Design, Transport/Molecular Scale Electronics, Electric Properties, and a Conventional Quantum Study of a New Potential Molecular Switch for Nanoelectronic Devices.

In this study, we examined the influence of an external electric field applied in two directions: horizontal (X-axis) and vertical (Y-axis) on the electronic and vibrational properties of a field-effect molecular switch, denoted as M. We employed density functional theory and quantum theory of atoms in molecules for this analysis. The current-voltage (I-V) characteristic curve of molecular switch system M was computed by applying the Landauer formula. The results showed that the switching mechanism depends on the direction of the electric field. When the electric field is applied along the X-axis and its intensity is around 0.01 au, OFF/ON switching mechanisms occur. By utilizing electronic localization functions and localized-orbital locator topological analysis, we observed significant intramolecular electronic charge transfer "back and forth" in Au-M-Au systems when compared to the isolated system. The noncovalent interaction revealed that the Au-M-Au complex is also stabilized by electrostatic interactions. However, if the electric field is applied along the Y-axis, a switching mechanism (OFF/ON) occurs when the electric field intensity reaches 0.008 au. Additionally, the local electronic phenomenological coefficients (Lelec) of this field-effect molecular switch were determined by using the Onsager phenomenological approach. It can also be predicted that the molecular electrical conductance (G) increases as Lelec increases. Finally, the electronic and vibrational properties of the proposed models M and Au-M-Au exhibit a powerful switching mechanism that may potentially be employed in a new generation of electronic devices.

Design, synthesis, and density functional theory studies of a new selective chemosensor for Pb2.

Herein, we have focused on a new colorimetric ligand synthesized from the reaction of 2-hydroxy-5-methylbenzene-1,3-dialdehyde with 2-amino-thiophenol, and investigated its activity as a sensor. In this regard, the sensory activity of the ligand towards different ions (Mn2+, Cu2+, Co2+, Fe2+, Fe3+, Zn2+, Ni2+, Cd2+, Ag+, Na+, Cs+, Mg2+, Al3+, Ba2+, K+, and Pb2+) was studied. The specificity of ion bindings is discussed through UV-Vis analysis. The ligand that was synthesized showed remarkable sensitivity, with a detection limit of 0.001 ppb. Additionally, the presence of Pb2+ ions can be visually detected through a color change from colorless to yellow. In the last part of this work, we seek to predict the available experimental measurements. Density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) are employed to examine the bonding between the ligand and the Pb2+ ion. The effect of water solvent was thoroughly examined for all the steps via the conductor-like Polarizable Continuum Model (CPCM). The theoretical findings revealed that electronic properties, including energy gap, adsorption energy, charge/energy transfer, and optical characteristics, undergo significant changes when Pb2+ cations are present. Hence, it can be inferred that the newly synthesized chemosensor (NC) is highly efficient in detecting Pb2+.

Molecular modeling of the structural, electronic, excited state dynamic, and the photovoltaic properties of the oligomers of n-corannulene (n = 1-4).

Despite the fact that n-corannulene oligomers (n = 1-4) have a variety of electronic and optical properties, including the ability to be tuned and the potential to be used as light-harvesting materials, there has not been a computational assessment of their structural, electronic, and optical properties. Herein, a computational evaluation of the concerned materials regarding their potent use in solar cell technology has been conducted via DFT/CAM-B3LYP and M062X/6-311+G level of theory. It was observed that the calculated 1st frequency of the n-Corannulene (n = 1-4) were 144.15, 106.36, 48.96 and 42.21 respectively. Notably, the computed cohesive energy value increased as the number of Corannulene units increases while the electronic characteristics revealed that the chemical activity of the structures increased as the number of oligomers rose. Both calculation techniques demonstrate that the number of n-Corannulene oligomers increases the HOMO energy while decreasing the LUMO energy based on the external electric field (EF) effect. The findings demonstrated that as EF intensity increases, the energy gap (Eg/eV = |EHOMO-ELUMO|) of these molecular systems decreases which can be attributed to a decrease in the electron transfer potential barrier. The 4-Corannulene systems showed the highest wave length of adsorption for the investigated compound at 546.18 nm, with the highest oscillator strength of 0.2708 and the lowest transition energy of 2.2700 eV, arising from S0-S1 (H-L) and the highest major percentage contribution of 93.34 % in comparison to the investigated compounds. We are hopeful that this research will help experimental researchers understand the potential of n-Corannulene, specifically 4-corannulene, as powerful material for a variety of applications ranging from solar cell, photovoltaic properties and many others.

Optic Disc Edema and Elevated Intracranial Pressure (ICP): A Comprehensive Review of Papilledema.

Papilledema is a swelling of the optic disc secondary to elevated intracranial pressure (ICP). We analyzed 79 peer-review journal articles and provided a concise summary of the etiology, epidemiology, pathophysiology, clinical presentation, evaluation, natural history, differential diagnosis, treatment, and prognosis of papilledema. Only studies written in English with the full text available were included. Although many etiologies of papilledema exist, idiopathic intracranial hypertension is the most common and, thus, a large focus of this review.

Report of cerebral vasospasm as a complication of intracranial subarachnoid hemorrhage following traumatic lumbar puncture.

Background: This case report is the first documented and illustrated case of the identification and treatment of intracranial vasospasm as a sequalae of traumatic lumbar puncture (LP). LP is a routine procedure performed for both diagnostic and therapeutic purposes. Although rare, this procedure has risks and complications that should be considered before performing. Case Description: A 58-year-old male was found to have intracranial subarachnoid hemorrhage (SAH) 2 days after a traumatic LP which occurred in the setting of subtherapeutic international normalized ratio. During his hospitalization, the patient developed both clinical and radiographic signs of vasospasm. He was taken for angiography, which demonstrated significant vasospasm of bilateral middle cerebral arteries and bilateral anterior cerebral arteries. All vasospasms resolved and the patient improved clinically after intra-arterial spasmolytic therapy. Conclusion: LP is a routine procedure with complications that are often overlooked. The authors describe intracranial vasospasm from traumatic LP before correction of patient's coagulopathy. Cases with similar hemorrhage occurring in the spine resulting in non-aneurysmal SAH and vasospasm were reviewed.

Intraoperative localization and "snowman" muscle pledget repair for ventral dural defect in a case of spontaneous intracranial hypotension.

BACKGROUND: This image report with technical notes is the first to illustrate and describe the technique used to treat spinal cerebrospinal fluid (CSF) leaks with the "snowman" muscle pledget. A 49-year-old male presented with orthostatic headaches as well as the left abducens nerve palsy. Patient's workup including findings of diffuse meningeal enhancement on magnetic resonance imaging, lumbar puncture opening pressure of 4 cm H2O, and CT myelogram demonstrating evidence of ventral spinal thoracic CSF leak. CASE DESCRIPTION: Procedure took place in a hybrid biplane operating room so that simultaneous digital subtraction myelogram may also be performed for intraoperative localization. Dural defect was identified intraoperatively and repaired with thoracic laminectomy and "snowman" muscle pledget technique. Postoperatively, the patient did well with resolution of his symptoms. CONCLUSION: The authors have proposed a grading scale to aid in the work up and management of intracranial hypotension. The use of a hybrid biplane operating room and "snowman" muscle pledget technique is a safe and effective technique to treat spontaneous spinal CSF leaks resulting from dural defects.

Cerebral vascular malformations and their imaging modalities.

Cerebrovascular malformations are uncommon diverse group of dysmorphic vascular communications that may occur sporadically or as part of genetic syndromes. These include non-neoplastic lesions such as arteriovenous malformations (AVM), cavernous malformations (CM), developmental venous anomalies (DVA), and telangiectasias as well as others like arteriovenous fistulas (AVF), vein of Galen malformations (VOGM), and mixed or unclassified angiomas. These lesions often carry a high degree of morbidity and mortality often requiring surgical or endovascular interventions. The field of cerebrovascular anomalies has seen considerable advancement in the last few years. Treatment and management options of various types of brain anomalies have evolved in neurological, neurosurgical, and neuro-interventional radiology arena. The use of radiological imaging studies is a critical element for treatment of such neurosurgical cases. As imaging modalities continue to evolve at a rapid pace, it is imperative for neurological surgeons to be familiar with current imaging modalities essential for a precise diagnosis. Better understanding of these cerebrovascular lesions along with their associated imaging findings assists in determining the appropriate treatment options. In the current review, authors highlight various cerebrovascular malformations and their current imaging modalities.

Patient Perspectives on the Participation of Neurosurgery Resident Physicians in Their Care.

Introduction Surgical residents play vital roles in day-to-day patient care as well as in the operating room. However, there is a paucity of literature regarding patients' perspectives on neurosurgical residents and their participation in their care. This current study investigates the knowledge, attitudes, and beliefs of patients regarding neurosurgical residents and their involvement in their healthcare process. Methods Patients older than 18 years who had undergone brain or spine surgery were requested to complete a survey questionnaire. The 7-point Likert scale response ranging from "strongly agree", "agree", "more or less agree", "undecided", more or less disagree", "disagree" to "strongly disagree" was used. The primary objective was to assess patient understanding and attitudes towards resident participation in surgical and medical care within the specialty of neurosurgery. The duration of the study was eight months. Patients having prior exposure to an informed-consent procedure by a neurosurgery team within a year prior to this study were excluded. Data were analyzed using Student's t-test, one-way analysis of variance (ANOVA), and standard averaging of responses. Results Fifty-one patients who had undergone elective surgery participated in the study survey. The majority of these respondents were between the ages of 46 and 60 years. Most of the responses were similar across gender and different age groups for most of the questions on the Likert scale questionnaire. Overall, when asked to assess their comfort level in medical and surgical care participation by residents, patients responded positively (strongly agree: 80.4%; agree: 92.2%). Patients also either disagreed or strongly disagreed (76%) about residents lacking medical knowledge. Patients overwhelmingly disagreed (91.5%) when asked if residents were unprofessional. In addition, 72.5% of the patients were able to accurately define a resident's role. Conclusion Well-formatted surveys can offer a convenient route for patients to provide objective as well as subjective feedback. The results indicate that patients had an overall positive attitude toward having residents involved in their care. These trends also indicate that patients knew the role that residents played in their healthcare process and they were comfortable with them doing so. Further studies may expand the trial to include a larger number of patients, as well as other specialties, to expand the scope of the study. Patient survey questionnaires could be thought of as a useful tool by the Accreditation Council for Graduate Medical Education (ACGME) to incorporate as part of the evaluation process of resident physicians.

Congenital Aneurysm of the Left Sinus of Valsalva Involving the Left Main Coronary Artery.

Successful surgical management of a case of congenital aneurysm of the left sinus of Valsalva involving the left main coronary artery has been reported. To our knowledge, this is the first report describing an unusual case of congenital aneurysm of the left sinus of Valsalva, which involves the left main coronary artery.

In vivo antioxidant and antiulcer activity of Parkia speciosa ethanolic leaf extract against ethanol-induced gastric ulcer in rats.

BACKGROUND: The current study was carried out to examine the gastroprotective effects of Parkia speciosa against ethanol-induced gastric mucosa injury in rats. METHODOLOGY/PRINCIPAL FINDINGS: Sprague Dawley rats were separated into 7 groups. Groups 1-2 were orally challenged with carboxymethylcellulose (CMC); group 3 received 20 mg/kg omeprazole and groups 4-7 received 50, 100, 200 and 400 mg/kg of ethanolic leaf extract, respectively. After 1 h, CMC or absolute ethanol was given orally to groups 2-7. The rats were sacrificed after 1 h. Then, the injuries to the gastric mucosa were estimated through assessment of the gastric wall mucus, the gross appearance of ulcer areas, histology, immunohistochemistry and enzymatic assays. Group 2 exhibited significant mucosal injuries, with reduced gastric wall mucus and severe damage to the gastric mucosa, whereas reductions in mucosal injury were observed for groups 4-7. Groups 3-7 demonstrated a reversal in the decrease in Periodic acid-Schiff (PAS) staining induced by ethanol. No symptoms of toxicity or death were observed during the acute toxicity tests. CONCLUSION: Treatment with the extract led to the upregulation of heat-shock protein 70 (HSP70) and the downregulation of the pro-apoptotic protein BAX. Significant increases in the levels of the antioxidant defense enzymes glutathione (GSH) and superoxide dismutase (SOD) in the gastric mucosal homogenate were observed, whereas that of a lipid peroxidation marker (MDA) was significantly decreased. Significance was defined as p<0.05 compared to the ulcer control group (Group 2).

Cytotoxic prenylated acetophenone dimers from Acronychia pedunculata.

Three new acetophenone dimers or Acronychia-type acetophenones, acropyrone (1), acropyranol A (2), and acropyranol B (3), were isolated from the trunk bark of Acronychia pedunculata and structurally characterized, together with four known acetophenone dimers, acrovestone (4), acrovestenol (5), acrofolione A (6), and acrofolione B (7), the acetophenone monomer acronyline (8), and four furoquinoline alkaloids. The chemical structures of the new isolated compounds were elucidated unambiguously by spectroscopic data analysis. The cytotoxic activities of the isolated acetophenone dimers were evaluated against the DU145 prostate and A2058 melanoma human cancer cell lines as well as the NHDF normal cell line. Acrovestone (4) and acrovestenol (5) exhibited substantial cytotoxicity, with IC(50) values of 0.38 and 2.8 µM against A2058 melanoma cells as well as 0.93 and 2.7 µM against DU145 prostate cancer cells, respectively.

Free radical scavenging, antimicrobial and immunomodulatory activities of Orthosiphon stamineus.

Orthosiphon stamineus is considered an important traditional folk medicine. In this study ethanol and aqueous extracts of O. stamineus were evaluated in vitro for their antioxidant, antimicrobial as well as for their immunomodulatory properties on human peripheral blood mononuclear cells (PBMCs). The DPPH radical scavenging method was used for the determination of antioxidant activity, while the antibacterial efficacy was investigated by both disc diffusion method and Minimum Inhibitory Concentration (MIC) against four bacterial strains (Gram-positive and Gram-negative). Furthermore, the immunomodulatory potential of the extracts was investigated through the MTT assay. Aqueous extract of O. stamineus exhibited significant free radical scavenging activity with IC50 50 9.6 µg/mL, whereas the IC50 for the ethanol extract was 21.4 µg/mL. The best antimicrobial activity was shown by the aqueous extract of O. stamineus against Staphylococcus aureus, with inhibition zone of 10.5 mm and MIC value 1.56 mg/mL. Moreover, the results observed from the MTT assay showed that both plant extracts stimulated the PBMCs proliferation in vitro in a concentration-dependent manner, but the aqueous extract has remarkable activity against PBMCs. These findings indicate that O. stamineus showed high antioxidant activity and may be considered as an immunomodulatory agent.

A Dimeric sesquiterpenoid from a Malaysian Meiogyne as a new inhibitor of Bcl-xL/BakBH3 domain peptide interaction.

In an effort to find potent inhibitors of the antiapoptotic protein Bcl-xL, a systematic in vitro evaluation was undertaken on 1470 Malaysian plant extracts. The ethyl acetate extract obtained from the bark of Meiogyne cylindrocarpa was selected for its interaction with the Bcl-xL/Bak association. Bioassay-guided purification of this species led to the isolation of two new dimeric sesquiterpenoids (1 and 2) possessing an unprecedented substituted cis-decalin carbon skeleton. Meiogynin A (1) showed the strongest activity with a K(i) of 10.8 +/- 3.1 microM.

ent-Dioncophylleine A and related dehydrogenated naphthylisoquinoline alkaloids, the first Asian dioncophyllaceae-type alkaloids, from the "new"plant species Ancistrocladus benomensis.

Three new fully dehydrogenated naphthylisoquinoline alkaloids, the 7,1'-coupled ent-dioncophylleine A (3a), the likewise 7,1'-coupled 5'-O-demethyl-ent-dioncophylleine A (4), and the 7,8'-linked dioncophylleine D (5), have been isolated from the leaves of the recently described Malaysian highland liana Ancistrocladusbenomensis. All of them lack an oxygen function at C-6; this so-called Dioncophyllaceae-type structural subclass had previously been found only in naphthylisoquinoline alkaloids from West and Central African plants. Moreover, compounds 3a and 4 are the first fully dehydrogenated, i.e., only axially chiral, naphthylisoquinoline alkaloids of this type that are optically active; compound 5, by contrast, is fully racemic, due to its configurationally unstable biaryl axis. The structural elucidation was achieved by spectroscopic and chiroptical methods. Biological activities of these alkaloids against different protozoan parasites are described.

Ancistrobenomine a, the first naphthylisoquinoline oxygenated at Me-3, and related 5,1'-coupled alkaloids, from the "new" plant species ancistrocladusbenomensis.

Three new 5,1'-coupled naphthylisoquinoline alkaloids, ancistrobenomine A (1), 6-O-demethylancistrobenomine A (2), and 5'-O-demethylancistrocline (3), have been isolated from the stem bark of a botanically as yet undescribed highland liana Ancistrocladus sp., proposed to be named "A. benomensis" according to the region in Peninsular Malaysia where it has been discovered on the mountain of Gunung Benom. Two of the compounds possess an unprecedented structure with a novel hydroxymethylene group at C-3 of the fully dehydrogenated isoquinoline moiety. The structural elucidation was achieved by chemical, spectroscopic, and chiroptical methods. As typical of the so-called Ancistrocladaceae type, all of the compounds isolated bear an oxygen at C-6. Biological activities of these alkaloids against different protozoic pathogens are described.

Adnexal masses and pregnancy: a 12-year experience.

OBJECTIVE: Our purpose was to describe pregnancy-associated adnexal masses in eastern North Carolina. STUDY DESIGN: A retrospective study was performed of 60 adnexal masses resected during pregnancy at a regional referral hospital from January 1990 to March 2002. RESULTS: Adnexal masses occurred in 0.15% of pregnancies. Average gestational age at diagnosis and surgery was 12 and 20 weeks, respectively. Fifty percent of ovarian tumors were mature cystic teratomas, 20% were cystadenomas, and 13% were functional ovarian cysts. Malignancy occurred in 13%. Tumors with low malignant potential comprised 63% of malignancies. Average cyst size was 11.5 cm for malignancies and 7.6 cm for benign lesions (P value <.05). The preterm birth rate was 9%, the miscarriage rate was 4.7% after elective cases, and average Apgar scores were 7.5 and 8.7 at 1 and 5 minutes. CONCLUSION: The incidence of malignancy in pregnancy-associated adnexal masses was high. Ultrasonography detected internal excrescences in the majority of tumors with low malignant potential. Fetal outcomes were not affected.

Acylated flavonol glycosides from leaves of Planchonia grandis.

Three acylated flavonol glycosides have been identified from leaves of Planchonia grandis Ridley. They possess kaempferol as aglycone and two triglycosidic chains substituting hydroxyl groups at the 3- and 7-positions. The first glycosidic unit of each chain is esterified by a cis or trans p-coumaric acid. Structural elucidation was achieved by means of UV, NMR and mass spectrometry.