Flow arrest during carotid artery stenting with a distal embolic protection device: A single-center experience and clinical implications.

OBJECTIVE: We aimed to investigate the incidence of flow arrest during carotid artery stenting (CAS) with filter-type embolic protection device (EPD), identify any predisposing factors for those situations, and contemplate intraprocedural precautionary steps. METHODS: CAS was performed in 128 patients with 132 arteries using filter-type EPD. The characteristics of treated patients and arteries were compared between groups with and without flow arrest. RESULTS: The incidence of flow arrest during CAS with filter-type EPD was 17.4%. In flow arrest group, cases of vulnerable plaques (p=0.02) and symptomatic lesions (p=0.01) were significantly more common, and there were more cases of debris captured by EPD in a planar pattern (p<0.01). Vulnerable plaques were significantly more common in the procedures showing a planar pattern than in the cases with other patterns (p<0.01). Flow arrest group showed a significantly higher rate of ischemic complications (p<0.05), although there were no significant periprocedural neurological changes. The planar pattern of captured debris in filter-type EPD was the only significant risk factor for flow arrest (adjusted odds ratio 88.44, 95% confidence interval 15.21-514.45, p<0.05). CONCLUSIONS: Flow arrest during CAS with filter-type EPD is not uncommon and associated with increased ischemic complications. Symptomatic stenoses and vulnerable plaque are related to this event. The planar pattern of captured debris on the EPD was the only significant risk factor for the flow arrest. Clinicians must pay attention to the occurrence of flow arrest and react quickly when performing CAS.

Modified apical dissection during robot-assisted laparoscopic radical prostatectomy: a systematic review and meta-analysis.

Robot-assisted laparoscopic radical prostatectomy (RALP) has improved patient recovery, but achieving optimal functional outcomes remains a challenge, especially early urinary continence. The Modified Apical Dissection (MAD) technique has been suggested to improve early continence compared to conventional RALP. A comprehensive search of PubMed, Embase, and Cochrane Central databases was conducted to identify studies on MAD from inception to March 2024. The risk of bias was evaluated using the ROBINS-I tool. Primary outcomes assessed included urinary continence, positive surgical margin rate, biochemical recurrence rates, and complication rates. Out of 789 studies screened initially, we selected 8 studies that met our inclusion criteria. Our analysis showed that patients who underwent the MAD technique had a significantly higher likelihood of achieving early urinary continence compared to those undergoing conventional RALP at the initial follow-up (Odds Ratio [OR] = 4.0, 95% CI = 1.87-8.57). This advantage continued at 1 month (OR = 5.44, 95% CI = 2.98-9.92), 3 months (OR = 5.36, 95% CI = 2.26-12.71), and 6 months (OR = 5.18, 95% CI = 1.51-17.75), though no significant difference was noted at 12 months. There were no significant differences in positive surgical margin rate or biochemical recurrence rate between MAD and conventional RALP. The overall complication rate was 10.9% (95% CI = 8.10-14.06), with most complications being classified as minor (Clavien-Dindo I-II). In summary, our meta-analysis suggests that the MAD technique may lead to earlier recovery of urinary continence without compromising oncologic outcomes in patients undergoing RALP. While there are published studies on the outcomes of MAD, only a few have the appropriate design with a comparison group needed for meta-analysis and discussing various endpoints. More randomized controlled trials are necessary, but the current literature still lacks retrospective studies with comparison groups.

The association between the severity of erectile dysfunction and left ventricular diastolic dysfunction in patients with and without cardiovascular disease.

PURPOSE: Erectile dysfunction (ED) is considered a microvascular disorder and serves as an indicator for the potential development of cardiovascular disease (CVD). Although left ventricular diastolic dysfunction (LVDD) reflects early myocardial damage caused by microvascular disorders, the association between ED and LVDD remains poorly elucidated. MATERIALS AND METHODS: A cross-sectional study was conducted on 123 patients with ED. They underwent RigiScan, and conventional echocardiography, and attempted International Index of Erectile Function (IIEF) questionnaire. ED severity was evaluated by measuring changes in the penile base circumference and duration of penile rigidity (≥70%) during erection. The early diastolic velocity of mitral inflow (E) and early diastolic velocity of the mitral annulus (e') were measured using echocardiography. The patients were grouped based on the presence of CVD. RESULTS: Among 123 patients, 29 had CVD and 94 did not. Patients with CVD exhibited more pronounced ED and more severe LVDD. Associations between increased penile circumference with echocardiographic parameters were more prominent in patients with CVD than in those without CVD (ΔTtop and e' wave, r=0.508 and r=0.282, respectively, p for interaction=0.033; ΔTbase and E/e' ratio, r=-0.338 and r=-0.293, respectively, p for interaction <0.001). In the multivariate linear regression, the increase of penile base circumference was an independent risk factor for LVDD (e', B=0.503; E/e' ratio, B=-1.416, respectively, p<0.001). CONCLUSIONS: ED severity correlated well with LV diastolic dysfunction, particularly in the presence of CVD. This study highlighted the potential role of ED assessment as early indicator of CVD development.

Variability of response on prophylactic prasugrel for endovascular treatment of intracranial aneurysms: Clinical implications.

BACKGROUND AND PURPOSE: Prophylactic prasugrel for endovascular treatment of intracranial aneurysms has been introduced and increased, but HTPR (high on-treatment platelet reactivity) or LTPR (low on-treatment platelet reactivity) of prasugrel is not uncommon in clinical circumstances. To investigate the predisposing factors of HTPR and LTPR on prasugrel premedication in the neurointerventional field and to determine its clinical implications. MATERIALS AND METHODS: Between February 2016 and December 2020, 191 patients treated with coil embolization using prophylactic prasugrel in 234 intracranial aneurysms were the final candidates for this study. Patient and aneurysm characteristics, clinical status, and laboratory study values were carefully reviewed retrospectively. We performed risk factor analyses for HTPR and LTPR on prasugrel. RESULTS: Ultimately, 20 patients (10.5%) had HTPR, and 74 patients (38.7%) were categorized as having LTPR. In multivariable analyses, the factors related to HTPR were BMI (adjusted OR 1.21, 95% CI 1.04-1.41, p = 0.01), history of antithrombotics (adjusted OR 3.79, 95% CI 1.39-10.34, p = 0.01), and hematocrit (adjusted OR 0.91, 95% CI 0.84-0.99, p = 0.03). Low BMI was the only risk factor for LTPR (adjusted OR 0.84, 95% CI 0.76-0.94, p = 0.001). CONCLUSION: In the neurointerventional field, high BMI and prior use of antithrombotic agents were related to HTPR, and low BMI was associated with LTPR on prophylactic prasugrel. High hematocrit levels decreased the risk of HTPR. When preparing endovascular treatment for intracranial aneurysms, attention to patients with these clinical features is required to address the possibility of ischemic or bleeding complications.

Weekend effect on 30-day mortality for ischemic and hemorrhagic stroke analyzed using severity index and staffing level.

BACKGROUND AND PURPOSE: Previous studies on the weekend effect-a phenomenon where stroke outcomes differ depending on whether the stroke occurred on a weekend-mostly targeted ischemic stroke and showed inconsistent results. Thus, we investigated the weekend effect on 30-day mortality in patients with ischemic or hemorrhagic stroke considering the confounding effect of stroke severity and staffing level. METHODS: We retrospectively analyzed data of patients hospitalized for ischemic or hemorrhagic stroke between January 1, 2015, and December 31, 2018, which were extracted from the claims database of the National Health Insurance System and the Medical Resource Report by the Health Insurance Review & Assessment Service. The primary outcome measure was 30-day all-cause mortality. RESULTS: In total, 278,632 patients were included, among whom 84,240 and 194,392 had a hemorrhagic and ischemic stroke, respectively, with 25.8% and 25.1% of patients, respectively, being hospitalized during the weekend. Patients admitted on weekends had significantly higher 30-day mortality rates (hemorrhagic stroke 16.84%>15.55%, p<0.0001; ischemic stroke 5.06%>4.92%, p<0.0001). However, in the multi-level logistic regression analysis adjusted for case-mix, pre-hospital, and hospital level factors, the weekend effect remained consistent in patients with hemorrhagic stroke (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.00-1.10), while the association was no longer evident in patients with ischemic stroke (OR 1.01, 95% CI 0.96-1.06). CONCLUSIONS: Weekend admission for hemorrhagic stroke was significantly associated with a higher mortality rate after adjusting for confounding factors. Further studies are required to understand factors contributing to mortality during weekend admission.

The Incidence of Brain-Dead Donors Based on Screening and Management Led by Intensivists.

BACKGROUND This study aimed to compare the incidence of brain-dead (BD) donors and potential brain-dead (PBD) donors before vs after the introduction of intensivists. MATERIAL AND METHODS This longitudinal retrospective study was performed between January 2012 and December 2020 at Seoul Metropolitan Government-Seoul National University Boramae Medical Center. Four dedicated intensivists were introduced in January 2016. The periods before and after introduction of the intensivists were defined as the pre-introduction period (2012-2015) and post-introduction period (2016-2020), respectively. RESULTS During the study period, there were 2872 discharges in the Intensive Care Unit, of which there were a total of 113 PBD (3.93%) and 36 BD (1.25%) donors. The number of PBD and BD donors increased in the post-introduction period compared in the pre-introduction period (PBD, 47.84 vs 27.14 per 1000 discharges; BD, 13.59 vs 11.03 per 1000 discharges). Poisson regression analysis showed the annual incidence rate of PBD donors significantly increased post-introduction (PBD, 27.53% vs 48.11%, P=0.044), while those of BD donors were similar between the 2 groups (BD, 11.41% vs 13.9%; P=0.743). The annual incidence rate of the total number of organ donations, multi-organ donations (>3 organs), and donation of organs (heart, lung, and kidney) increased in the post-introduction period compared to that in the pre-introduction period. CONCLUSIONS Our findings suggest a beneficial role of a dedicated intensivist, not only in improving actual organ donation and discovering PBD donors, but also in affecting the yield of the heart and lung transplantation in actual organ donation compared to donors without a dedicated intensivist.

Optimizing Mannitol Use in Managing Increased Intracranial Pressure: A Comprehensive Review of Recent Research and Clinical Experiences.

Mannitol, derived from mannose sugar, is crucial in treating patients with elevated intracranial pressure (ICP). Its dehydrating properties at the cellular and tissue levels increase plasma osmotic pressure, which is studied for its potential to reduce ICP through osmotic diuresis. While clinical guidelines support mannitol use in these cases, the best approach for its application continues to be debated. Important aspects needing further investigation include: 1) bolus administration versus continuous infusion, 2) ICP-based dosing versus scheduled bolus, 3) identifying the optimal infusion rate, 4) determining the appropriate dosage, 5) establishing fluid replacement plans for urinary loss, and 6) selecting monitoring techniques and thresholds to assess effectiveness and ensure safety. Due to the lack of adequate high-quality prospective research data, a comprehensive review of recent studies and clinical trials is crucial. This assessment aims to bridge the knowledge gap, improve understanding of effective mannitol use in elevated ICP patients, and provide insights for future research. In conclusion, this review aspires to contribute to the ongoing discourse on mannitol application. By integrating the latest findings, this review will offer valuable insights into the function of mannitol in decreasing ICP, thereby informing better therapeutic approaches and enhancing patient outcomes.

The Unique Relationship between Neuro-Critical Care and Critical Illness-Related Corticosteroid Insufficiency : Implications for Neurosurgeons in Neuro-Critical Care.

The brain houses vital hormonal regulatory structures such as the hypothalamus and pituitary gland, which may confer unique susceptibilities to critical illness-related corticosteroid insufficiency (CIRCI) in patients with neurological disorders. In addition, the frequent use of steroids for therapeutic purposes in various neurological conditions may lead to the development of steroid insufficiency. This abstract aims to highlight the significance of understanding these relationships in the context of patient care and management for physicians. Neurological disorders may predispose patients to CIRCI due to the role of the brain in hormonal regulation. Early recognition of CIRCI in the context of neurological diseases is essential to ensure prompt and appropriate intervention. Moreover, the frequent use of steroids for treating neurological conditions can contribute to the development of steroid insufficiency, further complicating the clinical picture. Physicians must be aware of these unique interactions and be prepared to evaluate and manage patients with CIRCI and steroid insufficiency in the context of neurological disorders. This includes timely diagnosis, appropriate steroid administration, and careful monitoring for potential adverse effects. A comprehensive understanding of the interplay between neurological disease, CIRCI, and steroid insufficiency is critical for optimizing patient care and outcomes in this complex patient population.

The Unique Relationship between Neuro-Critical Care and Critical Illness-Related Corticosteroid Insufficiency : Implications for Neurosurgeons in Neuro-Critical Care.

The brain houses vital hormonal regulatory structures such as the hypothalamus and pituitary gland, which may confer unique susceptibilities to critical illness-related corticosteroid insufficiency (CIRCI) in patients with neurological disorders. In addition, the frequent use of steroids for therapeutic purposes in various neurological conditions may lead to the development of steroid insufficiency. This abstract aims to highlight the significance of understanding these relationships in the context of patient care and management for physicians. Neurological disorders may predispose patients to CIRCI due to the role of the brain in hormonal regulation. Early recognition of CIRCI in the context of neurological diseases is essential to ensure prompt and appropriate intervention. Moreover, the frequent use of steroids for treating neurological conditions can contribute to the development of steroid insufficiency, further complicating the clinical picture. Physicians must be aware of these unique interactions and be prepared to evaluate and manage patients with CIRCI and steroid insufficiency in the context of neurological disorders. This includes timely diagnosis, appropriate steroid administration, and careful monitoring for potential adverse effects. A comprehensive understanding of the interplay between neurological disease, CIRCI, and steroid insufficiency is critical for optimizing patient care and outcomes in this complex patient population.

The relationship between non-aneurysmal spontaneous subarachnoid hemorrhage and basilar tip anatomy.

OBJECTIVE: Non-aneurysmal spontaneous subarachnoid hemorrhage (NASAH) has a good prognosis, but its cause has not been clearly identified. In this study, we assessed the clinical and radiological features of NASAH and suggested an anatomical relationship between the basilar tip anatomy and NASAH. METHODS: From August 2013 to May 2020, 21 patients were diagnosed with NASAH at our institution. We evaluated the clinical features of NASAH. NASAH was classified into a perimesencephalic pattern and aneurysmal pattern according to the distribution of hemorrhage based on initial brain computed tomography. Digital subtraction angiography was used to classify the basilar tip anatomy into symmetric cranial fusion, symmetric caudal fusion, or asymmetric fusion types. RESULTS: Of the 21 patients, twenty patients had a good clinical outcome (modified Rankin Scale (mRS) 1-2; Glasgow Outcome Scale (GOS) 4-5). These patients showed improvement in mRS and Glasgow Coma Scale (GCS) at the last follow-up (P=.003 and P=.016, respectively). Eighteen patients with NASAH (85.7%) had the caudal fusion type, and only three patients with NASAH (14.3%) had the cranial fusion type. Seven patients with the perimesencephalic pattern (77.8%) had the caudal fusion type, and eleven patients with the aneurysmal pattern (91.7%) had the caudal fusion type. CONCLUSIONS: In NASAH patients, the caudal fusion tends to occur frequently among patients with basilar tip anatomy. In the case of the caudal fusion, the perforators around the basilar tip would be more susceptible to hemodynamic stress, which could contribute to the occurrence of NASAH.

Preparation of copper-loaded porous carbons through hydrothermal carbonization and ZnCl2 activation and their application to selective CO adsorption: Experimental and DFT calculation studies.

CO is used as a raw material to produce valuable chemicals. Adsorption using solid materials can be employed to separate and recover CO from gas mixtures. In this study, cellulose-based, porous carbons were prepared via hydrothermal carbonization and ZnCl2 activation. The prepared porous carbons were used for CO separation after CuCl loading by a facile solid-state dispersion method to induce π-complexation and eventually enhance the affinity toward CO. The sample with the highest CO uptake of 3.62 mmol g-1 at 298 K and 101 kPa had a carbon:CuCl loading ratio of 1:1. This is the highest reported CO adsorption on porous carbons using CuCl as a π-complexation-inducing material. In addition, several factors, including the selectivity of CO against CO2 and the cyclic stability using vacuum regeneration, demonstrated the potential for industrial applications. Density functional theory (DFT) calculations theoretically elucidated that the presence of small and well-dispersed CuCl clusters induce excellent CO-selective adsorption performance, which is in accordance with the experimental results.

Modified apical dissection improves early continence in robot-assisted laparoscopic radical prostatectomy: Comparative study between modified apical dissection and anterior suspension stitch.

PURPOSE: Recently, the modified apical dissection (MAD) technique in robot-assisted laparoscopic radical prostatectomy (RARP) has shown excellent functional outcomes but has never been rigorously validated at various institutions. This study aimed to evaluate the effect of MAD on early continence and potency compared with the anterior suspension stitch (SS) technique. MATERIALS AND METHODS: A total of 100 patients who underwent RARP with SS and 100 who underwent RARP with MAD by a single surgeon were propensity score matched and retrospectively compared for continence and potency recovery at 1 week and 1, 3, 6, 9, and 12 months. RESULTS: Continence was reached in 20.6%, 33.3%, 67.2%, 74.1%, 81.1%, and 83.0% of patients in the SS group, compared with 49.2%, 73.3%, 86.8%, 96.6%, 100.0%, and 100.0% in the MAD group at postoperative 1 week and 1, 3, 6, 9, and 12 months, respectively. In the SS group, potency rates were 0.0%, 20.0%, 50.0%, 66.7%, 75.0%, and 83.3%; in the MAD group, the rates were 50.0%, 90.0%, 88.9%, 100.0%, 100.0%, and 100.0%. Recovery of continence was higher in the MAD group within the first 6 months (p=0.005, <0.010, 0.041, 0.016 at 1 week, 1, 3, and 6 months). There were no significant differences in potency recovery rates between the two groups (all p≥0.05). CONCLUSIONS: The MAD technique results in earlier recovery of continence compared with the SS technique.

Host-guest chemistry in the gas phase: selected fragmentations of CB[6]-peptide complexes at lysine residues and its utility to probe the structures of small proteins.

The gas phase host-guest chemistry between cucurbit[6]uril (CB[6]) and peptide is investigated using electrospray ionization mass spectrometry (ESI-MS). CB[6] exhibits a high preference to interacting with a Lys residue in a peptide forming a CB[6]-peptide complex. Collisionally activated CB[6] complexes of peptides yield a common highly selective fragment product at m/z 549.2, corresponding to the doubly charged CB[6] complex of 5-iminiopentylammonium (5IPA). The process involves the formation of an internal iminium ion, which results from further fragments to an a-type ion from a y-type ion, and the resulting 5IPA ion threads through CB[6]. Numerous peptides are investigated to test the generality of the observed unique host-guest chemistry of CB[6]. Its potential utility in probing protein structures is demonstrated using CB[6] complexes of ubiquitin. Low-energy collision induced dissociation yields CB[6] complex fragments, and further MS(n) spectra reveal details of the CB[6] binding sites, which allow us to deduce the protein structure in the solution phase. The mechanisms and energetics of the observed reactions are evaluated using density functional theory calculations.

A Universal Screening Strategy for SARS-CoV-2 Infection in Intensive Care Units: Korean Experience in a Single Hospital.

BACKGROUND: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection is not differentiated clinically from other respiratory infections, and intensive care units (ICUs) are vulnerable to in-hospital transmission due to interventions inducing respiratory aerosols. This study evaluated the effectiveness of universal SARS-CoV-2 screening in ICUs in terms of screened-out cases and reduction in anxiety of healthcare personnel (HCP). MATERIALS AND METHODS: This prospective single-armed observational study was conducted in 2 ICUs of a single hospital. The number of patients diagnosed with SARS-CoV-2 infection by the screening program and healthcare workers in ICUs that visited the SARS-CoV-2 screening clinic or infection clinic were investigated. RESULTS: During the 7-week study period, no positive screening case was reported among a total of 142 patients. Among 86 HCP in the ICUs, only 2 HCP sought medical consultation for SARS-CoV-2 infection during the initial 2 weeks. CONCLUSION: A universal screening program for SARS-CoV-2 infection in ICUs with the coordination of other countermeasures in the hospital was reasonably effective in preventing in-hospital transmission in a pandemic situation and making clinical practices and HCP stable.

Selective fluorogenic and chromogenic probe for detection of silver ions and silver nanoparticles in aqueous media.

A novel rhodamine-based fluorogenic and chromogenic probe for Ag(+) ions in aqueous media is developed, which can be also used for the detection of AgNPs. The sensing mechanism is based on irreversible tandem ring-opening and -forming processes promoted by Ag(+)-coordination to the iodide of the probe, which is accompanied by both color and turn-on type fluorescence changes. The probe shows remarkably high selectivity over other metal ions and detects silver ions up to 14 ppb.

A study of urea-dependent denaturation of beta-lactoglobulin by principal component analysis and two-dimensional correlation spectroscopy.

The water-urea-beta-lactoglobulin interaction was studied by means of principal component analysis (PCA) and two-dimensional correlation spectroscopy applied to the urea concentration-dependent FTIR spectra of aqueous urea-protein solutions. The two nu(CO) and nu(as)(CN) bands coming from urea's absorbance, instead of the amide bands arising from protein, were employed in the analysis. To get a precise view of the changes induced by the urea concentration-controlled unfolding process, the absorbance variations developed in the ternary water-urea-protein system were compared with those observed in a binary water-urea system [Y.M. Jung et al., J. Phys. Chem. B 2004, 108, 13008]. The comparative studies enabled to detect apparent differences between the absorbance changes caused solely by urea's concentration increase and by the urea-dependent unfolding process. Urea's ability to unfold protein was discussed in context of the indirect and the direct mechanism depending on urea's concentration. It was shown that both mechanisms are relevant, that is, the indirect for solutions below 3 M and the direct for solutions above 3 M concentration. The character of the mechanism is strictly correlated with the association level of urea molecules.

An in vitro study of the antifungal effect of silver nanoparticles on oak wilt pathogen Raffaelea sp.

In this study, we investigated the antifungal activity of three different forms of silver nanoparticles against the unidentified ambrosia fungus Raffaelea sp., which has been responsible for the mortality of a large number of oak trees in Korea. Growth of fungi in the presence of silver nanoparticles was significantly inhibited in a dosedependent manner. We also assessed the effectiveness of combining the different forms of nanoparticles. Microscopic observation revealed that silver nanoparticles caused detrimental effects not only on fungal hyphae but also on conidial germination.

Details of thermal behavior of spin-coated film of biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer studied by principal component analysis-based two-dimensional (PCA2D) correlation spectroscopy.

Principal component analysis-based two-dimensional (PCA2D) correlation spectroscopy was applied to the temperature-dependent infrared-reflection absorption (IRRAS) spectra of a spin-coated film of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)) (HHx=7.2 mol%) copolymer. In asynchronous PCA2D correlation spectra, we clearly captured the existence of two components in the crystalline band of the CO stretching mode, well-ordered primary crystals observed at lower wavenumber and less ordered secondary crystals observed at higher wavenumber, which is not readily detectable in the original 1D spectra. Furthermore, the intensity changes of bands at 1298 and 1280 cm(-1) are significantly different in the temperature ranges below and above the transition temperature around 140 degrees C identified by the 2D first derivatives plot. The result further confirms that the sequence of intensity changes with increasing temperature is such that bands for less ordered crystalline components of P(HB-co-HHx) (HHx=7.2 mol%) are changing first at an earlier (i.e., lower temperature) stage.

Hydrostatic pressure effect on the phase transitions of a closed-loop type block copolymer by using 2D FTIR correlation spectroscopy.

The effect of hydrostatic pressure (P) on the phase transitions of polystyrene-block-poly(n-pentyl methacrylate) copolymer [PS-b-PnPMA] was investigated with FTIR spectroscopy at various temperatures. The experiments were performed by using a specially designed pressure cell optimized for low-pressure regime (<100 bar) with a higher resolution ( approximately 1 bar). The size of the closed loop consisting of both the lower disorder-to-order transition (LDOT) and the upper order-to-disorder transition (UODT) measured by FTIR spectroscopy becomes smaller with increasing P, consistent with results obtained from birefringence measurement. At lower temperatures with increasing P, the PS main chains are found to move before the PnPMA main chains. This is because the mobility of the PnPMA main chains is restricted due to the cluster formation of the alkyl side chain. At higher temperatures, the PnPMA block chains are more mobile than the PS block chains due to their larger specific volumes. The results indicate that the LDOT is mainly affected by a favorable directional interaction between PS and PnPMA blocks due to the cluster formation of the alkyl side chain, whereas the UODT depends on the combinatorial entropy.

Two-dimensional gradient mapping technique useful for detailed spectral analysis of polymer transition temperatures.

This paper demonstrates the potential of a two-dimensional (2D) gradient mapping technique that utilized the eigenvalue manipulating transformation (EMT) of the spectral data set. The EMT technique, by lowering the power of a set of eigenvalues associated with the original data, enhances the contributions of minor principle components (PCs). The operation converts the original spectral data set to the one with subtle differences among the responses of the system being exaggerated. Small shoulders and obscure minor features may become much more visible, because such small differentiating features are often captured only by the minor PCs enlarged by the EMT treatment. This improvement for 2D mapping is potentially very important to determine the transition temperatures, which are not readily detected in convention spectral analysis.