A New Insight into the Mechanisms Underlying the Discoloration, Sorption, and Photodegradation of Methylene Blue Solutions with and without BNOx Nanocatalysts.

Methylene blue (MB) is widely used as a test material in photodynamic therapy and photocatalysis. These applications require an accurate determination of the MB concentration as well as the factors affecting the temporal evolution of the MB concentration. Optical absorbance is the most common method used to estimate MB concentration. This paper presents a detailed study of the dependence of the optical absorbance of aqueous methylene blue (MB) solutions in a concentration range of 0.5 to 10 mg·L-1. The nonlinear behavior of optical absorbance as a function of MB concentration is described for the first time. A sharp change in optical absorption is observed in the range of MB concentrations from 3.33 to 4.00 mg·L-1. Based on the analysis of the absorption spectra, it is concluded that this is due to the formation of MB dimers and trimers in the specific concentration range. For the first time, a strong, thermally induced discoloration effect of the MB solution under the influence of visible and sunlight was revealed: the simultaneous illumination and heating of MB solutions from 20 to 80 °C leads to a twofold decrease in the MB concentration in the solution. Exposure to sunlight for 120 min at a temperature of 80 °C led to the discoloration of the MB solution by more than 80%. The thermally induced discoloration of MB solutions should be considered in photocatalytic experiments when tested solutions are not thermally stabilized and heated due to irradiation. We discuss whether MB is a suitable test material for photocatalytic experiments and consider this using the example of a new photocatalytic material-boron oxynitride (BNOx) nanoparticles-with 4.2 and 6.5 at.% of oxygen. It is shown that discoloration is a complex process and includes the following mechanisms: thermally induced MB photodegradation, MB absorption on BNOx NPs, self-sensitizing MB photooxidation, and photocatalytic MB degradation. Careful consideration of all these processes makes it possible to determine the photocatalytic contribution to the discoloration process when using MB as a test material. The photocatalytic activity of BNOx NPs containing 4.2 and 6.5 at.% of oxygen, estimated at ~440 µmol·g-1·h-1. The obtained results are discussed based on the results of DFT calculations considering the effect of MB sorption on its self-sensitizing photooxidation activity. A DFT analysis of the MB sorption capacity with BNOx NPs shows that surface oxygen defects prevent the sorption of MB molecules due to their planar orientation over the BNOx surface. To enhance the sorption capacity, surface oxygen defects should be eliminated.

Amorphous MoSxOy/h-BNxOy Nanohybrids: Synthesis and Dye Photodegradation.

Molybdenum sulfide is a very promising catalyst for the photodegradation of organic pollutants in water. Its photocatalytic activity arises from unsaturated sulfur bonds, and it increases with the introduction of structural defects and/or oxygen substitutions. Amorphous molybdenum sulfide (a-MoSxOy) with oxygen substitutions has many active sites, which create favorable conditions for enhanced catalytic activity. Here we present a new approach to the synthesis of a-MoSxOy and demonstrate its high activity in the photodegradation of the dye methylene blue (MB). The MoSxOy was deposited on hexagonal boron oxynitride (h-BNO) nanoflakes by reacting h-BNO, MoCl5, and H2S in dimethylformamide (DMF) at 250 °C. Both X-ray diffraction analysis and high-resolution TEM show the absence of crystalline order in a-MoSxOy. Based on the results of Raman and X-ray photoelectron spectroscopy, as well as analysis by the density functional theory (DFT) method, a chain structure of a-MoSxOy was proposed, consisting of MoS3 clusters with partial substitution of sulfur by oxygen. When a third of the sulfur atoms are replaced with oxygen, the band gap of a-MoSxOy is approximately 1.36 eV, and the valence and conduction bands are 0.74 eV and -0.62 eV, respectively (relative to a standard hydrogen electrode), which satisfies the conditions of photoinduced splitting of water. When illuminated with a mercury lamp, a-MoSxOy/h-BNxOy nanohybrids have a specific mass activity in MB photodegradation of approximately 5.51 mmol g-1 h-1, which is at least four times higher than so far reported values for nonmetal catalysts. The photocatalyst has been shown to be very stable and can be reused.

Cognitive Dysfunction: Part and Parcel of the Diabetic Foot.

OBJECTIVE: The presence of a foot ulcer increases the self-treatment burden imposed on the individual with diabetes. Additionally, this condition increases the cognitive demands needed for adherence to medical recommendations. A potential gap could exist between medical recommendations and the individual's ability to implement them. Hence, the goal of this study was to examine whether the cognitive profile of people with diabetic foot ulcers differs from that of people with diabetes without this complication. RESEARCH DESIGN AND METHODS: This was a case-control study. Ninety-nine individuals with diabetic foot ulcers (case patients) and 95 individuals with type 2 diabetes (control subjects) (age range 45-75 years), who were matched for diabetes duration and sex, underwent extensive neuropsychological evaluation using a NeuroTrax computerized battery, digit symbol, and verbal fluency tests. A global cognitive score after standardization for age and education was computed as well as scores in the following six cognitive domains: memory, executive function, reaction time, attention, psychomotor abilities, and estimated premorbid cognition. RESULTS: Individuals with diabetic foot ulcers had significantly (P < 0.001) lower cognitive scores than individuals with diabetes without this complication, in all tested cognitive domains, excluding estimated premorbid cognition. Individuals with diabetic foot ulcers demonstrated a significant difference between precognitive and current cognitive abilities, as opposed to the nonsignificant difference among control subjects. The differences persisted in multivariable analysis after adjusting for depression and smoking. CONCLUSIONS: Individuals with diabetic foot ulcers were found to possess fewer cognitive resources than individuals with diabetes without this complication. Thus, they appear to face more self-treatment challenges, while possessing significantly fewer cognitive resources.

The Effects of Pilates Training on Balance Control and Self-Reported Health Status in Community-Dwelling Older Adults: A Randomized Controlled Trial.

OBJECTIVES: To evaluate the effect of a group-based Pilates training program on balance control and health status in healthy older adults. DESIGN: A single-blind, randomized, controlled trial. SETTING: General community. PARTICIPANTS: A total of 88 community-dwelling older adults (age 71.15 ± 4.30 years), without evidence of functional balance impairment, were recruited and allocated at random to a Pilates intervention group (n = 44) or a control group (n = 44). INTERVENTION: The Pilates intervention group received 36 training sessions over three months (3 sessions a week), while the control group did not receive any intervention. OUTCOME MEASURES: Standing upright postural stability, performance-based measures of balance, and self-reported health status was assessed in both groups at baseline and at the end of the intervention period. RESULTS: Compared with the control group, the Pilates intervention did not improve postural stability, baseline functional measures of balance, or health status. CONCLUSIONS: The results suggest that because Pilates training is not task specific, it does not improve balance control or balance function in independent older adults.

Modern clinical research: guidelines for the practicing clinician or source of confusion?

There is a dilemma in modern medicine, and, as a general family practitioner, this dilemma has great impact on me as a professional with a responsibility to my patients, and on the treatments I prescribe. Every day we receive a lot of updated information about relevant issues in treatment of various conditions we encounter in our daily practice. There is a great deal of interesting, serious research; however, frequently results and conclusions are very different and at times, contradictory. It is extremely difficult to evaluate updated research information, and to understand trends in current medicine. Our responsibility to our patients is to find a solution for this problem.

Periodic fever responds to vitamin B12 treatment.

UNLABELLED: Periodic fever of childhood is a group of diseases that cause repeated febrile illnesses with various associated symptoms. In our article, we present the case of a 6-year-old girl with unusual appearance of periodic fever syndrome. Our patient suffered from repeated episodes of high fever from the age of 2 years old. Each episode usually lasted 24-48 h, the interval between events was 1-3 weeks long. During high fever episodes the child usually felt well, without associated accompanying complaints. As a rule, the physical examination did not reveal any pathologic finding explaining the fever. During the 4 years of follow-up the patient sustained treatment attempts with prednisone for a number of months and half a year with colchicine without any response. We considered treatment with sublingual tablets of vitamin B12 (VIT B12). Beyond all expectation, we witnessed complete resolution of attacks during the first 2 months following treatment. After a long episode-free period, the parents withheld the treatment on their own accord, and in a short time the disease recurred. We advised to renew the treatment with VIT B12, and during approximately half year of follow-up there were no recurrences of periodic fever. CONCLUSION: we believe that our observation raises interest in systematic evaluation of the therapeutic role of VIT B12 as a treatment option for disorders of the periodic fever spectrum.

Effectiveness of vitamin B12 in treating recurrent aphthous stomatitis: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: The frequency of recurrent aphthous stomatitis (RAS), the most common oral mucosa lesions seen in primary care, is up to 25% in the general population. However, there has been no optimal therapeutic approach. Our objective was to confirm our previous clinical observation of the beneficial treatment of RAS with vitamin B(12). METHODS: A randomized, double-blind, placebo-controlled trial was done using primary care patients. A sublingual a dose of 1000 mcg of vitamin B(12) was used in patients in the intervention group for 6 months. RESULTS: In total, 58 patients suffering from RAS participated in the study: 31 were included in the intervention group and 27 were included in control group. All parameters of RAS among patients in the intervention group were recorded and compared with the control group. The duration of outbreaks, the number of ulcers, and the level of pain were reduced significantly (P < .05) at 5 and 6 months of treatment with vitamin B(12), regardless of initial vitamin B(12) levels in the blood. During the last month of treatment a significant number of participants in the intervention group reached "no aphthous ulcers status" (74.1% vs 32.0%; P < .01). CONCLUSION: Vitamin B(12) treatment, which is simple, inexpensive, and low-risk, seems to be effective for patients suffering from RAS, regardless of the serum vitamin B(12) level.

The master key effect of vitamin B12 in treatment of malignancy--a potential therapy?

Vitamin B12 plays a functional role in a variety of organs and body systems and the list of these organs and body systems is growing. According to our working hypothesis ("Master Key Effect") vitamin B12 has some unique functions, which are still not accepted; vitamin B12 functions to keep body systems in balance, even under the stress of severe pathology. What is the explanation for elevation of cobalamin level in oncological patients? As yet I have not been able to find another explanation for high level of vitamin B12 in oncology patients other than that it is a compensatory mechanism. Perhaps following this body's "warning sign", we should start treatment with high doses of vitamin B12 to try to help the stabilization of normal function of the organs and systems. Laboratory researches should be continued to substantiate introduction of cobalamin as preliminary treatment of particular diseases.

The critical role of vitamin B12.

UNLABELLED: Vitamin B12 affects the peripheral and central nervous systems, bone marrow, skin and mucous membranes, bones, and vessels, as well as the normal development of children. Although there is undoubtedly an association between vitamin B12 and homocysteinemia, their relative influence on cardiovascular events is controversial. Some large studies confirm that a supplementation with group B vitamins did not reduce the risk of major cardiovascular events or all-cause mortality in patients with vascular disease. The outcomes of these and similar trials could have been different had the researchers considered the following points: Using vitamin B12 or B-complex as secondary prevention of cardiovascular events for patients with irreversible changes of blood vessels is probably in error. Rather, vitamin B12 or B-complex should be used as primary prevention. Also, using high doses of vitamin B12 will probably be more effective than using low doses of "group B vitamins" The effect of vitamin B12 on the proliferation of malignant cells has been examined in vivo and in vitro in numerous studies. Their results indicate that methylcobalamin inhibits the proliferation of malignant cells and propose the possibility of methylcobalamin as a candidate of potentially useful agents for the treatment for some malignant tumors. There are many articles indicating the increasing prevalence of low vitamin B12 level in different segments of general population. In order to prevent serious health problems, vitamin B12 routine fortification should be seriously considered and discussed. KEYWORDS: vitamin B12; homocysteine; malignancy; vitamin B12 routine fortification; recurrent aphthous stomatitis.

Modern society and prospects of low vitamin B12 intake.

BACKGROUND: Vitamin B(12) deficiency can occur in individuals with dietary patterns that exclude animal foods and patients who are unable to absorb vitamin B(12 )in food. MATERIAL AND METHOD: Our clinic serves a high-income population living in Southern Israel. We hypothesize that a tendency to decrease of level of vitamin B(12) in our population is caused by a premeditated decrease in consumption of animal products. We analyzed 512 medical histories of patients undergoing blood tests for vitamin B(12) level for various reasons. RESULT: The level of vitamin B(12) in 192 patients (37.5%) was less than 250 pg/ml. CONCLUSION: As a result of media information disseminating the relationship between meat, cholesterol and cardiovascular diseases, consumption of meat, particularly beef, has decreased. Changes in life style among segments of the population with high socioeconomic level, on one hand, and the existence of poverty, on the other, are two main factors in the decreasing consumption of animal products. This causes a decrease in the level of vitamin B(12) in the general population, and as a consequence, this will increase pathology due to vitamin B(12) deficiency. In lieu of these possible developments and in order to prevent serious health problems, vitamin B(12) fortification should be seriously considered and discussed.

Vitamin B12 could be a "master key" in the regulation of multiple pathological processes.

Multifunctional systems must maintain homeostasis. Man is an ideal example of a system that constantly aspires to attain optimal regulation, even under the stress of severe disease. We assume that there are universal, interchangeable (as required) biologically active substances that regulate the system and try to keep it in balance. We propose that one of these substances is vitamin B12. Why vitamin B12? The list of organs and body systems in which vitamin B12 plays a functional role is constantly being added to. Vitamin B12 affects the normal growth of children, the peripheral and central nervous systems, bone marrow, skin, mucous membranes, bones, and vessels. It is possible that even when the serum cobalamin level is normal, treatment with vitamin B12 could correct defects caused by other biologically active substances. We call this phenomenon the "Master Key" effect. We suggest that this "Master Key" concept can be tested by treating diseases, such as recurrent stomatitis, various forms of hyperpigmentation, trophic ulcers, and burns, with vitamin B12, even if the B12 serum level is normal.

Successful treatment of chronic erythema nodosum with vitamin B12.

A 38-year-old woman presented with painful lesions on both shins that first appeared a few days earlier. Physical examination revealed multiple red tender nodules on both legs. The patient had been treated with nonsteroidal anti-inflammatory drugs for having a few months without any improvement. The patient was referred to a dermatologist and a rheumatologist, who confirmed our diagnosis of chronic erythema nodosum (EN). She returned to the clinic 3 months later complaining of having numbness in the soles of her feet for a few weeks. Her serum vitamin B12 level was 118 pg/mL (normal range 135 to 911). After 4 weeks of twice weekly injections of vitamin B12 at a dose of 1000 mcg, there was a clear alleviation of the numbness, and the EN completely resolved without evidence of recurrence on follow-up. Because it seems that vitamin B12 caused resolution of EN in this case, we recommend that physicians consider testing for vitamin B12 deficiency in patients with EN.

The binding pattern of two carbohydrate-binding modules of laminarinase Lam16A from Thermotoga neapolitana: differences in beta-glucan binding within family CBM4.

Carbohydrate-binding modules (CBMs) are often part of the complex hydrolytic extracellular enzymes from bacteria and may modulate their catalytic activity. The thermostable catalytic domain of laminarinase Lam16A from Thermotoga neapolitana (glycosyl hydrolase family 16) is flanked by two CBMs, 148 and 161 aa long. They share a sequence identity of 30%, are homologous to family CBM4 and are thus called CBM4-1 and CBM4-2 respectively. Recombinant Lam16A proteins deleted for one or both binding modules and the isolated module CBM4-1 were characterized. Proteins containing the N-terminal module CBM4-1 bound to the soluble polysaccharides laminarin (1,3-beta-glucan) and barley 1,3/1,4-beta-glucan, and proteins containing the C-terminal module CBM4-2 bound additionally to curdlan (1,3-beta-glucan) and pustulan (1,6-beta-glucan), and to insoluble yeast cell wall beta-glucan. The activity of the catalytic domain on soluble 1,3-beta-glucans was stimulated by the presence of CBM4-1, whereas the presence of CBM4-2 enhanced the Lam16A activity towards gelatinized and insoluble or mixed-linkage 1,3-beta-glucan. Thermostability of the catalytic domain was not affected by the truncations. Members of family CBM4 can be divided into four subfamilies, members of which show different polysaccharide-binding specificities corresponding to the catalytic specificities of the associated hydrolytic domains.

Thermotoga neapolitana bglB gene, upstream of lamA, encodes a highly thermostable beta-glucosidase that is a laminaribiase.

The gene for thermostable 1,3-beta-glucosidase BglB was cloned from the chromosome of Thermotoga neapolitana and its primary sequence was determined. The purified recombinant beta-glucosidase B had a monomer molecular mass of 81 kDa in accordance with the amino acid sequence predicted from the nucleotide sequence of clone pTT51. It was a member of glycosylhydrolase family 3 and belonged to enzyme class EC 3.2.1.21. beta-Glucosidase B had a specific activity of 255 U mg-1 on 4-nitrophenyl(PNP)-beta-glucoside at the optima of pH (5.5) and temperature (90 degrees C), and K(m) values of 0.1, 10 and 50 mM for PNP-beta-glucoside, laminaribiose and cellobiose, respectively. The gene bglB was located immediately upstream of the laminarinase gene lamA. Both genes were transcribed from the same DNA strand and were not separated by a palindromic transcription terminator. The two purified enzymes 1,3-beta-glucosidase BglB (laminaribiase) and 1,3-beta-glucanase LamA (laminarinase) were together capable of completely degrading laminarin to glucose.

Highly thermostable endo-1,3-beta-glucanase (laminarinase) LamA from Thermotoga neapolitana: nucleotide sequence of the gene and characterization of the recombinant gene product.

The nucleotide sequence of clone pTT26 (3786 bp), containing the gene for 1,3-beta-glucanase LamA (laminarinase) from Thermotoga neapolitana, was determined. It contains an ORF encoding a protein of 646 aa (73328 Da). The central part of the protein is homologous to the complete catalytic domain of bacterial and some eukaryotic endo-1,3-beta-D-glucanases and belongs to family 16 of glycosyl hydrolases. This domain is flanked on both sides by one copy on each side of a substrate binding domain homologue (family II). The recombinant laminarinase protein was purified from Escherichia coli host cells in two forms, a 73 kDa and a processed 52 kDa protein, both having high specific activity towards laminarin (3100 and 2600 U mg-1, respectively) and K(m) values of 2.8 and 2.2 mg ml-1, respectively. Limited activity on 1,3-1,4-beta-glucan (lichenan) was detected (90 U mg-1). Laminarin was degraded in an endoglucanase modus, yielding glucose, laminaribiose and -triose as end products. Thus LamA classifies as an endo-1,3(4)-beta-glucanase (EC 3.2.1.6). The optimum temperature of the enzymes was 95 degrees C (73 kDa) and 85 degrees C (52 kDa) at an optimum pH of 6.2. The superior thermostability of the 73 kDa enzyme is demonstrated by incubation without substrate at 100 degrees C, where 57% of the initial activity remained after 30 min (82% at 95 degrees C). Thus, LamA is the most thermostable 1,3-beta-glucanase described to date.