Impact of acid straightener's pH value in the hair fiber properties.

BACKGROUND: Acid straightener products are widely used, and it can cause changes in the hair shaft properties. The pH value of these products established by ANVISA (Brazil's National Health Surveillance Agency) as secure is above 2.0. However, the industries are interested in working at lower pH values in order to increase the straightening effect. Unfortunately, there are a lot of products in the market with pH value under the permitted. OBJECTIVE: Analyze two different pH values (1.0 and 2.0) of acid straightener formulation and the influence of this difference in the hair shaft properties. In order to provide information to professionals as cosmetologists, dermatologists, and hairdressers. METHODS: Combing and colorimetric analyses, tensile strength, differential scanning calorimetry (DSC), environmental scanning electron microscope (ESEM), and tryptophan content. RESULTS: The tresses treated at pH 1.0 had a better result in the straightening capacity, improving the combing test in 59.4%, while those at pH 2.0, only in 33.0% compared with virgin hair. However, the tensile strength, at pH 1.0 decreased by 16.0% and 9.0% to the pH 2.0. In addition, the tryptophan content was lower in the tresses treated with formulation at pH 1.0. The DSC analysis showed impairment in the straightened tresses. The images by ESEM, indicated a possible formation of a film around the fiber. CONCLUSIONS: It was possible to conclude that the pH value interferes in the hair shaft properties. Tresses treated with pH 1.0 had more modifications than tresses treated with pH 2.0.

Heat-damaged evaluation of virgin hair.

BACKGROUND: Hair-straightening treatments may involve the use of thermal devices, which potentially cause damages in the cuticle and cortex of the hair fibers. Particularly, the heat causes denaturation of the α-keratin and the degradation of the components of the hair cortex. OBJECTIVES: The aim of this study was to evaluate the effect of heating on the cuticle and cortex of the Caucasian and Asian virgin hair by using heat iron flat. METHODS: The effects of the heating in the tresses of Caucasian and Asian virgin hair were analyzed by thermogravimetry/differential scanning calorimetry-Fourier transform infrared/mass spectrometry (TG/DSC-MS/FTIR), protein loss analysis (PLA), Fourier transform infrared (FTIR-ATR), and scanning electron microscope (SEM). RESULTS: TG/DSC-MS/FTIR results were: formation of the H2 O between 25-170°C and CO2 , SCO and H2 S from 200°C. Denaturation temperature = 237°C. Protein loss: Asian hair>Caucasian hair. Data presented statistically significant alterations, α = 5, P ≤ 0.05, n = 3. FTIR-ATR: changes in the secondary structural conformation of the protein of hair cuticle. SEM: heat caused damage to hair cuticle. CONCLUSIONS: The results evidenced the importance of the control of temperature in the procedures involving heat. The damage caused by thermal devices showed be dependent of the ethnicity analyzed (Caucasian and Asian hair).

Avaliação das propriedades das fibras capilares tratadas com alisante ácido com diferentes valores de pH / Evaluation of hair fibers properties treated with acid straightener at different pH values

Os produtos para alisamento das fibras capilares são amplamente utilizados no Brasil principalmente, pelo público feminino. Porém, estes procedimentos podem causar danos ao cabelo do usuário e, também, para o profissional que está atuando. Os alisantes químicos podem ser divididos em dois grupos: alcalinos e ácidos. Os primeiros (tioglicolato de amônio e os hidróxidos de sódio ou guanidina) apresentam valor de pH elevado (superior a 9,0) e alisam por meio da quebra e reorganização das pontes de dissulfeto (S-S) presentes na queratina, proteína estrutural da fibra capilar. Os alisantes ácidos como o formaldeído, ácido glioxílico e seus associados, possuem pH baixo (≥ 2,0) e causam uma reorganização no interior da fibra e geralmente leva a formação de um filme na superfície do fio. O ácido glioxílico associado à carbocisteína e aminoácidos (nomenclatura INCI -International Nomenclature of Cosmetic Ingredient apresentada entre parênteses) (Glyoxyloyl Carbocysteine (and) Glyoxyloyl Keratin Aminoacids (and) Water) é o único ingrediente permitido ao uso como alisante ácido até o momento. O objetivo deste trabalho foi estudar o efeito deste alisante ácido incorporado em uma emulsão óleo e água (O/A) com valores de pH 1,0 e 2,0 (com reaplicações); e o impacto que podem causar nas propriedades mecânicas e químicas da fibra capilar, como força de ruptura, coloração, elasticidade e teor de triptofano da fibra capilar. E também o efeito da radiação ultravioleta nos fios alisados. Nos testes realizados observou-se que as mechas tratadas com a emulsão a pH 1,0 obtiveram melhor resultado de alinhamento das cutículas e capacidade alisante da fibra, com penteabilidade superior ao cabelo virgem (59,4 %), enquanto as mechas com a formulação pH 2,0 foi apenas 33,0%. Entretanto, a força de tração para a ruptura do fio foi inferior, diminuindo em 16,0% (pH 1,0) e 9,0 % (pH 2,0). Quanto a variação da coloração, a variação do tom de cor foi mais exacerbada para as mechas tratadas com a formulação em pH 1,0. O teor de triptofano foi inferior nas mechas alisadas com a formulação pH 1,0. Para o teste de DSC e Raman, ambas as mechas tratadas apresentaram modificações nas suas estruturas. As fibras alisadas e expostas à radiação UV apresentaram danos maiores nas cutículas, e certa proteção na degradação de proteínas em relação aquelas sem tratamento e irradiadas ao UV. Considerando as reaplicações do produto alisante ácido, quanto maior o número de aplicações, mais alinhadas e seladas tornaram se as fibras, mas mais rígida e suscetível à quebra ficaram. Devemos considerar a importância do valor do pH da formulação no impacto do alisamento e dano da fibra capilar

Hair straightening products are widely used in Brazil by the female public. However, these procedures can cause damage to the hair shaft and to professional´s and client´s health. Chemical straighteners can be divided into two groups: alkaline and acid. Alkaline straighteners has a very high pH value (> 9.0) and the straightening process is due to the break followed by reorganization of the disulfide bridges (S-S) present in the keratin, a structural protein of the hair shaft. Some examples of alkaline straighteners are ammonium thioglycolate and sodium or guanidine hydroxides. On the other hand, acid straighteners like formaldehyde, glyoxylic acid, and their associated, present a low pH value (≥ 2.0), which causes a rearranging within the fiber, and sometimes creates a film on the surface of the hair. Nowadays, the glyoxylic acid associated with carbocysteine and amino acids (INCI - International Nomenclature of Cosmetic Ingredient nomenclature presented in parentheses) (Glyoxyloyl Carbocysteine (and) Glyoxyloyl Keratin Aminoacids (and) Water) is the only acid straightener permitted. Therefore, the objective of this work is to study the effect of this acid straightener, incorporated into oil in water (o/w) base emulsions at two different pH values 1.0 and 2.0 ( with reapplication) on the mechanical and physicochemical properties of the hair shaft. Also, the impact of UV radiation in straightened tresses. In the experiments conducted, it was possible to observe that tresses treated with the emulsion at pH 1.0 had a better result on the alignment and the straightening capacity, improving the combing test (59.4%/), while the tresses with the formulation at pH 2.0, 33.0%. However, the tensile strength, to pH 1.0 decreased by 16.0% and to pH 2.0 only 9.0%. As for color, the difference when compared with virgin hair it was major at pH 1.0. The tryptophan content also was lower in tresses treated at pH 1, 0. For the DSC and Raman analyzes all the treated tresses presented modifications in their structure. Straightened strands exposed to radiation had major damage in the cuticles, and some protection in proteins degradation compared to untreated tresses exposed to radiation. Considering the reapplications of the straightening product, as higher the number of applications more aligned and sealed it becomes, however the hair fiber becomes stiffer and susceptible to breakage. Thats why we should consider the importance of the pH value in the product, and the impact of straightening and damage of the hai fiber

Viral load and epidemiological profile of patients infected by pandemic influenza a (H1N1) 2009 and seasonal influenza a virus in Southern Brazil.

Correlation between virologic profile and clinical features of patients infected by influenza virus provides important information for epidemiological control and clinical management of future disease outbreaks. Samples from patients in Southern Brazil, from June to December 2009, were examined and the viral load was correlated with epidemiological data. All samples were analyzed by qRT-PCR for detection of the 2009-pandemic Influenza A (H1N1). Relative viral loads were assessed based on the 2(-ΔCT) method and epidemiological data were obtained for each patient, following ethical policies. A total of 933 samples were positive for pH1N1 (2009) influenza; 172 were positive for seasonal influenza A; 13 were undetermined; 1992 samples were negative for influenza A. Combined molecular and epidemiological data were available for 38 seasonal and 198 pandemic samples. The median viral load was higher in pandemic than in seasonal influenza samples; in patients infected with pH1N1 (2009), viral load associated positively with chills, myalgia and rhinorrhea, and negatively with dyspnea, but no association was observed with other symptoms, nor with clinical conditions such as pregnancy, smoking, immunodepression and co-morbidities. Regarding patients infected with seasonal influenza, viral loads did not show statistically significant association with any of the symptoms. This is the first study in Brazil that examines epidemiological and molecular data from the 2009 influenza pandemic. The results may serve as a basis for developing strategies to control human-to-human infection and viral dissemination, and for implementing effective measures and public health policies against future novel disease outbreaks.