Ductile Copolyesters Prepared Using Succinic Acid, 1,4-Butanediol, and Bis(2-hydroxyethyl) Terephthalate with Minimizing Generation of Tetrahydrofuran.

Poly(1,4-butylene succinate) (PBS) is a promising sustainable and biodegradable synthetic polyester. In this study, we synthesized PBS-based copolyesters by incorporating 5-20 mol% of -O2CC6H4CO2- and -OCH2CH2O- units through the polycondensation of succinic acid (SA) with 1,4-butanediol (BD) and bis(2-hydroxyethyl) terephthalate (BHET). Two different catalysts, H3PO4 and the conventional catalyst (nBuO)4Ti, were used comparatively in the synthesis process. The copolyesters produced using the former were treated with M(2-ethylhexanoate)2 (M = Mg, Zn, Mn) to connect the chains through ionic interactions between M2+ ions and either -CH2OP(O)(OH)O- or (-CH2O)2P(O)O- groups. By incorporating BHET units (i.e., -O2CC6H4CO2- and -OCH2CH2O-), the resulting copolyesters exhibited improved ductile properties with enhanced elongation at break, albeit with reduced tensile strength. The copolyesters prepared with H3PO4/M(2-ethylhexanoate)2 displayed a less random distribution of -O2CC6H4CO2- and -OCH2CH2O- units, leading to a faster crystallization rate, higher Tm value, and higher yield strength compared to those prepared with (nBuO)4Ti using the same amount of BHET. Furthermore, they displayed substantial shear-thinning behavior in their rheological properties due to the presence of long-chain branches of (-CH2O)3P=O units. Unfortunately, the copolyesters prepared with H3PO4/M(2-ethylhexanoate)2, and hence containing M2+, -CH2OP(O)(OH)O-, (-CH2O)2P(O)O- groups, did not exhibit enhanced biodegradability under ambient soil conditions.

Glycerol-derived organic carbonates: environmentally friendly plasticizers for PLA.

Polylactic acid (PLA) stands as a promising material, sourced from renewables and exhibiting biodegradability-albeit under stringent industrial composting settings. A primary challenge impeding PLA's broad applications is its inherent brittleness, as it fractures with minimal elongation despite its commendable tensile strength. A well-established remedy involves blending PLA with plasticizers. In this study, a range of organic carbonates-namely, 4-ethoxycarbonyloximethyl-[1,3]dioxolan-2-one (1), 4-methoxycarbonyloximethyl-[1,3]dioxolan-2-one (2), glycerol carbonate (3), and glycerol 1-acetate 2,3-carbonate (4)-were synthesized on a preparative scale (∼100 g), using renewable glycerol and CO2-derived diethyl carbonate (DEC) or dimethyl carbonate (DMC). Significantly, 1-4 exhibited biodegradability under ambient conditions within a week, ascertained through soil exposure at 25 °C-outpacing the degradation of comparative cellulose. Further investigations revealed 1's efficacy as a PLA plasticizer. Compatibility with PLA, up to 30 phr (parts per hundred resin), was verified using an array of techniques, including DSC, DMA, SEM, and rotational rheometry. The resulting blends showcased enhanced ductility, evident from tensile property measurements. Notably, the novel plasticizer 1 displayed an advantage over conventional acetyltributylcitrate (ATBC) in terms of morphological stability. Slow crystallization, observed in PLA/ATBC blends over time at room temperature, was absent in PLA/1 blends, preserving amorphous domain dimensions and mitigating plasticizer migration-confirmed through DMA assessments of aged and unaged specimens. Nevertheless, biodegradation assessments of the blends revealed that the biodegradable organic carbonate plasticizers did not augment PLA's biodegradation. The PLA in the blends remained mostly unchanged under ambient soil conditions of 25 °C over a 6 month period. This work underscores the potential of organic carbonates as both eco-friendly plasticizers for PLA and as biodegradable compounds, contributing to the development of environmentally conscious polymer systems.

Preparation of Well-Defined Double-Metal Cyanide Catalysts for Propylene Oxide Polymerization and CO2 Copolymerization.

Reevaluating the composition of the double metal cyanide catalyst (DMC) as a salt of (NC)6Co3- anions with 1:1 Zn2+/(X)Zn+ cations (X = Cl, RO, AcO), we prepared a series of well-defined DMCs, [ClZn+][Zn2+][(NC)6Co3-][ROH], [(RO)Zn+][Zn2+][(NC)6Co3-], [(AcO)Zn+][Zn2+][(NC)6Co3-], [(RO)Zn+]p[ClZn+](1-p)[Zn2+][(NC)6Co3-], [(AcO)Zn+]p[(tBuO)Zn+]q[Zn2+][(NC)6Co3-], and [(AcO)Zn+]p[(tBuO)Zn+]q[ClZn+]r[Zn2+][(NC)6Co3-]. The structure of [(MeOC3H6O)Zn+][Zn2+][(NC)6Co3-] was precisely determined at the atomic level through Rietveld refinement of the synchrotron X-ray powder diffraction data. By evaluating the catalyst's performance in both propylene oxide (PO) polymerization and PO/CO2 copolymerization, a correlation between structure and performance was established on various aspects including activity, dispersity, unsaturation level, and carbonate fraction in the resulting polyols. Ultimately, our study identified highly efficient catalysts that outperformed the state-of-the-art benchmark DMC not only in PO polymerization [DMC-(OAc/OtBu/Cl)(0.59/0.38/0.15)] but also in PO/CO2 copolymerization [DMC-(OAc/OtBu)(0.95/0.08)].

Surgical Results of the Superior Vena Cava Intimal Layer-Only Suture Technique in Heart Transplantation.

Background: Superior vena cava (SVC) stenosis during follow-up is a major concern after heart transplantation, and many technical modifications have been introduced. We analyzed the surgical results of the SVC intima layer-only suture technique in heart transplantation. Methods: We performed SVC anastomosis with sutures placed only in the intima during heart transplantation. We measured the area of the SVC at 3 different points (above the anastomosis, at the anastomosis, and below the anastomosis) in an axial view by freely drawing regions of interest, and then evaluated the degree of stenosis. Patients who underwent cardiac computed tomography (CT) at 2 years postoperatively between June 2017 and May 2020 were included in this study. Results: We performed heart transplantation in 41 patients. Among them, 24 patients (16 males and 8 females) underwent follow-up cardiac CT at 2 years postoperatively. The mean age at operation was 49.4±4.9 years. The diagnoses at time of operation were dilated cardiomyopathy (n=12), ischemic heart disease (n=8), valvular heart disease (n=2), hypertrophic cardiomyopathy (n=1), and congenital heart disease (n=1). No cases of postoperative bleeding requiring intervention occurred. The mean CT follow-up duration was 1.9±0.7 years. At follow-up, the mean areas at the 3 key points were 2.7±0.8 cm2, 2.7±0.8 cm2, and 2.7±1.0 cm2 (p=0.996). There were no SVC stenosis-related symptoms during follow-up. Conclusion: The suture technique using only the SVC intimal layer is a safe and effective method for use in heart transplantation.

Surgical results of only antegrade del Nido cardioplegia infusion in conventional coronary artery bypass grafting: a retrospective study.

BACKGROUND: Additional retrograde cardioplegia infusion in conventional coronary artery bypass grafting (CABG) was introduced to address the concern of inappropriate cardioplegia delivery through the stenotic coronary artery. However, this method is complex and requires repeated infusions. Therefore, we investigated the surgical outcomes of only antegrade cardioplegia infusion in conventional CABG. METHODS: We included 224 patients who underwent isolated CABG between 2017 and 2019. The patients were divided into two groups according to the cardioplegia infusion method: antegrade cardioplegia infusion with del Nido solution (n=111, group I) and antegrade+retrograde cardioplegia infusion with blood cardioplegia solution (n=113, group II). RESULTS: The sinus recovery time after release of the aorta cross-clamp was shorter in group I (3.8±7.1 minutes, n=98) than in group II (5.8±4.1 minutes, n=73) (p=0.033). The total cardioplegia infusion volume was lower in group I (1,998.6±668.6 mL) than in group II (7,321.0±2,865.3 mL) (p<0.001). Creatine kinase-MB levels were significantly lower in group I than in group II (p=0.039). Newly developed regional wall motion abnormalities on follow-up echocardiography were detected in two patients (1.8%) in group I and five patients (4.4%) in group II (p=0.233). There was no significant difference in ejection fraction improvement between the two groups (3.3%±9.3% in group I and 3.3%±8.7% in group II, p=0.990). CONCLUSION: The only antegrade cardioplegia infusion strategy in conventional CABG is safe and has no harmful effects.

Emerging role for R-loop formation in hepatocellular carcinoma.

The pathophysiological characteristics of hepatocellular carcinoma (HCC) is closely associated with genomic instability. Genomic instability has long been considered to be a hallmark of both human genetic disease and cancers. It is now well accepted that regulating R-loop formation to minimized levels is one of critical modulation to maintain genome integrity, and that improper regulation of R-loop metabolism causes genomic instability via DNA breakage, ultimately resulting in replicative senescence and even tumorigenesis. Given that R-loop is natural by-product formed during normal transcription condition, and that several types of cancer have defense mechanism against the genomic instability resulted from R-loop formation, modulating functional implication of proteins involved in the intrinsic and specific mechanisms of abnormal R-loop formation in cancers therefore could play an important part in appropriated therapeutic strategies for HCC cohorts. In this review, we highlight the latest understanding on how R-loops promote genomic instability and address how alterations in these pathways link to human HCC.

Quantitative assessment of liver fibrosis using shore durometer.

PURPOSE: The purpose of the present study was to investigate whether hardness of liver surface correlated with degree of liver fibrosis, and its association with posthepatectomy liver failure (PHLF). METHODS: A shore durometer was used to measure hepatic hardness in 41 patients with hepatocellular carcinoma (HCC) and in 10 patients with normal liver. We investigated how hepatic hardness correlates with various values indicating the degree of liver fibrosis, and how it correlates with PHLF. RESULTS: In the normal liver group, the surface shore units (SU) was 15.06 ± 2.64. In the HCC group, there was a correlation between surface SU and preoperative results indicating liver fibrosis. Among patients with PHLF after resecting over 3 segments, the surface SU of patients with grade A PHLF was 21.85 ± 5.63, and the surface SU of patients with grade C PHLF was 35.75 ± 9.26. In patients with PHLF after resecting 2 or less segments, the surface SU of patients with PHLF grade A was 20.95 ± 5.18, and the surface SU of patients with PHLF grade B was 31.60 ± 5.57. In predicting PHLF, surface SU was more effective than preoperative platelet count, spleen volume, or liver fibrosis index. CONCLUSION: Hepatic hardness measured by the shore durometer was correlated with the degree of liver fibrosis. Liver surface SU was a more effective parameter for predicting PHLF, as compared to other indicators evaluated before hepatectomy. The decision to perform major hepatectomy should be reconsidered in cases with a liver surface SU of >30.

Intravitreal anti-vascular endothelial growth factor versus observation in acute central serous chorioretinopathy: one-year results.

PURPOSE: To evaluate the efficacy of anti-vascular endothelial growth factor (VEGF) compared with observation for treating acute central serous chorioretinopathy (CSC). METHODS: A retrospective study of 36 patients with acute CSC, including 21 patients treated with anti-VEGF (anti-VEGF group) and 15 patients with observation (observation group). Patients in the anti-VEGF group received a single dose of bevacizumab or ranibizumab at baseline. Best-corrected visual acuity (BCVA), central foveal thickness (CFT) and resolution of subretinal fluid (SRF) on optical coherence tomography (OCT) were assessed. The integrity of the foveal inner segment/outer segment (IS/OS) line at 12 months was also analyzed. RESULTS: Resolution of SRF was achieved in 20 of 21 eyes in the anti-VEGF group and in 12 of 15 eyes in the observation group (p = 0.151). Mean BCVA and CFT were not different between the two groups at 12 months (p > 0.05). The amount of change in BCVA, however, differed significantly between the groups (p = 0.044). Final OCT more frequently detected the foveal IS/OS line in the anti-VEGF group than in the observation group (p = 0.012). CONCLUSIONS: In terms of BCVA, anti-VEGF and observation only had similar therapeutic effects in acute CSC patients. In some patients, however, the rapid resolution of SRF by anti-VEGF might reduce the risk of photoreceptor degeneration and improve long-term visual acuity.

The possibility of microbial cellulose for dressing and scaffold materials.

In recent years, natural polymers such as cellulose, alginate and chitosan have been used worldwide as biomedical materials and devices, as they offer more advantages over synthetic polymers. The aim of this study was to clarify the usefulness of microbial cellulose (MC) for use as a dressing and scaffold material. For evaluating the biodegradability and toxicity of MC, we divided the rats (n = 12) into two groups (the implanted group and the non-implanted group). In the implanted group, we implanted the film type of MC in the backs of six rats. In the non-implanted group, however, we did not implant the film type of MC in the backs of the six rats. Four weeks later, we compared two groups by the gross, histological and biochemical characteristics by using blood and tissue samples. To evaluate the wound healing effects of MC, three full-thickness skin defects were made on the backs of each rat (n = 20). Three wounds on the backs of the same rats were treated with other dressing materials, namely, Vaseline gauze (group Con), Algisite M(®) (group Alg) and MC (group MC). We analysed the gross, histological and biochemical characteristics by western blotting. MC was found to be biodegradable and non-toxic. On day 3, the MC film was visible under the subcutaneous tissue; however, after 4 weeks, no remnants of the film were visible under the subcutaneous tissue. Furthermore, there was no evidence of MC-induced toxicity. Moreover, group MC showed more rapid wound healing compared with group Con. On day 14 after skin excision, group MC showed greater decrease in wound size compared with group Con (33% versus 7·2%). The wound healing effects were also substantiated by the histological findings (greater reduction in inflammation and rapid collagen deposition as well as neovascularisation) and western blotting (decreased expression of vascular endothelial growth factor and transforming growth factor-ß1 in group MC on day 14 after skin excision, unlike group Con). This study showed that, in addition to having wound healing effects, MC is biodegradable and non-toxic and can, therefore, be used as a dressing and scaffold material.

Medial epicanthoplasty without a vertical scar.

BACKGROUND: The epicanthal fold (Mongolian fold) in Asians reduces the aesthetic results of eyelid surgery, and thus, medial epicanthoplasty is commonly performed in combination with a double fold operation or blepharoptosis correction. Epicanthoplasty is one of the most popular cosmetic operations conducted in Asia, but scarring is a common problem. METHODS: From December of 2006 to July of 2011, we treated 60 cases using our epicanthoplasty method, which was designed to reduce scarring. A double fold operation and blepharoptosis correction was performed along with epicanthoplasty in 54 cases and an epicanthoplasty without a double fold operation in the remaining 6 cases. Follow-up periods ranged from 6 months to 4 years and 10 months. Previously, we used an elliptical excision epicanthoplasty method, which was simple and practical. However, the elliptical excision method leaves a vertical scar on the nasal side of the upper and lower eyelids. To avoid this scar, we placed an additional incision parallel with the ciliary margin of the lower and/or upper eyelids. The results of epicanthoplasty were evaluated by asking the patients and the surgeon involved to allocate visual analog scale scores. RESULTS: With the exception of 1 case of hypertrophic scarring and 4 cases of undercorrection, patients were satisfied with their results. Mean patient and surgeon visual analog scale scores were 4.6 and 4.2, respectively. The advantages of the described procedure are its simplicity and the minimal scarring caused in the epicanthal area. CONCLUSIONS: This method could become an effective means of removing the Asian epicanthal fold and minimizing vertical scars.

Near infrared ray annealing effects on the properties of Al-doped ZnO thin films prepared by spin-coating method.

In this research, we will present Al doped ZnO thin films for transparent conducting oxide applications. Aluminum doped zinc oxide (AZO) thin films have been deposited on the glass substrates by sol-gel spin-coating method using zinc acetate dehydrate (Zn(CH3COO)2 2H2O) and aluminum chloride hexahydrate (AlCl3 x 6H2O) as cation sources. In this study, we investigated the effects of near infrared ray (NIR) annealing on the structural, optical and electrical characteristics of the AZO thin films. The experimental results showed that AZO thin films have a hexagonal wurtzite crystal structure and had a good transmittance higher than 85% within the visible wavelength region. It was also found that the additional energy of NIR helps to improve the electrical properties of Al doped ZnO transparent conducting oxides.

Combined epicanthoplasty and blepharoptosis correction in Asian patients.

BACKGROUND: In ptosis surgery, not addressing the epicanthal fold leaves a persistent rounded nasal scleral triangle, which blunts the effect of ptosis repair and leads to patient dissatisfaction. To achieve satisfactory results, epicanthoplasty is usually performed with ptosis correction. Furthermore, surgeons usually choose epicanthoplasty methods based on personal preference, and no guideline exists for selecting optimal methods. The aim of this study was to demonstrate the usefulness of a concomitant procedure (ptosis correction and epicanthoplasty) and to provide recommendations for the selection of epicanthoplasty. METHODS: The medical records of 99 patients that underwent simultaneous ptosis correction and epicanthoplasty from September of 2003 to January of 2011 were reviewed. Differences between preoperative and postoperative interepicanthal distances were analyzed by using patient photographs, and interepicanthal distance changes were evaluated for each epicanthoplasty. RESULTS: Epicanthoplasty was performed in the 99 patients using elliptical excision epicanthoplasty in 24 cases, periciliary epicanthoplasty in 12 cases, half-Z epicanthoplasty in eight cases, and V-W epicanthoplasty in 55 cases. Some changes in interepicanthal distances were observed after epicanthoplasty. Interepicanthal distance changes depended on the method used (elliptical excision epicanthoplasty, 3.1 mm; half-Z epicanthoplasty, 4 mm; periciliary epicanthoplasty, 5.3 mm; and V-W epicanthoplasty, 5.4 mm). The greatest differences between preoperative and postoperative interepicanthal distance values were found for periciliary and V-W epicanthoplasty, and these differences were statistically significant. No revision operations were conducted, and most patients were satisfied with results. CONCLUSIONS: In general, concurrent ptosis and epicanthus should be corrected to provide optimal cosmetic benefit. Periciliary or V-W epicanthoplasty is indicated when epicanthal folds are severe. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Assessment of breast volume change after transverse rectus abdominis myocutaneous flap.

BACKGROUND: The evaluation of a breast after breast reconstruction depends on a surgeon's subjective criteria. We used computed tomography (CT) scans to obtain an objective evaluation of the postoperative results by measuring the breast volume of patients who had undergone breast reconstruction using pedicled transverse rectus abdominis myocutaneous (TRAM) flaps. This research will help in the objective postoperative evaluation of reconstructed breasts, and also in the preoperative flap size designs. METHODS: A total of 27 patients underwent breast reconstruction using pedicled TRAM flaps after mastectomy from September 2007 to July 2010. Of these, 10 patients who were followed up and underwent CT scans 2 or more times during the follow-up period were included in this study. We evaluated the change in breast volume over time using CT scans, and the interval breast volume change between CT scans. RESULTS: All of the 10 patients' reconstructed breasts showed a volume decrease over time. The breast volume changes in the intervals between CT scans were as follows: 5.65% decrease between the first CT and second CT scan, 2.3% decrease between the second CT and third CT scan, (statistically significant) and 1.89% decrease between the third CT and forth CT scan. (not statistically significant). CONCLUSIONS: This research shows the possibility of objectively evaluating the postoperative breast volume changes. The findings will be helpful in designing the size of TRAM flaps to use on defects after mastectomy. Based on these results, we should also closely observe the reconstructed breast volume for at least 2 years.

Comparative studies of Al-doped ZnO and Ga-doped ZnO transparent conducting oxide thin films.

We have investigated the influences of aluminum and gallium dopants (0 to 2.0 mol%) on zinc oxide (ZnO) thin films regarding crystallization and electrical and optical properties for application in transparent conducting oxide devices. Al- and Ga-doped ZnO thin films were deposited on glass substrates (corning 1737) by sol-gel spin-coating process. As a starting material, AlCl3⋅6H2O, Ga(NO3)2, and Zn(CH3COO)2⋅2H2O were used. A lowest sheet resistance of 3.3 × 103 Ω/□ was obtained for the GZO thin film doped with 1.5 mol% of Ga after post-annealing at 650°C for 60 min in air. All the films showed more than 85% transparency in the visible region. We have studied the structural and microstructural properties as a function of Al and Ga concentrations through X-ray diffraction and scanning electron microscopy analysis. In addition, the optical bandgap and photoluminescence were estimated.

Analysis of the patterns of lateral canthal rhytids and reference for botulinum toxin treatment in orientals.

BACKGROUND: One of the earliest signs of aging is the appearance of wrinkles in the skin at the outer corners of the eyes (lateral canthal rhytids). The purpose of this study was to divide the lateral canthal rhytids into classified groups and describe their clinical characteristics and suitable treatments. METHODS: A total of 525 patients were included in the study. These patients were groups according to age and sex. Digital photographs of the subject's lateral canthal rhytids (lateral view) were taken and classified as to type (upper, lower, and bidirectional) and degree of direction. RESULTS: A total of 425 patients (81 %) exhibited the bidirectional type of lateral canthal rhytids. The lower directional type was noted on 75 patients (14.3 %), while only 25 patients (4.7 %) exhibited the upper directional type. In the 30s age group, only 50 % exhibited the bidirectional type. However, this rate increased to a 100 % in the 60 year-old and above group. There seems to be no relationship between the type of lateral canthal rhytids and sex. The degrees of the angle of wrinkles were statistically significant only in the 30s and 40s age groups. CONCLUSIONS: We classified lateral canthal rhytids into three groups. This classification helps to decrease the complications of botulinum toxin by associating different treatments with the type of lateral canthal rhytids. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article.

The usefulness of MR imaging of the temporal bone in the evaluation of patients with facial and audiovestibular dysfunction.

OBJECTIVE: To evaluate the clinical utility of MR imaging of the temporal bone in patients with facial and audiovestibular dysfunction with particular emphasis on the importance of contrast enhancement. MATERIALS AND METHODS: We retrospectively reviewed the MR images of 179 patients [72 men, 107 women; average age, 44 (range, 1-77) years] who presented with peripheral facial palsy (n=15), audiometrically proven sensorineural hearing loss (n=104), vertigo (n=109), or tinnitus (n=92). Positive MR imaging findings possibly responsible for the patients' clinical manifestations were categorized according to the anatomic sites and presumed etiologies of the lesions. We also assessed the utility of contrast-enhanced MR imaging by analyzing its contribution to the demonstration of lesions which would otherwise not have been apparent. All MR images were interpreted by two neuroradiologists, who reached their conclusions by consensus. RESULTS: MR images demonstrated positive findings, thought to account for the presenting symptoms, in 78 (44%) of 179 patients, including 15 (100%) of 15 with peripheral facial palsy, 43 (41%) of 104 with sensorineural hearing loss, 40 (37%) of 109 with vertigo, and 39 (42%) of 92 with tinnitus. Thirty (38%) of those 78 patients had lesions that could be confidently recognized only at contrast-enhanced MR imaging. CONCLUSION: Even though its use led to positive findings in less than half of these patients, MR imaging of the temporal bone is a useful diagnostic procedure in the evaluation of those with facial and audiovestibular dysfunction. Because it was only at contrast-enhanced MR imaging that a significant number of patients showed positive imaging findings which explained their clinical manifestations, the use of contrast material is highly recommended.