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Artigo IPEN-doc 31179 Hydrophilic interaction chromatography coupled to high resolution mass spectrometry (HILIC-LC-HRMS)
2025 - VALLA, MONICA V.; LEBRUN, IVO; PUDENZI, MARCOS A.; OLIVEIRA, LAUDICEIA A.; ALMEIDA, HELOISA F.; SANTOS, NATHALIA G.; RODRIGUES, MARIANA S.; SPENCER, PATRICK J.; ROCHA, MARISA M.; PIMENTA, DANIEL C.; COELHO, GUILHERME R.
Although proteins in snake venoms have been extensively studied and characterized, low-mass molecules remain relatively unexplored, mainly due to their low abundance, secondary role in envenomation, and some analytical technique limitations. However, these small molecules can provide new important data related to venom toxins’ molecular structure, functions, and evolutionary relationships. This research aimed to characterize molecules below 10 kDa in the venoms of snakes from the Viperidae families (Bothrops, Agkistrodon, and Bitis) and compare two chromatographic approaches: reverse-phase chromatography (RP), a classic technique, and hydrophilic interaction liquid chromatography (HILIC), an alternative technique, both coupled with high-resolution mass spectrometry (HRMS). The results showed that the separation of the HILIC column provided a more efficient evenly distributed ion profile than RP, contributing to a 25.6% increase in the sequences identified. Homologous sequences for Bradykinin-potentiating peptides (BPPs) and fragments of major venom proteins, possibly cryptids, were found. In addition, BPP 13a, peptides rich in histidine and glycine (pHpG), and spacer sequences were identified in all snakes analyzed, especially with HILIC separation, suggesting that these sequences may be conserved within Viperidae. These findings indicate that the use of the HILIC column, compared to RP, is a promising approach for characterizing peptides in snake venom obtained by the ultrafiltration process. It contributes to the study of these still poorly understood molecules and is also a good option for studying other complex protein/peptide mixtures.
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Artigo IPEN-doc 31178 Balancing flexibility and strength of hydroxypropylated starch/cellulose nanofibrils biocomposites
2025 - DA COSTA, FERNANDA A.T.; LOPES, HENRIQUE S.M.; ALVES, LUCAS R.; KOMATSU, DANIEL; MENEZES, APARECIDO J. de; PARRA, DUCLERC F.
This study investigates the thermal-mechanical properties of hydroxypropylated starch (HPS) as a plasticizer for conventional thermoplastic starch (TPS) films, reinforced with cellulose nanofibrils (CNF). A previous study showed that hydroxypropylation of starch led to in-situ poly(propylene oxide) (PPO) formation, inducing gelatinization and yielding TPS with significant plasticizing effect. To address this, blending native cassava starch with HPS and incorporating CNF, as well as hydroxypropylated CNF (mCNF), was explored as a sustainable reinforcement strategy. Films were prepared by casting, and their properties were evaluated using tensile strength tests, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). Results indicate that the incorporation of unmodified CNF significantly increased the tensile strength of HPS/TPS films, demonstrating its effective reinforcing capability. Conversely, adding mCNF led to a reduction in tensile strength, suggesting that the chemical modification of CNF may hinder its reinforcing efficiency due to altered interactions with the starch matrix. FTIR confirmed molecular interactions, while DSC and TG provided insights into thermal transitions and stability. This research emphasizes the potential of combining HPS, native starch, and CNF to create sustainable, high-performance starch-based biocomposites with reduced synthetic plasticizer content, offering a promising approach for diverse applications.
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Artigo IPEN-doc 31171 Enhancing jawless VMAT plan quality for hypofractionated left breast cancer with the avoidance structure tool
2025 - CASTELO, J.H.M.; MENEZES, D.C.T.; MENEZES, D.C.T.; ROSA, L.A.R. da; BONIFACIO, D.A.B.
Introduction: The Avoidance Structure (AvS) tool shields a structure by maintaining the multileaf collimator leaves over the structure's projection in the beam's eye view. In this work, we tested the dosimetric impact of using part of the outlines of the heart and lungs as avoidance structure when creating knowledge-based left breast volumetric modulated arc therapy treatment plans. Methods: Dose-volume histogram estimates were calculated using a RapidPlan model for 30 patients who received whole breast radiation therapy in five fractions. Then, two sets of plans were generated for a Halcyon v2 linear accelerator by alternating the use of the AvS tool. Dose metrics for both procedures were compared. Results: Coverage on the target volume remained similar regardless of the use of AvS. The mean absorbed dose received by the heart, as well as the relative volumes receiving 1.5, 3.5 and 7.8 Gy, decreased with effect sizes (ESZ) 0.98, 1.43, and 0.63 respectively. Homolateral lung volumes receiving 1.5 and 3.5 Gy were also lowered using AvS. However, the dose received by 0.03 cc of the contralateral breast increased with an ESZ of 0.52. Conclusions: Except for the contralateral breast, the AvS tool improved DVH metrics for organs at risk without compromising target coverage or worsening hotspots.
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Artigo IPEN-doc 31694 Dental adhesive protection against development of noncarious cervical lesions
2025 - DENUCCI, G.C.; LIMA, L.C.; EKERT, G.J.; SILVA, F.; SCARAMUCCI, T.; SOCHACKI, S.; HARA, A.T.
OBJECTIVE: This study aimed to verify whether dental adhesives prevent noncarious cervical lesion (NCCL) development in an in vitro simulation model based on abrasive/erosive challenges. METHODS AND MATERIALS: Extracted human premolars were randomly assigned to one of three treatments (n=16): 1. reference adhesive (Clearfil SE, Kuraray Co., Ltd., Chiyoda City, Tokyo, Japan); 2. experimental adhesive (10 wt% [percentage by weight] beta-tricalcium phosphate nanoparticles); 3. negative control (no treatment). After treatment, specimens were submitted to 11 episodes of 18 hours of acid exposure (1% citric acid solution-0.052 molar (M), pH ~2.5) interspersed by toothbrushing abrasion. Three-dimensional images of teeth were captured at baseline and after 5000, 10,000, 15,000, 35,000, and 55,000 toothbrushing strokes using an intraoral scanner. Tooth wear (mm3) was calculated after each toothbrushing period by scan superimposition. Lesion angle was measured, and shape classified. Data were analyzed using analysis of variance (ANOVA) and Fisher Protected Least Significant Difference (PLSD) tests (α=0.05). RESULTS: Tooth wear increased with toothbrushing strokes overall (p<0.001) and within each treatment (p<0.05) except between 10,000 and 15,000 strokes (p=0.24). Reference had less tooth wear than control overall (mean difference [95% CI]: 0.68 [0.20,1.15], p=0.008) and for all toothbrushing periods (p<0.05) except at 55,000 strokes (0.54 [-0.38,1.46], p=0.25). Reference had less tooth wear than experimental overall (0.54 [0.01,1.07], p=0.046) and for 35,000 strokes (0.80 [0.13,1.46], p=0.019). Experimental had less tooth wear than negative control at 5000 and 10,000 strokes (p<0.05). Treatments had no effect on lesion angle (p=0.52). At 55,000 strokes, reference had more flat-shaped lesions than experimental (p<0.001) and negative control (p<0.001), but experimental and negative control were not different from each other (p=1.00) having more striated lesions. CONCLUSION: Adhesives showed some degree of protection against NCCL development at early stages; however, reference had longer-lasting protection than experimental.