Phenylalanine-Assisted Conductivity Enhancement in PEDOT:PSS Films.

Biological materials such as amino acids are attractive due to their smaller environmental footprint, ease of functionalization, and potential for creating biocompatible surfaces for devices. Here, we report the facile assembly and characterization of highly conductive films of composites of phenylalanine, one of the essential amino acids, and PEDOT:PSS, a commonly used conducting polymer. We have observed that introducing aromatic amino acid phenylalanine into PEDOT:PSS to form composite films can improve the conductivity of the films by up to a factor of 230 compared to the conductivity of pristine PEDOT:PSS film. In addition, the conductivity of the composite films can be tuned by varying the amount of phenylalanine in PEDOT:PSS. Using DC and AC measurement techniques, we have determined that the conduction in the highly conductive composite films thus created is due to improvement in the electron transport efficiency compared to the charge transport in pure PEDOT:PSS films. Using SEM and AFM, we demonstrate that this could be due to the phase separation of PSS chains from PEDOT:PSS globules which can create efficient charge transport pathways. Fabricating composites of bioderived amino acids with conducting polymers using facile techniques such as the one we report here opens up opportunities for the development of low-cost biocompatible and biodegradable electronic materials with desired electronic properties.

Safety and efficacy of the new CryoPop® cryotherapy device for cervical dysplasia in low- and middle-income countries: study protocol for a multicenter open-label non-inferiority clinical trial with historical controls.

BACKGROUND: Cervical cancer is the fourth most common cancer in the world, affecting mainly women residing in low- and middle-income countries. Progression from a pre-invasive phase to that of an invasive phase generally takes years and provides a window of opportunity to screen for and treat precancerous lesions. METHODS: This study is being conducted at four sites in north Karnataka, India. Community sensitization activities have been organized in the study areas to create awareness among stakeholders, including elected representatives, physicians, health care workers, and potential participants. Organized community based as well as hospital-based screening is being conducted using visual inspection with acetic acid (VIA). Screen positive women are referred to respective study hospitals for colposcopy and directed biopsy. Participants with confirmed high-grade cervical dysplasia (high-grade squamous intraepithelial lesions or HSIL) who fit all other eligibility criteria will be recruited to the study and will receive cryotherapy using CryoPop®, an innovative new cryotherapy device. DISCUSSION: There is a need to develop an inexpensive, simple, and effective cryotherapy device for use by frontline health care providers at locations where screening and timely treatment can be given, accelerating access to cervical cancer prevention services and minimizing loss to follow-up of women with precancerous lesions who need treatment. TRIAL REGISTRATION: Clinical Trial Registry - India CTRI/2019/01/017289 ClinicalTrials.Gov number NCT04154644 . Registered on November 6, 2019.

Electrical characterization of leaf-based wires & supercapacitors.

Electronic waste (e-waste) is a growing problem in the world due to increasing consumption and subsequent discarding of electronic devices. One of the ways to address this problem is to develop electronics made up of biodegradable components. Leaves are readily available, biodegradable and can be found with various types of architecture of the vascular conduits within. We investigated the possibility of developing electronic components based on leaves of a monocotyledon plant by introducing a conducting polymer inside the vascular conduits. We were able to construct conducting wires in those conduits extending to centimeters in length within a leaf. Furthermore, we were able to demonstrate the construction of a supercapacitor within a leaf by using the conducting conduits as electrodes. These results suggest the possibility of constructing embedded electronic components within leaves which may provide an alternative towards the development of biodegradable electronics.

Electrically conductive pili from pilin genes of phylogenetically diverse microorganisms.

The possibility that bacteria other than Geobacter species might contain genes for electrically conductive pili (e-pili) was investigated by heterologously expressing pilin genes of interest in Geobacter sulfurreducens. Strains of G. sulfurreducens producing high current densities, which are only possible with e-pili, were obtained with pilin genes from Flexistipes sinusarabici, Calditerrivibrio nitroreducens and Desulfurivibrio alkaliphilus. The conductance of pili from these strains was comparable to native G. sulfurreducens e-pili. The e-pili derived from C. nitroreducens, and D. alkaliphilus pilin genes are the first examples of relatively long (>100 amino acids) pilin monomers assembling into e-pili. The pilin gene from Candidatus Desulfofervidus auxilii did not yield e-pili, suggesting that the hypothesis that this sulfate reducer wires itself with e-pili to methane-oxidizing archaea to enable anaerobic methane oxidation should be reevaluated. A high density of aromatic amino acids and a lack of substantial aromatic-free gaps along the length of long pilins may be important characteristics leading to e-pili. This study demonstrates a simple method to screen pilin genes from difficult-to-culture microorganisms for their potential to yield e-pili; reveals new sources for biologically based electronic materials; and suggests that a wide phylogenetic diversity of microorganisms may use e-pili for extracellular electron exchange.

Expressing the Geobacter metallireducens PilA in Geobacter sulfurreducens Yields Pili with Exceptional Conductivity.

The electrically conductive pili (e-pili) of Geobacter sulfurreducens serve as a model for a novel strategy for long-range extracellular electron transfer. e-pili are also a new class of bioelectronic materials. However, the only other Geobacter pili previously studied, which were from G. uraniireducens, were poorly conductive. In order to obtain more information on the range of pili conductivities in Geobacter species, the pili of G. metallireducens were investigated. Heterologously expressing the PilA gene of G. metallireducens in G. sulfurreducens yielded a G. sulfurreducens strain, designated strain MP, that produced abundant pili. Strain MP exhibited phenotypes consistent with the presence of e-pili, such as high rates of Fe(III) oxide reduction and high current densities on graphite anodes. Individual pili prepared at physiologically relevant pH 7 had conductivities of 277 ± 18.9 S/cm (mean ± standard deviation), which is 5,000-fold higher than the conductivity of G. sulfurreducens pili at pH 7 and nearly 1 million-fold higher than the conductivity of G. uraniireducens pili at the same pH. A potential explanation for the higher conductivity of the G. metallireducens pili is their greater density of aromatic amino acids, which are known to be important components in electron transport along the length of the pilus. The G. metallireducens pili represent the most highly conductive pili found to date and suggest strategies for designing synthetic pili with even higher conductivities. IMPORTANCE: e-pili are a remarkable electrically conductive material that can be sustainably produced without harsh chemical processes from renewable feedstocks and that contain no toxic components in the final product. Thus, e-pili offer an unprecedented potential for developing novel materials, electronic devices, and sensors for diverse applications with a new "green" technology. Increasing e-pili conductivity will even further expand their potential applications. A proven strategy is to design synthetic e-pili that contain tryptophan, an aromatic amino acid not found in previously studied e-pili. The studies reported here demonstrate that a productive alternative approach is to search more broadly in the microbial world. Surprisingly, even though G. metallireducens and G. sulfurreducens are closely related, the conductivities of their e-pili differ by more than 3 orders of magnitude. The ability to produce e-pili with high conductivity without generating a genetically modified product enhances the attractiveness of this novel electronic material.

Synthetic Biological Protein Nanowires with High Conductivity.

Genetic modification to add tryptophan to PilA, the monomer for the electrically conductive pili of Geobacter sulfurreducens, yields conductive protein filaments 2000-fold more conductive than the wild-type pili while cutting the diameter in half to 1.5 nm.

The Low Conductivity of Geobacter uraniireducens Pili Suggests a Diversity of Extracellular Electron Transfer Mechanisms in the Genus Geobacter.

Studies on the mechanisms for extracellular electron transfer in Geobacter species have primarily focused on Geobacter sulfurreducens, but the poor conservation of genes for some electron transfer components within the Geobacter genus suggests that there may be a diversity of extracellular electron transport strategies among Geobacter species. Examination of the gene sequences for PilA, the type IV pilus monomer, in Geobacter species revealed that the PilA sequence of Geobacter uraniireducens was much longer than that of G. sulfurreducens. This is of interest because it has been proposed that the relatively short PilA sequence of G. sulfurreducens is an important feature conferring conductivity to G. sulfurreducens pili. In order to investigate the properties of the G. uraniireducens pili in more detail, a strain of G. sulfurreducens that expressed pili comprised the PilA of G. uraniireducens was constructed. This strain, designated strain GUP, produced abundant pili, but generated low current densities and reduced Fe(III) very poorly. At pH 7, the conductivity of the G. uraniireducens pili was 3 × 10(-4) S/cm, much lower than the previously reported 5 × 10(-2) S/cm conductivity of G. sulfurreducens pili at the same pH. Consideration of the likely voltage difference across pili during Fe(III) oxide reduction suggested that G. sulfurreducens pili can readily accommodate maximum reported rates of respiration, but that G. uraniireducens pili are not sufficiently conductive to be an effective mediator of long-range electron transfer. In contrast to G. sulfurreducens and G. metallireducens, which require direct contact with Fe(III) oxides in order to reduce them, G. uraniireducens reduced Fe(III) oxides occluded within microporous beads, demonstrating that G. uraniireducens produces a soluble electron shuttle to facilitate Fe(III) oxide reduction. The results demonstrate that Geobacter species may differ substantially in their mechanisms for long-range electron transport and that it is important to have information beyond a phylogenetic affiliation in order to make conclusions about the mechanisms by which Geobacter species are transferring electrons to extracellular electron acceptors.

Feasibility and Safety of Therapeutic Hypothermia and Short Term Outcome in Neonates with Hypoxic Ischemic Encephalopathy.

Therapeutic hypothermia is well known for neuroprotection in asphyxiated neonates with hypoxic ischemic encephalopathy. The authors aimed to study the feasibility and safety of therapeutic hypothermia and short term outcome in neonates with hypoxic ischemic encephalopathy (HIE). Total 31 neonates with moderate to severe HIE were enrolled in the study. Continuous temperature recording was noted in 31 neonates; 17 neonates were studied prospectively while 14 neonates were studied retrospectively. Rectal temperature was monitored in 31 neonates and maintained between 33 and 34 °C by switching off the warmer and using ice packs. Reusable ice packs were used which were inexpensive. Therapeutic hypothermia was maintained for 72 h and babies were then rewarmed 0.5 °C every hour. Therapeutic hypothermia was feasible and inexpensive. There was no major complication during the study. MRI was done in 17 neonates; 52 % were found to have normal MRI at the end of first week. Among the study neonates (n = 31) 64.5 % were neurologically normal at the time of discharge. To conclude, therapeutic hypothermia is feasible in a low resource setting and is a safe way of neuroprotection. Short term outcome was also favourable in these neonates.

Kinetics of Ion Transport in Perovskite Active Layers and Its Implications for Active Layer Stability.

Solar cells fabricated using alkyl ammonium metal halides as light absorbers have the right combination of high power conversion efficiency and ease of fabrication to realize inexpensive but efficient thin film solar cells. However, they degrade under prolonged exposure to sunlight. Herein, we show that this degradation is quasi-reversible, and that it can be greatly lessened by simple modifications of the solar cell operating conditions. We studied perovskite devices using electrochemical impedance spectroscopy (EIS) with methylammonium (MA)-, formamidinium (FA)-, and MA(x)FA(1-x) lead triiodide as active layers. From variable temperature EIS studies, we found that the diffusion coefficient using MA ions was greater than when using FA ions. Structural studies using powder X-ray diffraction (PXRD) show that for MAPbI3 a structural change and lattice expansion occurs at device operating temperatures. On the basis of EIS and PXRD studies, we postulate that in MAPbI3 the predominant mechanism of accelerated device degradation under sunlight involves thermally activated fast ion transport coupled with a lattice-expanding phase transition, both of which are facilitated by absorption of the infrared component of the solar spectrum. Using these findings, we show that the devices show greatly improved operation lifetimes and stability under white-light emitting diodes, or under a solar simulator with an infrared cutoff filter or with cooling.

Room-temperature acetylene hydration by a Hg(II)-laced metal-organic framework.

Thiol (-SH) groups within a Zr(IV)-based metal-organic framework (MOF) anchor Hg(II) atoms; oxidation by H2O2 then leads to acidic sulfonate functions for catalyzing acetylene hydration at room temperature.

Recurrent and novel GLB1 mutations in India.

GM1 gangliosidosis is a lysosomal storage disorder caused by mutations in the GLB1 gene, leading to the deficiency of the enzyme ß-d-galactosidase. In this study, we report molecular findings in 50 Asian Indian families with GM1 gangliosidosis. We sequenced all the exons and flanking intronic sequences of GLB1 gene. We identified 33 different mutations (20 novel and 13 previously reported). The novel mutations include 12 missense (p.M1?, p.E129Q, p.G134R, p.L236P, p.G262E, p.L297F, p.Y331C, p.G414V, p.K493N, p.L514P, p.P597L, p.T600I), four splicing (c.246-2A>G, c.397-2A>G, c.552+1G>T, c.956-2A>G), three indels (p.R22Qfs*8, p.L24Cfs*47, p.I489Qfs*4) and one nonsense mutation (p.Q452*). Most common mutations identified in this study were c.75+2InsT (14%) and p.L337P (10%). Known mutations accounted for 67% of allele frequency in our cohort of patients, suggesting that these mutations in GLB1 are recurrent across different populations. Twenty three mutations were localized in the TIM barrel domain, ß-domain 1 and ß-domain 2. In silico sequence and structure analysis of GLB1 reveal that all the novel mutations affect the function and structure of the protein. We hereby report on the largest series of patients with GM1 gangliosidosis and the first from India.

Rowell syndrome.

Rowell syndrome is a rare disease consisting of erythema multiforme-like lesions associated with lupus erythematosus. The syndrome occurs mostly in middle-aged women. The authors describe the syndrome in a 15-year-old boy who responded well to systemic steroids and hydroxychloroquine.

Vimentin positive acantholytic penile squamous cell carcinoma with rhabdoid features.

Acantholytic variant of penile squamous cell carcinoma (SCC) is an exceedingly rare and associated with bad prognosis. Histologically it mimics angiosarcoma due to pseudovascular spaces. Vimentin immunopositivity in such cases represent epithelial to mesenchymal transition manifested by cellular discohesion. We describe a case of vimentin positive acantholytic penile SCC in a 55-year-old patient.

Hypomelanosis of Ito with an unusual pulmonary abnormality in an infant.

Hypomelanosis of Ito (HI) is a neurocutaneous syndrome characterized by hypopigmented cutaneous lesions and extracutaneous manifestations frequently affecting the nervous system and the musculoskeletal system. Dysmorphic features, dental, ophthalmic, gastrointestinal, cardiac, and renal abnormalities are described in a minority of patients. The authors describe a 4-month-old infant having HI with unusual pulmonary hypoplasia that has not been reported so far.

An infant with chronic severe neutropenia.

Neutropenia in infancy and childhood poses a diagnostic challenge as the aetiology ranges from acute life-threatening conditions to chronic benign diseases. Chronic benign neutropenia of infancy is a rare disorder occurring in 1:100,000. The neutrophil count continues to be low for a prolonged period until spontaneous resolution by the age of 3-4 years. Such infants are having higher incidences of minor infections requiring treatment with antibiotics and rare incidences of meningitis and sepsis. The authors describe an infant presenting with fever and cervical lymphadenitis, who was found to have isolated severe neutropenia and its persistence posing a diagnostic challenge. The prolonged course with minor infections and absence of serious underlying conditions finally confirmed chronic benign neutropenia of infancy.

Hemiconvulsion-hemiplegia-epilepsy syndrome: clinical course and neuroradiological features in a 20-month-old girl.

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome involves initial sudden and prolonged unilateral convulsive seizures, followed by transient or permanent hemiplegia and epilepsy during infancy or early childhood. Seizures are prolonged, difficult to control and sometimes may require surgery. Hemiplegia varies in intensity, differs from Todd paralysis and disappears in about 20% of cases. Neuroimaging characteristically shows brain atrophy more pronounced on the hemisphere contralateral to the side of hemiplegia with dilation of the ventricular system. A 20-month-old girl presented with left hemiconvulsions and left hemiplegia lasting for a prolonged period. Seizures failed to resolve with various anticonvulsants even after many physician contacts. Characteristic neuroimaging findings, seizure control with carbamazepine and valproate, subsequent recovery of hemiplegia and attainment of developmental milestones observed on follow-up confirmed HHE syndrome. The case highlights the need for good seizure control in this syndrome.

Time to positivity of blood cultures in neonates.

Blood culture reports in neonatal sepsis aid physician in either optimizing therapy or discontinuing antibiotics. We determined the time taken for neonatal blood cultures to become positive using the aerobic BacT/Alert system. Of 944 blood cultures from 816 neonates, 139 (14.7%) were positive. Growth of all definitive bacteria, 95% of possible bacteria and 84% of fungi were detected within 48 hours of incubation.

Sixth hour transcutaneous bilirubin predicting significant hyperbilirubinemia in ABO incompatible neonates.

BACKGROUND: Neonates with ABO hemolytic disease are at greater risk for developing significant hyperbilirubinemia. We aimed to determine whether sixth hour transcutaneous bilirubin (TcB) could predict such a risk. METHODS: TcB measurements were obtained at the 6th hour of life in blood group A or B neonates born to blood group O, rhesus factor compatible mothers. Subsequent hyperbilirubinemia was monitored and considered significant if a neonate required phototherapy/exchange transfusion. The predictive role of sixth hour TcB was estimated. RESULTS: Of 144 ABO incompatible neonates, 41(OA, 24; O-B, 17) had significant hyperbilirubinemia. Mean sixth hour TcB was significantly higher among neonates who developed significant hyperbilirubinemia than those who did not (5.83±1.35 mg/dL vs. 3.65±0.96 mg/dL, P<0.001). Sixth hour TcB value >4 mg/dL had the highest sensitivity of 93.5% and >6 mg/dL had the highest specificity of 99%. Area under receiver operating characteristic curve was 0.898. CONCLUSION: Sixth hour TcB predicts subsequent significant hyperbilirubinemia in ABO incompatible neonates.