in toluene. Gels were prepared by using 12-hydroxystearic acid (12HSA) as gelator and different amounts of thenoyltrifluoroacetonato 1,10-phenanthroline europium(III) complex (Eu(TTA)3phen). The gelation properties and the thermoreversible behavior from solid-like to liquid systems were investigated by differential scanning calorimetry. At higher concentration, an interaction of Eu complex with the polar group of the gelator was revealed by DSC and FTIR analyses. The spectroscopic behavior of the complex was investigated in toluene solution and in the gel state. TEM analysis revealed that 12HSA is able to solvate the Eu diketonate complex inducing a remarkable increase in the Eu-Eu distance. The Eu(TTA)3phen in the gel state exhibits a very high emission quantum yield, Φ, which was found to be independent of Eu complex concentration, at least for the composition range analyzed. These results indicate that 12HSA organogels containing Eu(TTA)3phen are promising materials for optical applications.

Unilobar congenital pulmonary lymphangiectasis mimicking congenital lobar emphysema: an underestimated presentation?

BACKGROUND: Congenital lobar emphysema (CLE) is characterized by unilobar alveolar distension secondary to bronchomalacia or absent cartilage. In contrast, congenital pulmonary lymphangiectasis (CPL) is defined as distended lymphatics in the bronchovascular bundle, in the interlobular septa, and in the subpleural space. Little information is available regarding the radiologic presentation of CLE as it correlates with histological diagnosis. METHODS: In a retrospective chart review from 1995 to 2002, 8 patients (5 boys and 3 girls) with clinical and radiologic diagnosis of CLE were reviewed. RESULTS: The mean age at diagnosis was 26 months (range, 11 days to 10 years). All but one had classic respiratory symptoms of CLE. Six of 7 chest computed tomography (CT), scans were suggestive of CLE. Of 8 patients, 3 were treated without pulmonary resection with resolution of symptoms. Five patients underwent lobectomies, and histology results showed CPL in 3. CT failed to identify CPL in all cases. CONCLUSIONS: Diagnosis of CLE is not as straightforward as the literature suggests. Even retrospectively, radiologic distinction between CLE and CPL could not be achieved by an experienced pediatric radiologist. CPL, thus, mimics CLE clinically and radiologically and, therefore, should be considered in the differential radiologic diagnosis of CLE.

Two-dimensional echocardiography estimation of right ventricular ejection fraction by wall motion score index.

BACKGROUND: Radionuclide angiography (RNA) and echocardiography (biplane Simpson method) are the most accepted methods for right ventricular ejection fraction (RVEF) evaluation. The authors tried to determine a new method to measure RVEF based on wall motion score index (WMSI). OBJECTIVES: One hundred forty-one patients with RV dysfunction had transthoracic echocardiography (TTE) evaluation of the right ventricle. In a first group of 54 patients, a correlation between RVEF using the biplane Simpson method (four chamber and two chamber [4C+2C]) and RV-WMSI was established from a polar map using an eight-segment model to find a regression equation. With the second group of 51 subsequent patients, this equation (RVEF=73.07-20.7 x WMSI), comparing the RVEF-WMSI with the biplane Simpson RVEF (4C+2C), was validated. In a third group of 36 consecutive patients with abnormal RV contractility, the RVEF was calculated by RNA and this RVEF was correlated to the RV-WMSI. RESULTS: The first group of 54 patients had a correlation coefficient of 0.84 between WMSI and RVEF (biplane Simpson method). The results from the second group of 51 patients with RVEF derived from the estimated regression equation correlated well with the biplane Simpson RVEF (r=0.84). The correlation coefficient for these two groups taken together (105 patients), that is, between WMSI and RVEF (biplane Simpson method), was 0.92. The third group of 36 patients with RNA-EF displayed a correlation coefficient of 0.83 with RV-WMSI. CONCLUSION: This new semiquantitative method for estimating RVEF from RV-WMSI is easy to use in routine TTE and shows an excellent correlation with the biplane Simpson method and RNA.

A new tool for estimating left ventricular ejection fraction derived from wall motion score index.

BACKGROUND: Radionuclide angiography (RNA) and echocardiography (biplane Simpson method) are the most accepted techniques for left ventricular ejection fraction (LVEF) assessment. A new method to evaluate LVEF based on the regional wall motion assessment of the LV was attempted. OBJECTIVE: To develop a simple method for LVEF estimation using wall motion score index (WMSI) with transthoracic echocardiography (TTE). METHODS: Two hundred and forty-three patients with abnormal LV contractility had TTE and RNA performed less than three days apart. The WMSI was calculated in all patients using the 16-segment model as proposed by the American Society of Echocardiography. For the first 150 patients, a correlation between LV WMSI and RNA EF was established to create a regression equation. This regression equation (RNA LVEF=92.8-25.8xWMSI) was used on 93 consecutive patients to compare this equation with RNA EF. From the total cohort (243 patients), three subgroups were studied specifically: atrial fibrillation (AF) (n=50 patients), dyskinesia (DK) (n=40 patients) and aneurysm (AN) (n=42 patients). RESULTS: Correlation between RNA EF and WMSI in the first 150 patients was r=0.82. In the second group of 93 consecutive patients, WMSI EF derived from the estimated regression equation correlated well with RNA EF (r=0.86). Correlation remained high in the three subgroups: AF (r=0.87), DK (r=0.87) and AN (r=0.80). In the 111 patients without DK, AN or AF correlation between RNA and the studied method was even higher (r=0.91). In a random subgroup of 54 patients, RNA was compared with the biplane Simpson method (49 of 54 patients, r=0.82). In the same subgroup of 54 patients, the score was modified to allow for mild hypokinesia (score=1.5) and severe hypokinesia (score=2.5) (54 of 54 patients, r=0.83). CONCLUSION: LVEF assessment by this new simple mathematical model using the WMSI is feasible and easy to use during routine TTE. It has excellent correlation with other methods such as biplane Simpson and RNA.

Endobronchial tumors in children: Institutional experience and literature review.

BACKGROUND/PURPOSE: Endobronchial tumors are rare in children and often misdiagnosed as benign conditions resulting in delayed definitive treatment. The authors reviewed their experience to highlight pertinent aspects of diagnosis and treatment. METHODS: A retrospective chart review was conducted of children with endobronchial tumors diagnosed between 1980 and 2002. RESULTS: Nine patients had endobronchial tumors (5 girls, 4 boys), with average age of 13 years (range, 8.5 to 15 years). There were 5 carcinoid tumors, 3 mucoepidermoid carcinomas, and one pseudotumor. Preoperative bronchoscopic biopsy confirmed the diagnosis in 6 patients, was inconclusive in one, and not done in 2. All except one (pseudotumor) underwent surgical resection. Laser ablation was performed in 2 cases with complete cure in one. All had an uneventful postoperative course except one patient in whom ipsilateral pneumonia developed. Long-term follow-up was obtained with clinical examination, pulmonary x-ray, abdominal ultrasound scan, chest computed tomography scan, and serum 5-HIAA in those with carcinoid tumor. Bronchoscopy was performed twice yearly for the first 2 years, then yearly. No evidence of local or distant recurrence was reported. CONCLUSIONS: Endobronchial lesions should be considered in children with persistent pneumonia despite adequate treatment or with undiagnosed respiratory symptoms. Prognosis is excellent with surgical resection. Specific follow-up protocol is recommended.