Cation/Anion-Dual regulation in Na3MnTi(PO4)3 cathode achieves the enhanced electrochemical properties of Sodium-Ion batteries

Na3MnTi(PO4)3 (NMTP) emerges as a promising cathode material with high-performance for sodium-ion batteries (SIBs). Nevertheless, its development has been limited by several challenges, including poor electronic conductivity, the Mn3+ Jahn-Teller effect, and the presence of a Na+/Mn2+ cation mixture. To address these issues, we have developed a cation/anion-dual regulation strategy to activate the redox reactions involving manganese, thereby significantly enhancing the performance of NMTP. This strategy simultaneously enhances the structural dynamics and facilitates rapid ion transport at high rates by inducing the formation of sodium vacancy. The combined effects of these modifications lead to a substantial improvement in specific capacity (79.1 mAh/g), outstanding high-rate capabilities (35.9 mAh/g at 10C), and an ultralong cycle life (only 0.040 % capacity attenuation per cycle over 250 cycles at 1C for Na3.34Mn1.2Ti0.8(PO3.98F0.02)3) when used as a cathode material in SIBs. Furthermore, its performance in full cell demonstrates impressive rate capability (44.4 mAh/g at 5C) and exceptional cycling stability (with only 0.116 % capacity decay per cycle after 150 cycles at 1C), suggesting its potential for practical applications. This work presents a dual regulation strategy targeting different sites, offering a significant advancement in the development of NASICON phosphate cathodes for SIBs.

Defect engineering unveiled: Enhancing potassium storage in expanded graphite anode

Expanded graphite (EG) stands out as a promising material for the negative electrode in potassium-ion batteries. However, its full potential is hindered by the limited diffusion pathway and storage sites for potassium ions, restricting the improvement of its electrochemical performance. To overcome this challenge, defect engineering emerges as a highly effective strategy to enhance the adsorption and reaction kinetics of potassium ions on electrode materials. This study delves into the specific effectiveness of defects in facilitating potassium storage, exploring the impact of defect-rich structures on dynamic processes. Employing ball milling, we introduce surface defects in EG, uncovering unique effects on its electrochemical behavior. These defects exhibit a remarkable ability to adsorb a significant quantity of potassium ions, facilitating the subsequent intercalation of potassium ions into the graphite structure. Consequently, this process leads to a higher potassium voltage. Furthermore, the generation of a diluted stage compound is more pronounced under high voltage conditions, promoting the progression of multiple stage reactions. Consequently, the EG sample post-ball milling demonstrates a notable capacity of 286.2 mAh g-1 at a current density of 25 mA g-1, showcasing an outstanding rate capability that surpasses that of pristine EG. This research not only highlights the efficacy of defect engineering in carbon materials but also provides unique insights into the specific manifestations of defects on dynamic processes, contributing to the advancement of potassium-ion battery technology.

Entropy-Regulated Cathode with Low Strain and Constraint Phase-Change Toward Ultralong-Life Aqueous Al-Ion Batteries

During multivalent ions insertion processes, intense electrostatic interaction between charge carriers and host makes the high-performance reversible Al3+ storage remains an elusive target. On account of the strong electrostatic repulsion and poor robustness, Prussian Blue analogues (PBAs) suffer severely from the inevitable and large strain and phase change during reversible Al3+ insertion. Herein, we demonstrate an entropy-driven strategy to realize ultralong life aqueous Al-ion batteries (AIBs) based on medium entropy PBAs (ME-PBAs) host. By multiple redox active centers introduction, the intrinsic poor conductivity can be enhanced simultaneously, resulting in outstanding capabilities of electrochemical Al3+ storage. Meanwhile, the co-occupation at metal sites in PBA frameworks can also increase the M-N bond intensity, which is beneficial for constraining the phase change during consecutive Al3+ reversible insertion, to realize an extended lifespan over 10,000 cycles. Based on the calculation at different operation states, the fluctuation of ME-PBA lattice parameters is only 1.2 %. Assembled with MoO3 anodes, the full cells can also deliver outstanding electrochemical properties. The findings highlight that, the entropy regulation strategy could uncover the isochronous constraint on both strain and phase transition for long-term reversible Al3+ storage, providing a promising design for advanced electrode materials for aqueous multivalent ions batteries.

Tuning oxygen release of sodium-ion layered oxide cathode through synergistic surface coating and doping

Layered transition metal oxides have the greatest potential for commercial application as cathode materials for sodium-ion batteries. However, transition metal oxides inevitably undergo an irreversible oxygen loss process during cycling, which leads to structural changes in the material and ultimately to severe capacity degradation. In this work, using density function theory (DFT) calculations, the Ni-O bond is revealed to be the weakest of the M-O bonds, which may lead to structural failure. Herein, the synergistic surface CeO2 modification and the trace doping of Ce elements stimulate oxygen redox and improve its reversibility, thus improving the structural stability and electrochemical performance of the material. Theoretical calculations prove that Na0.67Mn0.7Ni0.2Co0.1O2 (MNC) obtains electrons from CeO2, avoiding destruction of the Ni-O bond by over-energy released during the charging process and inhibiting oxygen loss. The capacity retention was 77.37% for 200 cycles at 500 mA g-1, compared to 33.84% for the unmodified Na0.67Mn0.7Ni0.2Co0.1O2. Overall, the present work demonstrates that the synergistic effect of surface coating and doping is an effective strategy for realizing tuning oxygen release and high electrochemical performance.

Advanced Lithium Primary Batteries: Key Materials, Research Progresses and Challenges

In recent years, with the vigorous development and gradual deployment of new energy vehicles, more attention has been paid to the research on lithium-ion batteries (LIBs). Compared with the booming LIBs, lithium primary batteries (LPBs) own superiority in specific energy and self-discharge rate and are usually applied in special fields such as medical implantation, aerospace, and military. Widespread application in special fields also means more stringent requirements for LPBs in terms of energy density, working temperature range and shelf life. Therefore, how to obtain LPBs with high energy density, wide operational temperature range and long storage life is of great importance in future development. In view of the above, this paper reviews the latest research on LPBs in cathode, anode and electrolyte over the years, and puts forward relevant insights for LPBs, along with the intention to explore avenues for the design of LPBs components in the coming decades and promote further development in this field.

[Decolorization of skin and hair-derived melanin by three ligninolytic enzymes]

Objective: To compare the decolorization efficiency of lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase on eumelanin and pheomelanin, and to investigate the effect of topical administration of LiP solution on hyperpigmented guinea pigs skin induced by 308 nm excimer light. Methods: Pheomelanin-enriched specimens were prepared from human hair and cutaneous melanoma tissue using alkaline lysis method.Synthetic eumelanin was purchased from a commercial supplier.The same amount (0.02%) of melanin was incubated with the equal enzyme activity (0.2 U/ml) of ligninolytic enzymes for 3 h respectively.The absorbance at 475 nm (A(475)) in the enzyme-catalyzed solution was measured using ELISA microplate reader.The experimental hyperpigmentation model was established in the dorsal skin of brownish guinea pigs using 308 nm excimer light radiation.LiP and heat-inactivated LiP solution were topically applied at each site.Meanwhile, 3% hydroquinone and vehicle cream were used as control.The skin color (L value) was recorded using a CR-10 Minolta chromameter.Corneocytes were collected using adhesive taping method.The amount and distribution of melanin in the corneocytes and skin tissues was visualized by Fontana-Masson staining. Results: All three ligninolytic enzymes showed various degree of eumelanin and pheomelanin decolorization activity.The decolorization activity of LiP, MnP and laccase was 40%-70%, 22%-42% and 9%-21%, respectively.The similar lightening was shown in the skin treated with LiP solution and 3% hydroquinone.The amount of melanin granules in the corneocytes was 199±11 by LiP, which was less than that in untreated control (923±12) and heat-inactive control (989±13). The amount of melanin was decreased in the whole epidermis treated with hydroquinone, the epidermis thickness was increased as well. In contrast, melanin of LiP group was decreased only in the superficial epidermis, the epidermis thickness seemed to be normal. Conclusion: LiP exerts a potent decolorization activity for hair- or skin-derived pheomelanin as well as eumelanin.It remains to be further investigated whether LiP serves as a substitute for hydroquinone in skin lightening products.

Correlation of endogenous hormonal levels, fibroglandular tissue volume and percent density measured using 3D MRI during one menstrual cycle

BACKGROUND

We measured breast density (BD) on MRI and correlated with endogenous hormonal levels.

PATIENTS AND METHODS

Twenty-four premenopausal women received four weekly breast MRI. A blood sample was collected on the same day of MRI. BD was measured using a computer-based algorithm. The generalized estimation equation method was applied to model mean fibroglandular tissue volume (FV) and mean percent density (PD) from predictor variables including estradiol, progesterone, and week during a cycle.

RESULTS

In week 3, a borderline significant correlation between estradiol and PD (r = 0.43, P = 0.04), estradiol and FV (r = 0.40, P = 0.05) and between progesterone and FV (r = 0.42, P = 0.04) was noted. The FV and PD measured in weeks 4 and 1 were higher than in weeks 2 and 3, adjusted for variation in endogenous estradiol and progesterone, indicating that the hormone change could not account for the changes in density. No lag effect of endogenous hormone on the change of FV or PD was noted (all P-values > 0.05).

CONCLUSIONS

Our results showed that BD is not strongly associated with the endogenous hormone. Their association with breast cancer risk was likely coming from different mechanisms, and they should be considered as independent risk factors.

A Programmable Implantable Microstimulator SoC With Wireless Telemetry: Application in Closed-Loop Endocardial Stimulation for Cardiac Pacemaker

A low-power, wireless, and implantable microstimulator system on chip with smart powering management, immediate neural signal acquisition, and wireless rechargeable system is proposed. A system controller with parity checking handles the adjustable stimulus parameters for the stimulated objective. In the current paper, the rat's intra-cardiac electrogram is employed as the stimulated model in the animal study, and it is sensed by a low-voltage and low-power monitoring analog front end. The power management unit, which includes a rectifier, battery charging and detection, and a regulator, is used for the power control of the internal circuits. The stimulation data and required clock are extracted by a phase-locked-loop-based phase shift keying demodulator from an inductive AC signal. The full chip, which consumes 48 μW only, is fabricated in a TSMC 0.35 μm 2P4M standard CMOS process to perform the monitoring and pacing functions with inductively powered communication in the in vivo study.

Hemosuccus pancreaticus from a traumatic gastroduodenal pseudoaneurysm: an unusual cause of upper gastrointestinal bleeding

Hemosuccus pancreaticus, blood entering the gastrointestinal tract through the pancreatic duct, is a rare and elusive form of gastrointestinal bleeding with diagnostic difficulties. We report a 37-year-old man who had recurrent gastrointestinal bleeding from erosion of a pseudoaneurysm of the gastroduodenal artery into the pancreatic duct. The lack of history of pancreatitis, associated symptoms, equivocal endoscopic findings, and the rarity of this entity resulted in a delay in diagnosis. Pancreatic duct stenosis detected during surgery suggested the lesion might have been caused by blunt abdominal trauma. A nearly total pancreatectomy and splenectomy were performed. The patient remained symptom-free 8 months after the operation. This obscure cause of gastrointestinal bleeding should be considered when common causes of bleeding have been ruled out, even in the absence of pancreatitis.

Effect of vasodilator hydralazine on tumor microvascular random flow and blood volume as measured by intravoxel incoherent motion (IVIM) weighted MRI in conjunction with Gd-DTPA-Albumin enhanced MRI

We studied the effect of hydralazine on tumor blood volume fraction and microvascular random flow velocity magnitude by IVIM weighted MRI in conjunction with dynamic Gd-DTPA-Albumin enhanced MRI. Blood volume fraction maps were obtained from the dynamic Gd-DTPA-Albumin enhanced MRI measurements. The average blood volume fraction of R3230 AC adenocarcinoma decreased from 0.125 +/- 0.022 (s.d.) ml/g to 0.105 +/- 0.018 (s.d.) ml/g (p < 0.001) after the administration of hydralazine at a dose of 5 mg/kg. The microvascular random flow velocity magnitude maps were obtained from the IVIM weighted MRI signals by utilizing the Gd-DTPA-Albumin measured blood volume fractions as an input in the compartmental modeling analysis of the IVIM weighted MRI signal. The random-directional microvascular flow induced MRI signal attenuation was separated from the molecular diffusion induced signal attenuation. Flow induced attenuation was more significant after the administration of hydralazine. The mean microvascular random flow velocity magnitude increased from 0.52 +/- 0.15 (s.d.) mm/sec to 0.73 +/- 0.23 (s.d.) mm/sec (p < 0.05) in the presence of the above blood volume fraction change.

Magnifying colonoscopy in differentiating neoplastic from nonneoplastic colorectal lesions

OBJECTIVE

Because the medical management of persons with adenomatous colorectal polyps differs from that of those with hyperplastic polyps, accuracy of diagnosis is essential. This study reports our experience using a magnifying colonoscope combined with indigocarmine dye to diagnose colorectal polyps, emphasizing its ability to differentiate neoplastic from nonneoplastic lesions.

METHODS

The materials consisted of 175 polyps. A 0.2% indigocarmine solution was sprayed, and the colonoscope zoom apparatus performed a magnified observation after an ordinary colonoscopy identified the lesions. The pit patterns were classified into six categories: I, II, III(L), IIIs, IV, and V according to Kudo's modified classification.

RESULTS

The percentages of neoplastic changes in the lesions with pit pattern I, II, III(L), IIIs, IV, and V were 0, 12.2, 69.7, 80, 84.4, and 100%, respectively. The diagnostic sensitivity of neoplastic lesions was 93.8% and specificity was 64.6% when types I and II represented the pit pattern of nonneoplastic lesions and types III(L), IIIs, IV, and V represented neoplastic lesions. The overall diagnostic accuracy in differentiating neoplastic from nonneoplastic lesions was 80.1%. The diagnostic accuracy is not influenced by the size and shape of the lesions. The six neoplastic lesions that were misjudged to be nonneoplastic were histologically adenoma with only mild atypia.

CONCLUSIONS

The pit pattern analysis of colorectal lesions by magnifying colonoscopy is a useful and objective tool for differentiating neoplastic from nonneoplastic lesions of the large bowel. In its current state of development, however, this technique is not a substitute for histology.

Endoscopic treatment of colorectal polyps and early cancer

To analyze the efficacy and outcome of colonoscopic resection for colorectal neoplastic lesions, we retrospectively reviewed 338 colorectal lesions from 232 patients regarding the clinical profiles, colonoscopic findings, histological findings, complications, and outcome. Morphologically, these lesions were classified into three categories: pedunculated (n = 140), sessile (n = 176); and flat (n = 22). Histological findings of lesions included adenoma (n = 248), carcinoma in situ (n = 17), submucosal carcinoma (n = 2), hyperplastic polyp (n = 57), and inflammatory polyp (n = 14). Neoplastic lesions are generally larger than nonneoplastic lesions (chi2 test, P < 0.05). The incidence of carcinoma was 5.6% of 338 resected lesions. The rate of cancer or high-grade dysplasia in flat polyps was greater than in pedunculated and sessile polyps (13.6 vs 4.54 vs 5.71%; P < 0.05). There were no perforations or deaths after colonoscopic treatment, and only mild bleeding occured in two patients. To date, 19 patients with early colorectal cancer were treated successfully by endoscopy with no recurrence or metastasis. To reduce the incidence and mortality of colorectal cancer, colonoscopic resection is a simple and safe procedure for removing neoplastic lesions. Detailed histological examinations are essential to decide the indications of surgery.

Acute jejunogastric intussusception: report of five cases

The purpose of this study was to investigate the clinical manifestations and diagnosis of patients with acute jejunogastric intussusception. From May 1986 to June 1999, a total of 5 men (54-76 years old) were collected. Their initial presentations included epigastralgia (4), coffee-ground vomitus (3), frank hematemesis (1), and tarry stool (1). All patients had gastric surgeries 10-30 years previously. Radiograph of the abdomen showed a soft tissue density at the left upper quadrant in one patient. Panendoscopies were done in 4 patients. An obstructed efferent loop with a distended hyperemic small bowel protruding into the remnant of stomach was found in 3 cases, gangrenous change of the bowel wall in one of them. Stump cancer was diagnosed initially in the other patient. Barium study (3/5) showed efferent loop obstruction with "coil spring sing" and a central defect in the stomach. All 5 patients underwent segmental resection and end-to-end anastomosis between the 2nd to 6th hospital day. Operative findings were type II jejunogastric intussusception with retrograde invagination of a segment of efferent loop (30-100 cm in length) into the stomach. In conclusion, acute jejunogastric intussusception is an emergent condition. Early and accurate diagnosis is important. A high susception must be kept in mind in patients having a history of gastrojejunostomy with severe abdominal pain or upper gastrointestinal bleeding.

Correlation between clinical activity score and thyroid autoantibodies in patients with thyroid ophthalmopathy

To investigate the relation between clinical activity score (CAS) and thyroid autoantibodies of thyroid ophthalmopathy, we measured the level of TSH receptor antibody (TRAb), antithyroglobulin antibody (ATA), and antimicrosomal antibody (AMA) in 41 patients with thyroid ophthalmopathy. The results of thyroid autoantibodies level were compared with CAS. Under the multiple regression and correlation analysis among CAS and the levels of TRAb, ATA, and AMA, no correlation was shown in this study. In conclusion, there is no correlation of thyroid ophthalmopathy among CAS and the levels of TRAb, ATA, and AMA in our study. If we use these three kinds of thyroid autoantibodies to match the activity of thyroid ophthalmopathy, it seems to be inappropriate. Further search of other simplified index to reflect the activity of ophthalmopathy should be encouraged.

Prediction of gene therapy-induced tumor size changes by the vascularity changes measured using dynamic contrast-enhanced MRI

We studied the changes of tumor size after gene therapy treatment and its relationship with the changes of vascular volume as measured by dynamic contrast-enhanced magnetic resonance imaging (MRI), to investigate whether the vascular changes is predictive of tumor regression. The study was carried out using a spontaneously regressing rat tumor model (C6 Glioma grown subcutaneously in rats). Three rats were treated with recombinant adenoviruses expressing three genes, mouse interleukin 1-alpha (IL1-alpha), mouse interferon gamma (IFN-gamma), and human transforming growth factor beta (TGF-beta), one from each kind. Two rats were treated with saline as controls. Longitudinal studies were performed to monitor the changes of tumor volume (based on T(2)-weighted images) and the vascular volume (based on dynamic contrast enhanced images). In untreated animals, tumor regression was preceded by several days with a decrease in vascular volume. When the tumor growth was perturbed by expression of mouse IL-1alpha, the increase in vascular volume was correlated with the continuing growth in size, and the decrease in vascular volume was predictive of the onset of tumor regression. As new advances in immunotherapy in cancer treatment emerge, the ability to determine the efficacy of therapy as early as possible will enable optimization of treatment regiments. The vascularity changes measured by dynamic MRI may provide a means to serve for this purpose.

Antibiotic treatment of orbital cellulitis: an analysis of pathogenic bacteria and bacterial susceptibility

The proper choice of effective antibiotics is a mainstay for the treatment of orbital cellulitis. The lack of native data regarding the microorganism causing the infection and its antibiotic sensitivity prompted us to conduct this study. We retrospectively collected 29 cases of orbital cellulitis admitted to Chung-Ho Memorial Hospital of Kaohsiung Medical College from January 1994 to September 1998. The effectiveness of antibiotics with bacterial susceptibility was analyzed. Of the 29 cases, fifteen were male and fourteen female. The patients ranged in age from 7 months to 79 years (mean, 37.6 years). Sinusitis (9 cases, 31.0%) is the most common etiology. Fourteen cases received both medical and surgical treatments. Eighteen cases had purulent discharge from the infection areas sent for culture isolation of the microorganism. The culture positive rate was 50% (9 in 18 cases). The Staphylococcus aureus (5 cases) was the most common pathogen. The bacterial susceptibility test showed drug resistance of 100% for penicillin G (seven out of seven cases; 7/7), 100% for ampicillin (10/10), and 0% for amikacin (0/3) and vancomycin (0/7). Penicillin and ampicillin are not effective for those isolated bacteria. Oxacillin and gentamicin, frequently used in first line treatment, might encounter drug resistance in some cases. Amikacin and vancomycin, without any resistance in bacterial susceptibility tests, could be used in vision-threatening, critical, and intractable cases.

Kimura's disease of bilateral upper eyelids: a case report

We present a rare case of Kimura's disease of bilateral upper eyelids. A 41-year-old Chinese male had multiple masses over retroauricular, submandibular regions and bilateral upper eyelids since 13 years previously. Tumor recurred after each surgical excision, chemotherapy and Co 60 radiotherapy. Eosinophilia and elevation of blood immunoglobulin E (IgE) were noted in this admission. We operated on left upper eyelid to relieve the blocking of vision. A diffuse infiltration with numerous fibrotic bands was noted. Histological section showed a lymphoid hyperplasia, remarkable infiltration of eosinophils and proliferation of capillaries. Oral prednisolone 60 mg was given postoperatively. The patient had a satisfactory appearance and a relief of visual block.

Intraocular use of fluconazole in the management of ocular fungal infection

In this study, we investigate the efficacy and safety of intraocular use of fluconazole in the treatment of ocular fungal infection. Ten patients with intraocular fungal infections were examined. Among these patients, eight were infected with keratomycosis with intraocular spreading, one had postoperative fungal endophthalmitis after cataract operation with an intraocular lens implant, and another suffered from endogenous fungal endophthalmitis. In addition to the conventional local application with or without systemic administration of antifungal drugs, all ten patients were treated with intraocular administration of 5-10 micrograms/ml of fluconazole. The ocular fungal infections resolved in nine patients without obvious side effect. One failed in the antifungal treatment with loss of vision. In our experience, the results revealed that fluconazole is a safe and effective antifungal agent that can be administered intraocularly. We suggest that intraocular administration of this drug could be considered as an alternative or additional choice for the treatment of severe ocular fungal infections.

Indocyanine green clearance test in non-cirrhotic hepatitis patients: a comparison and analysis between conventional blood sampling method and Finger Piece Monitoring method

BACKGROUND

The indocyanine green (ICG) Finger Piece Monitor system is a non-invasive method for measuring blood ICG concentrations for the evaluation of hepatic function. This study was conducted to determine its clinical usefulness in non-cirrhotic patients.

METHODS

Traditional liver function tests, alpha-fetoprotein, prothrombin time, and ICG clearance tests, by both blood sampling method and Finger Piece Monitoring method were performed simultaneously on 56 non-cirrhotic hepatitis patients. The plasma clearance rate (K) and 15-minute retention ratio (R15) of ICG were analyzed and compared with traditional liver function test results.

RESULTS

The clearance rate using the Finger Piece Monitoring method was slightly lower than that of the blood sampling method (9.16 +/- 5.00%/min vs. 11.24 +/- 3.56%/min) with good correlation (r = 0.721, p = 0.0003). The 15-minute retention ratio using the Finger Piece Monitoring method showed better correlation with blood sampling method (32.83 +/- 23.99% vs. 28.49 +/- 23.74%, r = 0.944, p = 0.0002). Analysis between traditional laboratory tests and fR15 revealed a higher fR15 value in patients with bilirubin-total-T > or = 3 mg/dl (49.71 +/- 26.22% vs. 22.23 +/- 13.48%), alpha-fetoprotein > or = 100 ng/ml (61.96 +/- 15.84% vs. 28.52 +/- 21.74%), and PT prolongation > or = 3 sec (71.46 +/- 16.80% vs. 29.03 +/- 21.06%).

CONCLUSION

There is a good correlation between the conventional blood sampling method and the ICG Finger Piece Monitoring system method. The ICG Finger Monitoring system provides an alternative for traditional laboratory tests for the evaluation of hepatic dysfunction in hepatitis patients.

Characterization of N-ethyl-N-nitrosourea-induced malignant and benign breast tumors in rats by using three MR contrast agents

A carcinogen (N-ethyl-N-nitrosourea)-induced animal tumor model was established to grow malignant and benign breast tumors. In each tumor the pharmacokinetic characteristics were measured by using three contrast agents, gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA; <1 kD), Gadomer-17 (35 kD), and albumin-Gd-DTPA (70-90 kD). Infiltrating ductal carcinomas (IDC) with low, medium, and high Scarf-Bloom-Richardson grades and fibroadenomas (FA) were analyzed. We found that Gd-DTPA could differentiate between FA and malignant tumors, but not between malignant tumors of low and high grades. In contrast, the intermediate size agent Gadomer-17 could differentiate between high-grade and low-grade IDC, but not between low-grade IDC and FA due to their similar enhancement patterns (despite their different origins). The largest agent, albumin-Gd-DTPA, was capable of differentiating both, but the low contrast-to-noise ratio was its major technical concern. The results in this breast tumor model suggest that macromolecular agents provide useful information for differential diagnosis among IDCs of various grades, but they do not provide superior information than Gd-DTPA for differential diagnosis between IDC and FA.

Investigation of longitudinal vascular changes in control and chemotherapy-treated tumors to serve as therapeutic efficacy predictors

The impact of chemotherapy on longitudinal vascular changes taking place during the growth of an animal tumor, R3230 AC adenocarcinoma, was investigated. Two contrast agents of different molecular weights, gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA; < 1 kD) and gadomer-17 (35 kD), were used in the dynamic imaging studies. Enhancement kinetics were analyzed by a pharmacokinetic model to derive parameters related to vascular volume and permeability on a pixel-by-pixel basis. Responders and non-responders were separated according to tumor size 10 days after the therapy. Changes in the vascular volume measured by gadomer-17 at 4 days after therapy revealed a clear distinction between the controls and the responders/non-responders. Mean vascular volume decreased by 42% in responders but was not significantly changed in the controls. The one non-responder had increased vascular volume after chemotherapy. Enhancement kinetics of gadomer-17 detected the changes earlier and with greater sensitivity than Gd-DTPA. In the control group, vascular permeability determined by gadomer-17 correlated with the longitudinal growth rates of tumors, suggesting that vascular permeability assessed by gadomer-17 could potentially serve as an indicator of aggressive tumor growth.

Measurement of tumor vascular volume and mean microvascular random flow velocity magnitude by dynamic Gd-DTPA-albumin enhanced and diffusion-weighted MRI

Tumor vascular volume fraction and the magnitude of the mean microvascular random flow velocity were measured in an animal tumor model by combining dynamic Gd-DTPA-albumin enhanced MRI and diffusion-weighted MRI in conjunction with a compartmental modeling analysis. The vascular volume fraction maps were obtained from the dynamic Gd-DTPA-albumin enhanced MRI measurement. It was found that the vascular volume fraction for Walker 256 tumor was higher within the outgrowing rim and decreased towards the central region. The average value obtained from five animals was 0.062 +/- 0.009 ml/g. By using the vascular volume fraction from the Gd-DTPA-albumin enhanced MRI measurement, maps of the magnitude of the mean microvascular random flow velocity were obtained from the diffusion-weighted MRI measurements with the compartmental modeling analysis. The relative extravascular and intravascular contributions to the diffusion-weighted MRI signal were determined for three tissue groups with different Gd-DTPA-albumin enhancement characteristics, and the flow and molecular diffusion-induced attenuation factors for the intravascular compartment were also compared. The mean microvascular random flow velocity magnitude maps were obtained with an average value of 0.67 +/- 0.06 mm/s.

Magnetic resonance imaging of anatomic and vascular characteristics in a canine model of human aging

Dogs exhibit both neuroanatomical and cognitive changes as a function of age that parallel those seen in aging humans. This study describes in vivo changes in neuroanatomical and cerebrovascular characteristics of the canine brain as a function of age in a group of dogs ranging from 4 to 15 years old. Dynamic contrast-enhanced magnetic resonance imaging (MRI) was used to measure the kinetics of contrast agents in the brain. Measures of vascular volume and blood-brain barrier (BBB) permeability were derived from a pharmacokinetic analysis. Cortical atrophy and ventricular enlargement were characteristic features of the aged canine brain. Vascular volume did not vary as a function of age and BBB permeability exhibited a nonsignificant increasing trend with age. However, BBB dysfunction was detected in one middle-aged dog that in addition to having unusually large ventricles, demonstrated an early onset of diffuse senile plaques at postmortem. These findings indicate that BBB dysfunction detected by magnetic resonance imaging may be useful for predicting and potentially diagnosing early pathological conditions.

Risk factors of non-arteritic anterior ischemic optic neuropathy (NAION): ocular or systemic

We retrospectively analyzed 22 patients with non-arteritic anterior ischemic optic neuropathy (NAION) seen at Chung-Ho memorial hospital between 1994 and 1996 to investigate the risk factors of NAION. The risk factors were divided into two groups: ocular and systemic. The ocular factors include refractive state, intraocular pressure, and cup-disk ratio of fellow eye. The systemic factors include diabetes, hypertension and cardiovascular diseases. The analysis revealed: (1) only 22.6% of patients with NAION have systemic risk factors; (2) intraocular pressure is not specific to NAION; (3) most of fellow eyes (72.6%) have cup-disk ratio not more than 0.1; and (4) most patients (90.9%) are hyperopic or emmetropic, only 9% of patients are myopic in either affected or fellow eyes. The statistical comparison between ocular (including cup-disk ratio and refractive state) and systemic factors is significant. The correlation with systemic factors in our study was not so high as previous study had reported. On the contrary, crowding effect of small cup-disk ratio, which induces a vicious circle of generally circulatory compromised disk, may play an important role in NAION. Besides, hyperopic or at least emmetropic eyes are more prone to NAION than myopic eyes. This may be due to lack of flattening of the temporal excavation, therefore adding a predisposing factor to a generally circulatory compromised disk. The risk factors associated with NAION seem more strongly correlated with ocular factors than with systemic factors.

Tumor characterization with dynamic contrast-enhanced MRI using MR contrast agents of various molecular weights

Dynamic contrast-enhanced MR imaging was used to measure the kinetics of enhancement in three different animal tumor models (Walker 256, R3230 AC, MCF7) using three different Gd complexes (Gd-DTPA, Gd-DTPA-24-cascade-polymer 30 kD, and polylysine-Gd-DTPA 50 kD). The three tumor models varied in growth rate, with the most rapid growth demonstrated by Walker 256 cells and the slowest growth occurring in the MCF7 cells. For each tumor, the kinetics of enhancement using polylysine-Gd-DTPA was analyzed using a pharmacokinetic model to estimate the vascular volume of the tumor. The rate of entry of the contrast agent into the interstitial space served as the measure of vascular permeability. The smallest molecular-weight agent, Gd-DTPA, could not provide information about vascular permeability. The intermediate and the largest agents both demonstrated that the faster-growing Walker 256 tumor had greater vascular permeability than did the slower-growing R3230 AC tumor. The degree of vascular permeability in the MCF7 tumor could not be assessed fairly due to insufficient statistics. The current study provides evidence supporting the hypothesis that more rapidly growing tumors have higher vascular permeability than do tumors that grow more slowly.

Pharmacokinetic changes induced by vasomodulators in kidneys, livers, muscles, and implanted tumors in rats as measured by dynamic Gd-DTPA-enhanced MRI

The effects of three physiologically different vasomodulators, angiotensin II (a vasoconstrictor), hydralazine (a vasodilator), and histamine (a permeability modulator), on the pharmaco-kinetics of entry of small molecules (measured by Gd-DTPA concentration) into normal and abnormal tissue were studied in rats implanted with R3230 AC tumors. Sequential dynamic Gd-DTPA-enhanced MRI studies, one before and one after vasomodulator administration, were performed, and the signal intensities of various tissues analyzed. Angiotensin II (6 micrograms/kg) reduced blood flow in tumors, but increased it in muscles. Hydralazine (5 mg/kg) reduced blood flow in tumors, kidneys, and livers, and slowed Gd-DTPA clearance from tumors, livers, and muscles. Histamine (25 micrograms/kg) increased renal blood flow, hastening Gd-DTPA clearance causing reduced measurable blood flow in tumors and muscles. By simultaneously monitoring the effects in various tissues, the pharmacokinetic effect of each drug in the entire body could be obtained.

[Unusual spontaneous dural cavernous sinus fistula between right external carotid artery and left cavernous sinus--a case report]

A 64 year-old female had left exophthalmos which resulted from a spontaneous dural cavernous sinus fistula between the right external carotid artery and left cavernous sinus. The left cavernous sinus was fed directly from internal maxillary branches of right external carotid artery with the sparing of right cavernous sinus and intracavernous sinus. Symptoms and signs of dural cavernous sinus fistula developed slowly in the left eye only. Although this kind of spontaneou dural cavernous sinus fistula is very rare. The possibility of arterial feeding from contralateral carotid artery should not be ignored in any patient that is suffered from dural cavernous sinus fistula while angiographic study is performed.

Regional comparison of tumor vascularity and permeability parameters measured by albumin-Gd-DTPA and Gd-DTPA

Sequential albumin-Gd-DTPA and Gd-DTPA dynamic enhancement studies were performed in an animal tumor model for the comparison of regional vascularity and permeability parameters measured by these two different sizes of contrast agents. The early albumin-Gd-DTPA enhancement arises from the vascular compartment, and the averaged signal enhancement derived from the first 3 to first 6 images postinjection can be reliably used to assess vascularity. The signal intensity in the images during the period of 5-10 min post-albumin-Gd-DTPA injection shows a steady linear variation. The intercept of the linear relationship is another indicator of the vascularity and the slope represents the tumor permeability to albumin-Gd-DTPA. The Gd-DTPA enhancement study was analyzed by a two-compartmental pharmacokinetic model to calculate the regional vascularity and permeability. The permeability parameters measured from albumin-Gd-DTPA and Gd-DTPA show an excellent correlation. The vascularity parameters measured from albumin-Gd-DTPA show good linear correlation with the low vascularity groups measured by Gd-DTPA, but show saturation for the high vascularity groups. The enhancement mechanisms for both contrast agents are discussed to relate the imaging parameters to the physiological variables.

Measurement of vascular volume fraction and blood-tissue permeability constants with a pharmacokinetic model: studies in rat muscle tumors with dynamic Gd-DTPA enhanced MRI

We propose a compartmental model to explain the signal enhancement curves following the bolus injection of Gd-DTPA. The model incorporates vascular volume fraction contribution, and the possibility of having different transport constants between the plasma and extravascular components. A Walker 256 carcinoma grown in rat muscle was used to demonstrate the capability of this model. Several different types of tissues were included in the measurements: normal, quickly enhanced, slowly enhanced, and necrotic tissues. Blood volume and blood-tissue permeability information can be derived from the dynamic contrast-enhanced MRI study employing the proposed model. In the tissue contrast enhancement curve, the initial rising slope after injection is related to the blood volume (or, vascular volume fraction), the maximum enhancement ratio is related to the uptake of tissue, and the decay rate is related to the clearance of tracer from tissue. The measured permeability constant is not the conventional permeability; instead they are contrast agents uptake and clearance rates, which are limited by the blood perfusion. These parameters can be used to characterize different enhancement patterns.

Use of Gore-Tex sling in brow suspension procedure

A variety of materials have been employed for brow suspension surgery for ptosis. Gore-Tex (expanded polytetrafluoroethylene ePTFE) has been used as vascular prosthesis. We have used cylinder Gore-Tex in brow suspension surgery for 15 ptotic eyelids (11 patients), including 10 eyes (8 patients) of congenital ptosis, 1 eye of traumatic ptosis in a young male, and 4 eyes (2 patients) of myogenic ptosis in elderly patients. All of the eyelids had minimal or absent levator muscle function, and drooped to cover the visual axes. The surgical technique for the 10 congenital ptotic eyelids was a modified Fox's method. The remaining 5 adult eyelids were operated by a modified Crawford's method, with interlocking of the two suspension bands at the lower apex of each triangle and direct suturing of the bands to the tarsal plate. The use of Gore-Tex in brow suspension makes it easy to adjust the height and contour of the operated eyelids. Patients were followed-up from 2 to 16 months (average 9.1 months) postoperatively. The only complication was granuloma formation at the most upper knot area in 5 patients (6 eyelids), one of which also had granuloma at the ipsilateral fornix with the Gore-Tex band cutting through the conjunctiva. One eyelid drooped due to knot granuloma and infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Statistical description of microcirculatory flow as measured with an MR method

Quantification of microcirculatory flow is important for the functional assessment of biologic systems. The authors describe a method of analyzing the dependence of the magnetic resonance (MR) signal intensity on microcirculatory flow. A gel bead phantom was used to simulate the randomly oriented flow capillaries, and the MR signal intensity of the phantom was studied at different flow velocities by using velocity-sensitized and -compensated spin-echo pulse sequences. A theoretical model based on the spin-phase phenomenon is proposed to elucidate the effect of flow on signal intensity. The velocity phase of a spin depends on its path and the corresponding velocity-encoding gradients. A Monte Carlo simulation was used to generate the path of a spin on the basis of a statistical model for flow through a random capillary network. From the velocity-phase distribution of a group of spins within a voxel, the signal attenuation due to flow can be calculated. The results of the statistical model and experimental measurements agreed well. Also, T1 and T2 effects in MR flow measurements were investigated. The current study provides a theoretical framework for understanding MR measurements of microcirculatory flow.

Susceptibility effects in porous media in the presence of flow

Magnetic resonance (MR) imaging of microvascular flow is an important topic in biomedicine because it permits access to the functional state of a biologic system. The internal heterogeneous magnetic field due to susceptibility differences within tissues is one of the factors that can affect signal intensity. A glass bead phantom simulating a porous medium was used to experimentally study the effect of the internal magnetic field on MR flow measurements. A physical model was developed to simulate the paths of the moving spins and the local magnetic field distribution in the medium to estimate the signal intensity with spin-phase analysis. The susceptibility variation inside the glass bead phantom was estimated by comparing the simulation results with the experimental data. Experiments were also performed with a tissue-simulating phantom, and the results indicated that the effect of the internal field inhomogeneity on in vivo microvascular flow measurements was negligible.

A new device of incentive spirometry

Incentive spirometry is a feedback system to encourage patients to take a deep breath and produce a sustained maximal inspiration (SMI) for the primary purpose of opening and stabilizing atelectatic areas of the lung. However, currently available incentive devices are not reusable, expensive, and emphasize inspiratory effort only. We have designed a new device of incentive spirometer based on pursed-lip breathing technique. The device consists of a piece of paper hanging on a frame. The patient is instructed to take a deep and slow inspiration followed by holding the breath for 5 seconds. Then, using pursed-lip technique, the patient generates a flow to keep the paper attached to a bar as long as possible. The duration of paper blowing is recorded and is compared with vital capacity. In the present study 96 cases were recorded. Vital capacity was correlated well with paper blowing time (multiple regression test r = 0.87, p less than 0.0001). The advantages of our device include (1) reusibility and less cost, (2) equal emphasis of both inspiration and expiration, and (3) being especially helpful for patients with chronic obstructive lung disease (COPD). This is a preliminary result and further clinical study is needed.

[Intraocular lens implantation at Kaohsiung Medical College]

Between March 1984 and December 1987, 993 cataractous eyes in 884 patients (462 males, 422 females) were operated on using intraocular lens implantation at the Kaohsiung Medical College Hospital. The age of the patients ranged from half year to 93 years, with an average of 61.9 years. Primary lens implantation was performed in 98.4% of the cases, secondary implantation in 1.6% of the cases. There were 6 cases were done by using the triple procedure (combined keratoplasty with cataract extraction and intraocular lens implantation). Among these 742 eyes followed-up for from one to 43 months, final vision could be corrected to 6/12 or better in 63.5% of the cases. While 64.4% of the cases of post-operation cylinder were less than 2 diopters, the final refraction showed that the spherical equivalent diopters were within 2 diopters in 61.7% of the cases. Complications in the anterior chamber lens group included pupillary changes (21.2%), pseudophakic bullous keratopathy or decompensation (13.5%), lens subluxation or dislocation (13.5%) and cystoid macular edema (5.8%). Complications in the posterior chamber lens group included pupillary changes (16.2%), posterior capsular thickening (3.2%), anterior or posterior synechiae (2.7%) and lens subluxation or dislocation (2.8%).

Passive optical detection of meteorological parameters in launch vehicle environments

New optical detection systems are being developed which combine conventional passive photometry with advanced data processing and statistical analysis methods. These crossed-beam detection systems can continuously monitor meteorological parameters in rocket or aircraft environments. The outputs from several photometers are analyzed by cross correlation techniques to retrieve the transit times or transit distance of light emitting, absorbing, or scattering particles between the photometer lines of sight. These transit times and distances are then transformed into wind components and turbulence levels for preselected altitudes. A continuous near real time display of these meteorological parameters is also under development.